Heater not working ?.....Try bleeding it first

[MA70]

Since buying my Supra the heater has never worked properly, blowing air slightly warmer than outside.

Having read with some horror the effort required to change the heater matrix (Great write-up Jezz !) I had been putting off fixing this for some time.

 

After driving the car I noticed that one of the hoses to the heater matrix never got very hot, and when I disconnected it, it seemed full of air. I tried bleeding it by loosening the clamp on this pipe and running the engine. This resulted in water leaking out the joint, but did not fix the problem.

 

Before stripping the car down I decided to try blowing water through the matrix to see if it was blocked. To do this I disconnected the two hoses to the matix, above the engine, close to where they exit the firewall. As this is the highest point in the coolant system I didn't need to drain it at all. I connected a garden hose between my outside tap and one of the hoses (The one passing through the firewall on the left when viewed from the front of the car) and a second garden hose between the other pipe and a bucket half full of water. The hose end must be below the water surface !!

 

.......... A word of caution here ! .........

I do not yet have workshop manuals and am not familiar with the heater system in the MKiv, so I don't know how much pressure the system can take or if there are any flow control valves near the heater matrix (like the MKiii has). If you simply turn the tap on 'full bore' you may burst something and fill your car with water!

 

I switched the ignition on and set the heater to MAX. This was to ensure any valves would be open. I cracked the tap open slightly and checked that air was bubbling into the water in the bucket. This told me that matrix was not blocked and I could open the tap further. When I did this there was a lot of bubbling noises from the heater matrix and a lot of air bubbling into the bucket. After a short while the bubbling subsided leaving only water in the system.

 

I turned off the tap, and sealed the garden hoses to prevent syphoning. I then reconnected the heater hoses and briefly ran the engine with the clamps loose.

 

After doing up the clamps, checking the coolant level and running the car, I was very happy to have lovely HOT air comming out of the vents.

 

The whole process took about 45 minutes and is well worth a go if the alternative is a major strip-down, a new matrix and a air-con re-gass

[shervin_ice]

how much did u paid for ur matrix?

[Scoboblio]

Unless I read it uncorrectly..... he didn't buy one.

[merckx]

how much did u paid for ur matrix?

Nothing.

 

It's always satisying when you can fix something and save some money.