How can i reduce Oil temps?

[audia6]

My oil temps are spiking to 225F with rotella 5w40.

Is there any correlation between a specific Viscosity of Oil and temps?

I dont want to buy any aftermarket oil coolers, Im just wondering if i switch to another weight of oil, if its possible the temps go down.

This is on a 2.8 N/A audi a6

Some people say that thinner oil can yeild lower oil temps. All i want is temp to be around 212F

 

[LeakySeals]

My understanding is the opposite. That one of the reasons people like thin oil is it gets to operating temps faster. What device are you using to get that temp reading?

 

[audia6]

Originally Posted By: LeakySeals
My understanding is the opposite. That one of the reasons people like thin oil is it gets to operating temps faster. What device are you using to get that temp reading?

the oil temp gauge and vag-com.

i was told that thicker oil causes More friction hence raises the temp. This was compared to M1 0w-40 Vs Rotella 5w-40

EDIT:
I belive your right when you say thiner oil get to Full temp faster but what im saying is what oil yeilds a low operating temp.

 

[fdcg27]

There is some evidence that thinner oil may yield lower operating temperatures.
Trying M1 0W-40 would be one way to find out.

 

[HTSS_TR]

If you mix 20% M1 0W20 with 80% M1 0W40 you will have HTHS of 3.55, it meets the HTHS of A3 and your A6. The slightly thinner will reduce your operating temperature a little.

 

[bruno]

Doesn't your car have an oil/coolant heat exchanger ?

And why does an oil temp of 225 F bother you ?

 

[dparm]

I would not say that 225 is that high. T6 is rather thick for that motor with HTHS of around 4.2.

Lower HTHS will drop the oil temp slightly since there will be a bit less drag on the oil pump.

 

[CATERHAM]

Well first 225F (107C) are not high oil temp's to even warrant a heavy 40wt oil.
But as has been suggested M1 0W-40 or something even lighter would be the way to go. Yes it may lower your oil temp's but more importantly you don't need to run the heavier than necessary 5W-40 T6.

 

[audia6]

I dont like the 225F because over at audizine, they tell me 225 is a BIT excessive for my car especially since i drive it at 50MPH. They said it would be OK if it was 225 if it were HWY driving around 70ish.

and YES, i am switching back to M1 0w-40 and sticking to it.

 

[dparm]

Originally Posted By: audia6
I dont like the 225F because over at audizine, they tell me 225 is a BIT excessive for my car especially since i drive it at 50MPH. They said it would be OK if it was 225 if it were HWY driving around 70ish.

and YES, i am switching back to M1 0w-40 and sticking to it.



I would ignore what they're saying. The B7 RS4 guys get to 260-275 on the track with no apparent problems, though they do have huge 9-10L sumps.

I need to VAG-COM the DIS in my car to show oil temps. Curious to see what the tune & supercharger are doing to the Syntec I have in there.

 

[JimPghPA]

Oil cooling is also related to when "?" does the bypass valve for the output of the oil pump open (if it does).

Because the oil flow is tied to the RPMs of the engine because the oil pump is driven by connection to the engine, with a oil pressure gauge you want the recommended maximum pressure to occur when the engine is up to operating temperature, and the RPMs are at the normal maximum that the engine sees. An oil that is too thin may ( not will, but might) allow metal surfaces to come into contact and thus cause wear on those parts. An oil that is too thick will cause the bypass valve of the oil pump to open before the maximum RPMs of the engine is reached, and therefore cause the flow rate of oil through the engine to be less than a thinner oil.

Ideally the oil pressure would be just below the relive valve pressure when the engine is at maximum normal RPMs. That would provide the maximum oil cooling because it provides the maximum flow of oil.

So if you really want maximum oil cooling, besides an external oil cooler, you want to have a oil pressure gauge and an RPM gauge and then when the engine is up to maximum normal running temperature you want the maximum normal oil pressure to ONLY occur at maximum normal RPMs.

 

[thelazyhero]

I wouldn't stress it as others have stated. 225F on oil isn't high on any standard. I always thought it was standard operating temperature. That and the fact that its the summer time and I don't know about you, but where I live, it gets stupid hot here.

 

[CATERHAM]

Originally Posted By: JimPghPA

Ideally the oil pressure would be just below the relive valve pressure when the engine is at maximum normal RPMs. That would provide the maximum oil cooling because it provides the maximum flow of oil.

If the oil pressure indicated on your oil pressure gauge is just below the oil pump by-pass setting when your oil is as hot as it ever gets (and therefore has the lowest operational viscosity), it will be in by-pass 99.9% of the time when the oil doesn't get that hot.
Additionally, I don't know what the Audi by-pass level is but the by-pass setting on most German cars is set quite high; anywhere from 95 to 110 psi which represents an operational viscosity significantly heavier than necessary.
The optimum oil viscosity will be associated with an OP well below the by-pass point; typically an OP in the 60 to 75 psi range at maximum rev's.

Furthermore the maximum oil flow at high engine rev's is associated with the lowest OP readings on your OP gauge.
The OP gauge actually measures oil back-pressure. The lighter the oil, the lower your OP readings but the higher the oil flow through the engine.
When you start an cold engine your OP is high because the oil is thick and the oil flow is slow through the engine. But as the oil thins out as it warms up, the oil flow will gradually increase and this will be reflected in lower oil pressure readings on your OP gauge.

