1999 Chevy Lumina Heater/Cooling issue please read

JCORCIONE

MEMBER
1999 CHEVROLET LUMINA
6 CYL
FWD
AUTOMATIC
144,000 MILES

We have a 99 chevy Lumina 3.8 Litre engine. The radiator was replaced 18 months ago and upper and lower radiator hoses and thermostat were replaced about 5 months ago. Now that it seems to be getting cooler outside the heater is blowing luke warm to cool air at operating temp. We also noticed some steam or smoke comming from the front driver side which looks like it is comming from underneath the hose leading to the thermstat. Coolant level is fine in the reservoir and radiator.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,708 POSTS

Hi:
It sounds like there is a leak at the t-stat. The hose, if it was replaced, may just need tightend, or the t-stat housing may need tightend or a new gasket.

As far as the lack of heat, does the temp lever go all the way to hot and work smoothly? If so, there may be a clog in the heater core.

Find the heater core hoses. One line goes in and one comes out. With the car running and at operating temp, carefully feel the hoses. They should both be hot if the heater is on. If the inlet hose is hot and the outlet is only is warm, there is most likely a clog in the heater core.

NOTE: Make sure not to burn yourself on the hoses. THe coolant going through them can reach temps. Of over 200 degrees.

Let me know if this helps, or if you have any other questions.

Joe