About two months ago I replaced the oil cooler, HPOP STC fitting, IPR, water pump, rebuilt my turbo, ICP sensor, thermostat, and a host of other things. Everything has been great until this weekend. I've towed with it a couple of times with no problems, well even this time I didn't really have any driveability problems, but now I have an oil leak that I can't identify with the engine assembled. If I get underneath, I have the typical oil on the bellhousing. But if I look up further, there isn't any oil coming down from the engine's upper back plate area when it would leak had there been a HPOP cover leak. It's also leaking down both sides of the rear of the engine.

I also have noticed the leak on both sides of the front of the engine also. It streams down both sides of the front cover and over the lip of the oil pan on both sides. It's not really a stream, more of a drip. If it idles for about 15 minutes, there will be a 6" wide puddle under the starter.
My question would be, where should I start? I think the oil cooler cover plate is leaking. There seems to be some wetness aft of it, between it and the HPOP cover. Also, there may be a HPOP cover leak too, or it may also be the lone culprit. It does have a slight bit of oil present at the turbo's oil inlet connection and I will be replacing that gasket first. What else could cause a leak like this? The turbo oil return doesn't seem to be leaking, but everything is wet, like a mist.

 

What brand of oil cooler was used? Do you still have the braided turbo oil supply line? I would get some de-greaser and clean the top of the engine really good, let it dry or blow it off with compressed air then start it and watch for leaks.

 

I figured it out. I degreased the entire engine and allowed it to dry. Started it and found the oil cooler cover seeping along the forward edge, just below the intake. Well, when I'm fixing this I'm going to do a EGR delete while I'm in there. I'm going to leave the valve in.

 

Glad you got it figured out.