Trying to find the source of a coolant leak..

denalianyone said:

I have a coolant leak yet the “low coolant” message hasn’t popped up as of yet. As of yesterday, on start-up the exhaust has a high pitch growl tone. I’m not sure if the water pump is going bad or the radiator is the culprit. The leak is prominent on the driver side with fluid on the splash pan and by the radiator. With the temp(s) in the 35 degree range in NYC my electric fans kicked on yesterday which was very odd. There is also a small hole that I circled in the pic below that looks like it’s missing a plug of some sort. Any help will be greatly appreciated before I start tackling this job.


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NoReverseYukon said:

If this ^^^ photo is from the drivers side, you might be missing a drain valve. On my 2001, I have one and a drain tube there. Although I can't imagine that your radiator wouldn't drain immediately if the drain valve was missing.

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denalianyone said:

I have a coolant leak yet the “low coolant” message hasn’t popped up as of yet. As of yesterday, on start-up the exhaust has a high pitch growl tone. I’m not sure if the water pump is going bad or the radiator is the culprit. The leak is prominent on the driver side with fluid on the splash pan and by the radiator. With the temp(s) in the 35 degree range in NYC my electric fans kicked on yesterday which was very odd. There is also a small hole that I circled in the pic below that looks like it’s missing a plug of some sort. Any help will be greatly appreciated before I start tackling this job.




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Geotrash said:

That “hole” in the radiator doesn’t go anywhere. It’s molded into the tank and would be drilled and used if you had an engine oil cooler.

Based on the pictures though, it looks like the leak is coming from above that. Perhaps a crack in the radiator side tank plastic, or a leak at the upper radiator hose.


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1BADI5 said:

Looks like its time to replace it and move on, its not going to be an item you can repair.

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kbuskill said:

That leak looks just like mine did on my Burb. It was a crack in the plastic end tank on the driverside near the top.

That hole you circled is where the petcock/drain valve would be IF GM didn't cheap out on the NNBS trucks.

The older trucks had a petcock on the radiator and also had cabin air filters and lights under the hood... I wonder how much GM saved, as a whole, by deleting these items from every single truck in the GMT900 platform???

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