My car is acting SO weird. Please help, car gurus!

[midnight armadillo]

The other week I posted about poor mileage on my 98 Subaru.

I had the thermostat replaced. I now have hot heating vents - yay! And now the car randomly runs hot, as in the upper 1/3 to 1/4 of the thermostat, during my commute. It doesn't do this much while stopped, just while driving. It comes and goes. There are no symptoms of a leaking head gasket in terms of bubbly radiator coolant, etc. A bottle of Redline fuel injector cleaner seems to have cleaned up the gas smell on the morning startup, I suspect there was a leaky/clogged injector in there somewhere.

Also, the car stalled in the parking lot the other day, and it's now pretty consistently pausing for about 1 sec on 2->3 and 3->4 shifts. I'm wondering if my torque converter is going south and the tranny is slipping? Could this cause the hot running?

[slackmaster]

1. A leaky or dumping fuel injector or two could cause that

There are no symptoms of a leaking head gasket in terms of bubbly radiator coolant, etc.

I take it you mean it's not eating coolant too, correct?

Check the transmission fluid level. If bringing that up to full doesn't fix the pausing, have it looked at. It's probably nothing serious, and wouldn't explain the overheating.

[Submariner]

2. Try here

I suggest you post here for an answer, or look around threads for a similar problem. Good luck.

http://www.ultimatesubaru.net/forum/

[flvegan]

3. Could be the radiator fan(s)

Don't know much 'bout Saturns, but a great number of cars use plastic radiator fans. In time, the plastic on the gear gets worn down, and slips or stops. This happened to me a loooong time ago (the random running hot-ness) and that was the cause.

[Dr.Phool]

4. Electric fan

A few years back, a lot of cars switched to an electric fan instead of one driven by the crankshaft and belt. If this is going it could cause overheating, especially if stopped or driving slow in heavy traffic.

[Viva_La_Revolution]

7. after reading the post again, I suggest....

damn - you need a tune up! stalling, overheating, excessive gas use...get a standard tune up, it will be worth the $ outlay. May take care of most of the probs you mentioned...

[physioex]

5. When asking for car advice....

Mention your make, model, year, engine type, and mileage. This gives the person a frame of reference.

I have had some old GM cars, and I have had radiators themselves cause heating problems. The problems were caused by deposits restricting the flow of coolant. I removed the radiator and took it to a radiator shop to have it dipped in acid too remove the deposits.

Don't start diagnosing tranmission problems as they are very complicated. Your torque converter does not control the shifts in the transmission. It is simply a fluid connection between the flywheel and input shaft of the transmission. On older cars shifts were controlled by a speed sensor and vaccum regulator however on newer cars this is done through the computer from all the different sensors such as (Throttle Position, Speed Sensor, MAP). Shifts in the transmission are done by solenoids in the transmission.

I have no simple answers, but by going through a process of elimination you or a mechanic can figure it out.

[Wilber_Stool]

6. Could be a

bubble of air in the in the cooling system. Check the coolant level. It often happens when the system is opened up.

[physioex]

8. Certainly possible....

If he has a Japanese car such as a Honda or Mitsubishi, the manufacturers were nice enough to provide a little bleed valve.

[rwork]

9. The new thermostat

could be sticking.And you did'nt have this problem before the install.And what degree of new thermostat did they install,180,200 etc?

[midnight armadillo]

10. Thanks all

After searching that Ultimate Subaru site, it looks like the overheating problem is due to air trapped in the radiator - I will burp it this weekend.

The transmission behavior is still a mystery to me. I wondered about the torque converter since gas mileage decreases of 30% are apparently possible if the lockup function is failing...

Thanks everyone!