Coolant level at max. Coolant was changed 35000 miles ago. What should I tell the local chain garage to look for in both cases so they think I know what I'm talking about? Thanks
So 35000 that's thirty five THOUSAND correct? If so it might be time for a super flush and heater core flush. I'd do this myself as oil change centers are more likely doing a drain and fill with no flush.
Where did you check the level?
Another possibilities are:
1.) vacuum leak - take wd40 or carb cleaner and with the engine running spray around the TB, intake at each cylinder and at each vac line. When the engine sputters or RPMs change you hit the leak. Some lines go to a box under the battery and then to possibly the transmission ...
2.) air in the heater core. If this was it once you got heat from stepping on the gas it would continue.
3.) loose belt or slow or frozen pulley. Rev the engine at the TB wile watching the belt. Make sure it continues with the rpm and does not slow or stop.
4.) blocked heater core. With engine up to temp feel both hoses of the heater core one should be hot and one cooler. If both are about the same temp then it is likely blocked
5.) failing water pump - either the impeller is loosing its fins or is spinning on the pulley. With higher RPMs the initial and little contact to the shaft the impeller will turn if it were loose from the shaft. The impellers have been known to rot off.
6.) does this have a flow valve? Most jeeps don't. But the valve may be stuck.
