Temp Gauge Reading Low - thermostat problem?

[nia573 0]

Noticed the past week or so that the temp needle on my Mk2 Gti 8v (with Corrado 2l 2e engine & clocks) is staying at the low end of the scale even on longish journeys. Initially I thought it was because of the colder than normal temps here in Snowdonia, but the needle barely gets to the 70 degree mark, & will just go over when idling at the side of the house

 

The interior heater is pumping out hot air as normal & I felt the bottom rad hos & that gets hot after a few minutes. I changed the black temp sender at the front of the engine (just the one 4 pin one on 2e engine that does ecu temp & clocks) but its just the same

 

Car was fine up till recently & the rad fan kicked in normally too on hot days (havent had it up to a hot temp for me to hear it recently). Replaced the earth strap from engine to bulkhead/coil in the summer

 

Could it be the thermostat thats stuck? Im thinking if it was stuck closed the bottom hose would stay cold (& so the car may overheat?) but if it was stuck open (like Im assuming) would there any problem with it been like this (other than the car taking longer to warm up on cold mornings perhaps (cos the water's flowing through the complete system when cold)??

 

Perhaps its the gauge itself but I was wondering if a faulty thermostat could cause under-reading of the gauge itself?

 

Car has power steering & from a quick search on here it seems that it would be best to get a new plastic housing for the thermostat too - are they the same for all big block Mk2's - are these ok or is the dealer a better bet:

http://www.vwspares.co.uk/product_in...roducts_id=553

Think Ill get thermostat, housing, coolant etc from AVS too - anything else? (

Is it a PITA to change or fairly straightforward (on my back on the driveway)?

Cheers!

[Supercharged 2]

Yeah - sounds like it's stuck open, easy enough to change and yes buy all the parts including housing and bolts... only thing that makes it difficult will be the PAS bracket which needs to come out the way.

 

You could condsider changing the pump too as you're doing a full coolant change.

[nia573 0]

Ok thanks. Ill be getting the parts from AVS - do the seals come with the thermostat & housing or are they the ones that are listed seperately for 75p?

Also do you know off hand the bolt sizes as AVS dont sell these & I should be able to get some from work if theyre a common size

[Supercharged 2]

They'll be M6 bolts but not sure how long - use stainless though if you can...

 

I'd get the pump from VW if you can - pattern ones don't fit very well

[nia573 0]

Thanks for the advice!

Ordered the bits from AVS including some coolant - always had good service from there!

 

Looking at vagcat.com it shows the bolts as M6 x 22mm so Ill get a couple from work too

Thanks