94' Saturn SL2 -

[BoBo]

My girlfriend has a 94 Saturn SL2. She bought it a few months ago with 78k miles on it. Since she's had it, the engine revs up high for about ten seconds after start. It also did the same when she puts the car in park before turning the engine off. A couple of times, the came home with the coolant boiling out of the tank. The last time it did that, we took to the shop. They said that they would have to change the coolant temperature sensor, the tranmission fluid temperature sensor, and the air temperature sensor. Needless to say, they say that the bill will go up to $650. My girlfriend had a friend who also had a shop. He took it to his shop and he said all he did was take the termostat out. Not replace it, but just took it out. He said she could come back during winter and he could put it back in.

Is this okay to do this to a car? We live here in Houston, and it gets pretty hot and humid. Winters are pretty mild--the temperature hitting below freezing shuts the whole city down...

Just asking for opinions...

 

[Napalm Heart]

My girlfriend has a 94 Saturn SL2. She bought it a few months ago with 78k miles on it. Since she's had it, the engine revs up high for about ten seconds after start. It also did the same when she puts the car in park before turning the engine off. A couple of times, the came home with the coolant boiling out of the tank. The last time it did that, we took to the shop. They said that they would have to change the coolant temperature sensor, the tranmission fluid temperature sensor, and the air temperature sensor. Needless to say, they say that the bill will go up to $650. My girlfriend had a friend who also had a shop. He took it to his shop and he said all he did was take the termostat out. Not replace it, but just took it out. He said she could come back during winter and he could put it back in.

Is this okay to do this to a car? We live here in Houston, and it gets pretty hot and humid. Winters are pretty mild--the temperature hitting below freezing shuts the whole city down...

Just asking for opinions...

In a modern car that is computer controlled based on information that comes from sensors this is especially not a good idea. I would have to think that it would be running in default (open-loop) without the thermostat keeping temperatures within design parameters.

But, that's just my opinion, and I'm not a licensed mechanic.

Ken

 

[Robert Hancock]

If the car is overheating like that, taking out the thermostat will not help significantly unless the thermostat is stuck closed right now, but if that were the case, it would be just as simple to replace it rather than remove it. With no thermostat, the engine will also not warm up as fast as it should, which will kill the gas mileage and reduce the oil life.

I don't know about the transmission fluid temperature sensor, but a new CTS and IAT sensor should be nowhere near $650 to replace. It's unlikely that you need all 3 of those anyway, so it sounds like that shop is recommending parts replacement without any real diagnosis. Did they actually CHECK to see if any of the temp sensors was reading incorrectly?

 

[JJ]

Sounds like a sticky throttle body valve. Mine (95SL2) did much the same in ref. to the engine revs, but not the overheating. The two may not be related. Get some throttle valve cleaner and clean and see if that doesn't correct the over revving.

Jerry

"Robert Hancock" wrote:

If the car is overheating like that, taking out the thermostat will not help significantly unless the thermostat is stuck closed right now, but if that were the case, it would be just as simple to replace it rather than remove it. With no thermostat, the engine will also not warm up as fast as it should, which will kill the gas mileage and reduce the oil life.

I don't know about the transmission fluid temperature sensor, but a new CTS and IAT sensor should be nowhere near $650 to replace. It's unlikely that you need all 3 of those anyway, so it sounds like that shop is recommending parts replacement without any real diagnosis. Did they actually CHECK to see if any of the temp sensors was reading incorrectly?

 

[BoBo]

If the car is overheating like that, taking out the thermostat will not help significantly unless the thermostat is stuck closed right now, but if that were the case, it would be just as simple to replace it rather than remove it. With no thermostat, the engine will also not warm up as fast as it should, which will kill the gas mileage and reduce the oil life.

I don't know about the transmission fluid temperature sensor, but a new CTS and IAT sensor should be nowhere near $650 to replace. It's unlikely that you need all 3 of those anyway, so it sounds like that shop is recommending parts replacement without any real diagnosis. Did they actually CHECK to see if any of the temp sensors was reading incorrectly?

They claim to have checked the sensors with their computers... I wished I had taken some auto-mechanics class in high school...

 

[Robert Hancock]

Like I say, it's unlikely that all 3 sensors are bad, and even if they were, that replacement price is excessive. I'd take it somewhere else.

 

[Sal Malva]

I've read all the comments you've received. I don't know if I agree with any of them. I will however, share my experience with you. First, I am not a car guru. I had the SAME work completed as your shop identified for the SAME price. The only difference is they replaced the thermostat. The problem is gone. The work was done by a neighborhood garage in a suburb near Philadelphia PA. I've had other work performed here with satisfactory results. Your call.