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Topic: No heat from heater (Read 3865 times) previous topic - next topic

Re: No heat from heater

Reply #15 –
I wasn't meaning a hose on full blast  :D
However you could check water is free flowing through the matrix by testing the in out section only
1991 Tornado Red BB 8v GTI Moredoor
2008 Skoda Octy Scout aka dirty diesel

Re: No heat from heater

Reply #16 –
Thanks for the info. Will be tinkering again on Friday.
Hopefully update at the weekend 👍

Re: No heat from heater

Reply #17 –
The temp gauge should go to half way point. if it's not I suspect the stat is not operating properly, however it could be a red herring caused by a faulty temp sensor. I always check a thermostat in a pan on the hob before fitting to comfirm it opens and closes as required.

It's probabbly the coolant flange on the side of the block that was changed. I looks like it should be the termostat housing, and it's a sad state of affairs that a mechanic dosen't know. I have a slight leak from the coolant flange on mine and it came up in the MOT as an advisory, 'leak from thermostat housing'. That would have had me looking in the wrong place.

The thermostat housing is plastic and warps, so I treat them as a single use item. And every time I've done the job the bolt on the water pump sheers also. so I treat the water pump as a replaceable item too.

So new stat, water pump and stat housing and you'll be ready to takle it. If the car is PAS that adds an extra level of pain as the PAS pump needs to be moved out the way.

A test you can do, when running the car from cold the bottom radiator hose should stay cold for quite a while. It's not until the stat opens and lets hot water freely flow into the rad that the bottom hose will get hot.
Make sure car is cold, start car, hold bottom radiator hose, if it gradually gets warm from the start then Stat is stuck open.
If it never gets warm stat is stuck closed.
If it stays cold for a while then suddendly gets hot, stat is working as expected.

The flaps, did you do all of them? Did you do it with the heater box in situ or did you remove and dismantle the heater box? If the later, then makes sense to fit a new matrix while you're there.

If you didn't dismantle you might had missed the bottom flap that shuts off cold air from outside, so even when coolant system is working right you'll still only get slighty warm air inside when vehicle is moving as the cool air feed over powers any heating benefit.

Re: No heat from heater

Reply #18 –
Hi,

Thanks for all the info, it is really really helpful. I’ve just driven about 3 miles in the car. The top radiator hose is very hot, bottom hose warm. Bottom hose does get hot, I remember when I was massaging them on Saturday evening. I repaired 3 heater box flaps while it was in the car, I did the one at the front that moves with the heater direction control and the two that are hinged together, further back inside the box. These moved together when moving the hot/cold control. I’m currently running a radiator flush and will back flush the heater matrix on Friday. Thanks to your info I’m not going to touch the thermostat as it appears to be working and the car does have power steering.

I’m a bit out of practice doing these kind of car jobs as I’ve not done anything for about 34 years, but I am loving the challenge,

Thanks again 👍

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Re: No heat from heater

Reply #19 –
Have you managed to get all the sticky cr4p off your hands from doing the flaps ?  :D
Well done for fixing the flaps in situ you must have small hands or a "cunning" technique/fix.
1991 Tornado Red BB 8v GTI Moredoor
2008 Skoda Octy Scout aka dirty diesel

Re: No heat from heater

Reply #20 –
There wasn't any sticky stuff in the heater box, just lots of small bits of foam.
Not sure about the small hands, but I have lots of cuts/scratches and today they really ache :( .
Must be getting old...
Like the car!

Re: No heat from heater

Reply #21 –
So I've back flushed the heater matrix for about an hour and flushed the whole coolant system.
I've run the car and made sure there are not air locks etc and the heater is slightly better, but still on the cool side.
The in and out hoses to the heater matrix get very hot and the bottom radiator hose gets hot at the appropriate time, so the thermostat is working OK.
Any ideas??

Cheers.

Re: No heat from heater

Reply #23 –
Hi,
Thanks for your reply.
Is this the valve? It goes back into the engine, so I assume (quite possibly incorrectly) it’s a proper part of the coolant system.

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Re: No heat from heater

Reply #24 –
Also the out hose from the matrix has this copper pipe in it. I have paperwork to confirm a new matrix was fitted in about 2011/12, can’t remember the exact date without checking so it’s not 30 years old. I’m reluctant to dismantle all the heater if it could be something other than the matrix.
🚗

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Re: No heat from heater

Reply #25 –
The copper pipe is where the bypass parts would have been

Re: No heat from heater

Reply #26 –
The inlet manifold will also have a
Quote from: Dene on
Hi,
Thanks for your reply.
Is this the valve? It goes back into the engine, so I assume (quite possibly incorrectly) it’s a proper part of the coolant system.

Looks like this connects onto the inlet manifold, which is standard for a carb engine

Re: No heat from heater

Reply #27 –
Ok thanks.
Any ideas about getting more heat?

Re: No heat from heater

Reply #28 –
Get your car up to temperature and check both pipes to the matrix.  Are they both hot hot?  If so get the heater box out and replace your tape with foam.
If they are not hot or if there is a significant difference between them think about flushing or replacing the matrix.
Blockages before or after the matrix feed and return pipes is unlikely so I think the long term fix is box out, new matrix, foam the flaps.

Re: No heat from heater

Reply #29 –
Thanks for the info'
Looks like matrix out is the next step.

Cheers