1997 Wrangler 2.5L temp gauge

This sounds like three or four independent problems. The oil pressure thing sounds like worn crank bearings. These can be replaced from the bottom but if you are going to replace the engine anyway why bother? Coolant in the oil is bad, normally a sign of a leaking head gasket. The temperature gauge thing could be a stuck thermostat or a short to ground.

Earle

Earle hit the high points but if you just need wheels until an engine change in the near future you can do a couple of things that may let you limp by - or at least feel more a bit more comfortable about getting more than walking distance from the house. First thing I would do - based on the notoriously unreliable nature of those oil pressure senders/gauges - would be put a direct reading gauge in place of the sender and see if you really do have the drop to zero. Even 5 psi at hot idle will hold the engine together for a while. If the oil pressure really is low, change the oil. Use a 10-W-50 oil and see if that helps.

Temperature spikes can be caused by a lot of things. Assuming the gauge is accurate and Earle's checks for short/open wiring problems don't find anything, you could have had a stuck thermostat. They sometimes stick for no apparent reason then break free and work OK for a while. Don't start a cross country trip until you are sure. Remember that sticking thermostats tend to stick more and more often after the first time, so keep an eye on it. You could have had a strong tail wind, a blocked radiator, even a bubble in the line that caused a one-time over heat (but don't count on it!).

As for the leaking head gasket (or whatever got water in the crankcase), you'll do damage by driving, but how long do you intend to put off the engine change? Unless you crack a head or have a huge leak, you can get by with light use for a while.

If the oil pressure is really going to near-zero even at driving speed, you could see a complete seizure. Other than that, change the oil using a heavier oil and don't get crazy with your driving. It's a crap shoot but you plan on dropping a new engine in shortly anyway so you stand a fair chance of stretching it out for a little while. Of course, it will probably fail on your way to the parts store to get that new engine ;)

The drop to 0 on oil pressure is likely the sender shorting to ground. Pegged at 80 happens when the wire falls off. If the jeep is going to

0 and the engine isn't clattering like marbles in a tin can, then you still have enough pressure to keep the lifters happy.

The temp sender can do a similar trick, check the lead wire for any abrasion on engine bits and pieces.

By "some coolant" do you mean condensation on the dipstick or is the oil turning a greenish color, black blobs on the dipstick above the full mark?

Give this a shot. shut off the engine and let it set for an hour or two (best overnight) then unthread the drain plug and run some off into a clear glass or plastic bottle. Since water and antifreeze are heavier than oil they will puddle up at the bottom of the oil pan.

e bottom of the oil pan.

Thanks,

The oil looks greenish, but not too bad. You can only see a greenish/ yellow tinge when you run the dipstick along a paper towel. Other than that it is normal looking. Engine sounds fine. I am getting around

25-35 PSI oils pressure when the RPM's are at 3000-3500. I really noticed the oil pressure dropping off after an oil change I got at a garage. Not sure what kind of oil filter thay put in. I will change it wilth 10-W-50 soon. Just driving to and from work at this point.

Thanks,

The oil looks greenish, but not too bad. You can only see a greenish/ yellow tinge when you run the dipstick along a paper towel. Other than that it is normal looking. Engine sounds fine. I am getting around

25-35 PSI oils pressure when the RPM's are at 3000-3500. I really noticed the oil pressure dropping off after an oil change I got at a garage. Not sure what kind of oil filter thay put in. I will change it wilth 10-W-50 soon. Just driving to and from work at this point.

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10w50 just masks the symptoms, and may make it harder for oil to perfuse your bearings on a cold start. Greenish/yellow "tinge" sounds real odd to me. My advice is to put some brand name 10w30 and a brand name filter in it and see what happens.

Earle

Usually coolant in the oil isn't going to give a greenish color, it will instead make the oil look like a milkshake. An old mechanics test is to do this, get the engine hot (say a 15 minute non-stop drive) and take out the dipstick. Drip a drop from the dipstick on the exhaust manifold about an inch from the head. Does it just smoke, no sound, or do you hear or see sizzling? If just smoke, no bubbling or sizzling there is probably no water/coolant in the oil.

I'm not sure I'd go 10w50. Maybe 15W40 (such as Rotella) may be an interesting try.

Second that, Peter. I think I was the one who brought up the molasses grade lube - I was on a track where I was thinking that he really DID have pressure close to zero and just wanted to squeeze a few miles out of a tired mill. The key is to confirm the oil pressure - I don't trust those senders any further than I could throw one with my arm in a sling.

Nice tip, Doug - never thought about looking for steam or the sizzle effect to check for moisture.

Actually, that was PeterD's tip. I've always tapped the oil pan for about a pint of fluid and looked for water.

I usually don't think of it in time so the milkshake test gets used after I forget and start it up before checking ;)