'03 G35 just hit 180,000. Until now, no problems whatsoever.

Here's my issue: it will not heat while sitting in traffic; it even cools somewhat when I let out of the accelator. But when I accelerate, it seems to heat fine. Coolant is all good and I do not have any warning lights on. Thankfully, I only have about 15-20 minutes of my daily commute sitting in traffic. Then, I hit country backroads.

SO... any ideas/suggestions as to the nature of my heating problem would be helpful. I won't be able to get it looked at until the weekend...

THANKS in advance!

Really??? You just DID NOT reference the fact that because I'm a "gurl" you assume I know everything about bleeding!?!? Look...I didn't get the notification about bleeding in the other forum. I also thought that this could possibly be a separate issue - hence the new post. Yes, I'm a woman, but I'm learning as I go. I'm sure you wasn't Mister-Know-It-All when you first started working on cars either!! Also, there was no need to throw the fact that I'm a woman into this....it's an honest question that I thought I could help with on here. I certainly wasn't expecting this type of response!

I understand the frustration with two similar posts, but you were a little harsh.

Is coolant leaking from under your car? You have an air bubble or leak somewhere!!

Sorry for the comment, those are not allowed on Driver. Most of our other members are more respectful to each other than that.

I've not noticed a leak at all. In fact, for it to have 180,000 miles, she doesn't leak anything. I guess I didn't realize it could get an air bubble since I didn't add any coolant; however, I will seek a little assistance on bleeding it.

Thanks for everyone's kindness and helpfulness!!

Is you reservoir dry?

Her heater is not working right and the coolant is not the issue here. Coolant cools the engine and the the hot coolant circulate through the heater, and the blower blows the hot air into the cabin.

The issue here is the heater. I would suggest that you have a shop to check it out rather than getting inaccurate suggestions here.

The reservoir isn't dry. I checked it as soon as I got home last night.

Don't feel bad. I'm having the same issue right now. I just haven't gotten around to letting all of the air out of my system.

If your heater only puts out heat when the car is in motion your low on coolant or theres an air pocket but I would check the coolant level first best time is after the car as set for about four hours and then then check your coolant in the radiator first then the reservoir.

Can it be that the thermostatic valve is stuck open, so it always cool the engine, and when the car is accelerating it gains heat but when idleing it just cools down since the valve's open ?

I had the same problem! I changed the t-stat and it turned out the new t-stat had been faulty...so I got another t-stat and that solved the problem. Biggest thing is the air in the system...I believe there is a DIY on the forums that shows the best way to release air...so check that out

No if the thermostat was stuck open it would more than likely heat up while stop since there is no air moving through the radiator unless the fans are on but while moving you have a lot more air going through the radiator keeping the coolant cool that's why people you have cooling problems the water temp jumps up when you stop and starts to drop when you start moving again same as the air conditioner it cools more when your moving.