Hey everyone,
I have a bit of milkyness in the oil, white deposits on the last 2 plugs by the firewall, a loss of power it seems, and my mpg sucks. I think the power and mpg could be due to the bad plugs, but what about the oil and deposits? I'm gonna do a compression test soon to see what it's at. Motor is the renix 4.0, almost 242k on it, all original. Doesn't run hot, doesn't run rough, just has what I described. No smoke from the tailpipe either. A friend told me the compression numbers to range from 155-185psi, that right? I'll also look in my book to make sure. Thanks for any help, I need it. This thing has to last me till the summer at least, anything I can do to prevent a major blow I'll do. Once summer rolls around I'll replace the gasket and some other things.

 

Don't drive it!
The more you drive it the worst it will get. That is if it is a head gasket. You really would need to do some testing to know for sure if it is a head gasket or not.

 

The spec for my '98 is 120-150; I'm sure the earlier ones are the same or similar.

 

Are you losing any coolant?

 

Check the oil dipstick. Is it milky? Is it higher than normal?

 

Yup, 120-150 is the spec, with no more than a 30 psi variation between cylinders.

Get that compression test performed. Pronto.

 

I have a bit of milk on the end of the dipstick. It's not any higher than normal, cuz it leaks oil anyway. I have no choice but to drive it, I have to get to school and work. I'm gonna do the compression test as soon as possible. Luckily I have time now since I'm on spring break.

 

The coolant also leaks, so I can't tell if it's low because of the gasket either. Is there anything else that could give me these symptoms? My first guess was the head gasket.

 

Hey, was just wondering where everyone got their numbers from for the copression psi.? In my Haynes manual it says 155-185 psi???????

 

Rip that page out of your Haynes manual and insert a copy of page 9-94 of the '99 FSM in its place.

tjwalker gave you the proper compression pressure data for your '99.

 

if you keep driving it with coolant getting into the oil it will eat the bearings, and the crank and cam journals..... then you are in for an engine. just out of curiousity what is you're oil pressure since you have been driving it for a while like this already.

 

Oil pressure hasn't changed. Been perfect for months. 40psi when cold at idle and 20psi when warm at idle.

 

now just out of curiousity, does the jeep only make short trips where the engine does not reach operating temp or does not stay at temp for long??? if that is the case that could also explain condensation in the crank case.

have you checked for external leaks??? if not i would do this first.

 

Do the compression test. It takes about 20 minutes Max. That's a definitive answer as well. If it turns out to be a head gasket, call up a friend that enjoys working on vehicles and a nice weekend. My buddy and i have done 3 so far, and can knock it out in about 18 hours total. Good luck, ask any questions!

 

This week I haven't gone anywhere far, but during a normal week with school I drive 11 miles one way. Since it's winter it hasn't exactly heated up, but in the summer it runs at normal temp even on a 5 mile drive. The only thing holding me back with the compression test is my dad wanting to be there when I do it. I could have done it already this week since I'm off from school, but I gotta wait for him to have free time after work or wait till the weekend. Same thing with the valve cover gasket. Don't see why he has to be there, but I just do as he says.