oil cooler to lower engine temp?

[outlander]

quick question:Will an oil cooler lower overall engine temp much?

[Gnat5680]

my geuss is yes it will be able to run cooler and much better. i think it would have a good effect.

[cklaus]

we used to run oil coolers on our turbocharged cars that have oil lines running to the turbo. the oil cooler kept the oil.. well cooler... specifically it made the oil last longer (too much heat breaks it down) since turbo cars can kill oil pretty quick with a hot turbo. I think some of the older porsches that where predominantly "aircooled" had oil coolers to help cool the motor too ( i'm running on hear-say from stuff i heard years ago on that). i could not imagine it hurting you in anyway, but it may be overkill for a daily driver in a cool to temperate climate.

[POSXJGuy]

i was thinking of doing the same thing and after i acquired a new flexalite setup i learned that oil needs to be hot to burn off moisture. an oil cooler added can actually harm your engine by not allowing this moisture to burn off at the higher temps. i dont have specificas but it was overkill for what i needed. i now have a flexalite oil cooler kit brand new sittin doing nothing. i lowered temps by going through my cooling system and making sure it was all in tune. im kicking myself for even buying the oil cooler. totally not needed.

[Jim Mesthene]

quick question:Will an oil cooler lower overall engine temp much?
No. Oil does not play a significant role in engine temperature control.
The engine runs best, with greatest power and efficiency, when the operating temperature is high.

[my65289stang]

The engine runs best, with greatest power and efficiency, when the operating temperature is high.

HUH?
If the posters' jeep is running at 210 and he is trying to lower the operating temp then I would agree, don't do it, the engine was designed to run at 210*. To say that an engine runs best when the temp is high could be mis leading.

No. Oil does not play a significant role in engine temperature control.

Uh, not true. So if you had a jeep running at 240* and you added an oil cooler you don't think that the operating temp would decrease? I would agree that the actual temperature reading on your gauge is the coolant reading but cooler oil = cooler running temp.

[cklaus]

Hey all, just wanted to share some more thoughts.
the oil only has to be at or above the boiling point of water to get rid of the moisture in it....it definatly has this temp and i could not imagine a oil cooler chilling the oil lower than that. Think about a good tranny cooler getting temps to 180 degrees, and it doesn' have a combustion system inside it.
the Jeep 4.0's have cooling systems that should be able to adequatly keep the engine cool. If your car is running hot, work on the cooling system... not cooling the oil. If you are cooling the oil, it may help cool the motor ( but i don't forsee a big difference) but more importantly it will help maintain the longevity of the oil ( assuming we are talking about a small size oil cooler... no bigger than what most would run on there tranny's).
? to the poster... where you thinking about getting a unit that piggybacks onto the oilfilter housing or did you have something else in mind.

[HeightsHoustonXJ]

My two cents is that, though I've never seen an oil cooler on an otherwise stock XJ, I can't think of a reason to put one in, but can think of more than a few to not put one in. First, if you are having overheating issues, fix the problem with the cooling system. Second, and most important I think, is that most XJ I6's have enough problems holding the oil pressure at low rpm's, adding an air cooler and expecting the engine to push the oil through it seems like a bad idea.

[cklaus]

heights houston made an EXCELLENT point on the XJ's low oil pressure...

[BrettM]

it will help drop temperatures, but with a properly working cooling system you should only need additional cooling if you're doing something like desert racing or towing in a hot climate.

[8Mud]

I've thought of putting an oil cooler in my XJ. Back from my racing days, it was kind of accepted knowledge that 180 degress was the ideal oil temp.
I always install a pan temp. sensor in the motor and tranny pan. If either gets too hot, I just shut it down for awhile, a lot easier and cheaper in the long run.
Bathing the motor in 180 degree oil has almost got to be a good thing, for longevity. And still warm enough for water evaporation.
A good one with a 160-180 degree thermo bypass, so the oil doesn't over cool is probably the best choice. And likely installing a high volumn pump, just in case, may also be a good idea. Synthetic oil with an oil cooler would also probably be a plus, synthetic typically has a more constant viscosity in variable temperature ranges.

My 3/4 ton Chev. with the heavy duty trailer package, has an engine oil cooler setup, that runs through the radiator just like a tranny cooler.

