Hi All

I have an old Audi A4 which consumes a lot of oil and has done for years. MOT test fine and no obvious leaks nor particularly smokey. We have been using 5w30 fully synthetic oil and to be honest given how long a litre of it lasts (around 400 miles for a litre) I can't imagine whatever we put in it would make much difference.

I have looked online and some seem to say to use this oil and some mineral oil. Also, I was wondering if a thicker one would be better (assume 5w40 is thicker?).

Will changing to a synthetic 5w40 or even to mineral oil make any difference?

Any oil / engine buffs out there?

Thanks

Lee.

On 29/06/18 17:57, wrote:
Hi All

I have an old Audi A4 which consumes a lot of oil and has done for years. MOT test fine and no obvious leaks nor particularly smokey. We have been using 5w30 fully synthetic oil and to be honest given how long a litre of it lasts (around 400 miles for a litre) I can't imagine whatever we put in it would make much difference.

I have looked online and some seem to say to use this oil and some mineral oil. Also, I was wondering if a thicker one would be better (assume 5w40 is thicker?).

Will changing to a synthetic 5w40 or even to mineral oil make any difference?

Any oil / engine buffs out there?

10/40 prolly work best

But when you get to that stage, you are just getting the last out of te
engine so any old **** will do.

Prolly valve seals or guides gone


Thanks

Lee.



--
In a Time of Universal Deceit, Telling the Truth Is a Revolutionary Act.

- George Orwell

On 29/06/2018 19:42, The Natural Philosopher wrote:
On 29/06/18 17:57, wrote:
Hi All

I have an old Audi A4 which consumes a lot of oil and has done for
years. MOT test fine and no obvious leaks nor particularly smokey.Â* We
have been using 5w30 fully synthetic oil and to be honest given how
long a litre of it lasts (around 400 miles for a litre) I can't
imagine whatever we put in it would make much difference.

I have looked online and some seem to say to use this oil and some
mineral oil. Also, I was wondering if a thicker one would be better
(assume 5w40 is thicker?).

Will changing to a synthetic 5w40 or even to mineral oil make any
difference?

Any oil / engine buffs out there?

10/40 prolly work best

But when you get to that stage, you are just getting the last out of te
engine so any old **** will do.

Prolly valve seals or guides gone



Changing to 5-40 won't make much difference. That just changes the range
of viscosity compared to 5-30 over a wider temp range. Look he

https://mechanics.stackexchange.com/...nt-engine-oils

I'd not go to a thicker oil, such as SAE10-30. Chances are you've gunge
in there anyway and the last thing you want is trouble with oil circulation.

You could risk a semi-synthetic oil or bulk buy cheap synthetic.

A litre in 400 miles is a lot. I don't put in a litre in 10k miles! My
Honda CRV (80k miles) didn't need topping up between annual changes.


--

Suspect someone is claiming a benefit under false pretences? Incapacity
Benefit or Personal Independence Payment when they don't need it? They
are depriving those in real need!

https://www.gov.uk/report-benefit-fraud

On Friday, 29 June 2018 17:57:22 UTC+1, wrote:
Hi All

I have an old Audi A4 which consumes a lot of oil and has done for years. MOT test fine and no obvious leaks nor particularly smokey. We have been using 5w30 fully synthetic oil and to be honest given how long a litre of it lasts (around 400 miles for a litre) I can't imagine whatever we put in it would make much difference.

I have looked online and some seem to say to use this oil and some mineral oil. Also, I was wondering if a thicker one would be better (assume 5w40 is thicker?).

Will changing to a synthetic 5w40 or even to mineral oil make any difference?

Any oil / engine buffs out there?

Thanks

Lee.

20/50 is thicker, changing to that can reduce consumption. It's a common tweak on a worn engine, the cost is a fraction more friction, but not enough to notice any difference at idle on an open loop controlled engine.

A litre per 400 miles isn't good, you may want to consider the other dodge of adding a tin or 2 of that treacley oil to the engine oil. Really reduces oil burn.

