Last post on May 03, 2013 at 7:11 AM
You are in the Chevrolet Silverado & GMC Sierra
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GMC Sierra 1500, Truck
#63 of 79 Losing fluid from overflow resevoir
Aug 22, 2010 (11:17 am)
Please help. I have a 98 z71 silverado. It has begun to overheat. I've filled the radiator, replaced the cap and the thermostat and it still gets warm. When the truck heats up it spills into the overflow container. The container actually sucks in like theres a vacuum till the cap pops and fluid spills from the cap. I have flushed the radiator and still no change. Does anyone have any ideas. Water pump next? I do not see any leaks. Any ideas will be appreciated
#64 of 79 Re: Losing fluid from overflow resevoir [keonisierra]
Aug 22, 2010 (1:29 pm)
I would start out with a cold engine and take the rad cap off, start the engine and let it warm up. When the thermostat opens, you should be able to see the antifreeze circulate in the rad. If it does, I would then rule out the water pump unless it has very poor circulation.
Nice thing about the water pumps is that they are inexpensive and relatively easy to change.
Another thing to look at is the heater and if it blows hot air as it should. You could have a blocked heater hose or possibly a connection from the rad to the heater causing pressure.
I am not certain that this would cause your problem, but it could be a head gasket but you should be able to see white smoke out the exhaust. Another thing is the rad hoses. They have wire in them to keep them from collapsing but you never know.
A couple of google's should locate the problem as I am sure you are not the first with this issue. A call to a rad shop could also yield some answers.
Nothing to say that the thermostat was good either and hopefully you did not put it in upside down.
#65 of 79 01 5.3 gmc serria leak
Sep 18, 2011 (5:18 am)
i have a leak in a 1/4 inch metal tube that goes from drivers side to pass side and y's off and runs under the intake manifold does anyone know what it goes to and what it is called it is a pinhole leak and coolant is coming out of it also would anyone know where i can get a diagram that shows where this is and where it goes any help is great thanks
#66 of 79 Re: more info on coolant leak in 1998 4.3L 5-speed. [beaverman]
Jun 21, 2012 (3:47 am)
Had same problem. Was the intake manifold gasket leaking. Gasket only has a small bead of sealant around each port. Had gaskets changed and no more leaks
#67 of 79 2004 Silverado Engine Temperature Sporadic
Oct 30, 2012 (4:57 pm)
I have a 2004 Silverado and my engine temperature keeps changing between 205 and 235. I had a problem a while back and it was found that I had a stuck thermostat and bad radiator. Both were replaced then a couple months later the temperature gauge started showing my truck running warmer. Took it in and I was a gallon low on coolant. That was fixed and the mechanics said that it might have been caused by air pockets. About a month later my truck started doing the same thing and so I took it back in and they said my coolant was a pint low so they added a pint. They couldn't seem to find any leaks, and I haven't seen any leaks or evidence of a leak. My truck is starting to do it again, but this time it will get to close to 235 and then while I'm driving and I get to about 50 then the temperature goes back down to around 205. Does anyone know or have any idea as to what it could be?
#68 of 79 Re: 2004 Silverado Engine Temperature Sporadic [scotty_3998]
Oct 31, 2012 (2:37 am)
You state that they couldn't find a leak? If the leak is internal it wouldn't show up on the exterior of the motor. Any white smoke on start up? During idling?
If the coolant level remained the same and the temp goes down to 205 when driving on the freeway, it could be a bad fan clutch. At highway speeds the fan is less important to cool the truck.
A blockage in the motor could also cause overheating. When the radiator and thermostat was changed was the motor back flushed?
#69 of 79 Radiator drain or petcock.
Jan 23, 2013 (8:53 am)
#70 of 79 Radiator drain or petcock.
Jan 23, 2013 (8:53 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 (10:04 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@Edmunds HOST
Mar 09, 2013 (5:37 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