2003 CHEVY SUBURBAN COOLANT LEAK

  • Tiny
  • mattsoca
  • 2003 Chevrolet Suburban

Engine Cooling problem
2003 Chevy Suburban V8 Four Wheel Drive Automatic 80,100 miles

My 5.3l 1/2ton Suburban shows a very small coolant leak. When I crawl under the truck and look at it, I cannot see anything wet. When the puddle occurs, it's very small (about 1 - 2in. In diameter). I can go days or weeks w/o seeing any fluid on the ground - and then it's there again. When I'm laying on the ground and looking up, I can see a red-orange discoloration on a wiring harness - which would indicate something is leaking on the wiring harness, the leak is following the harness and dripping off of that at it's lowest point. The harness is on the passenger side is in the vicinity of the air compressor/trans. Fluid lines that follow the passenger side of the oil pan. The coolant tank itself has dropped 1/4 - 1/2 inch below the 'full mark' - and I topped off the tank back in January when my dash displayed a 'low coolant' msg (my first indication of trouble). Whatever it is - it's a really slow leak. I'd like to get it repaired before it gets worse. Any ideas?

Tuesday, June 1st, 2010 AT 2:26 PM

3 Answers

  • Tiny
  • hmac300
  • Expert
  • 42,086 posts

There is a small line that goes from one cylinder head to another. See if one of hte bolts holding it has loosened up there. Te fluid lines that go along the side are for the transmission. Also there is a smll line that goes from the radiator to the coolant tank, about 1/2" big. See if it has a small hole in it or not connected very well.

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Saturday, June 5th, 2010 AT 2:45 PM
  • Tiny
  • mattsoca
  • Member

Thanks for the response - I ended up dropping it off at my local garage. Turned out to be the water pump gasket. Took the opportunity to have them replace the thermostat/waterneck (who designed that combo-platter anyways?), Replace the water pump itself and flush and replace the Dexcool with conventional coolant. The truck itself has 83, xxx miles on it now. While the $506. Xx bill was a little tough, it was the first repair we've had on the truck since purchasing it new. I'll have some piece of mind when towing out to Yellowstone later this summer.

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Sunday, June 6th, 2010 AT 1:28 PM
  • Tiny
  • hmac300
  • Expert
  • 42,086 posts

The combo platter you talk about is done for a couple of reasons, one they get a price break by buying the parts like that from the supplier, two they don't need a person installing a thermostat and another installing the neck itself. Remember when a vehicle is assembled it is done for quick no problem assembly, not repair. Also you should have kept the dexcool as that is good for 5 years not 2 years like the green stuff.

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Sunday, June 6th, 2010 AT 1:45 PM

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