Help checking compression

[Thor]

I have a 94 6.5 TD that is starting to develop some blow by through dipstick and pass side valve cover. I need to know what psi I should have per cylinder, and how long do I crank the engine to get a good reading. Thanks

[DmaxMaverick]

About 300+ PSI, and all cylinders should be within about 10% of each other. NEVER try this with "wet" cylinders (added oil), like some may do on a gasser. This must be done when the engine is up to operating temp (gloves recommended), or you will not get an accurate test. 6 puffs (compression strokes) per cylinder. Remove all the glow plugs first, and make sure your batteries are fully charged throughout the process. Consistent cranking speed is important.

[Turbo Al]

How old is your CDR? (Crank Depression Regulator) on pass side valve cover. An old or malfuntioning one will cause these syptons as well.
Al

[Thor]

It is very old, probably the original. I did a compression check on the drivers side and have a cylinder that goes up to 360psi, but falls to 0 psi in about 10 seconds, any ideas of what this might be? It looks like I'm going to go in the injector holes on the pass side. I also appear to have coolant residue in the filler cap. Unsure where to start. Thanks

[Turbo Al]

My compression tester holds the reading untill you release it so if yours is suppose to do the same then the little valve in the tester needs to be replaced.

[rustyk]

Coolant residue in the (oil) filler cap is a sure sign of a blown head gasket. Time to break out the wrenches...:(

And ethylene glycol in the crankcase will turn that into something resembling a third-world coal mine if not addressed immediately.

Coolant in the lube oil will resemble mayonnaise in color and consistency.