View Full Version : 98 SLS Overheating in minutes

02-15-05, 04:18 PM
I have a 1998 Cadillac SLS that overheats drastically when I drive about 10-15 minutes. That's not including Freeway time which is considerably less. It starts off with a check coolant level light. Of course the coolant level is fine. Then it says coolant engine temperature or something similar. Next Engine overheated - AC Off. Next in extreme cases it will say idle engine. I have had the thermostat changed and it didn't work. I took it to a Caddy dealer and he informed me that it needed head gaskets. I was also informed by prior to taking it to the dealer that if it wasn't the 'stat than it probably was the head gaskets. Any insight, any similar problems.

02-15-05, 04:30 PM
Have you looked at the water pump drive belt and tensioner? There is a pulley on the driver side of the engine on the front-most valve cover. It's covered by a metal shield and driven off the cam. The pulley on the camshaft has a belt around it that also goes around a tensioner arm and the water pump drive pulley. The tensioner spring can become frozen or stiff after a while and may need to be flexed a bit to get it to properly tension the belt so it drives the water pump correctly. That's one idea. There are other possibilities, including some sort of blockage in the system, frozen water pump bearing, collapsed hose, etc. What is the condition of the water pump drive belt? Can you move the tensioner arm? (it takes a bit of force to move it, and that's normal) How many miles are on the car? Has it ever had the coolant drained and refilled? If so, was the supplement (pellets or powder) added to the system via the upper or lower radiator hose?

If it's not losing coolant, I don't see how it can be a head gasket problem. When you look in the surge tank, the coolant level should be an inch or two below the filler neck. If you fill it up to the neck, it will drop down to that level after you drive it one time because that's normal level. If it's lower than that or you can't see it, it is losing coolant somehow and that will need to be checked out.

02-15-05, 04:44 PM
It's funny you mention water pump, I was thinking the same but after taking it to the dealer I feared the worst. I will try to check out the things that you mentioned later today (at work now). But I am sure that the coolant level hasn't gone down. I just recently got the car and to my surprise, this happens. The radiator was recently drained, not sure if anything was added to the coolant. The car has 104k miles. I am not driving it now, but the few times I have driven it, the ride was smooth. No noises from the motor, just this overheating problem. I can't go 5 miles without the temperature guage crossing the half way mark.

02-15-05, 06:49 PM
Heater Core clogged?

02-16-05, 11:58 AM
Thanks to all for your help. I found that the source of my problem was not the Head Gaskets as the dealer service shop told me, but it was the Coolant Reserve tank that was clogged. This prevented coolant from going to the motor. Thanks.

02-16-05, 12:16 PM
Saved ya a coupla thousand dollars there, huh. Good call on getting a second opinion! :)

02-16-05, 12:29 PM
Glad you found it. Out of curiosity, how did you find it? Was the coolant supplement put in the surge tank at some point? What was clogging it?

Also, you may want to consider never going back to that dealership again. I've heard that same story way too many times. Cadillactech, caddywhizkid, why is that? Any other dealership reps care to help explain why YungHolla was told he needed head gaskets when only the surge tank was clogged, or care to comment on how often this happens or how a technician could be so far off base as to be in another galaxy? I know it helps keep techs employed, are there any other reasons? Meeting warranty quotas for the boss, perhaps? Does it help sell more new Cadillacs, or do you get kickbacks from the Lexus or Lincoln dealerships?