Hello Scotty, love your videos. I have a 2015 Chevy Colorado WT 3.6L truck, had it for 5 years now with 81,560 miles on it. Yesterday it over heated, I had checked the fluids the day prior and were good, but when I pulled over the reserve tank had no coolant in it. I ran a scan tool and it had no codes. I keep the truck in good shape and change oil and maintenance regularly. I also noticed that on the bottom carriage there was signs of oil. Have any idea of what it could be... I'm thinking it's the water pump. Thank you.
It could also be a stuck thermostat. Are you sure it was oil and not leaked coolant on the bottom carriage? The water pump is another place to check.
It was at night so it was hard to tell... but when I ran my finger across the frame of the truck it felt like oil and not coolant. I will be checking once I get home today.
replace the pressure cap
I checked the pressure cap and it looks good there was no sign of coolant around the cap or the reserve tank. It definitely Leaked from the bottom.
you wouldn't see any signs. The water would escape in gaseous form. The only way to test a cap is with a pressure tester. You said you found signs of OIL on the bottom, not coolant.
I remember listening to one of the last podcasts of Louis Althazan's "The Automotive Hour," out of Baton Rouge. I believe this topic came up, about the Silverado 1500s. Althazan and his GM, Brian Terry, discussed an issue around an air bubble in the heater core, which could be heard at certain points in the drive cycle. That's one possibility.
I also found this (#58) on the CarComplaints.com site, off a NTSHA complaint. It sounds similar, and reflects some of the previous comments from MountainMan Joe and Doc:
https://www.carcomplaints.com/Chevrolet/Silverado_1500/2015/engine/engine.shtml
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# 58 - I was on a family trip with my wife and kids and the engine temperature raised and system said to idle engine until it cooled down. I was able to cool the engine down and get the truck home. The Chevrolet dealer diagnosed a coolant leak at the radiator. Service bulletin pi1513F refers to this as being caused by a faulty thermostat which results in fractures in the radiator. "this condition may be the result of excessive thermocycles within the cooling system caused by excessive cycling of the thermostat. These excessive thermocycles within the coolant system may cause the tubes to fatigue, crack and leak at the radiator headers. To correct this condition, a new thermostat has been designed that eliminates the thermostats excessive cycling." The quoted cost to replace the radiator and thermostat at the dealer is $1800 GM has apparently extended the warranty to 100000 miles under a special coverage adjustment on the 2014 models, but not the other affected model years.
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