I've got a 3500HD with 6.5TD which I will be using as my welding truck. Both oil cooler lines are leaking where they attach to the fittings in the side of the block above the oil filter. I've got new plastic gaskets ordered from GM, but in the meantime, is it OK to disconnect the lines, remove the fittings from the block, and plug the passages? In other words, is the oil cooler an integral part of the oil system design on this block, or just an option that was sometimes added? It's a factory cooler, mounted in front of the radiator. The lines themselves are not leaking, it's where they connect to the fittings in the block. And both are leaking at a fast drip, not quite a stream. On a related note, engine oil pressure, cold or hot is showing around 18 psi at idle and 22 psi at 2200 rpm. I can only assume this is because of the pressure drop from these leaks - the truck and I have only been together for a day. I only need to run the engine for maybe a week with the oil cooler disconnected, and temps here in VA won't be a concern.

No,

One goes from oil pump to cooler, the other goes from cooler to filter.

Plugging it will block oil to engine.

You could bypass the cooler if you have to. Not sure what oil temps would go to.

Plugs woud shove oil thru cooler bypass valve directly into filter - not too good an idea, as would not be looping the out to the return.

Leaks where the rubber meets the aluminum, or at the fitting?

The fittings are o\ring sealed.

David,

Thanks, the oil flowpath is what I wanted to know. Not much point in bypassing the cooler; the cooler isn't leaking.

gmctd,

Thanks for the welcome. I searched your site as well as 2 others before posting. There is plenty of info on oil cooler line leaks, which would be great if that was my problem. As stated in the question, the lines are not leaking; it's where they connect to the fittings which screw into the block. The Chevy place ordered me what they're calling "plastic gaskets," which I'm sure are the o-rings you're talking about. Sorry about not having a sig yet, but I did include the necessary vehicle info in the body of my question. Not new to diesels or vehicle maintenance, just new to this site and the 6.5. Had a J-code 6.2 once, there was a reliable, decent nonturbo diesel.

I have my oil cooler removed?

The new penisular engine came plugged so I left it plugged?

That's interesting.

With no oil cooler, where is the heat from the oil-sprayed pistons going?

Your oil temps must be up around 300deg, even on a short trip to the grocery store.

Plugged permanently? Or can the plugs be unscrewed? I would seriously run an oil cooler on these engines - I don't think it is an option. Especially since your Peninsular is making substantially more power than stock, which is almost certainly generating higher oil temps. If nothing else, I would call Peninsular up and ask 'em.

yea, I am gonna put one on. I just have been super buisy. I run Mobile Synthetic Delvac so I run the best oil that i can.

I made all new hoses from hyrauilic line at my work, crimped and all that nice jaz. Just need to find a nice cooler and then spend the time to do it.

I agree, I do need it.

Hahaha, I made my oil cooler lines for my 6.2L out of hydrolic hose and used the swivel fittings. I didn't realize they required the pressure of a hydrolic system, not the pressure of our wussy little oil pump, to not leak! :p:

Needless to say, there is a tube of silicone covering the lines at the block!:rolleyes: