A friend of mine has an '89 Vette auto. The cooling light came on, the dealership replaced the radiator. Car came back, lights back on. They replaced the sensor (I'm not sure which). Lights on again, they replace the heads (I guess they cracked). Car comes back, unreal, the lights on again! The dealership says there's air in the system (I'm not a mechanic, so I don't know if that's true, but it doesn't sound right). We go for a drive, he thinks there's not as much power as there used to be. I drive a 4-cylinder, but I'm a fan of v8 torque, and I thought it was fine.

The car did have a rough idle(stock exhaust), but he said it's always been like that. I guess the '89 is a rough idler? Plus the car took too long to shift(near redline). Does anyone know if that's normal, or maybe the trans needs some maintenance? The car has 74,000 miles. Does anyone have any thoughts on this? Thanks.

 

Find a better mechanic!!

:rolleyes:

 

Thanks for the informative post.

 

What your friend doesn't have a computer?

The problem with your friends 89 is that the cooling system was never packed properly. If you do a search on this forum you will find the proceedure that is discussed at least once a week for the last 3 years.

I'll bet every cent he has spent has been for no reason at all. Cracked L98 D port aluminum heads? Could be, but not real common. Head gasket leak, could be and more common.

Jack is correct even though you took it the wrong way.

Can't help with the tranny.

Pete

 

I don't know if this would apply to a vette trans, but I had a trans act like this in an older car once, and it turned out to be a vacuum leak. The car had just been serviced, and somehow they messed up a hose fitting while working on it.

 

That is the funniest post I have read in a while.

Coolant light comes on , replace heads ?

My coolant light comes on every time I have air in the system. I purge the air and pack the cooling system with coolant.
Could also be a bad sensor.

Vic

 

Hey Jack !!Is that you up there ???

 

99sh,

Jack is correct, get another mechanic.

I personally know of an 89 vette owner who had an intermittant low coolant light problem for some time. One very hot day in traffic he overlooked the digidash temp climbing sky high. He warped his aluminum heads. Low coolant warning isn't something to laugh at.
Still, if attended to early on there is no reason for warped heads or
other damage.

Replacing the radiator for a low coolant light problem is a rip off by the mechanic. The light is set by the coolant sensor in the radiator just below the filler mouth. Unless the radiator was so clogged as to cover the sensor up to the filler mouth, it is unlikely you needed a new radiator to solve the coolant light problem. More coolant, or a purge of the system maybe, but not usually a new radiator.

The 89 and 88 vette use the same thermostat. An article in Corvette Fever recommended drilling a 1/8" hole in the thermostat to help purge the system of air when refilling the coolant system. Some thermostats already have a purge valve built in, but the stock 88/89 thermo does not.
I did this to mine and I have had no problems with purging air in the system when replacing coolant. Others have been successful just packing the system as mentioned.

The 89 L-98 isn't by nature a rough idle. It could be anything causing the poor shifting and rough idle. It could be an after-market chip installed by the previous owner. The chip controls idle fuel mixture once the car is warmed up and in closed loop operation. Prior to going into closed loop the chip has preprogrammed constants for idle mixture. An after market chip could have been programmed improperly in several areas causing the symptoms you're seeing. The chip also controls shift points on auto trannies so it can affect that also. It could be a correct 89 chip in an ECM that is defective. The ECMs do go bad over time. Or could be a vacuum leak as was already mentioned. Depending on age and abuse it could be leaking injectors or a bad O2 sensor causing the rough idle.

If the car was severely overheated the fuel injector windings may be toasted. With age (89 = 13 yqears old), mileage (high?) and overheating, the injectors probably need replacing or rebuilding. This would definately cause poor idle and lack of power. A bad O2 sensor ($25) will also cause performance problems since it is misleading the ECM on the true fuel mixture.

As jack said, get a new mechanic.

 

B&B...that is very common for older TH350/TH200 transmissions. That design uses a vacuum shift modulator ( say that 10 times fast ) which adjust gear shift rpm based on engine load as indicated by intake manifold vacuum.

BUT: The 700R4 in the 89 vette does not use vacuum as a trans shift input...it is strictly based on throttle position and output shaft RPM.

Mike, good reply, lots of valid points, but I have to point out to the trans control issue. It has nothing to do with an ECM or vacuum leak. The 700R4 has no vacuum input and it has no ecm input, other than when to lock the torque converter.


It sounds like this car is victim to a loss of coolant over time. It could be as simply as a small leak in the water pump that is not visible, or a bad radiator pressure cap, or even a leaking hose....and yes, an overheated car can cause cracked heads, blown head gaskets and even more damage.

Hope he gets it figured out.