jlaudio29

Ok, so i know my oil is milky, i need to get it out, but i need to do a compression test to find out if its a headgasket or just my manifolds.

So the question is, do i go through the whole process of flushing before or after the compression test?

Also as far as flushing goes, ive heard deisel fuel ive also heard there is some special stuff for flushing the oil? any links or steps to acheive this would be great.

Velocity Vector

I have used diesel before, I wouldn't think a compression test would mater either way cleaned or not. I wouldn't leave water in the oil very long though. Mine, come to find out was condinsation from the oil temp was to low and not burning off the condinsation. Lucky me.

jlaudio29

Thank you for replying. Another question though, with the deisel am i only flushing the oil pan? or should i be filling it through the valve over or something?

Velocity Vector

I drained a couple quarts of oil first then added the diesel to the rest of the old oil thru the oil fill to the full mark on the stick. Ran the engine for 30 seconds or so then drain it. After that get some cheap oil fill it up again, run the engine get it good and warm, drain that cheap oil out. Change the filter put the good oil back in and you should be good to go.

Thunderstruck

Be careful with compression test. Just because you get good compression does not mean the head gasket is not leaking water. The water jackets are close to the valley so you can push the gasket into the valley and not lose compression. Learned that one the hard way. I detonated a motor and pushed the head gasket into the valley filling the motor with water. The metal rings on the head gasket around the cylinders held air pressure and did not show a leak until a visual inspection was done with the heads off.

Pat McPherson

If your exhaust risers or manifolds are leaking it likely started as a slow leak and the exhaust ports on your heads will be rusty.
Another common place for a leak is at the intake to heads joint. Corrosion will eat the intake at this point and water leaks into the lifter valley.
Last would be the head gasket and it is tough to tell without pulling the heads.

tssteph

You need to do a leak down test instead of a compression test.

jlaudio29

yah the motor is old, it was supposedly rebuilt in 2005, but the intake manifold dosnt look to be in the greatest shape so im wondering if the gasket isnt bad, and who knows possible the headgasket as well.. im also thinking of replacing the exhaust manifolds and risers too. that way i know what kinda work went into the motor this time around.

Thunderstruck

Leak down may not show a water leak on head gasket either.

tssteph

If it is leaking into a cylinder it should. I also pressure tested my water system. Water normally comes in from one source and out two.