There is one gotcha with oil consumption: a diesel that burns oil can go into runaway & destroy itself.


NT

Brian Reay Wrote in message:
..

A litre in 400 miles is a lot. I don't put in a litre in 10k miles! My
Honda CRV (80k miles) didn't need topping up between annual changes.

I had an Alfasud that used a litre per 500 miles, from new!
Apparently this was "within normal consumption range" for an Alfa
back then.

Tim
--

Yes, but if its not smoking one has to ponder where its all ending up?
In the old days when i were a lad, running old engines was the usual way of
things on old bangers my father had. Nobody cared about smoking engines then
of course.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"The Natural Philosopher" wrote in message
news
On 29/06/18 17:57, wrote:
Hi All

I have an old Audi A4 which consumes a lot of oil and has done for years.
MOT test fine and no obvious leaks nor particularly smokey. We have been
using 5w30 fully synthetic oil and to be honest given how long a litre of
it lasts (around 400 miles for a litre) I can't imagine whatever we put
in it would make much difference.

I have looked online and some seem to say to use this oil and some
mineral oil. Also, I was wondering if a thicker one would be better
(assume 5w40 is thicker?).

Will changing to a synthetic 5w40 or even to mineral oil make any
difference?

Any oil / engine buffs out there?

10/40 prolly work best

But when you get to that stage, you are just getting the last out of te
engine so any old **** will do.

Prolly valve seals or guides gone


Thanks

Lee.



--
In a Time of Universal Deceit, Telling the Truth Is a Revolutionary Act.

- George Orwell

But all Alphas sound like a bag of bolts from new, so what do you expect?
I had a friend with one and it did indeed rattle all the time.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Tim+" wrote in message
...
Brian Reay Wrote in message:
.

A litre in 400 miles is a lot. I don't put in a litre in 10k miles! My
Honda CRV (80k miles) didn't need topping up between annual changes.

I had an Alfasud that used a litre per 500 miles, from new!
Apparently this was "within normal consumption range" for an Alfa
back then.

Tim
--

In article ,
wrote:
Hi All

I have an old Audi A4 which consumes a lot of oil and has done for
years. MOT test fine and no obvious leaks nor particularly smokey. We
have been using 5w30 fully synthetic oil and to be honest given how long
a litre of it lasts (around 400 miles for a litre) I can't imagine
whatever we put in it would make much difference.

I have looked online and some seem to say to use this oil and some
mineral oil. Also, I was wondering if a thicker one would be better
(assume 5w40 is thicker?).

Will changing to a synthetic 5w40 or even to mineral oil make any
difference?

Any oil / engine buffs out there?

Thanks

400 miles per litre is higher than you'd expect these days, although once
would have been well within spec for many engines.

Have you checked Ebay etc for a source of the correct oil at the best
price? Your garage doesn't pay anything like the 15 quid or so a litre
they charge you. By buying in bulk.

--
*Everybody lies, but it doesn't matter since nobody listens*

Dave Plowman London SW
To e-mail, change noise into sound.

On Saturday, 30 June 2018 11:15:29 UTC+1, Dave Plowman (News) wrote:
In article ,
wrote:
Hi All

I have an old Audi A4 which consumes a lot of oil and has done for
years. MOT test fine and no obvious leaks nor particularly smokey. We
have been using 5w30 fully synthetic oil and to be honest given how long
a litre of it lasts (around 400 miles for a litre) I can't imagine
whatever we put in it would make much difference.

I have looked online and some seem to say to use this oil and some
mineral oil. Also, I was wondering if a thicker one would be better
(assume 5w40 is thicker?).

Will changing to a synthetic 5w40 or even to mineral oil make any
difference?

Any oil / engine buffs out there?

Thanks

400 miles per litre is higher than you'd expect these days, although once
would have been well within spec for many engines.

Have you checked Ebay etc for a source of the correct oil at the best
price? Your garage doesn't pay anything like the 15 quid or so a litre
they charge you. By buying in bulk.

the 'correct oil' is the wrong stuff for a well worn engine.


