[89Bullitt]

Bought a 89 mustang yesterday and drove it basically all day.
The car has between 250 to 350 thousand miles on it.

Im having a little bit of an overheating problem. I was driving down the freeway at 65 mph and was getting a surge between 170 and 240. The car was running just fine and the fan was on. Seems to do it between 30 and 70 mph. Anything before or after that cools just fine. Thermostat not functioning properly mabe?


Also the car is known to have a new transmission and hasn't been driven that much since it got one back in 2005. It wont go into overdrive and its kind of hard to get good gas milage going 70 at 3800 rpms lol. Are these cars known for linkage problems or do you think its something more than that?

[OHC230]

Most likely the transmission issue is a 3-4 shift solenoid.

I would start with the thermostat on your car, but I would be suspicious of the condition of the rest of the cooling system.

Has the system been flushed?

What does the radiator look like inside?

[89Bullitt]

Took off the cap and antifreeze looks good, although it has some white corrosion on the inside on the "fins" pointing outward(in the radiator)

Probably needs to be flushed to get rid of the stuff. It comes off quite easy. So im thinking thermostat change and flush radiator?

If you dont mind me asking, wheres this shift solenoid? Is it like a vacumm modulator on a c4?

[OHC230]

Where's this shift solenoid? Is it like a vacuum modulator on a c4?

No, you will have to drop the pan on the transmission. The solenoid is located on the side of the valve body. It is not hard to replace, it's just a messy job.

While you are under the car, you might want to do a band adjustment. If you use the search feature on this Forum, you will find a post on band adjustment. Not hard to do and will extend the life of your trans.So will a transmission cooler for that matter.

[89Bullitt]

Thanks for the info.