I have a 2000 Silverado Z71 1500 with the 5.3. I have a slight coolant smell in the cab. I only smell it when I get out of my truck. ...

I have a 2000 Silverado Z71 1500 with the 5.3. I have a slight coolant smell in the cab. I only smell it when I get out of my truck. I have heat and the defrost works and no smell when I run those. Though I’ve noticed my temp gauge dropa notch or two when I run the defrost. I haven’t had any oily film on the window. I havent noticed or felt any dampness in the passenger floor board. I’m afraid it’s the heater core. Anyone have any ideas as to what it could be? Thank you in advance

Check the quick connectors in the engine compartment to the heater core. They are plastic and known to leak when they get old.

CobeZ71 wrote:I only smell it when I get out of my truck. I have heat and the defrost works and no smell when I run those

Like ASTE25 replied, check your hose connectors and also everything else relating to the cooling system under the hood. If nothing is obvious, get the truck to temp and, while still running, use a flashlight to inspect. I one time had a radiator seperate slightly when hot and by the time I lifted the hood, it would dry up. Point is to have the system pressurized while inspecting.

I went to check the quick connectors one of the hoses looked wet around the clamp touched it and the connectors on both hose broke. When I went to raise the hood I could really smell coolant

So you found the issue. The parts aren't that much I don't think, but it may be tricky to get in there and replace them. You'll need a special tool to remove whatever is left on the manifold side. Two new connectors and the tool will run you maybe $25... It's not recommended to use a regular hose clamp, as that can cause other issues. If the OEM clips last this long, just replace them with OEM again and be good for another 10-15 years or more..

I want to thank everyone for the help. I ran my truck to operating temp ran the heater and defrost and could not smell coolant in the defrost vents. I really hope those connectors were the problem. The hardest part was getting the broke connectors out of the hoses. They were so brittle they kepts breaking into pieces. Thanks everyone

Glad to hear that you were able to find the problem and fix it!

Now that it has been a bit is the coolant smell gone in cab? My wife's 2006 Tahoe has a strong coolant smell in cab and I'm hoping it is these connectors and not heater core.