have a 2002 Cadillac Seville SLS norhtstar. 174,000 miles original owner. recently overheating. radiator and cooling system flushed by a garage. Mentioned it was very very 'plugged' up with gunk. Later, the mechanic after putting it back together said: blown head gasket. Now: No white smoke from tail pipe. Engine runs smooth. No water in oil:clean. Engine heats up after 15min driving and then cools back down to 'just over heating zone, but not back to normal. upon checking: cap has sprayed fluid around the neck of the 'bottle'. Next day I notice it is low approximately 1-1/2 gallons....I fill with GM orange raditor fluid and water/50/50. Currently drove car and still overheats...but upon driving...returns back to one 1/4 over normal on the gage. Is this a thermostate problem? Also the fluid, yes orange in color is sort of a whipped orange foam at top of cap upon upon opening.
What's up with this? Help!
thanks
u4s

 

I would say to have the thermostat checked. Maybe also check the radiator cap. If they cleaned out the cooling system, and it's no longer blocked, it sounds like the thermostat is opening too hot.

 

1) Look at the waterpump. The impeller is pressed into the shaft. When hot, the impeller will expand, come loose and spin independantly. The impeller speed will slow down because of the resistance of coolant circulation. Results in erratic temerature absorption.
2) Also inspect the radiator cooling fans. they are ECT controlled. Make sure they come on as indicated in service information. (service manual)
3) The foam on the inside of the radiator cap is oil. Blown head gaskets will leak oil into the cooling system and mix with the coolant.
4) Check the transmission fluid. The trans cooler is in the radiator. If it leaks, the coolant will become contaminated and cause erratic thermostat operation. Remember transmission fluid pressure (approx 70psi in drive range) is higher than cooling system pressure (approx 13 psi). The radiator will see contamination first.

Hope this helps.

 

I thank all of you for your fine comments.
The latest on my STS Seville is:

My corner garage has been attempted to 'overheat' the engine by leaving it running for long periods. They have driven it somewhat but no overheat. I took the car for a 40 min run back when the outside temps were 70f and it only overheated for a brief moment then cooled down.

My corner garage mechanic seems to think it is a leak in the head gasket on the exhaust side. He says he's had to top off the coolant. He advised two things:
1) use the car the way it is for short drives ...(which ain't gunna happen)
2) try to put a sealer in the coolant to seal the very small leak.

What do I do? I need to get this either fixed or sell the vehicle the way it is.
In the meantime we got a new XTS.....for her to drive....yet I want to 'keep' the 'ole SLS cuz she's so clean and near perfect in appearance.

Help!

 

OK, Another $200 lighter and here's what's happening;

The corner garage performed the sealant with another flush fill with Dexcoolant.

Still overheats but cools back down. NO HEAT into the cabin. (Cabin did heat for a few mins in my test drive but cooled to cold.) Weather here in MI is now cold.

I think your comments on thermostat are in order and I'll have the new service done elsewhere and have them check the ignition connectors.

I'll let you know the final on this.
thanks all!

 

classic issue ..

have you read our FAQ thread on the subject?
i bet engine overheats easily while running at high speed or climbing a steep hill.

BTW, are the oil levels rising?


...

 

After an coolant test, exhaust fumes were detected.
Thanks all for you most kind and astute help.

 

it is really very nice and informative forum ,thanks for sharing .i really appreciate this ....