Thermostat location

[Dunkf]

Hi All

Hope everyone is trying to stay safe at the moment.

The old Yeti seems to be fairly slow to warm up in the morning, obviously it has been chilly.

I was wondering if anyone knew the location of the thermostat? I thought that as They are (usually) a cheap part it would be worth changing it.

Its a 2009 4x4 2.0 TDI 170.

I’d like to know whether it’s worth doing Myself or if it’s buried in the engine bay it may be worth getting the local garage to change it

Cheers

Dunk

[langers2k]

It's not an easy job, I think the book time is about four hours as it requires taking quite a few parts off to get access. When the dealer did mine, they had a few issues with a leak and bleeding so it took an entire weekend to complete the job...

 

 

They used part 03L121111AE, it might not be the correct one for your car but will give you an idea what it looks ike.

 

Do you have a manual or DSG gearbox? If it's a DSG, there is a second thermostat that's a more common failure and also much easier to reaplace :)

[Dunkf]

Hi Langers
it’s a manual.

as I have some time off I’ll have a look underneath and identify it with Your part no info

then I’ll decide if it’s worth bothering with

i did look earlier and everything is so tightly packed into the engine bay I started to lose interest a bit!!!!!

thanks

[langers2k]

This might give some ideas too:

 

edit:

There is also this thread https://forums.tdiclub.com/showthread.php?t=371430

Edited 27 March, 2020 by langers2k

[Dunkf]

WOW

I think I’ll put up with it until it absolutely needs doing. . . Then get Our local VAG specialist to do it. 
I feel that I would be capable, but not sure I’d have the patience 

thanks again 

[langers2k]

Heh, that's pretty much what I thought when I saw what was invovled

[silver1011]

Are you saying it's getting slower to warm up, or just that it's slow to warm up?

 

There have been many threads over the years from diesel owners unhappy with how long it takes heat to make it's way into the cabin during the colder months.

 

Diesels are more thermally efficient than petrol engines so take much longer to warm up, but Skoda rarely fit the ceramic heating elements in the heating system too, and those that they do fit aren't overly effective , at least compared to those from some other manufacturers.

[Dunkf]

I‘ve had it around 14 months and it’s always been slow to warm up.

It may just be this car, but the last 2 diesels (Peugeot) would start to defrost a windscreen within 5 mins of running on the drive and then be up to temp within a couple of miles.

[Llanigraham]

How long does it take to warm up?
 

[Dunkf]

My journey to work is 20 miles that takes around 35 mins, mixture of 20, 30 and 60 mph roads. At this time of year it sometimes doesn’t reach full temp by the time I get to work

[Llanigraham]

38 minutes ago, Dunkf said:

My journey to work is 20 miles that takes around 35 mins, mixture of 20, 30 and 60 mph roads. At this time of year it sometimes doesn’t reach full temp by the time I get to work

 

From my experience with a 2010 car that sounds perfectly normal, especially if the slow speed bits are first.

[Dunkf]

In that case I’m glad I checked on here before wasting time/money!

looks like My expectations, based on other cars was a bit high.

thanks to everyone who has given help/info

[Robjon]

2 hours ago, Dunkf said:

My journey to work is 20 miles that takes around 35 mins, mixture of 20, 30 and 60 mph roads. At this time of year it sometimes doesn’t reach full temp by the time I get to work

 

2 hours ago, Llanigraham said:

From my experience with a 2010 car that sounds perfectly normal, especially if the slow speed bits are first.

 

Different animal I know - but my 2009 Roomster TDI used to take a similar amount of time to fully warm up.

[Zib]

On one of those cold mornings, try turning your climate control off completely.  Defrost the screen with tepid water if necessary.  The engine coolant temperature should be up to 90 degrees C within about 5 miles.  Then turn the climate control back on, and you should have a warm cabin quickly after that.  If not, you might have a thermostat problem.

 

I have had VW, Seat and Skoda TDIs, and they have all been slow to get warm in cold temperatures, but the technique outlined above does work.

