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Jeep 4.0 and Oil Coolers

Desert4x4

NAXJA Forum User
Location
Phoenix
Hi all,

I just figured I'd share something I've learned with you guys/girls.

I put an oil cooler on my 99 xj 4.0/aw4/np242.... It was the aluminum filter sandwich style, and a tube and fin 6 pass aluminum cooler mounted in front of the electric fan on the driver's side of radiator. It used 1/2" hose. I ran with it for about 10 months. I took it off because I wanted a simpler setup with less risk of leaks. Also I got pissed trying to find a plate and fin style cooler with 1/2" fittings.

The oil pressure at hot idle would be at the 30 psi mark with the cooler. When I removed the cooler, and changed nothing else (same oil and same filter) the oil pressure at hot idle was 25 (halfway between 20 and 30 on the gauge).

So the engine oil cooler definitely does something. As far as the engine temps are concerned, I really didn't see any difference with or without the cooler.

On a side note, I did notice a lower oil pressure with the larger filter.

Sorry if this info has already been talked about.
 
I've always heard it recommended that a high volume pump be put in if using an oil cooler over 3-4 rows / passes. I'm sure there are other opinions though.
 
Installing a cooler without oil temp data is a bad idea. You don't know if you are running your oil too cold. Just because you have more pressure doesn't mean the cooler is helping.
 
Depends on if the cooler has a thermostat in it. If it does, then the lack of gauges, although not the best idea, is acceptable as the T-Stat will ensure the oil reaches an acceptable minimum.

High volume Oil Pump. I highly recommend these if a remote filter and remote heat exchanger is fitted. Not a high pressure, a high volume pump. Only to make sure that the oil will flow...

For an installation such as Talyn is performing, changing the pump is not, IMO, a requirement at all...
 
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