Tempture gauge goes up and down and blows cold air all the time

Kelly

• 3740 Answers
• Posted on Jan 27, 2010

SOURCE: car overheating, blows cold air out vents, changed

A couple of things to check because as you describe your symptoms you actually have 2 problems

1. No heat from vents.

Sounds like the heater water flow valve cable is kinked disconnected or the valve itself is stuck You will need to follow your heater core water supply lines to find the valve usually to the right of the center console in the ducting area / large plastic housing for heater and AC internal coils. If the valve works then there is a possibility that the heater core water supply lines have been bypassed on the engine side of the firewall with a coupling due to a leaking heater core. And l;astly the heater core could just be clogged. (quite rare!!)

As for the overheating engine after all of the work you have done.. Perform this simple test.

1. remove radiator cap
2. have someone else start the car
3. watch for water coming out of the open radiator cap area DURING start...
4. have person in the car rev engine gently 2 or 3 times. No need to exceed 2000 RPM. If water rapidly flows out of the radiator during engine revs.. you have some major engine issues.
If it passes all of these checks then the only thing left is improper hose connections on the engine side of the firewall and or a hydraulic water lock in the block that should clear itself by starting and stopping the engine many times with the radiator cap off.

SOURCE: 2004 pontiac gran prix gt

I would suggest replacing the blower motor resistor. When this component fails the blower will only work on one spped or none. This is a very common issue with all automotive models

Luis Rondon

• 56 Answers
• Posted on Nov 19, 2008

SOURCE: 1999 Pontiac Grand Am Overheating

It is probably the problem. To make shure that need to change the gaskets, one of the symptoms use to be thet the temp rises when you are running at speed 50+ average, where is supposed that the car gets a lot of air due by the speed and nobody thinks that will be overheated.