NT

In article ,
wrote:
On Saturday, 30 June 2018 11:15:29 UTC+1, Dave Plowman (News) wrote:
In article ,
wrote:
Hi All

I have an old Audi A4 which consumes a lot of oil and has done for
years. MOT test fine and no obvious leaks nor particularly smokey. We
have been using 5w30 fully synthetic oil and to be honest given how long
a litre of it lasts (around 400 miles for a litre) I can't imagine
whatever we put in it would make much difference.

I have looked online and some seem to say to use this oil and some
mineral oil. Also, I was wondering if a thicker one would be better
(assume 5w40 is thicker?).

Will changing to a synthetic 5w40 or even to mineral oil make any
difference?

Any oil / engine buffs out there?

Thanks

400 miles per litre is higher than you'd expect these days, although once
would have been well within spec for many engines.

Have you checked Ebay etc for a source of the correct oil at the best
price? Your garage doesn't pay anything like the 15 quid or so a litre
they charge you. By buying in bulk.

the 'correct oil' is the wrong stuff for a well worn engine.


400 miles a litre is *not* a badly worn engine. Even more so if it runs
OK. Could be something as simple as valve stem seals failed. And using a
much thicker oil in an attempt to reduce costs may just result in the
engine really wearing out faster.

--
*"I am " is reportedly the shortest sentence in the English language. *

Dave Plowman London SW
To e-mail, change noise into sound.

"Brian Gaff" Wrote in message:
But all Alphas sound like a bag of bolts from new, so what do you expect?

The Alfa flat four most definitely did not sound like a "bag of
bolts". One of the best sounding four cylinder engines
around.

Tim

--

On 30/06/2018 12:39, Dave Plowman (News) wrote:



400 miles a litre is *not* a badly worn engine. Even more so if it runs
OK. Could be something as simple as valve stem seals failed. And using a
much thicker oil in an attempt to reduce costs may just result in the
engine really wearing out faster.


As you almost suggest, the devil is in the detail.

This is what tabby said earlier

"20/50 is thicker, changing to that *can* reduce consumption. It's a
common tweak on a worn engine, the cost is a fraction more friction, but
not enough to notice any difference at idle on an open loop controlled
engine.

A litre per 400 miles isn't good, you *may* want to consider the other
dodge of adding a tin or 2 of that treacley oil to the engine oil.
Really reduces oil burn"

and he's right, that was one of the traditional routes from the days
where bore and ring wear, or valve stem wear, resulted in significant "burn"

As you say, it *could* be failed valve stem seals. No such thing in the
old days, but I've never seen a comparison of how much of the historical
improvement in consumption comes from the introduction of seals, and how
much from improved materials and engineering of piston rings and bores,
plus better anti-wear oil additives.

My academic friends in places like Leicester and Warwick reckoned that
one of the big steps forward was the introduction of plateau honing for
bores. You arrange for the first machining to introduce deep scores (and
high peaks), then you remove the peaks by honing to provide the running
surface for the rings, while the scores provide an oil reservoir which
gets replenished from below. It's certainly remarkable how you no longer
have to "run in" a new engine, or pistons following a rebore like we all
did when I first started rebuilding engines in the 1960's.

---
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On 29/06/18 17:57, wrote:
Hi All

I have an old Audi A4 which consumes a lot of oil and has done for years. MOT test fine and no obvious leaks nor particularly smokey. We have been using 5w30 fully synthetic oil and to be honest given how long a litre of it lasts (around 400 miles for a litre) I can't imagine whatever we put in it would make much difference.

I have looked online and some seem to say to use this oil and some mineral oil. Also, I was wondering if a thicker one would be better (assume 5w40 is thicker?).

Will changing to a synthetic 5w40 or even to mineral oil make any difference?

Any oil / engine buffs out there?

Thanks

Lee.

Petrol or diesel? If it's diesel with a PD engine you need to stick to
an oil suitable for the PD injectors or it'll ruin the camshaft quickly.

Thanks all for your help. To answer a few questions and add some clarity.

