[Paul Berks]

Tonight temp light came on. I checked under the bonnet and got as far as this.
Heater on hot but only cold air, rad expansion bottle not lost any water, the bottom hose on the tank is hot, pipe coming from the distribution housing on the right side hot at rear, the pipe going into the bulkhead hot, and pipe coming out cold. Does this sound like an air lock or possibly water pump or Thermostat stuck??
Should water be coming back through this pipe when running? If it isn't would a stuck thermostat prevent it?

 

[SXI_1.2]

So all hoses are hot apart from the return pipe from the heater matrix, i am no mechanic but would have thought even if the heater were blocked coolant should still flow round the engine and not cause problems, i am sure one of the more technically minded will correct me if i am wrong.

 

[Paul Berks]

Threads merged by Admin.


My corsa D has a heat / water issue.
What I have done/tested so far.
Initially son drove and temp warning light came on, so got him to stop car
Initially I found no hot air from blower, but pipe going into matrix was hot coming out cold.
Replaced thermostat and temp sensor in rad.
Removed matrix, blew out, seemed something was blocking, so run hose through all seemed good.
Put back in car but now no hot pipe going to matrix, bled cooling system, initially cold was coming out, now hot.
Do I still have air in system? running to about 109 degrees fan cutting in, then bit nervous so switching off at that point.
Why no hot water getting to matrix, feeling in pipe bulkhead side it is warm/hot, suggests I still have air, but how do I get it out?

 

[SXI_1.2]

My fan kicks in at 105c so yours is not too far off at 109c these engines are well known for running at those temperatures so nothing wrong there as long as its not boiling over.

Why no hot water getting to matrix, feeling in pipe bulkhead side it is warm/hot, suggests I still have air, but how do I get it out?

You said in your original post -

the pipe going into the bulkhead hot, and pipe coming out cold.

Here is a trick i used many years ago when i had a similar issue, get a short piece of copper pipe and clamp (using jubilee clips) both ends of the heater matrix hoses to it (the ends where they go into the bulkhead) now run the car to temperature and see if hot water is flowing through if yes you have either a blockage in the matrix or a stubborn airlock.

Edit to add -
I am not sure but its worth checking if there is a valve in the heater system that shuts off the hot water supply to the matrix in summer if yes it may be jammed.

 

[Paul Berks]

My fan kicks in at 105c so yours is not too far off at 109c these engines are well known for running at those temperatures so nothing wrong there as long as its not boiling over.
You said in your original post -
Here is a trick i used many years ago when i had a similar issue, get a short piece of copper pipe and clamp (using jubilee clips) both ends of the heater matrix hoses to it (the ends where they go into the bulkhead) now run the car to temperature and see if hot water is flowing through if yes you have either a blockage in the matrix or a stubborn airlock.
Edit to add -
I am not sure but its worth checking if there is a valve in the heater system that shuts off the hot water supply to the matrix in summer if yes it may be jammed.

Thanks.
I have removed matrix, I can run a tap in one end it comes out the other, at the moment not doing that in car, but as I pulled pipes off the matrix water then flowed in from the pipe and that was warm, I am guessing either matrix/air or water pump is the issue, as if pump is not pumping water won't go round the matrix and system, not sure how to rule in/out water pump.

 

[SXI_1.2]

If the water pump was not working surely non of the hoses would get hot and the car would overheat straight away.

Give the copper pipe trick i mentioned in my last post a try to see if you are getting a good flow.

 

[Paul Berks]

If the water pump was not working surely non of the hoses would get hot and the car would overheat straight away.

Give the copper pipe trick i mentioned in my last post a try to see if you are getting a good flow.

Ordered one from Eurocarparts, stick it in, if that don't work only leaves me with water pump.