H2 Saying Its Overheating But Its Really Not

Asked by PUMBAYZF Jun 20, 2018 at 05:36 PM about the 2005 Hummer H2 Luxury

Question type: Maintenance & Repair

I Have A 2005 Hummer H2 That Keeps Indicating On The Dash Hot Engine Coolant And Engine Over Heated Also The Temp Gauge Goes Crazy Back And Forth From Normal To Overheated Pretty Fast.  But The Crazy Thing Is That The Truck Is Not Really Overheating. I Have Already Changed Out The Thermostat, Temp Sensor, Water Pump And The Clutch Fan. Engine Is Not Smoking and It Idles Perfect Also Doesn't Have The Check Engine Light On. Has Anyone Ran Into This Kind Of Problem?

17 Answers

Use a non contact thermometer to measure the actual temperature. Point it at the top radiator hose at the thermostat.

I suspect air in the system. Do a purge of the cooling system.

2 people found this helpful.
60

hi, i was wondering if you figured out how to fix the problems with your hummer? my dad’s is having the exact same issues, and mechanics in our town are having a hard time figuring out how to fix it.

6 people found this helpful.
40

I have been having the same problem and my techs are so baffled and frustrated!

70

Radiator cap stuck. Replace radiator cap when it doesn’t work it makes pressure pressure makes air so you have air bubbles is why your Radiatorgauges and everything‘s going crazy

4 people found this helpful.
10

hi, i was wondering if you figured out how to fix the problems with your hummer? i have the exact same issues

1 people found this helpful.

My 2007 H2 transmission temperature is going up on cold start. If goes up and down while driving. Does anyone know why is it doing that. I have dropped it to a transmission guy and still waiting. I changed the fluid and the trans pressure sensor. Still the same, i need help

40

I have been going through this since March... finally my mechanic has thrown his hands up and zeroed out a very high balance due... replaced all the following: Radiator Fan Clutch Temp Sensor Water Pump System Fluid Flush 4x (In the mix of in and out of the shop, air conditioner went out and replaced it) Thermostat Assembly All radiator hoses Serpentine Belt Thermostat Assembly And now still at, under 2000 RPMS, FLASHES Engine Coolant Hot and the Gage is I’m the red. If I am at a red light, it does it... I put the truck in park, rev my engine and it goes back down to 210 and light goes off.. PLEASE ADVISE KIM kmoynahan14@gmail.com 832.876.0392 I am desperate

4 people found this helpful.
30

I had the same issue, it was the temperature sending unit. I was chasing a ghost as I put a new sending unit in and it was still doing it however the brand new sending unit was bad! Put a new AC Delco unit in problem solved

3 people found this helpful.
15

Hi all, mine just started this. However no gages are showing moved just the engine light. My reader says low coolant. Did anyone else check the temperature sending unit? @Mark Were your gages moving or did you just get the engine warning?

1 people found this helpful.
50

Ok group I'm having issue with my coolant getting hot. I drive it about 30 minutes and its slowly creeps up and then it will almost hit the red over heating mark. Of course I don't let it get that hot and pull over. So the things I have replaced: all hoses, radiator, water pump, thermostat, temperature sensor and removed the old clutch with fan and installed a oversized 18" dual electric fans. It still over heats!! Can anyone tell me what the deal is? I'm thinking maybe I have a cracked head? Not sure.

5 people found this helpful.
10

hi, i was wondering if you figured out how to fix the problems with your hummer? i have the exact same issues

Mine is doing the sane thing except now it says engine overheating, low coolant and engine powering down

Have 04 H2. Only 65K Miles. First said, low coolant. A couple weeks later I parked it fine. In the morning temp guage started at 210 and quickly went to red. ( 5 min ) Trouble shooted cooling system, all good. Felt like electrical to me. (communication with computer) I disconnected the ground on battery for 1 min. Put it back and all is good. It never actually was overheating at all.

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