Alright so for the past week it's been getting noticeably colder in the morning where I live. And of course I have to be up at the a$$ crack of dawn for work. Every day ill be driving and at almost the exact same point in the commute ill come to a stop an my rpms will stay at like 2000-2500 like I never even stopped. It'll stay like this until I begin to go again an then the rpms will shutter down and almost stall out my car. Today it kept doing it so bad that my a/ c off light switched on an off an then began overheating.

- I've checked for leaks, nothing. No visible signs of coolant.
- I allow my car to warm up to 900 rpms every time I start it.
- Only happens in the mornings

If anyone has ideas or has experienced the same I'd greatly appreciate it, I have a feeling it's air flow problems but I'm not sure, thank you for any words of necessary wisdom.

 

Nothing to offer but hopefully there will be someone along to guide you on your way.

Chris

 

Check the basics. If it is throwing any codes, check those first. Cleaning your throttle body and MAF sensor may help. There are how to threads on this forum. Make sure your coolant level is where it is suppose to be and your air filter isn't stopped up. The two problems may be unrelated. Keep us up to date on what you find.

 

YEAR and MODEL first and always if you want an accurate answer. Without that, I'll just guess.

When your DIC displayed "AC OFF" that is one of the first layer of overheat protection in a 3, so you have a cooling problem. The increased RPM is your PCM (since you provided no year and model I have no idea which PCM you have) trying to increase clutch fan cooling by moving air into the radiator at a stop, another layer of overheat protection.

What is your temp gauge doing? What is it doing later on in the day after this problem seems to dissipate? If your radiator was dirty, it would be hot all the time.

My guess...... a stuck/slow moving thermostat. It slowly closes when the vehicle is at rest (like overnight) and takes way to long to open back up when you start the motor and go in the AM. Once open (especially if not all the way) it may not cycle so temps may end up lower than normal after a while. There is more to it, but you get the idea.

If you have access to a tech scan (not just a code reader), plug it in when cool and you can see this happening as cold start up strategies fade to normal operating temp, or not.

 

Thanks for the in depth help I really do appreciate it. It's a '08 H3 3.7 with 57,000, with a brand new factory installed radiator from this past summer. I was thinking it could be a stuck thermostat too given it only does it in the mornings. I drove it all day today an it was fine. I have a Matco code reader an I'm not getting any codes currently. Thanks again.

 

How hard are the thermostats to replace on them?

 

It is not too bad, and it won't break the bank either. You are in luck because there are threads here on that topic and procedure, just search them out. I think they are just a few months old.

BTW I believe we were all aware you have an H3, what I meant by model is: Base, Adventure, Lux, and Lux Off Road, Alpha, etc.... The year tells me which PCM you have and whether there is a TCM. Model is important for other issues, as different T Case Actuators, TCCMs, and BCMs are used in different models within the same year.

 

mine did this for several months i replaces vacuum line and fixed it

 

Her ya go! directions to changing the t-stat and cts...


https://sites.google.com/site/happyh...ts-replacement


Chris