I have a fin and tube cooler that is stacked, two seperate tube systems in a common fin package, I may plumb it in and run the surge tank return through one set of tubes and the engine oil through another. The size is right to install it under the radiator, behind the bumper. It will likely work OK year round. I think I'll install a high volumn pump the next time I have the pan off and give it a try. Install a remote filter adaptor to tap the oil system. Just a thought, that may or may not work out, but sounds interesting enough to try.
I have most of the pieces on the shelf in my shop, it won't cost me much to experiment a little.
I'd still feel better about the whole thing if I could find a below 180 degree bypass. Summit used to sell them, though I haven't seen any recently.

[Saudade]

To answer the freaks question, I'd say Yes, it will lower the engine temp. By how much depends on a number of things (such as the size and placement of the cooler).

As others have said, if you're trying to address an overheating problem, fix your cooling system first.

[SCW]

So let me make sure I have everything straight-

One person heard that the oil has to get hot to remove water, so the cooler is a bad idea.

Another person claims oil temp will have no effect on operating temps, but in fact oil is the only way to cool the bottom end of the engine (the bottome doesn't get as hot as the head, but there are still no coolant passages there).

Another has never seen it on an XJ, therefore is can't/shouldn't be done/work.


Hmmm. Anyone actually TRY an oil cooler?

Here is my experience- I had an oil cooler in my '95 F250 with the 5.8 motor. In the 8 years I owned the truck it spent about 40% of the time pulling a trailer, that's a LOT by comparison. With the oil cooler I never had temperature issues even pulling the larges loads on the hottest days (110+F). the Ford I had before that would get warm, but not overhead with less loads. My VW bug had a tendancy to run hot, as all air-cooled engines can, add an oil cooler and don't look back, never had engine heat trouble again. Water? Good hell, how hot do you think it has to be for water to evaporate? It boils at 212F at sea level, lower temps at elevation. If you use a thermostat controlled oil cooler that only allows oil into the cooler at 185F, your oil is plenty hot enough to drive water into the atmosphere, providing your CCV system is not plugged. There is a lot of splashing, turbulence and aeration going on in the oil pan as soon as the engine start, all of this helps the entrained water to dissapate. We aren't talking about 50F oil here that will stay as thick as 90W the whole time.
The problems I see with oil coolers stem from the pressure, I wouldn't be content to run some rubber hose with hose clamps from the filter to the grill and back. At 20-50psi the hose will expand and contract wuite a pit, and with the temp canges contribute to the accelerated deterioration of the hose. Steel lines or braided lines are bood, imo, but not rubber hose.

Summit sells a thermostatic bypass that sandwiches between the block and oil filter. At start up (cold oil) only 10% of the oil passes through the cooler, just to keep it flowing and warm all the oil. At 185F it opens fully and allow 90% of the oil to pass through the cooler. This keeps your oil at about 185F as long as you have a large enough cooler in front.

Is it worth it on the XJ? Sure, if you want to do it. Just like the electric fan mod, there are pros and cons that you have to be prepared for but wither way won't cause any earth-shattering changes.

When I build my front bumper it will have an oil cooler mounted in it, and plumbed with steel and/or braided lines, nothing rubber. I pulled the oil cooler off of an old F250 at the junk yard and if it only gives me a few (10-20) degrees of cooling, it will at least make the overall cooling system that much more resilient. But then I tow my trailer for camping, etc and find that I

[HeightsHoustonXJ]

SCW, I don't need experience with an oil cooler on an XJ to have an informed opinion about them, however, you do ask an insightful question. "Anyone actually TRY an oil cooler?"

OK, everyone with an oil cooler on their XJ raise their hand. I think the show of hands speaks volumes.

Not discounting the usefulness on a truck that tows 40% of the time, or an XJ built for racing or extreme engine stress, just discounting the usefulness on OEM XJ's.

[xjtrailrider]

Just another place to leak oil and loose pressure on a 4.0. I had a engine oil cooler and a dual filter kit on my 96' Bronco and when one of the lines decided to let go....well what a mess, oil everywhere!

[19CHEROKEE89]

I think some of the older porsches that where predominantly "aircooled" had oil coolers to help cool the motor too ( i'm running on hear-say from stuff i heard years ago on that). i could not imagine it hurting you in anyway, but it may be overkill for a daily driver in a cool to temperate climate.

All porsches were air cooled up through 96 until the boxter came out in what i beleive was 97 from that point on all of the porsches since then have been liquid cooled.

just a bit o knowledge cause knowledge is power.

oh i used to work for porsche. Cause i dint honestly knwo that until i worked with them every day.

