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Beretta Overheats And Stalls

Q. Hello, I just happened to come across your site and I have a rather interesting situation.

1993 Chevrolet Beretta GT
3.1 liter V-6
Automatic Transmission
87,000 miles
Fuel Injected
ABS Brakes
P/S, A/C
Cruise Control

Okay... I believe it all started back in June, when my car initially overheated. It sat for about 7 minutes outside on a rather hot day, in park, but still running. It ended up leaking coolant, so I brought it to the mechanic that day. He checked the entire cooling system, only to find that the thermostat was now blown, but nothing else! He found that the car was running very warm and flushed the radiator, but he said that it did not help much.

The only advice he could give me was to NOT let it run while parked for very long and watch the temperature gauge to make sure that it never overheated. His last suggestion to me was that I would most likely need a new radiator, but he said he was not positively sure, so he didn't say "do it",he just suggested it. The car ran fine for the next few months so I never ended up getting the radiator.

In November I noticed a slight sluggish feeling in driving it and the temperature gauge usually stayed at the ¾, but no more no less. Since this is where the gauge was back in June after the overheating, I never really gave it much thought, however a few times when I would stop at a stop light or stop sign (thank god never in traffic), the car would stall. I would just start it up again, and it would go. I figured the car was just getting old, so it was not much to worry about.

My father borrowed my car for the month of January and agreed that the car felt sluggish sometimes when driving, so we did a complete overhaul. She got new spark plugs, new wiring just about everything an overhaul consisted of. And she seemed okay for about a week.

Then I took her back to school with me and I go to school about an hour and a half away. My dad had never had the "stalling" problem that I had experienced the entire month that he had the car (he only drove it to work and work was less than a half an hour away), so I figured the car was okay, but when I went back to school (that night), it stalled and wouldn't run in gear. It would stall, I would restart the car in park, shift into drive and it would just stall again (immediately).

I could have it running in park forever and it wouldn't stall but the second I switched gears it would just shut off completely. This has happened probably about four times now. I would have to wait until the car cooled off and then I could drive it for about 15 minutes before it started to stall again.

I took it to the mechanic the second time it happened (funny enough the second time it happened I was on the way TO the mechanic). The mechanic ran a diagnostic on the engine only to find that there were no control signals coming from the engine, a.k.a there were no problems with the engine, everything seemed to be running fine. (This was a different mechanic than the first one, because I have one at home and one down here at school). The only thing that the test could tell me was that the fan was turning on at 227 degrees, which was too hot.
My assumption (because this mechanic seemed to be lacking in the intelligence department) was that the fan was not coming on to cool the engine down fast enough so the car would "turn off" before it could overheat completely, thus stalling. The mechanic just assumed that the computer (which he pointed out, controlled the fan, but I already knew that) was not turning on the fan early enough or at the right temperature, so he said buy a new computer.

The computer on the car had just been replaced approximately a year and a half ago, so I was not happy with his suggestion for two reasons 1) this $74.00 diagnostic test told me NOTHING that I didn't already know and 2) he was not definitely sure about the computer because he had nothing to test it with, so again, it was only a suggestion.

So here I sit with a car that can run for about 20 minutes before she stalls when I stop, so at least she's good for very local driving. My friend suggested that the fan sensor needed to be replaced, and a lower thermostat couldn't hurt. Luckily my father works for an automotive parts company so he can get very cheap parts and a very cheap computer.

Do you have any suggestions on what the problem might be? I know this is a lot and I really appreciate you reading it and giving me any kind of response you might have. We plan on replacing the thermostat and the fan sensor in about a week and a half, then going on to replace the computer if necessary, unless you have another idea??!??

Thanks for reading,
Karen

A. Well Karen, what you are describing sounds like a bad transmission torque convertor clutch solenoid. Very common on G.M. 3 speed automatics. You can test this theory by unplugging the connector on the transmission. This solenoid will only come on over about 40 mph. It "locks" up the torque convertor for optimum fuel mileage. When it stays on it will act like a manual shifted car coming to a stop without pushing in the clutch, a violent shudder and stall.

Your overheating problem could be a partially clogged radiator, bad thermostat, water pump with a worn impeller. Lots of possibilities! The fan on temperature is around 228 degrees. It should shut off at 218. Make sure there is no leaks and the system is full with no air pockets. Also check the electric fan for full speed. If it's "tired", it may not be spinning fast enough to do the job. This would explain why it seems okay as long as you are moving and not sitting at a light.