Temp gauge - possible faults ?

[Stu!!!]

Hi guys,

My temp gauge is occasionally inconsistant, after a few mins of driving, it usually sits at 90 - however, on occasions, Ive witnessed it drop back down to 50, only for it to rise again to 90 just a few mins later.

What is responsible for this ? Thermostat or Temp sensor etc ?

I did use the search function, but couldnt find a definitive answer - any help would be greatly appreciated

 

[quattrojames]

Temp sensor I expect, easiest place to start anyway.

 

[Stu!!!]

Ive just seen a part on ebay, is it a DIY jobbie or specialist job ?

Also, is there any danger or issues driving with a dodgy sensor - may sound silly, but Id rather know either way :icon_thumright:

 

[quattrojames]

No real issues running with it, assuming it's not overheating and isn't the thermostat.

What engine?

 

[Stu!!!]

Its a 1.8T (BEX) - and fortunately, its not overheating, it never rises above 90

 

[quattrojames]

There are a few threads on here about the CTS, here's a useful guide:

:: a4mods.com :: - The Premiere Audi A4 Modification Guide and Pictures Library

 

[boddhi]

Hi

Mine did exactly the same thing - it was the thermostat. Not expensive.

 

[Seeker_UK]

HiMine did exactly the same thing - it was the thermostat. Not expensive.

I assume Audi put the 'stat in a more sensible place in the 1.8 engine.

 

[quattrojames]

I assume Audi put the 'stat in a more sensible place in the 1.8 engine.

Yes they did, saves you a considerable amount of money!

 

[bowen]

where is the thermostat on a 1.8t?

I changed my temp sensor recently, what a ***** that was. so tight no room to move!

 

[pj123]

If the temp drops while there is less load on the engine, i.e. driving down a hill, then it'll be the thermostat. As they get old they get slower to close and dont always close all the way. How old is your waterpump? As the plastic impellers get old they break up and bits travel around with the water in the engine. This plastic can get stuck in you thermostat and prevent it closing properly.

If its the temp sender then it should show up with a vag com scan.

 

[Jama665]

stat is buried under the intake manifold behind the alternator. The housing is plastic with two pipes and a sensor on it. I changed the whole unit as mine was broken. Managed to do it with out taking the alternator off.

But I eventually found out that the problem with mine was the actual temp guage it self. Must of had a dirty connection as i swapped it with the fuel guage and they both work fine now

 

[marktdisport]

id of said your thermostat is at fault not sender ??? senders usually work or they dont never seen one incorrect temps fault etc seems your thermostat is sticking open at times

 

[Stu!!!]

The last few times Ive used the car, short runs admittedly (3-5miles) the temp gauge hasnt budged from 50 .... which is unusual