Compression and Leakdown Test

[GMDiesel]

I need the equipment to do a compression and leakdown test on a 1998 Van 6.5 Turbo Diesel Engine. Can this be rented and what do you utilize to pressurize the cylinder during a leakdown test? Does it need to be at 400 psi? if so, can you use bottled Nitrogen to attain the high pressure?

The engine is using water. It runs fine, just can't operate it with it using water and overheating. Not sure of the diagnosis as to cracked head, blown head gasket or cracked block.

Aprreciate all comments and advice.

Thanks!

[DmaxMaverick]

What you need can be had at Harbor Freight. I have them. Get the LARGE Diesel compression tester (about $65-80) AND the cylinder leakage tester. You will need the compression tester, because it has the adapter you need for the glow plug hole, and happens to fit the coupler to the leakage tester. The leakage tester only needs normal shop air, and has its own regulator and gage pair (marked with leakage ranges). If you follow the instructions with the leakage tester, it works very well.

If you aren't sure what to get, I can look them up for you.

[GMDiesel]

As diesel compression is around the 400 psi range, wouldn't it be advisable to mimick that when doing the leakdown. We're trying to track coolant leakage.

[DmaxMaverick]

No. Diesel static compression is 300-400 PSI. The actual combustion pressure is thousands. A correct leakage test is with the correct tool, which will identify the suspect cylinder, and the direction of the leak. All at LOW, regulated and monitored pressure. If all you want to do is dump high pressure into a cylinder to see where it comes out, more power to ya. You'll blow every seal it leaks into at that dynamic pressure. Perform a cylinder leakage test correctly, and it will tell you everything you need to know. Been doing it that way over a hundred years (not me, personally). If there were a better way, we'd be doing it.