hi by the way car is running good thanks for info. Now i notice my heater dosnt work very well at all if i drive for a while it will blow out warm air on 90 but other than that the heater sucks im thinking of replaceing the heater core and changing the coolnt i dont want to chang e the coolnt yet couse u u have to us the pellets and im affraid if the heater core is clogged it will clogg it for good. and is my heater core located in the glove box? and my car is a 91 eldorado designer series thanks..

Try flushing the heater core before you start replacing anything.