[Dunkf]

I do defrost the screen with warm water, but have not tried turning climate off completely.

ill give it a go next time I go to work

thanks

[Frenchtone]

 ^  That'll be next autumn then ;-))

[langers2k]

How are you checking the temperature?

 

The coolant guage lies so anything between around ~75 and ~105'C will show as a steady 90'C. If it's not hitting 90'C on a 35 minute drive, there is definately something amiss...

 

I graphed the coolant and oil temperatures when I got my thermostat replaced:

 

[Dunkf]

Hi

Zib, great help, thanks.

although it was around 6 degrees this morning I did as You said. I could see the needle rising within half a mile of leaving home. Around 3 miles it was at 90 degrees. 
Thanks for the help, it has saved either a lot of time and swearing or a lot of money!

Thanks again

Dunk

[Urrell]

On 30/03/2020 at 10:46, Zib said:

On one of those cold mornings, try turning your climate control off completely.  Defrost the screen with tepid water if necessary.  The engine coolant temperature should be up to 90 degrees C within about 5 miles.  Then turn the climate control back on, and you should have a warm cabin quickly after that.  If not, you might have a thermostat problem.

 

I have had VW, Seat and Skoda TDIs, and they have all been slow to get warm in cold temperatures, but the technique outlined above does work.

 

The climate control uses power and the condenser radiator at the front puts out warm air so all I can see is that would help to heat the engine up quicker.
Perhaps you would explain how the opposite occurs.

[Zib]

23 hours ago, Urrell said:

 

The climate control uses power and the condenser radiator at the front puts out warm air so all I can see is that would help to heat the engine up quicker.
Perhaps you would explain how the opposite occurs.

 

The amount of power the climate control uses is quite small compared to the energy used to move the vehicle.

 

I typed what I did based on years of observed experience, not theory, and I am not an automotive or heating engineer.  However, I think the reason is a mix of physics and physiology.

 

As far as I know, the Yeti (and other previous VAG cars I have owned) do not have supplementary heaters in the vehicle cooling system.  When the heater controls are set to heat the cabin, that energy comes from the engine coolant.  On a cold day and from a cold start, the waste energy from the engine heats up both the engine and the cabin, the thermal mass of what is being warmed is quite large, therefore the coolant takes a long time to get to operating temperature.  By leaving the heating off or very low, the coolant will reach operating temperature much more quickly since it is only heating the engine.

 

Movement of cool or tepid air over skin makes us feel cold (the wind-chill effect).  Sitting in the car, even at low temperatures, is much more bearable with little or no airflow.  Even without any other thermodynamic efficiency considerations, the effect of waiting until the engine coolant reaches normal operating temperature, then turning the heat on, means that the air that comes through is properly warm and therefore does not have that cooling effect.  It also means that there isn't a lot of lowish temperature air being flushed through the cabin and out of the exit vents (which in effect wastes the little heat there is).

[SuperbTWM]

yes, its not that difficult to understand, if your taking heat out of the engine nearly as fast as heat is being generated through combustion it stands to reason that warm up time will be longer.

 

The Euro 6 diesels are absolutely brilliant because of their horrendously complicated cooling circuits, they warm up in no time and with the additional electric cabin heater it makes it much more pleasant in winter 

[silver1011]

It was the reluctance my 2x MkII Octavia's, 1x MkIII Octavia and 1x MkII Superb to warm up on frosty mornings that made me appreciate the heated windscreen option.

 

So when looking to replace the Superb with a Mercedes-Benz E-Class I was frustrated at the lack of a heated windscreen option form Mercedes, a bit backwards I thought. I needn't have worried, unlike Skoda, Mercedes fit either a supplementary electric heater or ceramic heating elements in the system somewhere. Simply start the engine, hit the max windscreen defrost button and voila warm air blowing on the screen, a few minutes later completely clear. In the Superb (without the heated screen option) I'd have been sat there ages.

 

Once, when my wife and I were leaving the house at the same time one morning, her in the Skoda Kodiaq with the heated windscreen and me in the E-Class, we watched to see which car cleared the screen the quickest, it was more or less a tie.