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Heaters Taking a Long Time to “Get Hot”

ben

Active Member
Nov 26, 2015
87
6
The heaters in my Leon Cupra 280 seem to take quite some time to get hot. It takes in excess of 10 mins for any heat to show and probably excess of 15 mins to get to full heat.

In the meantime, if it starts getting warm and I whack up the flow and heat, it gets colder again.

I do have a coolant leak “suggestive of water pump” according to garage when I had previous work done and am looking to get this sorted.

I’ve had the car since April and haven’t noticed any improvement or deterioration.

Is it likely that this is related to the coolant leak? I can’t think of much else since it will reach full temp but only when the engine is at proper operating temps. The AC works perfect for cold settings.
 

Legojon

I only wanted a remap
Staff member
Moderator
Jul 7, 2015
5,014
2,528
Sounds like the thermostats not opening at the right temperature.
 

Damo H

Carbon Snob
Staff member
Moderator
Oct 3, 2012
3,818
2,248
Car Length In Front
The heaters in my Leon Cupra 280 seem to take quite some time to get hot. It takes in excess of 10 mins for any heat to show and probably excess of 15 mins to get to full heat.

In the meantime, if it starts getting warm and I whack up the flow and heat, it gets colder again.

I do have a coolant leak “suggestive of water pump” according to garage when I had previous work done and am looking to get this sorted.

I’ve had the car since April and haven’t noticed any improvement or deterioration.

Is it likely that this is related to the coolant leak? I can’t think of much else since it will reach full temp but only when the engine is at proper operating temps. The AC works perfect for cold settings.
Possible cause yes, as the engine coolant is what is also used to heat the interior I believe. So if there is an airlock in the system due to coolant loss, then the heater matrix may not just be full of an airlock.

I'm sure someone more technical will confirm if I'm wide of the mark.
 

Damo H

Carbon Snob
Staff member
Moderator
Oct 3, 2012
3,818
2,248
Car Length In Front
Sounds like the thermostats not opening at the right temperature.
Or what he said lol

And this would be fixed by a water pump replacement?
Thermostat is part of the water pump housing.

I'm sure I've read on here that you can replace the thermostat by itself, but a new pump comes with the thermostat. Something about someone not being able to get the thermostat as part of warranty quickly enough so a dealership having to get permission to take it off a pump they had in stock.
 
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ben

Active Member
Nov 26, 2015
87
6
Thanks for your responses. It seems that my thoughts are in line with your ideas. Hopefully this reflects when I finally get round to sorting it out. At the min it’s just like 100ml every 1000 miles or something but looking to get DSG and Diff serviced so will probably get it sorted then, prior to winter!
 

ben

Active Member
Nov 26, 2015
87
6
Just had thermostat housing leak repaired. Issues remain. Any ideas?
 

BigJase88

Jase
Nov 21, 2018
1,075
387
Dumfries & Galloway
How would I sort that out?
Start engine from cold with coolant reservoir cap removed and compress radiator hoses to get any trapped air out of the system. Have heaters on hot while doing so.

that should force any trapped air out of the system

obv replace coolant reservoir cap after doing so
 

BigJase88

Jase
Nov 21, 2018
1,075
387
Dumfries & Galloway
Did you ever replace the thermostat itself?

the thermostat could be stuck open which would then circulate the water round the radiator at all times thus taking forever to get any heat into the system and unable to maintain 90 degree’s water temp.

will also be effecting your mpg if that is the case
 

ben

Active Member
Nov 26, 2015
87
6
MPG isn’t great or terrible -
Get between 26 and 31 so assume that’s normal
 

ben

Active Member
Nov 26, 2015
87
6
So the problem was present before and still remains, could be an air lock I guess caused by initial leak. I’m scared it’s the matrix you see Cos that’s another pricey job and I’ve already spent quite a lot since buying this car in April (4x fuel injectors, fuel pump, thermostat.. plz no more)
 

BigJase88

Jase
Nov 21, 2018
1,075
387
Dumfries & Galloway
I had it done at a JCT600 dealership
You find most dealerships employ school leavers and they work from computer slideshows of how to do a job. Very rarely you will find a real mechanic at any of them.

I suspect air lock would be rotten luck for a matrix on what should still be a relatively new car
 

ben

Active Member
Nov 26, 2015
87
6
Aye - my pals partner works in sales dept so got diagnosis, DSG service and stat replacement for £500 which I thought was a decent price as some places quoted me up to £850 for pump replacement alone!
 

ben

Active Member
Nov 26, 2015
87
6
They reckon a seat master tech looked at the car but they’ll always tell you rubbish like that haha
 

BigJase88

Jase
Nov 21, 2018
1,075
387
Dumfries & Galloway
They reckon a seat master tech looked at the car but they’ll always tell you rubbish like that haha
Aye its always a master tech.

had the same rubbish at a VW garage once they somehow managed to smash a wheel bearing. Personally i think the car fell from a height off a ramp but was assured the “master tech” did the job. Asked to speak to said “master tech” and when he came out he would he lucky if he was 20 years old. Do not believe their nonsense. If he was a master tech he would have his own garage
 
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