It is a petrol Audi A4 s-line 1.8 turbo which has done 125k miles so likely the engine is a bit worn. It had always used oil but not to the current extent. Besides the cost there is always the hassle of constantly topping it up. When the oil pressure sensor detects you have forgotten to top it up and you are in the middle of nowhere and you realise you forgot to top up the spare can in the boot. All a bit of a PITA.

Wrote in message:
Thanks all for your help. To answer a few questions and add some clarity.

It is a petrol Audi A4 s-line 1.8 turbo which has done 125k miles so likely the engine is a bit worn. It had always used oil but not to the current extent. Besides the cost there is always the hassle of constantly topping it up. When the oil pressure sensor detects you have forgotten to top it up and you are in the middle of nowhere and you realise you forgot to top up the spare can in the boot. All a bit of a PITA.


Istr the official "fully synthetic oil from new" regime has been
implicated in this excessive oil consumption. Something to do
with the piston rings not getting a chance to bed in
properly.

Also the timing chain & tensioner does not like low oil levels
with potentially catastrophic results.

Does the warning you see on the dash relate to oil level & not
pressure? The latter could open a whole different kettle of pish
:-(
--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 30/06/2018 21:00, Jim K wrote:
Wrote in message:
Thanks all for your help. To answer a few questions and add some clarity.

It is a petrol Audi A4 s-line 1.8 turbo which has done 125k miles so likely the engine is a bit worn. It had always used oil but not to the current extent. Besides the cost there is always the hassle of constantly topping it up. When the oil pressure sensor detects you have forgotten to top it up and you are in the middle of nowhere and you realise you forgot to top up the spare can in the boot. All a bit of a PITA.


Istr the official "fully synthetic oil from new" regime has been
implicated in this excessive oil consumption. Something to do
with the piston rings not getting a chance to bed in
properly.

Certainly true that fatty acid impurities in mineral oil may help
running in. The advantage of fully synthetic is that it degrades less at
the higher temperatures of modern engines.

Also the timing chain & tensioner does not like low oil levels
with potentially catastrophic results.

Does the warning you see on the dash relate to oil level & not
pressure? The latter could open a whole different kettle of pish
:-(



---
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On Saturday, 30 June 2018 16:50:17 UTC+1, newshound wrote:
On 30/06/2018 12:39, Dave Plowman (News) wrote:



400 miles a litre is *not* a badly worn engine. Even more so if it runs
OK. Could be something as simple as valve stem seals failed. And using a
much thicker oil in an attempt to reduce costs may just result in the
engine really wearing out faster.

does it?

As you almost suggest, the devil is in the detail.

This is what tabby said earlier

"20/50 is thicker, changing to that *can* reduce consumption. It's a
common tweak on a worn engine, the cost is a fraction more friction, but
not enough to notice any difference at idle on an open loop controlled
engine.

A litre per 400 miles isn't good, you *may* want to consider the other
dodge of adding a tin or 2 of that treacley oil to the engine oil.
Really reduces oil burn"

and he's right, that was one of the traditional routes from the days
where bore and ring wear, or valve stem wear, resulted in significant "burn"

As you say, it *could* be failed valve stem seals. No such thing in the
old days, but I've never seen a comparison of how much of the historical
improvement in consumption comes from the introduction of seals, and how
much from improved materials and engineering of piston rings and bores,
plus better anti-wear oil additives.

My academic friends in places like Leicester and Warwick reckoned that
one of the big steps forward was the introduction of plateau honing for
bores. You arrange for the first machining to introduce deep scores (and
high peaks), then you remove the peaks by honing to provide the running
surface for the rings, while the scores provide an oil reservoir which
gets replenished from below. It's certainly remarkable how you no longer
have to "run in" a new engine, or pistons following a rebore like we all
did when I first started rebuilding engines in the 1960's.

As you say we can't know from here what the cause is. I remember one where consumption was traced to oil being dumped on the exhaust manifold. When I say 'traced' I mean it all became clear when it caught fire.


