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Update: overheating 4.0L

Well I had a few people take a look at the engine and all signs pointed to the water pump. So I changed it and the thermostat just to make sure, flushed the heater core and the rad, and cleaned out the overflow bottle. I filled the system and let it run with the cap off, and it overheated just as it did before. I have a new fan clutch, but I don't think it is faulty, so I may not install it. I ran the Jeep with the electric fan jumped to the battery, and it still overheated. The rad feels hot at the bottom and warm on top and the overflow bottle has a lot of flow inside. I am now thinking the head gasket may be the problem, as there are tiny bubbles in the coolant in the overflow. Any suggestions???? I am tired of throwing parts into it...

Dave...

Reply to
dcollivier
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Reply to
L.W.( ßill ) Hughes III

Well I know you triple checked to make sure you installed the correct rotation water pump for your engine. And I will ASSuME that you correctly wired up the electric fan. I remember seeing a car that was overheating at a shop. I felt for air flow and felt no real air flowing through the radiator. The fan was wired backwards. lol Of course crud blocking air flow through the fins of the radiator and/or a/c condenser will also allow for a overheating problem.

When I first started driving mine with a rebuilt engine, I noticed the temperature starting to rise when driving fast. This I believe was partially due to a faulty EGR system.

How long does it take for the engine to overheat? And you are sure that the coolant sensor for the gauge is fine?????

Reply to
dave AKA vwdoc1

It overheats after about 10 minutes at idle and quicker on the road. The electric fan does not turn on, but I wired it direct to the battery and it still over heated. The water pump is the same as the one I took out, and that one was fine for about three years of driving. I suspect the head gasket is faulty and at 35.00 Canadian not a bad price. I have to seal the cover anyway so my time is cheap, but not sure on the dye test for cracks on the head after it is off. There is lots of air flow through the rad, and the fan seams to be pulling lots of volume. I bought the book yesterday and will tackle it later today. The little bubbles in the overflow are too suspicious not to. Thanks to all who replied...

Dave....

Reply to
dcollivier

How old is the vehicle? could be a cloged radiator.

Patrick

Reply to
Patrick Ô¿Ô

Check for a collapsed hose on suction side of radiator. I have seen the springs that are suppose to be in there to hold them open rust to the point of nonexistance.

-- jeff

Patrick ?Ô wrote:

Reply to
jeff

There is one sure way to test the fan before you start ripping it apart. Heat up the engine and have someone shut it off while you watch the fan. If the fan does not stop almost instantly, the clutch is dead.

Tiny bubble can be caused by the little bypass hole in some thermostats. They have this little brass plug that flops around.

Headgasket foam looks like dishsoap bubbles and keeps on growing.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

dcollivier wrote:

Reply to
Mike Romain

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