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  1. #1

    Default mystery coolant leak 1994 s10

    I have an intermittent anti freeze leak on my 1994 S10 2.2 engine with 130,000.About every 6months or so it will leak a few cups of coolant then stop as quick as it started.I changed the water pump last year because it was leaking,but that's not where this leak is from. From what I can tell its on the drivers side about in the middle of the engine possibley behind the exhaust manifold. Its really hard to tell.It was leaking yesterday topped off it off drove it to work 15 miles now no leak. I got some dye to put in maybe that will help ID this leak.I wouldnt think a head gasket would intermittently leak. My AC compressor is dead so I may just remove it so I can get a better look.There has never been any sign of coolant in the oil or white smoke.This has been going on for more than 2yrs now.Any guesses?

  2. #2


    It doesn't sound like a blown head gasket to me. The engine would be overheating if so. Trust me, I know from experience. I have a Dodge Stealth and it blew the front head gasket on it (transverse V-6) and it actually cracked the head, from overheating of the engine. Smoke poured out of the exhaust, almost like a train, but not quite because it was white not black! Your oil not being "milky" in appearance also rules out the head gasket. I would recommend checking your hose clamps to make sure they are tight.
    I had a mystery leak on my Stealth a while back and I took it to a mechanic who I know quite well and he stuck a pressure tester on it and it turned out to be the upper radiator hose and I could have sworn that I had it tight. But it was a real gradual leak. I'm not saying that it is the hoses, but it could be. When diagnosing vehicle problems, try to start out with the simple stuff first because at times, it can be something very small that seems to be a catastrophic problem, like with my upper radiator hose leak. I'd also suggest sticking a pressure tester on it. You can borrow tools like that from AutoZone. Good luck and hope that helps! Welcome to the site!

  3. #3


    I've not had an S10 with the 2.4, but one of my trucks had a 2.8 (I know, yours is an I4). There was a metal tube (6 to 8 inches) that helped move water through the dome.

    It developed a small pin hole leak and let a very small amount of water out, it was so small, the puddle always evaporated when it hit the block. The only way I could find it was to run my fingers over it while there was pressure.

    I don't know if there are any metal hoses on the 2.2, but it's worth a look.

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  4. #4


    It looks like the dye I put in may have found the leak. It looks like the front freeze plug is leaking.Its still kind of hard to see the whole plug from the flap behind the front tire,but that looks like the spot.I think thats where you usually put in a block heater so I will do that.Ill let you know if it works.

  5. #5


    Well, I hope you can get something figured out man. That's aggravating when a vehicle has a difficult to find leak.

  6. #6


    It was the freeze plug that was leaking. Not enough room in this one for the heater so I went with a new plug.It was tough to get out. You couldnt really get it turned sideways to pull out easily.I did finally get it,but the new one has a very slight drip.Not sure what Im going to do next.I might just have to get another plug and try again.I didnt feel any scratches in the block from when I took the old one out,but it was hard to reach and check.Im just going to monitor for a little while This truck is really not a daily driver so I have leeway on what I can drive to work.I usually have been riding the motorcycle or taking the GEO Tracker ragtop in the summer months.

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