Hi Guys,

Havbe done a quick search on the subject but i can't really find a specific answer.

My car (vRS 1.8T) usually displays a temp of 90degs. Recently its been showing around 80-85, sometimes drops to 75 if its quite cold outside.

From what i've read about the Temp senders they usually show symptoms different to that (either show nothing or fluctuate between nothing and 90degs).

I've seen on other cars where the thermostat isn't functioning correctly and the engine runs cooler than usual due to it being stuck open, could this be the case? Is it common or not?

Cheers,

Phil

Hi Guys,

Havbe done a quick search on the subject but i can't really find a specific answer.

My car (vRS 1.8T) usually displays a temp of 90degs. Recently its been showing around 80-85, sometimes drops to 75 if its quite cold outside.

From what i've read about the Temp senders they usually show symptoms different to that (either show nothing or fluctuate between nothing and 90degs).

I've seen on other cars where the thermostat isn't functioning correctly and the engine runs cooler than usual due to it being stuck open, could this be the case? Is it common or not?

Cheers,

Phil

I may be wrong but I believe they have a stabiliser circuit built in to give a constant central reading. If this had failed, this would allow the temp gauge to give the true reading, cooler on cold days?

I know that the previous owner had to replace the CTS when he first bought the car, so it has been replaced within the previous 18 months or so..

depends on whether the previous owner did go for a cheap-crap ebay CTS or a genuine one. CTS (the new green revision) don't quite fail often... and if they do it's usually the ECU feed not the one for the gauge. is the CEL on ?

i'd slam VAGCOM on the car first to verify the ECU feed of the CTS. if the readings stay constantly around 90 it's either the CTS, a wiring fault or the well known instrument cluster fault. if not, you might have an open thermostat (although 75 is kinda low even for a thermo problem in my opinion)

Mine does it when its really cold need to get round to change the stat

I've got a similar problem ATM where when going down hill at motorway speeds, on a light throttle opening the temp gauge starts to drop, but then when back on throttle it climbs again. And it's taking longer to warm up from cold than it used to. I have a new thermostat that I'm gonna change over the weekend so I'll let you know it that's solved it. As I already have a green temp sensor ts the next logical step to change the thermostat.

In order of cost and effort to fix it could be:

Coolant temp sensor

Thermostat

Water pump

I'd get a fault code scan first that should show if the CTS or Thermostat is bust (you should get a 17704 fault code).

Tips for changing the thermostat on this thread:

http://briskoda.net/forums/topic/150282-thermostat/

Unless it's gone open circuit the CTS doesn't usually cause the ECU to throw a code. (17704)

I'd put my money on the stat being stuck open.

No CEL on.

I've just bought a cable and going to plug in with VCDS lite to see what's what (might as well seeing as the cable was only £19).

Start with thermorstat as mine was doing same, changed thermorstat and its been fine since

Buy a genuine thermostat. Topran one failed for me about 6 months later from GSF.

My car was doing just what you describe, and changing the thermostat fixed it. Here's my recent thread http://briskoda.net/forums/topic/219845-is-this-a-stuck-thermostat/page__p__2585934#entry2585934

Can you purchase genuine ones online? I'm miles away from a VW/Skoda/Audi garage!

Allams Skoda of this parish have an online parts shop, as do Dennis Horton in Lincoln.

Changed my thermostat at the weekend as I had this very similar problem and pleased to say it fixed it as I hoped. It now warms up alot faster and dosnt drop when going down hill on the motorway. I found that you don't need to remove the oil dip stick extension tube as its not really in the way. I was prepared for it to be a PITA as reported by people. But it turned out to be pretty easy to do.