[cklaus]

All porsches were air cooled up through 96 until the boxter came out in what i beleive was 97 from that point on all of the porsches since then have been liquid cooled.

just a bit o knowledge cause knowledge is power.

oh i used to work for porsche. Cause i dint honestly knwo that until i worked with them every day.

http://cgi.ebay.com/ebaymotors/PORSCHE-912-356-OIL-COOLER_W0QQcmdZViewItemQQcategoryZ33617QQihZ016QQi temZ260014517862QQrdZ1

http://vista.pca.org/stl/911car84.htm

I stand by what i said... some of the old "air cooled porsches" used oil coolers. ;)

[outlander]

I did some research on oil coolers and decided against one because I don't think my stock pump will put out enough pressure to run a cooler and I don't want to have to drop the pan just to install a hi flow pump.

[Jim Mesthene]

I think some of the older porsches that where predominantly "aircooled" had oil coolers to help cool the motor too ( i'm running on hear-say from stuff i heard years ago on that).
I used to build air-cooled Formula Vee race motors and high performance VW dune buggy motors, along with the occasional Porsche. The effect of oil coolers is slight. If your oil temperatures threaten to rise above 250 degrees, you need an oil cooler, other than that, they're useless; especially on a liquid cooled motor.

[MrShaft696]

I dont think you will need one, I had one on my gmc 4.3 motor and just took it off because the lines were so leaky and the replacments leaked, so I did away with it and mounted the oil filter right to the block and it has made no difference in regular DD operation.

[Matthew Currie]

Just adding to the above: air cooled engines are a different thing. VW and Porsche aircooled engines are, in a sense, oil cooled too. As far as I know, ALL air cooled VW's and Porsches had an oil cooler, built into the air passages. You won't see it but it's there, and was part of old Ferdinand's original design back in 1939 or whenever. It was the bane of the old upright fan VW engines, because the cooler obstructed air flow to #3 cylinder, causing that one to run hotter and burn valves. But that doesn't necessarily mean you need an oil cooler on your cast iron, water cooled, front mounted Jeep engine. An air cooled engine is always one small step away from thermal disaster.

My old Mercedes diesels have oil coolers as well, as befits the heavily loaded bearings of a diesel. Oil does have a significant role in cooling bearings, so it's a good thing to keep it from overheating. However, those coolers also have a thermostat to help speed up cold weather heating. A well designed cooler will undoubtedly help keep bearing temperatures from going too high if there is a danger of that, but will do little else, and will have almost no effect on overall engine temps unless there is already a critical problem with oil temperature. It's no solution if the problem is really in the cooling system.

An oil cooler in a Jeep that does heavy towing and offroading seems like a pretty good idea, but if you live in a temperate climate, I would not put one in unless it has a thermostat, or can be switched out of the circuit in cold weather.

[Jim Mesthene]

ALL air cooled VW's and Porsches had an oil cooler, built into the air passages. You won't see it but it's there, and was part of old Ferdinand's original design back in 1939 or whenever. It was the bane of the old upright fan VW engines, because the cooler obstructed air flow to #3 cylinder, causing that one to run hotter and burn valves.
...and changing the size or location had no effect on overall engine temperature. Moving the cooler out of the airflow did make a difference on that one cylinder head temperature.
The lesson learned here was that obstructing cooling air with an oil cooler was counter-productive.
Bearings don't need to be cooled separately as they don't suffer heat damage until long after the oil stops lubricating, at about 250 degrees.
As I said, if your oil temperatures stay below 250, an oil cooler is useless.

[SuzysJ]

It's an old thread, but there are some other points to be made about oil coolers not addressed here. First, one need not run oil to a separate heat exchanger but do it the other way: there are coolers that mount between the oil filter mount and the filter (a sandwich cooler) which runs lower pressure coolant piped rearward.

The second point is that this warms the oil to operating temperature sooner (quick warmup is better), and will keep oil temperatures from spiking under certain conditions.

Third is that oil provides 40% of engine cooling needs (not a misprint); the valvetrain and combustion chambers would weld together without it.

Finally, an oil that warms more quickly and is "prevented" from reaching temps above 240F is one that will last longer and do it's job more effectively. One needs to decide if the expense, added maintenance and possible problems are outweighed. Akin to coolant filters and added heat exchangers for ATF and PSF (plus auxiliary filters) downstream of OEM pieces.

