The car is a 1999 base model v70 with 183k miles. It overheated a once in the past when my wife was driving the car. The radiator had a leak so I replaced it with a new missens two weeks ago. I know that the overheating had nothing to do with the small leak. I drove the car today and the temp quickly climbed the red and then 4th gear locked out. Any help would be appreciated. Is it as simple as a thermostat?

THanks
--
1983 242 GLT / 1991 244 / 1993 245 / 1999 v70

In addition to checking the (very much possible) stuck thermostadt possibility, have you noticed if the radiator fan is clicking on as it should?

I'm just wondering if it were that the coolant is still circulating through radiator but not being cooled by the fan, would it transfer enough heat to the ATF (via the radiator trans cooler) to cause shifting trouble?

I take it that the trans shifts OK until the engine gets hot???

If you used a non-OEM thermostat, it could be stuck in the closed position and overheat your engine in about 2 miles. Easy enough to check, the top radiator hose will not be hot to the touch.

But the tranny lockout is strange. Usually that happens when the ATF gets too hot.
--
My name is Klaus and I am a V♂lv♂holic

You are correct. I replaced the thermostat with a one from napa. THe problem remained. So I gutted the new one and put it back in problem solved, I learned a lesson and will put on a volvo part.

Thanks
--
1983 242 GLT / 1991 244 / 1993 245 / 1999 v70