NT

wrote in message
...
On Saturday, 30 June 2018 16:50:17 UTC+1, newshound wrote:
On 30/06/2018 12:39, Dave Plowman (News) wrote:



400 miles a litre is *not* a badly worn engine. Even more so if it runs
OK. Could be something as simple as valve stem seals failed. And using
a
much thicker oil in an attempt to reduce costs may just result in the
engine really wearing out faster.

does it?

Yep, because the parts of the engine which hasnt got the
problem with ****ed valve seals wont get lubricated as well.

As you almost suggest, the devil is in the detail.

This is what tabby said earlier

"20/50 is thicker, changing to that *can* reduce consumption. It's a
common tweak on a worn engine, the cost is a fraction more friction, but
not enough to notice any difference at idle on an open loop controlled
engine.

A litre per 400 miles isn't good, you *may* want to consider the other
dodge of adding a tin or 2 of that treacley oil to the engine oil.
Really reduces oil burn"

and he's right, that was one of the traditional routes from the days
where bore and ring wear, or valve stem wear, resulted in significant
"burn"

As you say, it *could* be failed valve stem seals. No such thing in the
old days, but I've never seen a comparison of how much of the historical
improvement in consumption comes from the introduction of seals, and how
much from improved materials and engineering of piston rings and bores,
plus better anti-wear oil additives.

My academic friends in places like Leicester and Warwick reckoned that
one of the big steps forward was the introduction of plateau honing for
bores. You arrange for the first machining to introduce deep scores (and
high peaks), then you remove the peaks by honing to provide the running
surface for the rings, while the scores provide an oil reservoir which
gets replenished from below. It's certainly remarkable how you no longer
have to "run in" a new engine, or pistons following a rebore like we all
did when I first started rebuilding engines in the 1960's.

As you say we can't know from here what the cause is.

But that level of oil use without smoky exhaust can only be due to one
problem.

I remember one where consumption was traced
to oil being dumped on the exhaust manifold.

But that produces a smoky exhaust, which he doesnt have.

When I say 'traced' I mean it all became clear when it caught fire.

On Sunday, 1 July 2018 06:54:42 UTC+1, Rod Speed wrote:
tabbypurr wrote in message
...
On Saturday, 30 June 2018 16:50:17 UTC+1, newshound wrote:
On 30/06/2018 12:39, Dave Plowman (News) wrote:



400 miles a litre is *not* a badly worn engine. Even more so if it runs
OK. Could be something as simple as valve stem seals failed. And using
a
much thicker oil in an attempt to reduce costs may just result in the
engine really wearing out faster.

does it?

Yep, because the parts of the engine which hasnt got the
problem with ****ed valve seals wont get lubricated as well.

does oil flow reduce if thicker? Or does the oil pump just deliver higher pressure? If it's an engine driven gear type I'd expect the latter.


As you almost suggest, the devil is in the detail.

This is what tabby said earlier

"20/50 is thicker, changing to that *can* reduce consumption. It's a
common tweak on a worn engine, the cost is a fraction more friction, but
not enough to notice any difference at idle on an open loop controlled
engine.

A litre per 400 miles isn't good, you *may* want to consider the other
dodge of adding a tin or 2 of that treacley oil to the engine oil.
Really reduces oil burn"

and he's right, that was one of the traditional routes from the days
where bore and ring wear, or valve stem wear, resulted in significant
"burn"

As you say, it *could* be failed valve stem seals. No such thing in the
old days, but I've never seen a comparison of how much of the historical
improvement in consumption comes from the introduction of seals, and how
much from improved materials and engineering of piston rings and bores,
plus better anti-wear oil additives.

My academic friends in places like Leicester and Warwick reckoned that
one of the big steps forward was the introduction of plateau honing for
bores. You arrange for the first machining to introduce deep scores (and
high peaks), then you remove the peaks by honing to provide the running
surface for the rings, while the scores provide an oil reservoir which
gets replenished from below. It's certainly remarkable how you no longer
have to "run in" a new engine, or pistons following a rebore like we all
did when I first started rebuilding engines in the 1960's.

As you say we can't know from here what the cause is.

