333pg333

Perhaps the Squirrels are trying to get out!?!

Has to be exhaust leak.

Tedro951

I learned much at the Fest. Its a rodent in #2. PET doesn't have the part # for it, but the aftermarket has them.

Chris White

Its an exhaust leak, either at the manifold to head or a cracked runner. The frequency is slow enough it is probably not a header to cross over leak (but guessing by a video is not the most precise method!)

The overheating is caused by air in the coolant – the only ‘fool proof’ way to bleed all the air out of the coolant system after the head has been off is to use a pressure tester to pressurize the coolant expansion tank and force the coolant through the block/head/radiator. With the thermostat closed (cold engine) coolant will not want to go in to the head.

The 50% leakdown in one cylinder is not a good thing – but that may have been a bad test. Leakdown tests are very fussy on 944s, if the piston is not in just the right position it will give a bad reading.

951D

Thanks everyone for your input! I will try driving it for a little while hoping that it is the lifters and and will check up on the exhaust leak. Will let you guys know how things turn out.

Supachink

what does your oil pressure look like? I had a similar problem with the lifters when i rebuilt my head a few weeks ago, it would start and run a 0 oil pressure for about 30 seconds and the noise would cease after what seemed like the lifters pumping up along with oil pressure coming up. did you use an oem oil filter? my problem turned out to be a gummed up OPRV, i removed it and cleaned out all the gunk and flushed clean oil through the hole with a compressor, emptied and refilled the oil and it has not had the same problem since.