Improved oil or aux cooling?
#1
Improved oil or aux cooling?
I was wondering if anyone here has done anything to improve the oil cooling on their XJS? or fitted a seperate radiator on a coolant line such as an aftermarket fan+rad unit or oil-to-coolant heat exchanger?
I have a bit of free space behind the body panels in my car after removing some things like the fuel vapor canister, I was going to have a body shop add vents or gills like you see in newer cars on the very edge of the car below the front bumper and fit something in there, possibly relocate my coolant filter or some other aux fan/rad combo unit there.
I have a bit of free space behind the body panels in my car after removing some things like the fuel vapor canister, I was going to have a body shop add vents or gills like you see in newer cars on the very edge of the car below the front bumper and fit something in there, possibly relocate my coolant filter or some other aux fan/rad combo unit there.
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#4
Good to know, I forgot about the trans. I'm going to have to measure the avg coolant temp before and after once a separate trans cooling system is fitted, I'm sure it'll be interesting.
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Grant Francis (07-08-2018)
#5
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#7
That is why I used Full Synthetic ATF for a very long time in transmissions and steer systems for a very long time.
I agree with those temps, but it does not take long for a trans to raise its fluid temp very quickly. .Open highway in top gear, cool as it gets, traffic, firm driving etc all have a temp increase very quickly.
I agree with those temps, but it does not take long for a trans to raise its fluid temp very quickly. .Open highway in top gear, cool as it gets, traffic, firm driving etc all have a temp increase very quickly.
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#8
That is why I used Full Synthetic ATF for a very long time in transmissions and steer systems for a very long time.
I agree with those temps, but it does not take long for a trans to raise its fluid temp very quickly. .Open highway in top gear, cool as it gets, traffic, firm driving etc all have a temp increase very quickly.
I agree with those temps, but it does not take long for a trans to raise its fluid temp very quickly. .Open highway in top gear, cool as it gets, traffic, firm driving etc all have a temp increase very quickly.
The power steering cooler is fine as it is. I'm just not sure if I should go to full synthetic or use a standard Dexron II/III. Probably full synthetic...
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Grant Francis (07-08-2018)
#10
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There is, so I'm a little confused as well.
Jaguar used both a full-flow cooler and a by-pass oil cooler. USA cars and some others got the by-pass cooler. The rationale, I think, was to prevent the oil from being over-cooled. One of the guys here -- Greg or Daim I think-- did quite a study on oil cooler effectiveness but, to be honest, I can't remember the details of the conclusion. Worth searching the archives for.
Cheers
DD
#11
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Grant Francis (07-08-2018)
#12
Basically, oil coolers without a thermostat won't do any good. There is really very narrow range of temperature where the lubrication is best (a little wider for synthetic oils, but not much). Keeping oil from reaching the optimal temperature with cooler is no favor to your engine.
#13
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Asking, not arguing.....
Where does 35ºC come from as an ideal temperature? That's quite low. Typically ATF runs quite safely in the 75-90ºC range.
I'm sure there's a 'designed' operating range for (let's say) Dexron III although I couldn't quickly find the specs. I know that one of enhancements of the Dex III spec, eons ago, was improved low temperature performance....implying that a too-low temp might not be entirely desirable. Back in the early 90s, when electronic shift transmissions were being introduced, many were designed to hold lower gears longer when cold for the specific purpose of getting the fluid up to xxx-minimum temperature, again suggesting the colder isn't entirely desirable.
IMO, the most important thing, especially if using non-synthetic, is to keep the temps below 110ºC as that's when the fluid begins to degrade, and quite rapidly !
In my heart it's hard to argue against keeping the trans cooler but I wonder if efforts to keep it ultra-cool are one of those "....point of limited returns...." type of things?
Cheers
DD
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Grant Francis (07-08-2018)
#14
Asking, not arguing.....
Where does 35ºC come from as an ideal temperature? That's quite low. Typically ATF runs quite safely in the 75-90ºC range.
I'm sure there's a 'designed' operating range for (let's say) Dexron III although I couldn't quickly find the specs. I know that one of enhancements of the Dex III spec, eons ago, was improved low temperature performance....implying that a too-low temp might not be entirely desirable. Back in the early 90s, when electronic shift transmissions were being introduced, many were designed to hold lower gears longer when cold for the specific purpose of getting the fluid up to xxx-minimum temperature, again suggesting the colder isn't entirely desirable.
IMO, the most important thing, especially if using non-synthetic, is to keep the temps below 110ºC as that's when the fluid begins to degrade, and quite rapidly !
In my heart it's hard to argue against keeping the trans cooler but I wonder if efforts to keep it ultra-cool are one of those "....point of limited returns...." type of things?
Cheers
DD
Where does 35ºC come from as an ideal temperature? That's quite low. Typically ATF runs quite safely in the 75-90ºC range.
I'm sure there's a 'designed' operating range for (let's say) Dexron III although I couldn't quickly find the specs. I know that one of enhancements of the Dex III spec, eons ago, was improved low temperature performance....implying that a too-low temp might not be entirely desirable. Back in the early 90s, when electronic shift transmissions were being introduced, many were designed to hold lower gears longer when cold for the specific purpose of getting the fluid up to xxx-minimum temperature, again suggesting the colder isn't entirely desirable.
IMO, the most important thing, especially if using non-synthetic, is to keep the temps below 110ºC as that's when the fluid begins to degrade, and quite rapidly !
In my heart it's hard to argue against keeping the trans cooler but I wonder if efforts to keep it ultra-cool are one of those "....point of limited returns...." type of things?
Cheers
DD
#15
Erm, the V12 reaches it's oil temperature really quickly. The oil cooler really drops the temperature. Especially as Jaguar intended the oil to be used as a coolant in the V12. Which is why higher speed countries (basically the rest of the world apart for the States) all got the full flow cooler.
#16
We are not talking about the same thing. My point was about controlled oil temperature, it is beneficial. You tell about "dropping the temperature", uncontrolled I assume? This is exactly what I do not want to happen to my engine. There was an extremely comprehensive research on Porsche forums. The conclusion was: keep it as close as you can to 85-95° C.
#18
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ronbros (07-08-2018)
#19
AFAICS part of this thread is discussing automatic gearbox fluid temps, and part engine oil temps. I know nothing about ATF temps, except to say that using Grant's type cooler the stuff never gets too hot as far as I can see.
Concerning engine oil temps:
As Doug mentioned, I did some pretty careful measurements of engine oil temps on my V12 bypass oil cooling engine. This was because I had a project to change it to full flow and I wanted to see what the engine oil temps were. results as follows:
Temp strips on the sump; the oil filter block, the oil distribution casting on top of the engine at the rear of the V; the cam covers; and the input and output side of the oil cooler.
Tests done in hot summer weather (say 33C shade temp) and over a fast road test lasting an hour or so. Results:
Greg
Concerning engine oil temps:
As Doug mentioned, I did some pretty careful measurements of engine oil temps on my V12 bypass oil cooling engine. This was because I had a project to change it to full flow and I wanted to see what the engine oil temps were. results as follows:
Temp strips on the sump; the oil filter block, the oil distribution casting on top of the engine at the rear of the V; the cam covers; and the input and output side of the oil cooler.
Tests done in hot summer weather (say 33C shade temp) and over a fast road test lasting an hour or so. Results:
- Hottest was the cam covers at 90C max
- oil cooler took 20C out of the temperatures
- everywhere else 80C to 85C never higher.
Greg
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ronbros (07-08-2018)