But that level of oil use without smoky exhaust can only be due to one
problem.

I remember one where consumption was traced
to oil being dumped on the exhaust manifold.

But that produces a smoky exhaust, which he doesnt have.

it didn't. Nor did it produce any noticeable oil on the ground, that's why it was slow to get diagnosed. Presumably oil only got dumped on the ground on a long bend at speed.


NT

wrote in message
...
On Sunday, 1 July 2018 06:54:42 UTC+1, Rod Speed wrote:
tabbypurr wrote in message
...
On Saturday, 30 June 2018 16:50:17 UTC+1, newshound wrote:
On 30/06/2018 12:39, Dave Plowman (News) wrote:



400 miles a litre is *not* a badly worn engine. Even more so if it
runs
OK. Could be something as simple as valve stem seals failed. And
using
a
much thicker oil in an attempt to reduce costs may just result in
the
engine really wearing out faster.

does it?

Yep, because the parts of the engine which hasnt got the
problem with ****ed valve seals wont get lubricated as well.

does oil flow reduce if thicker?

Corse it does, particularly in the areas where
there is reduced space for the oil to get thru.

Or does the oil pump just deliver higher pressure?

Nope, a lower pressure in fact due
to how the oil works in the pump.

If it's an engine driven gear type I'd expect the latter.

More fool you.

As you almost suggest, the devil is in the detail.

This is what tabby said earlier

"20/50 is thicker, changing to that *can* reduce consumption. It's a
common tweak on a worn engine, the cost is a fraction more friction,
but
not enough to notice any difference at idle on an open loop controlled
engine.

A litre per 400 miles isn't good, you *may* want to consider the other
dodge of adding a tin or 2 of that treacley oil to the engine oil.
Really reduces oil burn"

and he's right, that was one of the traditional routes from the days
where bore and ring wear, or valve stem wear, resulted in significant
"burn"

As you say, it *could* be failed valve stem seals. No such thing in
the
old days, but I've never seen a comparison of how much of the
historical
improvement in consumption comes from the introduction of seals, and
how
much from improved materials and engineering of piston rings and
bores,
plus better anti-wear oil additives.

My academic friends in places like Leicester and Warwick reckoned that
one of the big steps forward was the introduction of plateau honing
for
bores. You arrange for the first machining to introduce deep scores
(and
high peaks), then you remove the peaks by honing to provide the
running
surface for the rings, while the scores provide an oil reservoir which
gets replenished from below. It's certainly remarkable how you no
longer
have to "run in" a new engine, or pistons following a rebore like we
all
did when I first started rebuilding engines in the 1960's.

As you say we can't know from here what the cause is.

But that level of oil use without smoky exhaust can only be due to one
problem.

I remember one where consumption was traced
to oil being dumped on the exhaust manifold.

But that produces a smoky exhaust, which he doesnt have.

it didn't. Nor did it produce any noticeable oil on the ground,

The oil must have been burnt then.

that's why it was slow to get diagnosed. Presumably oil
only got dumped on the ground on a long bend at speed.

But if that was the case, it should have been visible in the pipe.

In article ,
Jim K wrote:
Istr the official "fully synthetic oil from new" regime has been
implicated in this excessive oil consumption. Something to do
with the piston rings not getting a chance to bed in
properly.

Synthetic oils were developed to extent oil change intervals. If they
stopped piston rings bedding in - which is basically wear - they'd also
stop other bits of the engine ever wearing out.

--
*Don't sweat the petty things and don't pet the sweaty things.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
wrote:
does oil flow reduce if thicker? Or does the oil pump just deliver
higher pressure? If it's an engine driven gear type I'd expect the
latter.

Oil systems usually have a maximum pressure limiting valve. And yes, a
thicker oil isn't going to circulate as quickly. Oil also helps to cool
bearings etc. Which it won't do as well if circulating more slowly.

--
*Puritanism: The haunting fear that someone, somewhere may be happy.

Dave Plowman London SW
To e-mail, change noise into sound.

