running hot...thoughts?

[dgjks6]

So just a little history. 2006 Grand Prix GT. 3.8SC. Approx 160,000 miles. Few years ago was losing coolant - and always had a coolant smell. Replaced literally everything. LIM, elbows, water pump, radiator, hoses, heater core. Continues to havea coolant smell, but did not lose coolant. Car never, ever ran warm. Temp never got above half way. Maybe 18 months ago water pump started making noise and I replaced it again (part from autozone so it was free). Last few months has been losing coolant - not a lot, but noticeable, had to add coolant every few trips when my kids came home from college.

On the way home this weekend my son said temp got a little above half way on the temp gauge while driving on the high way. Took it for a test ride, coolant full, coolant smell present, and temps normal. Let it sit in the driveway at idle for a while with the a/c off. It heated up to just above half way, fans kicked on and temp came down. In all my work on the cooling system I could never get the temp gauge above half way.

So why is the car running warmer, what should I look for and where to start? System holds pressure, no leaks that I can find. I am tempted to replace the thermostat and water pump again.

[Scottydoggs]

its normal, 04 up cars have higher temp fan settings, hook a scanner to the the obd port and read the temp there, the dash gauge is not accurate.

your gonna hit 217 degrees before the fans come on, high speed fans come on at 226.

[dgjks6]

You still here Scotty? You walked me through all the crap I went through a few years ago. How's your car running?

I assume the fans are working normally. But why is the car running getting than it ever has before?

[SgtMarshal]

maybe your thermostat isn't working as good as it should, or maybe your temperature sensor is losing accuracy. I've changed temp sensor's a few times, and the one I got from carquest isn't as accurate as the ac delco I ordered off amazon.

[Scottydoggs]

its now 80 degrees out, aka summer hit you.

cars running good. thanks for asking. my temps went from 180 to 200 already in this heat we got here now, i got my fans tuned to 185 as well. stock 195 t stat.

your t stat dont open till it hits 195, so its a quick jump to 200 plus from there. and your fans dont even turn on till you hit 217.

[idrivejunk]

You could also have a fan motor slowing down due to wear. But as mentioned, the halfway mark is no cause for alarm. You could be smelling air being pushed out of the recovery tank, too.

[dgjks6]

I need a tool to get the exact temps. Whats my best bet?

As far as the themostat - temp gauge goes up to just below 1/2 mark. I assume this is where the thermostat opens because temp then drops back down to between 1/4 and 1/2 mark and stays there - until recently.

It is also the autozone thermostat. May be going bad and not opening all the way?

[Scottydoggs]

if you have a droid phone or tablet the torque app works well for showing more live data then you can shake a stick at. you also need a elm 327 obd2 bluetooth adapter fo rit to work.

[dgjks6]

You could also have a fan motor slowing down due to wear. But as mentioned, the halfway mark is no cause for alarm. You could be smelling air being pushed out of the recovery tank, too.

Air out of recovery tank? Never heard that one but that would explain my years long obsession with coolant smell on the grand prix

If I was still driving I would not care, but I worry with my son commuting to columbus and back. He's a good kid, but car repairs are not his thing. I had to have the if it gets too hot turn the heater all the way up and open the windows conversation. Better than the always use a condom conversation I guess.

[dgjks6]

if you have a droid phone or tablet the torque app works well for showing more live data then you can shake a stick at. you also need a elm 327 obd2 bluetooth adapter fo rit to work.

no driod, used iphone here. You just plug something into the ODB? Cool. Will start a search.

[Scottydoggs]

theres one for the i fail too, it just dont scan for kr, what most of us care about most. dash commander iirc?

[SgtMarshal]

I haven't heard too many issues with aftermarket thermostats, it's the temp gauges that I'm wary of.

[idrivejunk]

When you pressure tested the system did you also test the cap?

There can be a little learning curve on that whole bluetooth ODB thing. Its simple but stay way from the super-cheap adapters is my advice.

You could always drill and tap the manifold for a mechanical gauge, lol.

[idrivejunk]

I haven't heard too many issues with aftermarket thermostats, it's the temp gauges that I'm wary of.

I've had them stick open more than shut. But now theres the fail safe kind and thats what they do.

[SgtMarshal]

I had a drilled thermostat in once and forgot it was drilled. one morning I had to drive several hours and the temperature was about 0* F. the engine temp gauge never got to the bottom mark on the gauge. the head didn't work very good because the engine never got to operating temperature.

[dgjks6]

When you pressure tested the system did you also test the cap?

There can be a little learning curve on that whole bluetooth ODB thing. Its simple but stay way from the super-cheap adapters is my advice.

You could always drill and tap the manifold for a mechanical gauge, lol.

Did not test the cap, but it is newer - also form autozone

[idrivejunk]

If one of the seals on the cap is bad that could cause the recovery tank to see more flow than normal, displacing more smelly air. I didn't mention pinhole leaks because you said it holds pressure but its possible for an air-only leak to exist, at a higher-up and farther from the heat point in the system like heater hose connections. Even then it might only leak when everything is hot and soft. But I'm no expert.

Just tossing out ideas.

Go for the $30 bluetooth adapters, not the $3 kind. Didn't work on mine and I have two 99s. Just sayin'

[mguzzo]

find an OEM cap. If you're smelling coolant and losing small amounts, but not leaking / dripping I'd suspect the cap too.

[J57ltr]

They get above the half mark before the fans come on. It's pretty normal especially if you aren't using the AC. I have had issues since getting my 05' where even on the freeway it will not cool enough to maintain a lower temp when the temp is over 85*. I can run down the freeway at 70 and the temp will climb up to 217 and then the temp will start to drop back down to about 200 then it will cycle between 200-217. I bought a tuner and set the low speed fans to come on at 210 and high speed at 217. During the "winter" my temps ran 186-188 with a 195* stat. now that it's getting hot the temp is about 190* in traffic with the AC running and when I get onto open freeway the temp climbs up to 210 before the fans take over. The halfway mark is right at 210 FYI. I use an Android phone and a BAFX ELM327 to monitor temps and all the other various things I want to watch while my Iphone stays in my pocket. You should be able to pick up a small tablet or an old phone to just run Torque Pro for monitoring car related things. It REALLY, REALLY, REALLY comes in handy. It is the best thing since sliced bread and really saves a lot of headaches trying to troubleshoot issues with any OBD2 car.


There's not really much for the IPhone I looked. Bosch has one out that you can buy from Hi Lo, but it's $99 and I have had a couple of friends that have mixed feeling about it. If you buy the BAFX one they are about $23 shipped and they are the only ones I don't hear people having issues with them. I bought one of the cheaper ones that was from the same seller as someone that bought it on here and it worked on everything EXCEPT GM. I ended up giving it away since it was a hassle to send back.

Jeff