I've got a 1998 Sportage, manual transmission, 100+thousand miles, that has started running hot. The coolant is topped off. It use to have the typical temperature rise when running the AC, which shutting off the AC would cause the temp to drop back down to the normal range. That has stopped being a solution, when the temp guage starts to climb, shutting off the AC stops the climb, but the temp doesn't drop. It will sometimes get hot enough that the AC automaticly shuts off (this IS a feature of the '98s, right? <img src="/forums/images/graemlins/rolleyes.gif" alt="" />)

Its got a new heater core (1 year old). My knee jerk reaction is to replace the thermostat and radiator (us "shadetree mechanics just throw parts at 'em <img src="/forums/images/graemlins/smile.gif" alt="" />) but I thought I'd see if the collective knows of a specific cause for this issue. I know the cooling system on these vehicles are weak, mine has just gotten "weaker". The fan is spinning, but this occurs running down the highway also.

Is it possible that the system just needs a "burp" from when the heater core was replaced? If so, how do I go about doing that?

Thanks,

John