Possible thermostat going bad?

[GTIEagles]

I think the inline stats keep the cooling system compartmentalised until such time as the engine block itself is sufficiently warm.

Once warm enough the inline stats open and allow water to go to the heater core and DSG gearbox.

If your inline stats are stuck open the car will take longer to heat up.

If your main stat is gone not only will the car take longer to heat up but the temperature will actually drop from 90 (ish) to 70 (ish) when you're driving on the motorway.

I'm not sure there was anything wrong with my inline stats but I changed them anyway cos they're pretty cheap and I just fancied fitting all new gubbins.

That's my understanding of it. But I'm open to correction??

Cheers mate, makes sense.  I think I'll change my inline one as well because it still seems to take ages to warm up when cold!

Hi Pudding.

I don't believe a manual Edition 30 has any inline thermostats, only a DSG would have one.

[pudding]

I think the inline stats keep the cooling system compartmentalised until such time as the engine block itself is sufficiently warm.

Once warm enough the inline stats open and allow water to go to the heater core and DSG gearbox.

If your inline stats are stuck open the car will take longer to heat up.

If your main stat is gone not only will the car take longer to heat up but the temperature will actually drop from 90 (ish) to 70 (ish) when you're driving on the motorway.

I'm not sure there was anything wrong with my inline stats but I changed them anyway cos they're pretty cheap and I just fancied fitting all new gubbins.

That's my understanding of it. But I'm open to correction??

Cheers mate, makes sense.  I think I'll change my inline one as well because it still seems to take ages to warm up when cold!

Hi Pudding.

I don't believe a manual Edition 30 has any inline thermostats, only a DSG would have one.

Ah OK, I ordered one from the stealer earlier    I've read manual cars have 1 main and 1 inline, and DSG has 1 main and 2 inlines.  Does that not apply to the ED30 then?

[ducman77]

I thought a manual ed30 had one inline thermostat alright?

[GTIEagles]

I think the inline stats keep the cooling system compartmentalised until such time as the engine block itself is sufficiently warm.

Once warm enough the inline stats open and allow water to go to the heater core and DSG gearbox.

If your inline stats are stuck open the car will take longer to heat up.

If your main stat is gone not only will the car take longer to heat up but the temperature will actually drop from 90 (ish) to 70 (ish) when you're driving on the motorway.

I'm not sure there was anything wrong with my inline stats but I changed them anyway cos they're pretty cheap and I just fancied fitting all new gubbins.

That's my understanding of it. But I'm open to correction??

Cheers mate, makes sense.  I think I'll change my inline one as well because it still seems to take ages to warm up when cold!

Hi Pudding.

I don't believe a manual Edition 30 has any inline thermostats, only a DSG would have one.

Ah OK, I ordered one from the stealer earlier    I've read manual cars have 1 main and 1 inline, and DSG has 1 main and 2 inlines.  Does that not apply to the ED30 then?

It's the earlier manual GTIs that had 1 inline <2006 but after they stopped using them.

To further complicate things DSGs had 2 inline <2006 but after just had 1!

[pudding]

I think the inline stats keep the cooling system compartmentalised until such time as the engine block itself is sufficiently warm.

Once warm enough the inline stats open and allow water to go to the heater core and DSG gearbox.

If your inline stats are stuck open the car will take longer to heat up.

If your main stat is gone not only will the car take longer to heat up but the temperature will actually drop from 90 (ish) to 70 (ish) when you're driving on the motorway.

I'm not sure there was anything wrong with my inline stats but I changed them anyway cos they're pretty cheap and I just fancied fitting all new gubbins.

That's my understanding of it. But I'm open to correction??

Cheers mate, makes sense.  I think I'll change my inline one as well because it still seems to take ages to warm up when cold!

Hi Pudding.

I don't believe a manual Edition 30 has any inline thermostats, only a DSG would have one.

Ah OK, I ordered one from the stealer earlier    I've read manual cars have 1 main and 1 inline, and DSG has 1 main and 2 inlines.  Does that not apply to the ED30 then?

It's the earlier manual GTIs that had 1 inline <2006 but after they stopped using them.

To further complicate things DSGs had 2 inline <2006 but after just had 1!

Weird!  My dealer took my reg and said it showed up as having one.  Mine's a 2007.  Oh well, I'll see if I can find this extra thermostat over the weekend and if it is indeed missing one, never mind.  I'll have one available if somebody needs one 

[lukemk5gti]

I think the inline stats keep the cooling system compartmentalised until such time as the engine block itself is sufficiently warm.

