Confusing Problem

[chrisstewart6904]

Hello I have a 93 ford explorer that is 4x4, the vehicle has done good up until this point. I first realized the problem when the heater core went out and i replaced it. When i put the new heater core in it was blowing hot air and working perfectly, then i put it in 4x4 to get up a hill when i took it out of four wheel drive it was making a clanking noise. I figured that it did not kick out of gear completely, this continued four a few miles then it would not go over 35mph even with the pedal to the floor then it died. this was all within like a 20 or 30 minute period, I pushed it into a parking lot and realized it was overheating bad and it would not start back up. so i let it sit for about an hour and during that time i was examining everything that i could think would be the problem, not taking anything apart just looking it over. then it started and made it home which was only like 3 miles away. I then realized that the radiator overflow smells like exhaust and has some black gunk floating in it. right now it still runs and drives but sometimes does not want to start and whenever i turn the vehicle on it makes the overflow bubble (which i think is from the exhaust going in there). I asked my neighbors who work on cars but are not "Mechanics" and they said its either a cracked head or head gasket, I asked auto zone and the guy there told me it sounds like the Intake manifold gasket. I have worked on a lot of vehicles but never really the motor so i have no idea. So i figured i would see if anyone on here has had a similar problem or knows what the problem is, I'm really hoping its not a head or head gasket issue. Any help would be greatly appreciated oh yea it is a 4.0 v6

 

[Iron Weasel]

If you're getting bubbles in the cooling system from the compression of the engine, you probably have coolant in your oil too. Pull the oil dipstick out and check for any coolant globules. If you can get a compression gauge, run a compression test on each cylinder. If one (or more) cylinders are a lot lower than the others, then that's most likely where the gasket blew out at. If all the cylinders are within 10% of each other, then you should be OK as far as a gasket goes.

A little more diagnosis will confirm or disprove the head gasket / cracked head theory.

 

[chrisstewart6904]

I checked the dipstick and it does not have any globules on it, I was also told that if the dipstick is milky then it is a head, and the dipstick is fine it just looks like oil. the only thing off with the oil is that i did an oil change about 3,000 miles ago and i made sure the right amount of oil was added back and then when i just looked at the dipstick there is too much oil, like the oil level has jumped which i have never heard of before.

 

[Dlee6204]

This sounds like a head gasket/cracked head problem. I would take Iron Weasel's advice and do a compression test to verify.

How much did the oil level rise?

 

[chrisstewart6904]

well it had rose about a 1/8 or a 1/4 but i started the car and went and checked again and it is right at the full mark, yea a friend of mine has a compression tester and I am going to test that today so i can be sure of what the problem is, so I'm not just buying parts and wasting money on guesses.Is there anyways to test the intake manifold gasket or is it just a take it off and find out type thing?

 

[huntman58]

When the oil leave is right it should show low about one Qt. as soon as you shut the motor down because of all the oil in the motor. if sitting over a period of time like over night it should show full before you start it any thing over full is bad same with not showing on the stick.

If the level went up after the problem then as others have said blown head gasket / cracked head. A compression test will help you see what side and what holes are affected. also when you pull the plugs to do the test read them also as they can also tell you the same info as in wet and black wet and rusty or just wet or normal tan and so one.

But it sounds like you over heated it and the 4.0 dose not take to that well at all and is one of the few ways to kill these motors fast.

 

[rocko1025]

I had the same problem with my 94 XLT. The radiator was leaking along with the overheating. I put some KW block sealer in and it seemed to work. I replaced the radiator and the valve cover gaskets, and started running again and then it blew. I'm not sure if it was the head gasket or the head, haven't ripped it down again, found another 94 XLT with the complete history with it.