Coolant temperature sensor

[JasonS]

I noticed that the engine took longer than usual to get up to temp, then didn't stay there and dropped back to 80ish.

I started to worry about the thermostat, mine's a 2.5TDI so tough to get at.

I thought if better take a look and see if it was anything else.

Upon inspection, the CTS seemed to be weeping a bit and after some careful jiggling, I got the plug off to discover that it's full of coolant. I expect that isn't helping.



Fortunately I've been able to source a replacement, so will get that fitted and watch the temperature gauge like a hawk on my next journey.

 

[S4_dan]

Hopefully it was a genuine replacement you got? Pattern CTS's don't often work too well.

 

[swarcup]

Fingers crossed, when mine went. It was ok then the gauge would drop to nothing for a split second and return to normal. It does sound like the thermostat.

 

[pauldazzle]

As S4_dan already stated use a genuine VAG CTS only.

 

[Mike.M]

Weird........must have a crack somewhere to be leaking inside the plug

 

[JasonS]

It's not a genuine CTS, £18 in a green 'Lucas' box. I'll fit this and order up a VAG part as well.

 

[ruffrida]

Dont know what the 2.5 is like bu the 1.9 has a ****ty pipe above it that leaks onto the plug, mine was the same, but it was the pipe rather than the temp sensor its self, but yeh get a genuine 1, all the rest are crap lol.

have you checked your thermostat, very common problem on these

 

[JasonS]

After fitting my non-genuine CTS and driving 70+ miles, the temperature quickly reached 90C and stayed there solid for the whole trip.
MPG seemed a little better as well.

So I'm hoping the thermostat is OK and I'll get a genuine VAG CTS to fit when this cheap one fails..