Compression test on cold engine?

[Erase_The_Eraser]

Hey there! I hate that my first post is going to be a troubleshooting issue on here, however I guess thats just how it goes sometimes....so, the dilemma. I read about these amazing little 1.6 diesels and fell in love...after doing some searching a friend told me about one that was sitting out at a dealership. I ended up purchasing a 1992 Jetta turbo-diesel (eco-diesel model) for a total of about 600 dollars. High miles but the test drive told me otherwise, seemed solid...minus the few things it needed. Since then I have replaced parts and am now just waiting on several bolts before I start driving her. Along the way I decided to run a compression test and then it all came to a somewhat discouraging halt when my numbers came back, 350-150-180-200.
Yikes! So, the question I'm asking is - Will compression numbers be significantly higher with a warm engine? since the vehicle can not be run right now I can not find out until the end of the week when the rest of my parts come in.

Thanks!

[Doug]

Yes, it will trend higher. If it starts and runs without difficulty then run it for a few weeks before testing again. There may just be some foreign matter on the valve seats or some stuck rings. If there is still the difference then maybe a valve job and or rings is in order.

[jtanguay]

Hmmm... I remember seeing some compression numbers on a toyota diesel 2.4D engine.

Compression went like this: 320-190-140-90

(not exact numbers, but close enough)

The engine wanted to run, but blew out some serious black smoke.. that one cylinder was trying to run the whole motor  :lol:  what a beast!

Basically what probably happened was the driver let the EGT's go too high, and burned out the last 3 cylinders, since thats the orientation of the exhaust manifold.

I'm wondering if your car has the same problem.  The most problematic cylinders of heat failure would be the 2 middle ones by the way that the exhaust manifold is ducted.  As Doug stated though, it is quite possibly a valve/ring problem, maybe caused by overheating.