Once warm enough the inline stats open and allow water to go to the heater core and DSG gearbox.

If your inline stats are stuck open the car will take longer to heat up.

If your main stat is gone not only will the car take longer to heat up but the temperature will actually drop from 90 (ish) to 70 (ish) when you're driving on the motorway.

I'm not sure there was anything wrong with my inline stats but I changed them anyway cos they're pretty cheap and I just fancied fitting all new gubbins.

That's my understanding of it. But I'm open to correction??

Hey @ducman77

How much work was involved in changing the inline? My main one is changed and I never had an issue with the warm up time but now it's taking a 25min drive before I get to 90 deg.

I'm manual so I just have the one.

[v4rley]

@lukemk5gti

I changed all my thermostat main and inline 2 years ago, now according to polar fis it's not reaching temperature 

With regard to the inline they are fairly straight forward, you will have one down the front, between your radiator and inlet manifold. I drained the coolant and undid the most reachable pipe clips at the top and bottom and pulled it out with the inline stat in the middle.

[lukemk5gti]

@lukemk5gti

I changed all my thermostat main and inline 2 years ago, now according to polar fis it's not reaching temperature 

With regard to the inline they are fairly straight forward, you will have one down the front, between your radiator and inlet manifold. I drained the coolant and undid the most reachable pipe clips at the top and bottom and pulled it out with the inline stat in the middle.

Thanks @v4rley

I was really hoping it was a screw on so I could rip it out handy enough without draining the coolant.

Can you do the work from the bonnet without removing any gear.... From memory there is enough space there between the engine and battery no?

[v4rley]

I thought the battery inline one is only for the early dsg?
Ok, if it is near the battery I managed to change with coolant still in think I bunged the pipes.

If it's down the front:

If you look at the photos in this thread:

http://www.mk5golfgti.co.uk/forum/index.php/topic,78341.msg963886.html#msg963886

The 3rd photo by dazza has removed the clamp from the bottom hose, then if you trace it back to the top of the engine bay you should be able to pull it up rather than trying to remove the thermostat between the block and the radiator

[r5gtt]

Weirdly enough I have a 55reg late November model and it only has two stats. One near the alternator and one on the dsg box. Some have another inline as mention but I've checked and I've not got one.

[lukemk5gti]

I thought the battery inline one is only for the early dsg?
Ok, if it is near the battery I managed to change with coolant still in think I bunged the pipes.

If it's down the front:

If you look at the photos in this thread:

http://www.mk5golfgti.co.uk/forum/index.php/topic,78341.msg963886.html#msg963886

The 3rd photo by dazza has removed the clamp from the bottom hose, then if you trace it back to the top of the engine bay you should be able to pull it up rather than trying to remove the thermostat between the block and the radiator

You're right!

So I just bought a hose clip pliers and now I'll get my hands on an inline stat - 4E0 121 113

I'll probably tackle this job next month when everything arrives since I cheaped out and bought the pliers for €10 from China.

Ideally I'll bung the pipes so as not to drain the coolant considering it's fairly fresh. Anything that I do lose I'll just top up with my premixed G13+

[Pesky jones]

To further complicate things DSGs had 2 inline <2006 but after just had 1!

Are you confident on this?

[Pesky jones]

Weirdly enough Rightly so I have a 55reg late November model and it only has two stats. One near the alternator and one on the dsg box. Some have another inline as mention but I've checked and I've not got one.

according to

It's the earlier manual GTIs that had 1 inline <2006 but after they stopped using them.

To further complicate things DSGs had 2 inline <2006 but after just had 1!

[mrw]

I believe it's only DSG's that have them over the gearbox / by the battery (Mine's a 08 DSG with one inline in that location).

[Saintsteve]

I've been told that the 2.0 TFsi engines may also suffer with a just a faulty temperature sensor and not the thermostat giving the faulty temp readings. This is a very cheap fix and worth checking before assuming it's the main engine thermostat.

A point worth remembering , if you have a remapped engine, that's also been tuned, your engine will not be producing full power if the engine temps are too low.
I know that R Tech maps have 5 different power settings depending on engine and intake temps readings, that if your running around at 75 degrees, you remap will not be selecting Map 5 or most powerful output one ) .Also as has been mentioned your MPG will suffer if the engine isn't at optimal Readings.