1999 Cadillac Deville Overheating

CADILLAC DEVILLE
Avatar
PINSEEKER2
  • MEMBER
  • 1 POST
I have a 1999 Sedan Deville. I recently has the thermostat changed with a 180 degree Stant... which was reccommended by the auto parts store. I replaced the fluid with dextron II 50/50.

Since the repair the car has reached temps of 260 and shut off (prior to change the max temp was 222).

What happend? What should I look for?

All advice is welcome.
Mar 22, 2007 at 11:02 AM
Advertisement
Avatar
MERLIN2021
  • ✓Experienced Mechanic
  • 17,250 POSTS
start the car let it reach normal temp. See if the cooling fan comes on. if not try replacing the temperature sensor.
Mar 27, 2007 at 8:15 AM
Avatar
PCADDY
  • MEMBER
  • 2 POSTS
You probably have a blow head gasket or crack head by now. Do you see coolant on the ground near you radiator cap accesss hose? if you do, their might be too much pressure in your cooling system cause the radiator cap access hole to open up and leak out coolant, this can be while you driving and eventually you are low on coolant and cause to overheating. you can have someone or take it to a shop to put in this blue solution in the coolant and run it up at 2000rpm for 5 to 10 minutes. get it hot and see if the blue color change to green. if it is, you have a blown head gasket or crack head. that is what happen to my caddy. I just try this K & W nanatechnolgy permanent head gasket & crack sealer and it seems to work. I now put about 250 miles without overheating. This product is made from this company CRC industries, Napa carries it,part no. 401232.around $20. follow the direction explicitly in order to work. it is inexpensive solution rather than replace the whole motor.
Apr 9, 2007 at 7:08 AM

Suggested Repair

Warm the engine to normal temperature and confirm the cooling fan comes on. If it does not, replace the coolant temperature sensor.

Conversation Summary

The owner of a 1999 Cadillac Deville reports overheating to 260 degrees and shutdown after installing a 180-degree Stant thermostat and Dexron II 50/50 coolant; previously the temperature peaked at 222. An expert advises checking whether the cooling fan operates at normal temperature and replacing the temperature sensor if it does not. Another participant speculated about a blown head gasket or cracked head and mentioned a chemical sealer, but that was not an expert recommendation.

Related Repair Questions

Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle