Oil cooler causing leaks?

[E30_Beau]

Hi all,

So I've just installed an aftermarket oil cooler to my engine and it has seemingly given the M20 oil leak problems, I've used aftermarket for everything to make up the kit like the sandwhich plate, the oil line the mount and the oil cooler itself. I noticed the leak coming from between the cylinder head and block between cylinder 3 and 4 on the exhaust side about 2 days after I installed it all and even took it all off again to check that nothing was blocked but couldnt find any faults.

Am i better off not using an oil cooler on the car or is this something that happens sometimes with these engines after you install an oil cooler to them?

[Jaxx_]

you're saying it's leaking at the head gasket?

Personally I'm not convinced that the leak is above the cooler and caused indirectly by the cooler. I would guess that either the leak was there and you didn't notice it or it is related to the cooler, but directly, either from install or leak after installation. If you are interested in keeping the oil cooler and want to be sure of the source of the leak, a trick that worked well for me(even spotting leaks of fresh clean oil) is using foot powder spray around the area of the leak. Use the cheap stuff that doesn't advertize going on without white residue.

I had a sandwich plate installed and to be honest it was hard for me to tell where a leak was coming from -- I also had a -10AN line looped for a future oil cooler and 1/8 NPT sensors in the same location.

[E30_Beau]

Yeah so the oil is coming from the head gasket between cylinder 3 and 4, and I had been regularly checking the car since the last race day for maybe about a month now and no leaks at all.

Unless it's just horrible timing, I thought it might be pushing the oil out because of the extra volume or because of the fact that the oil cooler is mounted higher towards the top of the radiator, but from what I see Other have done pretty much the same with no hassles.

Either way I need to replace the head gasket now so I'll just do that and maybe swap the oil out for something thinner and triple check everything.

[Jaxx_]

Perhaps there is some factor there. Are the in and out lines of the cooler oriented in a way that they won't drain back? Besides oil pressure issues when starting I could imagine this could have some contribution to your theory.

[digger]

I'd be surprised if the oil cooler was the cause, might be a coincidence. I dont see how oil pressure in the head would increase