1994 Cadillac SLS my car overheats when it wants

TORISMOMMY24

MEMBER
1994 CADILLAC SLS
V8
2WD
AUTOMATIC
145,000 MILES

I have a 94 cadi, sls and it overheats when it wants. It doesnt matter if I am stopped, on the freeway or climbing a mountain. Sometime it overheats really bad and sometimes it overheats a little and then goes back down or sometimes I have no problems at all. I have changed the thermostate twice, water pump, radiator fan, flushed radiator, block/pressure test, all done and it is currently in the shop and they have no idea what is causing it. They even ran it for 4 hours straight and could not get it to overheat. PLEASE HELP! Any ideas?

3 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Is it actually overheating/boiling over or just the temperature gauge that's indicating it -If so could be the coolant temperature sensor out of calibration-Could also be air lock in the cooling system, try bleeding it

SPONSORED LINKS

Was this

answer

helpful?

Yes

No

Saturday, September 26th, 2009 AT 9:42 PM

FACTORYJACK

MECHANIC
4,159 POSTS

If it is in a shop, have them block test it for combustion gases in the cooling system. This can be done with an exhaust gas analyzer. After a good roadtest, place the analyzer at the tank as the radiator cap is removed. Anything over 30 ppm hydrocarbons suggests internal leakage.

Was this

answer

helpful?

Yes

No

Saturday, September 26th, 2009 AT 11:31 PM

RASMATAZ

MECHANIC
75,992 POSTS

I have changed the thermostate twice, water pump, radiator fan, flushed radiator, block/pressure test, all done and it is currently in the shop and they have no idea what is causing it.

You said they did the block and pressure tests right-Yea the 5 gas analyzer will catch it by sniffing it out of the radiator open this is our way of being a certified emission control I/M specialist-The gas machine does a lot of wonders to include a vacuum gauge-

Was this

answer

helpful?

Yes

No

Saturday, September 26th, 2009 AT 11:37 PM