: 98 sts overheating problems



ernie69
08-13-06, 12:01 PM
Bought a 98 sts with 152000 miles cheap . The problem is it overheats and then may drive it for 75 miles and dosent overheat fluid is full no sign of smoke out the exaust. Having the a/c on seems to aggravate the problem any help would be a plus thanks

Ranger
08-13-06, 09:31 PM
Check the purge line, cooling fan operation, surge tank cap, water pump drive belt tentioner, coolan/water mix, thermostat & condenser fins (bugs & debris). Do a search dor "overheating". It has been discussed at length many times.

ernie69
08-14-06, 06:27 PM
its hard to figure out seems like it overheats mostly when a/c is on and going up a steap grade. Do you think its a head gasket or possibally a water pump?

ernie69
08-14-06, 06:33 PM
its hard to figure out seems like it overheats mostly when a/c is on and going up a steap grade. Do you think its a head gasket or possibally a water pump?
im wondering if i have bought a lemon..

zonie77
08-14-06, 10:04 PM
It may be head gaskets. If you got it cheap you aren't gonna get hurt too bad as you can probably sell it to someone willing to fix it for a similar price.

At 152K miles you knew it wasn't gonna be perfect.

There is a thread in tech tips on N* head gasket repair. You don't indicate if you would fix it yourself or not.

jss
08-14-06, 11:17 PM
ernie,

I own a 94 Seville with a Northstar and have experienced the agony of blowing a head gasket and have experienced non-headgasket related overheating problems. I'm not a Northstar guru like some of the guys on this page, but I do have an unfortunate amount of experience in the overheating area.

You stated that it's not loosing fluid? If it isn't loosing fluid then odds are it's not a head gasket. It takes special equipment to diagnose a head gasket, but if you drain the oil and don't observe any water in it, then odds are it's not a head gasket. (the water will be at the bottom of the pan)

You state that it's worse with the A/C on. Is it also worse at higher speeds? This is telltail of a stopped up radiator. If the 75 miles with no problems that you cited were in town, that hints at a stopped up radiator. If you get her out on the road and she quickly overheats, then something (like a stopped up radiator) is reducing your cooling capacity.

Then of course there's always the possibility of a bad thermostat (if you're very very lucky).

Ranger
08-16-06, 10:10 PM
Overheating on a grade makes the head gaskets highly suspicious, but check out all the other options first, then do a cylinder pressure test. That will positively condemn or rule out the head gaskets.