Cooling Systemin 1999 Caddy DeVille.


Asked by Aug 05, 2014 at 01:06 PM about the 1999 Cadillac DeVille Concours Sedan

Question type: Maintenance & Repair

My check coolant level warning is coming on.  I am not overheating but I need to add a gallon of coolant every 50 miles.  Had a pressure test done and all was O.K.  Radiator cap seal was bad so he replaced with a Motorad 16 radiator cap.  I'm still getting the warning every 50 miles and the last time I had to add 3 qts. of coolant.  Could the new radiator cap be the wrong one?

2 Answers


The most common cause is a bad thermostat. You can purchase a thermostat, gasket, and some blue rtv and do the job your self. After the car has cooled, locate the thermostat housing, remove the bolts and remove the housing. Remove the thermostat, and the old gasket. Be sure to clean the surface thoroughly. If the surface of the housing has corroded then that will need to be replaced as well. Assemble the termostat, gasket, and housing using the blue rtv. Allow it to cure for an hour at least. Add coolant and crank. Drive 30 miles, leave the car running, check all hoses, hose ends, around the thermostat housing and the water pump for signs of leaks. If you smell a sick sweet smell then antifreeze is leaking out and burning. If the tailpipe has that sickly sweet smell then you may have a warped head or blown head gasket.

1 out of 1 people think this is helpful.

Thank you, I will tell my mechanic what you said.

Your Answer

Add photo

Related Questions

Search Cadillac DeVille Questions

Cadillac DeVille Experts

#1 kikero
Reputation 1,870
#2 Js08016
Reputation 1,300
#3 Cynthiasmith
Reputation 1,260
View All

Related Models For Sale

Used Cadillac Eldorado"
444 listings starting at $2,950
Used Lincoln Town Car"
55 Great Deals out of 2,408 listings starting at $1,542
Used Cadillac Escalade"
377 Great Deals out of 11,171 listings starting at $2,999
Used Chevrolet Impala"
892 Great Deals out of 35,540 listings starting at $795
Used Mercedes-Benz S-Class"
180 Great Deals out of 6,605 listings starting at $2,900
Used BMW 7 Series"
208 Great Deals out of 5,862 listings starting at $2,995
Used Chevrolet Tahoe"
1,039 Great Deals out of 36,536 listings starting at $1,695

Used Cars For Sale

2004 Cadillac DeVille For Sale
346 listings starting at $1,995
2003 Cadillac DeVille For Sale
301 listings starting at $1,600