Missing coolent in the overflow

[skibum2u]

For the past year or so coolent has been dissapearing from the overflow bottle. If I don't fill it after a while my trucks temp guage seems to gradually climb to almost overheating. Once coolent is replaced into the overflow the temp guage seems to stay almost all the way down. I have yet to notice any white smoke or milky oil. Also I haven't noticed any dripping on the ground.

Any ideas??

 

[Positive Vibes]

I had a slow leak on the tranny cooler. It was small enough to where it wouldn't drip on the ground but large enough to slowly drain the overflow. I could see where dirt and dust was collecting. That was the only way I could tell it was leaking. Hope this helps.

 

[CADDYBILL]

I had the same problem. It was driving me crazy for almost a year. I kept losing fluid the same way never all the way down just a little. It wound up being that damm plastic radiator. The crimp weekend, fluid dripped out and dried up before I could find it. Once the weather got colder it started to leak really bad. I had to replace the radiator a few weeks ago.

 

[DOGMAN]

First thing that comes to mind is a slightly cracked head, or possibly a bad head gasket. I have a 91 and experienced the exact symtoms you are experiencing now, although mine never got hot like yours, probably because I checked the fluid level pretty often. Sad to say, but mine was a cracked head on the passenger side. This is not an uncommon problem on fairly high mileage 4.0L motors. The original head design created a weak area that is suseptable to cracking. I hate to be the bearer of bad tidings, but a cracked head would be my choice for source of your problem.

I never once noticed white smoke, milky oil, or anything dripping on the ground.

How many miles on the motor? One method of investigation is to pull the plugs and inspect them, looking for signs of coolant. On mine, the passenger side plugs had coolant on them, with the outboard one having the most.

One word of encouragement. I probably drove 80K miles after first noticing the coolant consumption until the head finally gave way, so maybe you could have the same luck. Just check coolant level often (at least once a week), and replenish when necessary. For a long time, I was using about a quart of coolant every 750 miles, until it progressively got worse leading up to failure.

I wish I could give another possibility, but your description sounds exactly like my experience.

 

[DesertSpive]

Woah! Slow down here. Sometimes it is much more simple than a head. Sometime the radiator cap gets old and can't seal the pressure in the cooling system, so as you drive, the heated coolant explands, and the cap burps out coolant. First and foremost, do a pressure test on the cap.

--Sean

 

[DOGMAN]

Hopefully it is something simple like the radiator cap, leaky radiator seam, etc. I've experienced those as well, but usually with those simple problems, there usually is coolant visible.

Pull the plugs and inspect them. If they're clean, hopefully the problem is elsewhere. But if there is that nasty green fluid on them ....... Let's hope not! Good luck.

 

[espnfreak]

Originally posted by CADDYBILL
I had the same problem. It was driving me crazy for almost a year. I kept losing fluid the same way never all the way down just a little. It wound up being that damm plastic radiator. The crimp weekend, fluid dripped out and dried up before I could find it. Once the weather got colder it started to leak really bad. I had to replace the radiator a few weeks ago.

I know exactly what your talking about! I had some plastic thing that controled something with radiator fluid and it leaked immensly on my 96. Fortunately, I got it fixed! I think it was about $30