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Showing results for tags 'overheat'.
Found 6 results
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I have an interesting overheating problem with my 1990 C3500 Silverado 7.4L. I recently bought the truck from an uncle who, I'm guessing, screwed me on the deal... We use the truck to tow our travel trailer (22ft. roughly 5000lb). Prior to our first voyage out, we drove the truck around town to make sure everything worked well. After a few trips to our main hike spot I noticed the truck would run warm, 220-240, for a short time and then spike down to 210. I assumed it was the thermostat sticking. So I replaced the thermostat with a 180 degree unit. I topped off the coolant in the reservoir and it seemed to have fixed the problem. We went on our first trip, now pulling the trailer, and at our halfway point, I got off the freeway to fill up the truck. about 20 seconds after we dropped our speed below 30 mph the truck spiked, redlining above 260. After starting it up, it quickly started to overheat again until we hit the freeway speeds and all was good. This behavior continued up until we hit our destination. Thankfully, my mechanic brother-in-law was camping with us. He thought it was the fan clutch but after looking at the radiator, I was about 2.5 gallons low on coolant. Since we were out camping, I used the rest of the gallon I had and filled the rest up with water. Brother-in-law said the water pump looked like it was running good and it might have just been under-filled when my uncle replaced the radiator. Ran ok until we slowed down off the freeway. It looked like the coolant would get hot and boiling out of the reservoir. I just kept topping off the radiator and driving home (picked up coolant 50/50 on the way back) Looked at it at home and noticed a leak above the drain valve. Tightened the valve about 1/4 turn, filled up the radiator and again the truck ran fine until our next trip. Same problems, had someone bring out a new radiator cap since it looked like the coolant was not being pulled back into the radiator. Coming back we had the same problem. I since replaced the hose from the radiator to the reservoir and "burped" the system by running the truck and squeezing the upper radiator hose until the coolant level would no longer drop in the radiator. The oil looks really clean (not milky or showing signs of water/bubbles). Coolant looks clean and I have topped of the radiator last with concentrate coolant to account for the water I added before. So I don't think it's the head gasket. I rotated the fan with the truck off and it stopped immediately after letting go. There wasn't any play when I tried moving the fan around so I don't think it's the fan/fan clutch. I hear an electric fan on when it's overheating/hot and the fan clutch kick in when its really hot. Rather than purchasing a bunch of new parts I thought I would get on here and ask a couple questions and see if anyone might have some things to try out. Would having enough air in the cooling system keep the coolant from being sucked back into the radiator? Could the fan clutch not be engaging at a low enough temperature? If the radiator is a 2 core, would that cause the coolant to boil enough to cause an air gap that would then keep coolant from being pulled back into the radiator? This truck was originally purchased new by my grandpa in 1991. He was a mechanic and took amazing care of the thing (all receipts). My Uncle purchased it from him a couple years back and I believe it was just sitting on his property for most of the time. -
Story: transmission overheated @ 60k miles. Warranty replaced with new transmission. I’ve had the vehicle (2018 suburban LT 4x4) since new and always sit around 190 degrees give or take and back and fourth around 200 when towing. With the new transmission I keep hitting 210 up to 220 driving around town and not driving hard. I haven’t towed yet but tow often and I am very concerned and afraid to tow. I just finished a thermostat delete to test that out and driving for about 30 min around town and freeway it was over 190 and climbing. It took a while to get there compared to normal but still got hot. Dealership has no clue and the transmission shop has no clue. I need help in figuring out what could be causing the heat. I am so for an oil change and my AC blow nice and cold. -
Fellas and Gals! I am having a problem with my cooling fans not coming on my 2006 GMC Sierra, 5.3. I can force them on by running the A/C constantly. But if the A/C isn’t on, the fans won’t come on till the truck reaches almost 230 degrees F, which I’m on the road to cracking a head at the temp. I’ve already replaced the fans, thermostat, engine temp sensor, checked to make sure I’ve got good water flow through my radiator, I’ve replaced all three cooling fan relays and I’ve checked the wiring harness. The fans will come on when I reach in there and manually unplug the harness from the temp sensor while the truck is running and it sometimes will throw a code after that. The only thing I can imagine may be happening is the CPU is not sending the ground signal to command the fans to come on when the engine reaches the appropriate temp (≈ 202, without the A/C being on). Has anyone ever experienced the CPU messing up and not send a ground signal to the system, what am I missing? S.O.S. PLEASE SEND HELP!!
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So, I have a 2011 Sierra half ton, it’s overheating at idle in gear. In park it won’t. Soon as you start moving it cools off, the fans do turn on but they don’t seem to turn on fast enough. It’s already starting to overheat by the time the e fans kick on. Soon as you start moving, cools right off instantly. This tells me maybe sticky t stat? Maybe coolant temp sensor? What temp are the fans supposed to kick on? Thoughts...tia -
So I'll make this topic as detailed and informative as I possibly can because I'm running out of options here. Video of the issue is included. I did a coolant and radiator flush on my '03 Sierra 5.3 to change the coolant from green ACDelco to orange Prestone. All the old coolant was flushed out of the engine and in with the new. The radiator was bled properly. After driving around for a while, I noticed my temp gauge starting to rise just above midway on the highway, and I can hear the fans kicking on high (did an electric fans swap). I didn't think much of it, but then it refused to cool down even though both the fans and the outside air are blasting through the radiator, and I know that the radiator is clean because there was no corrosion on the inside or outer debris blocking the airflow. I took it back to the shop, reflushed it, bought a new OEM thermostat, nothing helped. As a last resort, I did the following things to make sure everything is working correctly, and I'll mention some notes: *Thermostat has been replaced *Coolant was changed back to green 50/50 ACDelco, which faired a bit better than the orange Prestone. *Changed the temp sensor and its wiring *Bought a new fan harness from Nelson Performance because the old one got busted from how long the fans were running on high. *Radiator hoses were inspected, nothing is cracked or kinked. *Oil is not milky, nor getting smoke from the exhaust, and I'm not losing coolant, so no head gasket issues. *Car was running fine before the flush. *The car isn't drastically overheating, but there's no reason for the temperature to rise on or above midway when I'm cruising down the highway, and this will make the fans and the harness run harder. *This only happens after I push on the gas or the engine is underload such as cruising on the highway. *Sometimes when the car is idling, it takes awhile for the low fans to turn off, as in, it is cooling down slower than usual. The only two things that are left to suspect are the water pump (not leaking or making noise though), and that there is an air pocket trapped in the engine, and I'd appreciate if someone tells me how to check if there is one. If this behavior is normal, which I'm sure it isn't, please let me know. Here's the video. When the temp begins to rise I'm cruising around 55mph, and only cooled down when I came to a stop and slowly took off again. https://youtu.be/J5jeolKdtc8 -
I did a coolant flush on my 5.3 '03 Sierra and changed the fluid from green to Prestone orange coolant. I had mild overheating issues prior to the flush, so I figured flushing the coolant and changing to orange Prestone might help (I did the same exact thing in my '04 GTO with LS1 and haven't had overheating issues since forever). Now the temp always goes above midway, and here's the thing... It does the same thing even on the HIGHWAY with fans on high speed, and it sometimes goes down in traffic only (basically when I'm not giving the engine any acceleration). I changed the coolant again with dexcool, and did an air bleed, changed the temp sensor and thermostat two months ago, and cannot see any leak from the pump but still nothing is helping. I'll note that the green coolant didn't look dirty when it I flushed it out, and that it only heats up when I'm accelerating.