 

[Brit33]

In regards to your comments here I'd like to compare your theory with my readings.
My bypass is fully open at 88 psi.
When hot I get 60 psi max at high revs (5-5500rpm).
At medium revs 3000 rpm I get around 45 psi.

Would this appear to have a good flow and correct viscosity of oil chosen?


Originally Posted By: CATERHAM
Originally Posted By: JimPghPA

Ideally the oil pressure would be just below the relive valve pressure when the engine is at maximum normal RPMs. That would provide the maximum oil cooling because it provides the maximum flow of oil.

If the oil pressure indicated on your oil pressure gauge is just below the oil pump by-pass setting when your oil is as hot as it ever gets (and therefore has the lowest operational viscosity), it will be in by-pass 99.9% of the time when the oil doesn't get that hot.
Additionally, I don't know what the Audi by-pass level is but the by-pass setting on most German cars is set quite high; anywhere from 95 to 110 psi which represents an operational viscosity significantly heavier than necessary.
The optimum oil viscosity will be associated with an OP well below the by-pass point; typically an OP in the 60 to 75 psi range at maximum rev's.

Furthermore the maximum oil flow at high engine rev's is associated with the lowest OP readings on your OP gauge.
The OP gauge actually measures oil back-pressure. The lighter the oil, the lower your OP readings but the higher the oil flow through the engine.
When you start an cold engine your OP is high because the oil is thick and the oil flow is slow through the engine. But as the oil thins out as it warms up, the oil flow will gradually increase and this will be reflected in lower oil pressure readings on your OP gauge.

 

[LeakySeals]

Originally Posted By: CATERHAM
Originally Posted By: JimPghPA

Ideally the oil pressure would be just below the relive valve pressure when the engine is at maximum normal RPMs. That would provide the maximum oil cooling because it provides the maximum flow of oil.

If the oil pressure indicated on your oil pressure gauge is just below the oil pump by-pass setting when your oil is as hot as it ever gets (and therefore has the lowest operational viscosity), it will be in by-pass 99.9% of the time when the oil doesn't get that hot.
Additionally, I don't know what the Audi by-pass level is but the by-pass setting on most German cars is set quite high; anywhere from 95 to 110 psi which represents an operational viscosity significantly heavier than necessary.
The optimum oil viscosity will be associated with an OP well below the by-pass point; typically an OP in the 60 to 75 psi range at maximum rev's.

Furthermore the maximum oil flow at high engine rev's is associated with the lowest OP readings on your OP gauge.
The OP gauge actually measures oil back-pressure. The lighter the oil, the lower your OP readings but the higher the oil flow through the engine.
When you start an cold engine your OP is high because the oil is thick and the oil flow is slow through the engine. But as the oil thins out as it warms up, the oil flow will gradually increase and this will be reflected in lower oil pressure readings on your OP gauge.

Does this have any impact on oil filtration and the oil filter bypass?

 

[Leonardo629]

I went from TWS10w60 to Mobil 0w40, no change in oil temp

 

[thelazyhero]

Have you noticed that your oil gets to normal operating temp significantly faster?

Your little project is very interesting to me as we have the same car. What worries me with 0W40 is that during spirited drives here, my oil still reaches into the 220-230F range. I'm wondering if it would do the same with a thinner oil as there would be less friction.

 

[Brit33]

Originally Posted By: r34dy2fly
Have you noticed that your oil gets to normal operating temp significantly faster?

Your little project is very interesting to me as we have the same car. What worries me with 0W40 is that during spirited drives here, my oil still reaches into the 220-230F range. I'm wondering if it would do the same with a thinner oil as there would be less friction.


0w will get to its operating temp faster because it is thinner of course.
But 60 to 40 is a big jump.


I don't notice any difference in temp either but between a 15w50 and 10w60, in fact probably the TWS remains cooler due to it's excellent high performance properties.

There could be more friction with a thinner oil, it may not hold up well with spirited driving and you will encounter metal to metal friction. All depends on your car, style of driving and climate of course.
If the oil flows through the big ends too fast it won't transfer the heat efficently. Why do racing cars slow down their water pump drives? So the water picks up the heat better. Too fast and it won't conduct the heat. Basic physics.

 

[SteveSRT8]

Please do not worry about that oil temp. It's not high enough to do any harm. It is actually good for the oil to get nice and hot to flash off water and fuel, etc.

Worry at 280-300 maybe, but even that is not too hot for most synthetic oils at all.

Note that many race cars slow down the water pump because they run the engine at high rpm for extended periods of time causing cavitation and excessive flow issues. They can't idle in traffic.

 

[benjy]

i have use amsoil 10-30 real full synthetic in my 1.8T vw 199,xxx miles no issues, only consumption at HI boost, not stock!!! on my recently purchased audi TT 225 quattro with 1.8L turbo'd engine will get same, unless engine is worn and using oil or pressure is lo a REAL group IV amsoil or group V aka redline will do the job, i do not understand the 5-40 recommendation although they say other grades listed in manual, are acceptable. amsoil 1 yr 25,000 mile drain will defray costs, changing the filter every 5,000 miles is what i do until full change is due