Heater wacky
09-03-10, 10:23 AM
#1
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Heater wacky
What could be wrong with the heater in my 1998 LS400?
When I turn the heater on, it usually sends out cold air. This is true in the summer time too.
Sometimes the heater air gets warm briefly then goes back to cold.
Sometimes turning it to Max Hot helps, sometimes that has no effect.
We tried having the repairman who had replaced the starter to check, he checked and said everything they had moved was back in the right place, and that all air ducts were connected.
We tried adding fluid to level, the condition didn’t change.
When I turn the heater on, it usually sends out cold air. This is true in the summer time too.
Sometimes the heater air gets warm briefly then goes back to cold.
Sometimes turning it to Max Hot helps, sometimes that has no effect.
We tried having the repairman who had replaced the starter to check, he checked and said everything they had moved was back in the right place, and that all air ducts were connected.
We tried adding fluid to level, the condition didn’t change.
09-03-10, 10:35 AM
#2
Hi,
Not sure if the later model is the same but there should be a heater flow control valve which is mounted on the rear engine fire wall,there is normally a plastic cover over it which unclips and you should then see the valve with 2 rubber hoses connected to it.
Start the car and allow the engine to warm to normal temperature then get someone to operate the climate control from cold to max and see if the valve is being operated.
You can also disconnect the linkage and manually open the valve to see if the heat is getting to the heater matrix inside the car.
This part has been the cause of similar problems so I would start there.
Not sure if the later model is the same but there should be a heater flow control valve which is mounted on the rear engine fire wall,there is normally a plastic cover over it which unclips and you should then see the valve with 2 rubber hoses connected to it.
Start the car and allow the engine to warm to normal temperature then get someone to operate the climate control from cold to max and see if the valve is being operated.
You can also disconnect the linkage and manually open the valve to see if the heat is getting to the heater matrix inside the car.
This part has been the cause of similar problems so I would start there.
Last edited by steve2006; 09-03-10 at 10:35 AM. Reason: spelling mistake
09-03-10, 03:14 PM
#3
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Would check as steve2006 suggested first.
Had similar prob with my 95. Turned out that one of the coolant lines from the engine to the bottom of the coolant tank had some silicone plugging it. Came from when the water pump was changed out and who ever changed it used too much silicone which squeezed out when re-assembled and eventually came off and plugged that hose. This caused the coolant tank to appear full when actually the engine itself was all but dry. Arrrgh! Good luck.
Had similar prob with my 95. Turned out that one of the coolant lines from the engine to the bottom of the coolant tank had some silicone plugging it. Came from when the water pump was changed out and who ever changed it used too much silicone which squeezed out when re-assembled and eventually came off and plugged that hose. This caused the coolant tank to appear full when actually the engine itself was all but dry. Arrrgh! Good luck.
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