Engine temp fluctuations.....head gasket?
Thread Starter
Teching In
Joined: Aug 2009
Posts: 18
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From: Pittsburgh PA
Engine temp fluctuations.....head gasket? I have an 06 Impala SS, 66,000 miles. I honestly do not beat on the car. This morning on my way to work I noticed that the temp gauge, which normally sits exactly 1/2 way on the gauge was up to almost 3/4. I blasted the heat for a second and it dropped....but then went back up, and as it went back up the air coming from the vents went cold. This continued the entire 30 minute drive to work. The engine never overheated, just went from 1/2 to 3/4 and back....as it went up the air for cooler and as it went down it got warmer. Has anyone experienced anything like this? It seems very similar to a problem I had in a 3.1 Malibu when the head gasket went. Any input is greatly appreciated.
Thread Starter
Teching In
Joined: Aug 2009
Posts: 18
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From: Pittsburgh PA
I have not looked yet, I will check coolant and oil levels when I am on break. Some of the maintenance guys at work think its the thermostat. I really have never experienced problems like this with a thermostat though.
Well...heat not coming out of the vents tells me that there's a blockage somewhere. Has the cooling system ever been flushed/serviced before? I hope that in 66K you've done it at least once...
Thread Starter
Teching In
Joined: Aug 2009
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From: Pittsburgh PA
I bought the car GM Certified, and the dealer claimed to have done it, but I can't swear to that. One Guy here says the same thing, he had his own shop for years and thinks DexCool is the devil.
Check the coolant level, it's probably just a bit low.
Not saying you have a bad head gasket but when my wife unintentionally killed her Lumina with a bad head gasket the fluid was extremely low and the temp gauge would fluctuate from the middle to the high end and she wouldn't get any heat because the heater core wasn't getting much coolant.
Not saying you have a bad head gasket but when my wife unintentionally killed her Lumina with a bad head gasket the fluid was extremely low and the temp gauge would fluctuate from the middle to the high end and she wouldn't get any heat because the heater core wasn't getting much coolant.
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I too would have to say its your coolant. I had the same problem not too long ago. Check out to be that the coolant was really low. The over flow was full but the radiator was empty. So I flushed out all that damn dex cool and put in the yellow coolant (the kind that mixes with any color) and all is well now. To sum up, dex cool sucks.
Thread Starter
Teching In
Joined: Aug 2009
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From: Pittsburgh PA
Thanks everyone for all of the help. I am going to check the fluids and add coolant if needed. Hopefully that's all it is....if not, she has a date with the dealer tomorrow. I will keep everyone posted.
Thread Starter
Teching In
Joined: Aug 2009
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From: Pittsburgh PA
OK, I checked the coolant and t is low. The oil is fine in level and color so I think the head gasket is safe. So when I add the coolant I know I put it in the radiator, how do I bleed It to avoid air pockets? Is there a valve somewhere?
Launching!
Joined: Aug 2007
Posts: 293
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From: Phila, PA
I had my Monte flushed at dealer. I am not sure if there is a different way of doing it on the LS4 cars, but this is what I did on my Bronco after I put it back together after a tear down. This is a copy and paste from a truck forum:
Its easy to do and all you need is engine coolant and common sense
1) Start with a cold system - DO NOT DO THIS ON A WARMED UP TRUCK
2) Open Radiator cap and fill system
3) Fill your reservoir
4) With the Radiator cap still OFF the radiator start your engine
NOTE: DO NOT REV YOUR ENGINE
this will force coolant out the open radiator and spill everywhere.
5)Turn on your heater to MAX DEFROST
6) You will want to run the engine until warms up and kicks off of high idle and then a few minutes after that (or until operating temp)
Keep and eye on your thermostat to make sure it doesn't overheat. An overheated engine can warp your heads blow out a gasket ect. ect.
* IF you notice bubbling out of the top of your radiator then you may have air in the system. This is normal, it just the air tiring to escape and pushing the coolant up. Keep the truck running unless the bubbling is excessive.
7) Once your engine hits the running temp turn it off and let it cool.
8) If your coolant level dropped, that means you've displaced some of the air in your system. Refill it and repeat the process.
9) Drink a beer
10) Repeat as necessary
Its easy to do and all you need is engine coolant and common sense
1) Start with a cold system - DO NOT DO THIS ON A WARMED UP TRUCK
2) Open Radiator cap and fill system
3) Fill your reservoir
4) With the Radiator cap still OFF the radiator start your engine
NOTE: DO NOT REV YOUR ENGINE
this will force coolant out the open radiator and spill everywhere.
5)Turn on your heater to MAX DEFROST
6) You will want to run the engine until warms up and kicks off of high idle and then a few minutes after that (or until operating temp)
Keep and eye on your thermostat to make sure it doesn't overheat. An overheated engine can warp your heads blow out a gasket ect. ect.
* IF you notice bubbling out of the top of your radiator then you may have air in the system. This is normal, it just the air tiring to escape and pushing the coolant up. Keep the truck running unless the bubbling is excessive.
7) Once your engine hits the running temp turn it off and let it cool.
8) If your coolant level dropped, that means you've displaced some of the air in your system. Refill it and repeat the process.
9) Drink a beer
10) Repeat as necessary
Teching In
Joined: Jul 2010
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From: Windsor ontario
Probably would have been easier, but engine was still in the car. Took just over an hour filled with cursing, and had to come up with a few creative ways of putting sockets together to make hillbilly extentions. Smart thinking GM to put 1 bolt behind the manifold lol
On The Tree
Joined: Aug 2010
Posts: 110
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Since it was certified I would take it back to them and explain the problem let them deal with it. If something else happens down the road it will be documented and not your fault. GM Certified comes with a 12-Month/12,000-Mile and $0 deductible so your covered. http://www.gmcertified.com/what-is-gmcertified
