Last post on May 03, 2013 at 8:11 AM
You are in the Chevrolet Silverado & GMC Sierra
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GMC Sierra 1500, Truck
#70 of 79 Radiator drain or petcock.
Jan 23, 2013 (9:53 am)
Does anyone know if my 2012 Sierra, 4 x 4, 5.3L has a drain or petcock on the bottom of the radiator? I have crawled underneath but cannot see one. Before I remove the plastic shield under radiator I'd like to know if there is a way to drain radiator w/o removing the hose. I just had my truck in the dealership to get free oil change and asked them to lower freeze protection to -60 from -30. (I'm in AK). The untrained service "advisor" in Wasilla wanted to charge me $140. I asked him why they couldn't just drain a gallon of 50% antifreeze out and add 1 gallon of undiluted antifreeze in. He didn't know if there was a drain or not and that they would have to make a "special" mix themselves. This isn't exactly higher math and you would think a dealer in AK would have run into this type of request before!
#71 of 79 Fogged Windows, No Leak In Cab, Evap Core Drain Leaking
Mar 09, 2013 (11:04 am)
Hi, I have something goofy going on with my truck. When I turn on the heater, the windshield fogs up and I can smell the coolant. However, there is no water leaking on the floor inside the cab - as I would expect if there was a leak in the heater core. Water does, however, leak from the evaporator drain located on the other side of the firewall.
Additionally, if I run the A\C, water leaks from the evaporator drain as well. It's more than condensation, as it will eventually drain all of my coolant.
I have several questions running through my head:
1) Could I have a bad heater core without it leaking inside the cab?
2) Could a bad heater core result in a leak through the evap. core drain?
3) Would a bad evap core cause the windows to steam up when running the heater or defroster without the A/C button on at the same time?
4) Without having to take it to a shop and pay their $120 diagnosis fee, is there some way an average guy - like me - can figure out for sure if the heater core is bad? Same thing with the evaporator core?
Thanks in advance. I've spent so much time looking for anyone that has these same issues online, but virtually everyone that has a bad heater core says it leaks inside the cab. Mine doesn't, but something definitely is going on...
#72 of 79 Re: Fogged Windows, No Leak In Cab, Evap Core Drain Leaking [sierratruck]
by kcram HOST
Mar 09, 2013 (6:37 pm)
Sounds like a combination of heater and evap cores. The heater core could be ruining the evap with a coolant leak into the A/C system instead of the floor.
kcram - Pickups/Wagons/Vans+Minivans Host
#73 of 79 Re: Fogged Windows, No Leak In Cab, Evap Core Drain Leaking [kcram]
Mar 11, 2013 (1:01 pm)
Thank you for the reply. I was scared that that was what you would say.
Naturally it couldn't be straight-forward and easy to determine. Is there any way I can test both of these cores?
It's about $1,000 to replace the heater core, which I don't have laying around, so I was going to spend a long weekend doing it myself. The thing that scares me is that I tear everything down, replace the heater core, put it all back together and find out the evap core it bad too (or it wsa the only thing bad in the first place). And, although I might be wrong on this, I think the evap core is quite a bit more than the heater core.
To test them, do I need to tear everything down, then pull each core and take it to a shop?
Thanks for your help.
#74 of 79 Re: Fogged Windows, No Leak In Cab, Evap Core Drain Leaking [sierratruck]
by kcram HOST
Mar 11, 2013 (5:36 pm)
I would definitely recommend having them tested before you swap out. If you can, take pictures and/or video of the leaking water before you tear down so that the mechanic testing the cores has an idea of what you're experiencing.
kcram - Pickups/Wagons/Vans+Minivans Host
#75 of 79 Re: Fogged Windows, No Leak In Cab, Evap Core Drain Leaking [kcram]
Mar 12, 2013 (11:30 am)
Good idea, thanks for the help, I really appreciate it.
#76 of 79 Re: 2004 Silverado Engine Temperature Sporadic [scotty_3998]
Mar 19, 2013 (8:00 am)
my truck is doing the exact same thing did you ever figure out what was wrong with your. i have 2006 gmc sierra
#77 of 79 Re: 1989 C2500 5.7 Water Pump Rotation [1989c2500]
May 03, 2013 (7:04 am)
If I understand correctly you replaced these items, and now it stays cool and doesn't get up to temperature. If this correct, replace your thermostat. The failsafe thermostat is stuck open. I had the same problem, and when I removed and inspected the thermostat it was in fact stuck open. Replaced with a regular thermostat.
#78 of 79 I have an Interesting Situation
May 03, 2013 (7:30 am)
I have a 94 K-1500 Suburban 350ci, that we just purchased, it had a crack in the tank of the radiator. So I replaced the radiator, water pump, and thermostat. The original radiator was a single core, was replaced with a 2 core, that's the only one AutoZone had in a 34'' core (between the tanks). Problem 1:The thermostat I had bought didn't fit in the seat in the intake manifold (it was smaller and moved around a lot, in fact you could slide it to one side and there would be a gap that would allow water to pass), I took it back thinking that they gave me the wrong one, I was assured it was the correct one. Has anyone ever run into this situation with a thermostat? As I have never in my 20+ years working on cars.Problem 2: The engine doesn't want to get up to temperature, 180 degree thermostat. My guess it that the thermostat had moved allowing a gap to allow water to pass. The gap guessing would be maybe a 1/4'' or less, that just doesn't seem like a big enough passage to keep it that cool, it barely get off of the 100 degree mark. The fact that the radiator is a 2 core instead of a 1 core entered my mind, but the thermostat basically keeps the water in the engine until it reaches the proper temp that would allow it to open exchanging hot water and for cool water. And my experiences with over sized radiators not matching water pump volume usually causes an over heating problem. Your Thoughts
#79 of 79 Re: Fogged Windows, No Leak In Cab, Evap Core Drain Leaking [sierratruck]
May 03, 2013 (8:11 am)
If your are constantly having to add coolant, then its the heater core. Newer style climate boxes houses both the evap and heat cores with using an exchange door that opens and closes to allow heat or to block the heat to the cab area. So the both being housed in the same box this would allow for any heater core coolant leak to exit in the same drain as the condensation. One easy way to test for coolant leak at the climate box, is to run the engine with A/C off, heat on. If you see liquid coming from the drain at the firewall it is coolant.