I have an 1997 LHS and the engine has been running fine, I have had this car 4 months now it has 70,000 miles on it and all summer long never had a problem even with a/c on. Now when I idle for long periods of time or sit in traffic the resovoir seems to overheat but the engine temp gauge is not even 1/2 way up.. I changed the thermostat, and the temp sensor, I checked fan fuses and relays all are ok, the fans work they do come on. Don't know what to do next. I am gonna get a new radiator cap and try this.. Anyone have this happen to there 3.5 liter motor.. please help..[sm=wtf.gif][sm=wtf.gif][sm=wtf.gif][sm=WTFsgign.gif]

Well I changed the cap still the same thing.. And I don't ssee any oil in coolant or vis/versa..There is no bubbles in resevoir when running, and there is no movement of coolant in there either, the only time there was any movement is when I raised the idle to any rpm after 1400 then I could see some flow.. Maybe water pump fins are bad???? and no coolant is getting circulated around, that's why it's only overheating in the resevoir..

 

Did you bleed the air out when you changed the t-stat i am not sure but i think their is a bleeder valve on the housing(not positive) If their is an air pocket your not gonna get flow

 

yes I bleed the system doesn't seem to have any air in it.. I am gonna change the water pump and timing belt, the car has 70000 miles on it and they reccomend changing belt at 100000 so I am just gonna do it a bit earlier.. and while I have it apart I got a new radiator for 60.00 so I am gonna replace that also, can't hurt, and at least if it's not the water pump and it's the radiator I don't have to take it out again..I will let you guys know how it goes, I am gonna do it tommarow at work..