911T oil cooler

[Forssling]

Hi All,
I started dismantling my -71 T engine yesterday.

The (mounted on engine) oil cooler looked quite good and had no signs of leaks or damage. It is now soaking in degreaser for a proper cleanup.

Even though I didn't see any signs of damage should I still test it for leaks? Are they prone to fail?

Appreciate all input.

Jörgen Forssling
Gothenburg
SWEDEN

[7783911]

seals are usually a culprit, getting it flushed and tested while out makes sense, then new sels (including oil pressure valve). I have a cooler running engine after that work and no spots on the garage floor!

[Forssling]

Thanks! I'm doing the whole engine so new seals it will be. I look to find a firm to pressure test it for me.

//Jörgen

[Walt Fricke]

J: they are your Euros to spend, but if the cooler shows no signs of leakage, a pressure test is hardly on the must do list. When they start to leak, you will have ample evidence of it. Internal cleaning is often reserved for an engine which has blown up. Of course, when buying used coolers there is more reason to pressure test, and then do an internal clean.

[dannobee]

Walt brings up a few good points. If it's leaking, you'll know. It'll have a grimy black film around the leak. Pressure test and clean if buying a used one. Even then, you're relying on the seller to be honest about why he's selling it.

When we had a bearing failure on one of our race cars, the coolers were tossed, along with the steel braided hose parts of the lines. It wasn't worth the risk.

Tangentially related, the engine mounted cooler is on the pressure side of the pump. The front mounted oil coolers are on the scavenge side of the pump. In dry sump race engines (except, of course, Porsche), coolers are almost always installed on the pressure side. There's just too much air in the scavenge side to effectively cool, necessitating larger and/or more coolers. And the flow restriction through the cooler and lines reduces the effectiveness of the scavenge, contributing to horsepower loss due to windage. FWIW

[mepstein]

Originally Posted by Forssling

Hi All,
I started dismantling my -71 T engine yesterday.

The (mounted on engine) oil cooler looked quite good and had no signs of leaks or damage. It is now soaking in degreaser for a proper cleanup.

Even though I didn't see any signs of damage should I still test it for leaks? Are they prone to fail?

Appreciate all input.

Jörgen Forssling
Gothenburg
SWEDEN

If it's not leaking now, a pressure test won't tell you when it might leak in the future. And like the guys said, if it comes from a known good engine, unless you find material in the case at teardown, there's really no reason to send it out to get cleaned.

[Forssling]

Thanks all!
It looks good and no evidence of leaks so I clean it and get new seals then.

//Jörgen