Why does my heat work only when I get to a certain speed? Coolant levels are where they should be. I've had the radiator flushed, replaced the thermometer, radiator cap, and heater control valve.

Asked by Feb 03, 2015 at 11:53 PM about the 1988 Cadillac DeVille Base Sedan

Question type: Maintenance & Repair

I have a heater issue. My heat only works when I hit about 30 mph. It stays hot only if I
maintain or increase that speed. I have replaced the thermostat, flushed the radiator, and
replaced the heater control valve. My vehicle is a 1988 Cadillac DeVille. It has
approximately 90,000 miles and seems to be in good condition otherwise. The ac service
light comes on and throws the system into ECON mode instead of AUTO.

2 Answers

95,035

I've seen this a couple of times, both times it was the water pump impeller was partially corroded away, might not be your problem, but just a thought if it has never been replaced.

20

i have a similer problem with my 93 i'm going to replace my heater core it may be clogged from age. when i flushed the system the coolant was really rusty looking and its never been done.

Your Answer

Add photo

Related Questions

Search Cadillac DeVille Questions

Cadillac DeVille Experts

#1 kikero
kikero
Reputation 2,140
#2 Js08016
Js08016
Reputation 1,820
#3 Cynthiasmith
Cynthiasmith
Reputation 1,580
View All

Related Models For Sale

Used Cadillac Eldorado
349 listings starting at $2,450
Used Lincoln Town Car
36 Great Deals out of 1,791 listings starting at $1,500
Used Cadillac Seville
3 Great Deals out of 330 listings starting at $1,100
Used Ford Mustang
537 Great Deals out of 45,845 listings starting at $1,999
Used Chevrolet Corvette
147 Great Deals out of 20,685 listings starting at $3,995
Used Dodge Charger
451 Great Deals out of 29,327 listings starting at $2,300
Used Chevrolet Camaro
245 Great Deals out of 31,195 listings starting at $369
Used BMW 7 Series
164 Great Deals out of 5,957 listings starting at $2,999

Used Cars For Sale

2005 Cadillac DeVille For Sale
234 listings starting at $2,450
2003 Cadillac DeVille For Sale
205 listings starting at $1,988

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.