Hi all,
My car has been having some trouble shifting into gear (either 3rd or 4th). This usually occurs after two or 3 minutes of driving (and shifting fine) but then the temperature gauge shoots up to hot and my engine just revs but wont go into the next gear. This lasts for about 30 sec.-1 min. and then the temperature gauge goes back to normal and the car goes into gear. It happens several times, every time I drive the car. The fan also stays on for what seems a long time after I've driven it but I'm not sure if those are related issues or not.

Any advice is greatly appreciated.

2000 XK8 Conv. 78K miles

 

First off do not drive the car. Repeated overheating can destroy your engine.

Start by replacing the thermostat, it sounds like it may be sticking.

My theory is the the coolant is getting so hot that the radiator is actually heating the transmission fluid, rather than cooling it, causing a shift malfunction. Once the fans cycle on to provide auxiilary cooling, everyhing starts functioning again until the cycle repeats.

If the new thermostat solves the overheating, then a transmission fluid change may be a good preventative measure.

Also, if you have not changed your secondary chain tensioners, it will be even more critical to do it once the original problem is resolved because the plastic will be even more brittle from the overheating cycles.

 

Welcome to the forum!

You absolutely must resolve the over heating problem . . . immediately!

Many engines have died with only one spike in temperature. Never mind the shifting issue until you get that resolved. If the over heating has occurred every time on 'several' drives I would not even drive it to a shop but have it towed.

 

What they said.

Fan on after Shutoff = Bad Thermostat. Replace it before Starting Engine again!!!

 

+1.
It might also be wise to replace the plastic thermostat housing and connecting pipe at the same time. Those plastic parts become brittle with age, and overheating helps the process.

 

Thanks. My boyfriend figured he should start with replacing the thermostat this weekend. Sounds like he's on the right track. I will not drive it until then....hoping I didn't do too much damage already since I've driven it several times like that.

 

Please let us know how it turns out.

The feedback really helps out other folks and helps us all get better at identifiying the problems.

 

Boyfriend, what Boyfriend - you never mentioned a Boyfriend.

Seinfeld..............

 

And to repeat what was suggested above, even if the engine temp gets fixed with the new t-stat, your tranny fluid has likely been compromised with the high temps to, causing it to negatively alter its cooling, frictional, and lubricating properties...just like motor oil is capable.. It won't magically heal thyself. Drain or flush and fill that as well.

 

Thermostat and housing replaced (were very brittle BTW). Problem resolved. Will get transmission fluid changed as well and secondary chain tensioners as recommended. Parts cost for anyone who may be interested was:
Thermostat: $65
Housing: $107
Cap & seal:$10
Cover: $35

Thanks again to all who replied.

 

Good job...you may pass that along to the BF.