centuryhouse

I have a 2000 GC 4.7L 2WD. I opened the hood to work on something and noticed a little bright green coolant on the inside of the hood, inside the fan shroud, and on top of the engine.

The engine had not gotten hot, just normal temperature on a short drive to the store and back.

I can't seem to locate a leak though. I replaced the radiator cap just in case, and the upper radiator hose.

I see no wetness on the radiator itself, near the pulleys where I assume the water pump is, or on the thermostat housing. The lower hose had a little wetness but not around the connection itself, and it looks like it just dripped onto it from where a little had pooled up inside the fan shroud.

Ideas? I could take it to a shop, but in my experience they usually lie, diagnose the most expensive part to replace, and then say 'oops lets try something else' when that doesn't fix it.

blueseasons

It could be from anyplace coolant resides within your engine. Or any connection point. Check hose connections between radiator, heater core, engine block. Could be from the radiator. How old is it? When was it last replaced? Could be from the water pump as well, though that usually drips down. Start the engine and observe it while running. As heat builds up, so should pressure and the likely hood you might see where a leak is. Coolant in a lower part of the truck, can be running down from a leak higher in the system.

If you cannot self diagnose, you will need to take it to a reputable mechanic. Ask what he see's and maybe a pressure test is in order. I have to disagree with your assertion that all mechanics lie to make money. Often mistakes are made especially when its a difficult problem to figure out. This is pretty straight forward. Over my 65 years, most mechanics I have meet have been spot on honest and have done a great job. I am certain with a little research you will be able to find a good one in your area.

centuryhouse

Thanks for the recommendations.

As to mechanics, one of many experiences I went through:

Two different shops doing an estimate on my 67 Mustang (with a 3 year old rebuilt engine) both told me the engine was blown and repairs would be close to $3000. I ended up finding on (on my own) that the problem was a cracked distributor cap that cost $10. I drove the car for another 10 years before I sold it, and it was fine.

I also worked in the auto parts industry and saw a constant supply of shops deliberately ripping people off, and even trying to rip us off on the parts.

That isn't to say there aren't great, honest mechanics out there - just that no one seems to know which few those are. Where there is smoke, there is fire, and the cliche of the dishonest mechanic is there for a reason.

dave1123

Look for a pinhole on one of your hoses. My 4.0 sprayed the entire engine with coolant from a tiny pinhole in a heater hose. These things don't always open until max pressure, so a pressure test with a pump will find it.

Bustedback

Look at the radiator tanks. They're made of plastic and will crack.

centuryhouse

Radiator tanks?

Bustedback

Yes, the tanks on each side of the radiator. They're plastic and crimped to the radiator core. After more than a decade of heat cycles they will crack and leak once the cooling system in under pressure.

blueseasons

Everybody's experience is different. I haven't had yours. You seem experienced
enough to find a trusted mechanic. YELP , is a good place to start and so is friends, family and neighbors. Putting that aside, how are you coming along with tracking down the source of random coolant in your fan shroud?
Is it recurring? Are you losing coolant in the reservoir?

centuryhouse

Thanks for the info.

I haven't gotten any closer to figuring it out yet, but I've taken the XJ to work the last two days and been working on that instead (new fan clutch, etc.).

When I get back to the WJ/GC, I'll inspect those tanks first. I'm not losing any significant amount of coolant - not even enough that there is a single drop on the ground. But every time I drive it for any real amount of time I have a little leaked out in the engine compartment.


Something new I remembered. Last year, before I quit driving the GC, there was a slight leak of radiator coolant. I took it to a shop and was told a freeze plug was leaking. I know nothing about freeze plugs. But he said that is where the leak came from and that it couldn't be fixed short of a rebuild, and that he had put some sealant on it that might or might not fix it. To me that sounded odd. But I have no knowledge of freeze plugs or how that works.

The reason I quit driving the GC a year ago was because I was tired of the constant issues. For the 2 years I've owned it, it has been one thing after another, to the point that I don't drive it once it's working because I'm afraid of the next thing failing within a day or two. The last big thing was the heads needing replacing ($1300). I've decided to sell it though, so I'm trying to get everything fixed and ready. And of course a new problem (the leak) has popped up.

wjlizard

Had a similar problem, I had a hairline crack at the top of the rad where the top hose connects .don't notice untill the engine got to operating temp. It sprayed a very fine mist

blueseasons

I am not a big fan of radiators with plastic tanks. I have had that exact experience. The tanks fail over time from the heat, expansion and contraction. Mine had developed a fine hairline crack over time in the top tank and I saw signs of coolant, before I noticed the crack. I was able to change it before it blew. The crack was so fine, I barely could see it, until it got worse.

The only way to avoid these is by having custom radiators built by a shop. The shops are getting harder and harder to find. This could be whats happening here.

Freeze plugs are another story. I am not aware if Jeep put steel or brass plugs in these engines. Brass won't rust, but could leak. The freeze plug experience that I had with a different make of vehicle had the coolant leaking down, not up. Eventually this issue will reveal itself. Hopefully your not a million miles from home, or out in the boonies when it does.

dave1123

Ya know, I'm going to have to watch mine. I have a slow coolant loss over time and a slight smell of coolant occasionally, but no signs of steam or wetness anywhere. This is after replacing my cracked 0331 head! Luckily it only cracked into the exhaust so I had steam from the tailpipe.