On 01/07/2018 12:12, Dave Plowman (News) wrote:
In article ,
Jim K wrote:
Istr the official "fully synthetic oil from new" regime has been
implicated in this excessive oil consumption. Something to do
with the piston rings not getting a chance to bed in
properly.

Synthetic oils were developed to extent oil change intervals. If they
stopped piston rings bedding in - which is basically wear - they'd also
stop other bits of the engine ever wearing out.

The *big* difference with synthetics is that because they don't contain
such a variety of molecules as mineral oils, their oxidation performance
is better. So they last longer at higher temperatures. Bedding in is
influenced by by boundary lubrication. This comes from the anti-wear
additives like ZDDP in either mineral or synthetic lubes. Mineral oils
often have enhanced boundary lube properties because they contain fatty
acids (as impurities) which, if you like, are nature's anti wear
additives. Automotive lubricants (whether mineral or synthetic) are
fairly highly "engineered" to optimise their properties (because the car
manufacturers specify the required performance for a given engine).
Further down the market, the effectiveness of things like 3 in 1 is
almost certainly partly down to the fatty acids. (This product also
contains effective anti-rust additives, which I suspect are responsible
for the distinctive smell, although I have never managed to find anyone
to confirm that).

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On Sunday, 1 July 2018 12:20:58 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:

does oil flow reduce if thicker? Or does the oil pump just deliver
higher pressure? If it's an engine driven gear type I'd expect the
latter.

Oil systems usually have a maximum pressure limiting valve.

but we don't know at what point that operates.

And yes, a
thicker oil isn't going to circulate as quickly.

that's only true if pressures are the same. They aren't. Closer to say flows are the same, thus pressure higher.

Oil also helps to cool
bearings etc. Which it won't do as well if circulating more slowly.

if.


NT

wrote in message
...
On Sunday, 1 July 2018 12:20:58 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:

does oil flow reduce if thicker? Or does the oil pump just deliver
higher pressure? If it's an engine driven gear type I'd expect the
latter.

Oil systems usually have a maximum pressure limiting valve.

but we don't know at what point that operates.

And yes, a thicker oil isn't going to circulate as quickly.

that's only true if pressures are the same. They aren't. Closer to say
flows are the same, thus pressure higher.

Even sillier and more pig ignorant than you usually manage.

If the flows are the same, there would be no point in using thicker
oil in a car which is using a lot more oil than it should do.

Oil also helps to cool bearings etc. Which it
won't do as well if circulating more slowly.

if.

It if didnt, there would be no point in using thicker oil, stupid.

In article ,
wrote:
On Sunday, 1 July 2018 12:20:58 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:

does oil flow reduce if thicker? Or does the oil pump just deliver
higher pressure? If it's an engine driven gear type I'd expect the
latter.

Oil systems usually have a maximum pressure limiting valve.

but we don't know at what point that operates.

it will be set at a safe limit for the oil recommended. To avoid excess
load on the pump, etc.

And yes, a
thicker oil isn't going to circulate as quickly.

that's only true if pressures are the same. They aren't. Closer to say
flows are the same, thus pressure higher.

See above.

Oil also helps to cool
bearings etc. Which it won't do as well if circulating more slowly.

if.


NT

--
*The more people I meet, the more I like my dog.

Dave Plowman London SW
To e-mail, change noise into sound.

On Monday, 2 July 2018 18:41:19 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Sunday, 1 July 2018 12:20:58 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:

does oil flow reduce if thicker? Or does the oil pump just deliver
higher pressure? If it's an engine driven gear type I'd expect the
latter.

Oil systems usually have a maximum pressure limiting valve.

but we don't know at what point that operates.

it will be set at a safe limit for the oil recommended. To avoid excess
load on the pump, etc.

and we don't know what pressure that is

And yes, a
thicker oil isn't going to circulate as quickly.

that's only true if pressures are the same. They aren't. Closer to say
flows are the same, thus pressure higher.

See above.

it wasn't informative

Oil also helps to cool
bearings etc. Which it won't do as well if circulating more slowly.

if.


NT