Thorpe991

The other day i noticed my jeep was running a little warm.(around 220) I have a 180 degree thermostat installed an normally i run from roughly 160 to 200 degrees. after getting to my destination an letting the jeep cool down i checked my radiator. when i opened the rad it was milkshake i then checked my oil an my oil is normal. when i bought the jeep 2 years ago the previous owner said he had ran a sealant threw the coolent system because he had a leaking head gasket. i had flushed an used a cleaner on it shortly after buying the jeep. havent had problems till now.

Do you think the head gasket went? letting oil into the coolent at the head or i have a crack in the block? in the 2 years iv owned the jeep it has never overheated. i installed the thermostat very near the time i got the jeep. it dosent smoke or smell sweet. no skipping or misfires , runs extreamly well.

1995 Jeep Cherokee sport 95xxx miles 4.0 I6 auto trans

318SixPack

Sounds like the classic symptoms of a head gasket leak. Plus, it was know to be leaking before.

awg

perform a compression test before dismantle if possible, that will almost always give a strong indication

tjwalker

I agree, get a compression test done. It is often a good test for a failing headgasket. Low compression in two adjacent cylinders is often the signature.

How has your oil pressure been? If caught early enough, a headgasket or cracked head can often be repaired without major damage to the engine bearings. If not, the coolant mixed with oil will wipe the bearings.

The 95 has a pretty strong head, hopefully this is just the headgasket. If so, have a machine shop go through the head and do what is necessary, check for cracks, straightness, parts needed etc. before you do the repair. Money well spent. Then perform a few oil changes with VERY short intervals during the first miles you put on it to clean it out.

Good luck and be sure to keep us updated!

dave1123

Are you sure it's not transmission fluid? There really isn't much of a way engine oil can get into the coolant since there's no oil pressure passages in a 4.0L head. Oil is supplied thru the pushrods and drains back thru the pushrod clearance holes. A blown head gasket will show coolant in the oil, not the other way around. Possibly a blown trans cooler in the radiator.

PatHenry

Agree - another possibility is that you're seeing the leak stopper chemical gunking it up... either way, can't hurt to do some testing, keep an eye on the oil, flush the hell out of the coolant system, etc.

You can get a lab analysis on the oil and coolant if you want to spend a little cash.

third coast

All above is good advice. Transmission fluid in the coolant from a bad trans cooler was my first thought (definitely check the transmission fluid level) but I wonder if on cooldown cycles the dropping pressure in the cooling system might suck in some engine oil from the head area through a crack or bad head gasket. ?? Or it might just be the stop leak stuff, it will stay in the cooling system nearly forever.

The indication of higher than normal cooling system temperature and previous report of a possible head gasket issue concern me and would not seem to be explained by a trans cooler problem. If the high temperature is due to a head issue it’s likely that combustion gas is entering the cooling system. A combustion gas test is a great way to check that but it does not completely eliminate a head/gasket problem. You can rent/borrow a combustion gas tester (also called a block tester) from major auto parts stores and buy a bottle of the test fluid for about $13. It is a relatively fast, easy and inexpensive test so I would put it in the top couple of things to do initially. Just follow the directions and avoid getting coolant into the tester.

awg

about the easiest thing is take oil cap off, and examine it, if there is a creamy residue, head has to come off

certainly check trans fluid though