oil cooler to lower engine temp?

[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.