JTProuhet

I have a 93 xj with the 4.0 with 202k.. Several weeks ago I noticed that I was losing coolant.. And there was milky stuff on the bottom of the dipstick after about 600 miles on an oil change.. I know that the radiator has a small leak but the reservoir is going from full to add in about a week.. So at first I assumed a head gasket. I kinda had to put it on the back burner since I just has shoulder surgery. Well today I decided to do a block check and compression test on it.. Block cheaper checked out fine.. The checker fluid never turned a shade of color.. So I did the compression test.. Here's what I got..
#1 - 83psi
#2 - 84psi
#3 - 97psi
#4 - 95psi
#5 - 98psi
#6 - 96psi

I'm told that is supposed to be up around 120-150psi.. What do you all think is going on? Where is the coolant going? What's the milky substance? I only drive about 4 miles one way to work and I don't go on that long of trips that often so would condensation build up that fast? I'm clueless on this thing.. And ontop of it, I've only had it for about 3 months..

stockli

Milk oil = coolant in oil. Unexplained coolant loss = head gasket.

I would think you probably have a head gasket leaking.

Any sweet smell or white smoke from the exhaust?

JTProuhet

Even if the head gasket is blown, it wouldnt make all the cylinders low on compression would it? I mean yea 1 and 2 are considerably lower than the others but still 95 down the rest of the board is still real low according to the Haynes manual..

tjwalker

Replace your radiator.

Trying to troubleshoot an issue when you have a "known" issue is not a good strategy. Small radiator leaks can turn into huge leaks in a microsecond and then you'll have another thread to post. It's really difficult to gauge how much you're losing from the radiator. Not a good idea to try. See where you are at after radiator is replaced.

As for your compression numbers, you are looking more for consistency between cylinders, which you have. Sometimes the gauge itself is responsible for the low readings. If you want to be sure, redo your compression test with a different gauge.

If you truly had a blown head gasket, you should have hydrocarbons in your coolant and your block test didn't show that. I'd be more concerned if it did.

JTProuhet

Alright thanks I'll pull the radiator out and see if it can be fixed and go from there..