Help! Temp sensor replaced now reads lower!! Genuine VAG

[Stevepd]

Me too, this thread even to find about the other thermostats is immensely valuable. I've just bought our car and the temp gauge did not go above the first thick mark at 45 degrees. I naturally went straight for the main thermostat and changed it for a VW item the found out the ECT sensor had failed so got that changed, now it does go to 90 but takes 12 miles (sadly made a note each day this week) @ 65 mph on my 32 mile each way commute. So today I've ordered the bypass stat from my local VW dealer who has never sold one according to records and I think this will solve my lazy warm up.

Steve

[Human Joist]

Read this. I changed my inline stats last month. Sorted the slow warm up. Did not take long and that included tea breaks.

http://www.mk5golfgti.co.uk/forum/index.php/topic,78341.msg817626.html#msg817626

[homesqueeze]

Sorry to resurrect this, but I thought this would be the relevant place for good info 

Anyway, I have had the secondary inline thermo replaced and it's worked wonders for my slow warm up. Up to temp steadily in 3-4 miles now. However, occasionally the temp will drop back fractionally to about 88 degrees and then go back up. I'm guessing this means I'm gonna have to change the main thermostat as well? Opinions please.

Any thoughts on this guys?

[Human Joist]

Either a temp sensor or man thermostat. If it gets to temp when stationary or in slow moving traffic then drops when you drive then it's the main stat.

[homesqueeze]

Cheers. It doesn't drop back specifically when stationary or low speeds. It's just going back those couple of degrees now and then when driving at any speed. Is the temp sensor also called a temp sender?

[Stevepd]

Isn't there 2?, one on the battery side of the head and the other down in the thermostat housing.

[homesqueeze]

Isn't there 2?, one on the battery side of the head and the other down in the thermostat housing.

Two what? If you mean inline thermostats, then only DSG cars have two, manuals have one.

[xjay1337]

I'd not be too worried personally. If it gets up to temp and then goes SLIGHTLY down and back up (once) and stays at 90...?

I'd say that to be main thermostat.

[Stevepd]

Isn't there 2?, one on the battery side of the head and the other down in the thermostat housing.

Two what? If you mean inline thermostats, then only DSG cars have two, manuals have one.

Sorry two temp sensors. One in the head the other down by the main stat housing

[homesqueeze]

I'd not be too worried personally. If it gets up to temp and then goes SLIGHTLY down and back up (once) and stays at 90...?

I'd say that to be main thermostat.

Thanks. Yeah, i'm not too worried about it, it's nice that it actually gets up to temp now! Just a little annoying that something is still not right. It does it's drop and rise intermittently though, not just once. Might just live with it for now though and maybe try a new thermostat when I get my cambelt done.

[homesqueeze]

Isn't there 2?, one on the battery side of the head and the other down in the thermostat housing.

Two what? If you mean inline thermostats, then only DSG cars have two, manuals have one.

Sorry two temp sensors. One in the head the other down by the main stat housing

Oh right, cheers.

[Stevepd]

Well I had my bypass thermostat changed today and the car warm up was a massive improvement, something close to 3 miles to 90 as opposed to 12 miles before the change.

[Timvgti]

Ok, finishing the story for completeness - I've replaced both of these bypass thermostats today and now my temp goes from ambient (currently 5c) to 90c on the gauge in 5 mins flat and then is rock solid.

If you think you have problems you can remove these bypass stats really easily and just test them in a pan of water.

If you take them out try blowing through them first of all at normal air temp. They should be shut. They should start opening at about 77c and be fully open at 88c, co-ordinating with the main stat opening.

Hi guys, I hope you can help with my 'temperature problem':

I live in The Netherlands and have a 06-2005 AXX DSG mk5 GTI.
My temperature gauge reaches the 90 degrees celcius quite quickly, but I noticed it often points just a milimeter in front of the centered 90 degrees (so say 85 analog degrees celcius).
So I took al look in my climatronic, option 19.2, to see how many degrees my coolant temp digital is. I also used vcds a few times to monitor this temperature.
Digital readings say my coolant temp is around 74 degrees celcius.
I found out that the analog meter stabilizes at 90 degrees when in real life it is between 75 and 108 degrees celcius (stabilizes because otherwise people would get 'scared' seeing the fluctuations all the time).

Digital I can only get 80+ degrees celclius coolant temperature when I do a spirited drive and let it run stationary / traffic jam after that drive.
No real difference between city driving and highways, it just reaches around 85 degrees on analog meter within reasonable time (15 minutes city driving!?), but in real life (digital) this is only around 74 degrees and it won't get significantly hotter.
I think it should also reach around 90 degrees on accurate digital readings? (healthier for the engine?, because my oil temp is also under 90 degrees celcius because of this)
So one of the thermostats must be faulty...

Do I need to replace the MAIN-THERMOSTATE? Or is this one of the two (do I have two?) small thermostates?

[bacillus]

Tim before panicking I suggest you try reading and monitoring your temp with vcds

[Timvgti]

Tim before panicking I suggest you try reading and monitoring your temp with vcds

As you i can read in my post, i did this; climatronic and vagcom.