The fans do work. Properly I dont know but I checked that they both were working the last time I stopped the car when it was hot.
I am thinking about taking the thermostat out tomarow and driving to and from work to see what the temp gage does. It is only about 15-20 is this a good idea or not?
The milage seems to be about the same and no drivability issues.
On warm up it never jumps above the normal line only when im driving uphill or idle for a period of time like if I have to wait through 2-3 stoplights with little movement.

 

Taking the thermostat completely out may cause the coolant to circulate to fast through the radiator not allowing it to be cooled sufficiently before it returns to the engine, which will cause your engine to overheat.

When your engine temp first begins to overheat pull over somewhere safe and check your heater core hoses
if one is real hot and one is alot cooler, then your heater core maybe intermitantly getting clogged, which will reduce the circulating ability of the water pump, causing it to overheat.

 

Taking the thermostat completely out may cause the coolant to circulate to fast through the radiator not allowing it to be cooled sufficiently before it returns to the engine, which will cause your engine to overheat.

When your engine temp first begins to overheat pull over somewhere safe and check your heater core hoses
if one is real hot and one is alot cooler, then your heater core maybe intermitantly getting clogged, which will reduce the circulating ability of the water pump, causing it to overheat.

 

checked the hoses last time it got hot and both heater core hoses are equally hot. This weekend I put in a new thermostat and changed the belt for the water pump.
I put the garden hose into the upper radiator hose and removed the drain plug for the radiator and let the water run through the radiator to try to unclog it and make sure water is flowing through. There was equal water coming out as going in with no signs of blockage.
The guy at the parts store told me that if the sender unit was faulty it would throw a code, and seems to think it is the waterpump going out.
What do you guys think?

OPTION 1- Radiator $200.00
OPTION 2- Water pump $60.00 + $20.00 for the water pump removal tool = $80.00
OPTION 3- get dealer to look at it $80.00 per hour X multiple hours of diagnostics
OPTION 4- Sell the damn thing! andbuya new problem

 

Replaced water pump today $60.00+$25.00 for tool. and it did nothing to improve my problem. I drove it untill it warmed up and it seemed fine then it jumped up to hot. I checked all conections and the pump housing for leaks and found none. I had the heat all the way up and it did not seem to help.
Is there any way of testing the radiator to see if it is clogged or not working.
I dont know what else to do, I would like to find the problem and fix it but it seems my next move is to bring it in to the dealership to see what they can find out but I really dont want to. Any last hints or things I should check before doing so? Also I am still looking for the temp sending unit, does anyone know where it is located at on this car?

 

Make sure you are using the proper mixture of anti-freeze in your cooling system because it raises the boiling point by fifty degrees. Just plain water in your cooling system will cause the engine to overheat.

I took my 98 deville to the cadillac garage and they were convinced it was the head gasket, even though it was'nt loosing any fluid. I had changed water pump, thermostate twice, radiator, had it flushed out twice,
nothing worked, so they assumed it must be the head gasket and gave me a quote around $4,000 to change the two head gaskets and they said they wouldn't even gauranty it, because the head bolts are known for stripping out. To make a long story shorter I bypassed the heater core by connecting the upper core hose together with the lower core hose, and to my surrprise it solved the overheating problem. My heater core was apparently intermittently getting clogged , causing the fluid not to circulate properly in the rest of the engine. I changed the heater core and my car has not had a over heating problem since.

 

I vote #3
we would charge 1 hr.
It hate to speculate on these types of problems but a head gasket issues is a strong possibility.
Theseengines have aunique issue in some cases with the head bolts coming lose and causing overheating while driving with no other visible signs of failure.

If you search this site it has been covered several times.

 

this weekend I connected the heater core hoses together and took it for a drive. As soon as it got hot it stayed hot. Usually when the temp rises I turned the heater on and it would drop the temp. Now I had no heater and it stayed hot. I let it sit for an hour and when I went to drive it again it got hot quickly.
Next stop the dealership, I will let everyone know what they say.

 

UPDATE- after last week I had had it with the car and was at Auto zone getting more dex-cool and was looking at the head gasket repair items. I know what you are thinking- that stuff does not work. I have been told by many people that you cant fix a blown head gasket with a bottle. I agree but dont know what I was thinking and bought it anyway because it said double your money back guarantee so I thought there was nothing to loose. It was a product from called K&W nanotechnology permanent head gasket and block repair in a green bottle. I hope this does not sound like a comercial or anything but it worked!
The car has not even past the normal since. All I had to do is flush the system of all coolant add the bottle to the upper hose, top off with water and run the car for 20 min. drain overnight, flush system. refill system and now everything is cool.
I dont know how long it will work for but its running good for now.

 

its been 2+ years .. how is that repair doing?