Several oil analyses, done consecutively, with an oil analyst and laboratory can help make this determination. Towing, dusty conditions, a marginal cooling system, etc might make it worthwhile.

Corvettes had such an oil cooler before MOBIL ONE was the factory oil fill. I have seen schematics online for their sandwich cooler. Ford trucks also had them at some point and so did DODGE CARAVANs with HD cooling package (a MOPAR part at one point that would fit the JEEP thread pattern.)

[winterbeater]

Don't see your point at all! Oil cools very little unless you have an oil cooler. Certainly not 40% without an oil cooler. Why will an oil cooler make the engine oil warm up faster? Not unless the ambient air is warmer than the engine oil. A mini cooler that mounted between the oil filter adapter and the filter without a seperate heat exchanger would not do shit. Synthetic oil can get VERY hot without degrading. I would worry a whole lot more about the engine coolant boiling over.

[SuzysJ]

Try some homework, winterbeater. The OEM's have been doing it for decades.

40% is no misprint. Oil doesn't cool engine components your motor internally welds itself. Highest temps are seen at valvetrain (keep those drainbacks cleared).

Heat exchangers are about time & temp. Bring it to op temp fast (with a fluid-to-fluid exchanger), and keep temp spikes from occurring. Synthetics are great, but they aren't enough in some cases. Do you even know the temps you're attempting to correlate between dino and synthetic oils? And why did Mopar put those "mini coolers" on V6 engines?

Because they work.

Do you have to have one on a 4.0? Different question. Will it help? Yet another question.

By the way, why DOES engine coolant boil over? Do you even understand what you're saying?

Your attitude and knowledge . . . .

[orange]

The oil cooler, w/thermostat (cool oil bypasses the cooler,hot oil goes thru the cooler) is a big in help keeping the oil at 180*f. This is good for rear main seal life, which is one of the big problems in XJ's, and the life of the oil and engine.

That 180*f is the temp going INTO the engine and it goes up inside the engine, so it usually gets above boiling inside and gets rid of water, fuel, and other contaminates. A few feet of hose and cooler have little effect on oil pressure
and keeping the oil at 180*f (175-185) keeps it from thinning out at higher temps and dropping pressure.

Regards,
O

[Milford Cubicle II]

The oil cooler, w/thermostat (cool oil bypasses the cooler,hot oil goes thru the cooler) is a big in help keeping the oil at 180*f. This is good for rear main seal life, which is one of the big problems in XJ's, and the life of the oil and engine.

That's a good point. The rear main is a known issue for XJ's and oil is essential for cooling bearings.

Just another place to leak oil and loose pressure on a 4.0. I had a engine oil cooler and a dual filter kit on my 96' Bronco and when one of the lines decided to let go....well what a mess, oil everywhere!

If you install it right it will be the LAST place you'll end up leaking oil.

[orange]

The oil will help with the cooling. Same for Trans ATF.

I suspect the main cause of our problems with Rear Main Seals AND Crank Position Sensors (RMS, CPS) is the high heat of the Torque Converter. It is putting so much extra heat into that area that its a wonder RMS,CPS parts last as well as they do.

(Those having trouble with the FRONT main seal please raise hands !!! ;) ).

It would be interesting to see some IR temperature readings from around the bellhousing area under different conditions. Idleing in Drive with brake on while stopped, or going up a hill probably runs the temps right on up! and Summertime-Whew!

That is why I believe Trans Coolers and Engine Oil Coolers are a very good thing. Just be sure to get and keep a good, reliable installation.

Regards,
O

[Davinator61]

The major reason why I installed an engine oil cooler on my vehicle was so I'd be able to tow a 2500+ pound trailer without overheating the engine on long hauls. The same reason applies to my replacing the OE fluid clutch cooling fan assembly with the Ford Taurus dual speed electric fan. As I'm starting my own mobile automotive services business, I plan to carry all of my tools and equipment around in a utility trailer. As the trailer's gross weight will likely be at least 2500 pounds when fully loaded, I'll definitely need the extra cooling potential the oil cooler would provide, especially when pulling up hills on hot days. It also seems to be an added bonus for off-pavement wheeling when my vehicle speeds are under 30 miles per hour (or 48 kilometers per hour for you Metric-System users). So, it all comes down to whether or not you drive your vehicle a lot in conditions that require the use of an engine oil cooler. That and personal choice.