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Small Coolant Leak

I have a 1993 JGC with the V8 engine. Recently it has begun to leak a fluid out of the radiator cap. It only leaks fluid after the engine has warmed up, and is cooling down. I was able to follow the trickle of coolant to the radiator cap. At first I thought that the cap was bad, so I replaced it with a new one from Checker Autoparts. That didn't seem to work, so my next thought was that it is building up too much pressure. The only problem is that I can't think of a reason why it would build up extra pressure. Is this a possible sign that my water pump or radiator is dying? Or, does anybody have another idea.

The only thing that has changed on my car was that I had the oil and transmission fluid changed before I noticed this problem. Also, I had a new radiator put in 2 years ago, and a new fan put in last year.

Reply to
YouGoFirst
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Check that the hose from the radiator to the recovery bottle isn't plugged.

Reply to
Matt Macchiarolo

On my 99 Wrangler I spotted similar symptoms. As it turned out, the radiator needed to be replaced. The end caps are plastic and crack after awhile.

Cal

Reply to
calmyers

Your cap has 2 seals. One at the rad and one at the top lip of the filler neck. This is so the fluid that comes out of the rad as it heats up is contained at the top lip and sent to the overflow bottle. Then when it cools down, the top lip seal holds so it sucks fluid back to the rad.

I would suspect either a deformed top lip on the rad or a leak at the overflow tube or a leak a the neck to rad joint.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >
Reply to
Mike Romain

All vehicles use a coolant recovery system because the coolant is toxic to the environment. The radiator cap has two valves. The large rubber one allows coolant to escape under pressure into the coolant bottle. When it cools down again, vacuum in the radiator is supposed to suck the coolant from the bottle, through the other valve (the small metal one in the center of the rubber one) and into the radiator. In order for this system to work, the seal between the radiator flange and the top of the cap must be tight. Some caps use a metal plate as a seal, but the better ones use an O-ring or rubber top plate. If your cap looks okay, check the hose leading from the radiator to the bottle. Most use clear plastic tubing that just slips on and it can get brittle over time and leak.

Reply to
Bill Lahr

I replaced the radiator about 2 years ago, so would the end caps have been replaced then? If they were, then is there any way to check to make sure that the plastic part that the cap attaches to is still flat and forms a good seal?

Reply to
YouGoFirst

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