New Thermostat/Car still saying overheating

[LadywiththeBuick]

Hi,

I just got a new radiator and thermostat. My car says "Turn Engine off car is overheating". No smoke, no leaks, Any ideas?

Buick Lucerne 2008

 

[Rand]

need more information.

is the car actually warmed up?
does it do it immediately cold?

etc?

 

[exranger06]

Possibility: Cooling fan not turning on when it should.
Possible causes: bad fan, bad fan relay, broken or corroded wiring

Another possibility: The car isn't actually overheating but the computer thinks it is
Possible causes: bad coolant temp sensor, bad wiring to temp sensor

I do NOT recommend replacing ANY of these parts until you've done some troubleshooting and have actually FOUND the problem, and you're 100% certain that replacing the part will fix it.

 

[demarpaint]

Was the cooling system properly bled? That is the first thing I would make certain of before tossing any money at it.

 

[deanm11]

I had an '06 Lucerne. It had a bleed/vent on the thermostat housing... even with the use of that, I had a hard time getting air pockets out of the cooling system.

 

[ecotourist]

You've received some good advice - need to do the troubleshooting first.

But here's another possibility. The radiator on my then 10 - 12 year old Volvo just needed a good cleaning inside and out. That solved my overheating problem.

It would overheat on a hot day when you slowed down to in-town speeds after a highway drive (ie lots of residual heat and not as much airflow). No problem while in town, and no problem while on the highway either. You just couldn't slow down after a drive on the highway. Which made for interesting long distance driving!

With the coating of bugs outside and scale inside, it must have had very marginal cooling capacity.

 

[ecotourist]

Originally Posted by ecotourist
You've received some good advice - need to do the troubleshooting first.

But here's another possibility. The radiator on my then 10 - 12 year old Volvo just needed a good cleaning inside and out. That solved my overheating problem.

It would overheat on a hot day when you slowed down to in-town speeds after a highway drive (ie lots of residual heat and not as much airflow). No problem while in town, and no problem while on the highway either. You just couldn't slow down after a drive on the highway. Which made for interesting long distance driving!

With the coating of bugs outside and scale inside, it must have had very marginal cooling capacity.

Sorry, on re-reading your post I see you already have a new radiator. My comments don't apply.

 

[MParr]

Is it possible that the thermostat was put in upside down? Clean out your radiator. Twenty years of bugs will cause it to overheat. Make sure cooling fan is working.

 

[sloinker]

Need more info. Is the alarm after the car has been driven? What are the temperatures of the top and bottom radiator hoses relative to each other after driven. Water pump impeller is a possibility. Are you using any coolant? Is there emulsion under the oil cap.....can still be a myriad of things, Some cheap and easy, others expensive and hard.

 

[bunnspecial]

I had a car that would occasionally scream about overtemp and would go into "limp home mode" with the fans blasting.

The problem was an errant air bubble causing one of the sensors to read hot when the engine temp was perfectly fine.

If it were mine, I'd check temps on radiator and on metal parts of the block with an IR thermometer to get an idea of whether what it claims as overheating is actually overheating.

 

[FowVay]

Assuming that the mechanical work involved in replacing the thermostat and radiator was performed correctly, the only other variables would be for the water pump to be pumping and the cooling fans to be activating when required. The cooling fan activation can also involve the input of a temperature sensor that could possibly be bad.

You don't state whether you have the 3.8 liter or 4.6 liter engine but regardless, don't operate the engine in the overheat condition until you know why/if it's overheating.

 

[Mad_Hatter]

Take it back to whoever put in the new radiator and stat. They obviously didn't fix your problem or created a new one for you (if you weren't getting the CEL before the new rad and stat install)

Make them diagnose it and fix it...be warned though, if the shop is too far away and there's a chance that you get the overheat warning - don't drive it. Use your AAA to have it towed to the shop or demand the shop have it towed if you don't have a roadside assistance plan.

(if the shop absolutely won't cover it and you don't have a roadside assistance plan, you could sign up for one and wait the 24hrs before requesting the tow...then cxl it before it renews. If you do that make sure the plan you choose covers the distance needed to tow it back to the shop. I think Allstate is like $10 for the 1st month, much more affordable than paying a full price tow out of pocket)

 

[Yah-Tah-Hey]

Originally Posted by demarpaint
Was the cooling system properly bled? That is the first thing I would make certain of before tossing any money at it.

Exactly