temp switching between 90 and 95
 

Hi all
this is a new one for me just fro my last trip I had the Cts replaced at the start of the year but when I'm getting is randomly the needle moves from the rock solid 90 up to
95 the odd thing is that when I let the car sit an Iidle it sits at
90 good as gold I have checked coolant and all is fine not smell just this odd move upto 95 and the back down to 90.
any tips ....thinking it could be cts playing up again.
Could do with this as have a house move to save up for.:mad:

cts ??
Have you put scanned it with VCDS?

Coolant Temperature Sensor? The green thing presumably (if it's the same on a D3 as a D2).

Thanks gents

That's what I'm hoping it will be ..I'm off to the garage after work and they're going to plug it into the Vagcom to check..
...its been as good as gold sitting at 90 all the time.

It will be a far easier and cheaper job to do than a new thermostat which when I noticed it happing was what I was thing was the problem.

please make it the CTS

My 'stat just failed and the temperature was just an uncontrollable, steady rise. Got it home by taking the engine covers off and switching the heating full on to assist cooling, taking it easy and stopping every few miles for a cool down. Yours definitely sounds like a sensor issue - I hope! +++

Thank you I hope so......too kids school kits to get and a house move coming up is taking every £££.

Will see what the boys say at the garage

was it a hard job for your stat to be replaced ......all seems fine with mine apart from the reading , on warning lights or crazy fan running. I can have the car sit ideling for ages and it stays at 90....my thinking would be if the stat was the problem then with no air flow it was start to rise up past 90

....so hoping that its the CTS...

:mad: they gave it a check and looks like it's the stat that is playing up

Well, thats not good news. The 'stat requires removal of quite a lot and its generally considered a good idea to replace timing belt and pulleys, water pump at the same time.... which can be a big expense. I just paid that bill today ..... :-( - Dont ask.
However, I am not sure how a 'stat failure/defect can cause the behavior you have outlined. Failure is normally a on/off situation whereby failure leads to it not opening and overheating of the block. I cannot conceive of a failure mode whereby it operates at a different temperature.
BTW, Why was the CTS replaced earlier?

I can bet that bill was ££££.....
it is a odd one as my thinking would be that on idle still then the temp would just get higher and higher on the read out but what we did is was that on the dash it was sitting at 90 all the time but on the Vagcom it was upto over 100. this reading was coming from the G62 CTS I think. Its in with my local Audi indy will not get round to it until Friday at the very earliest. They are going to give it a nother check in the morning just to make sure ....I would be far happier with a bill for a new CTS that a Stat strip down bill.

The CTS was replaced around Feb of this year as it started to play up after having the rad replaced.It was giving no reading at all on the dash , fan running full speed and also the low coolant light was on. As soon as it was replaced all was good...until now:Confused::Confused:.

My D2 has just started to do the same (or similar). It seems OK for ages and sits at 90C, but when I slow down or get stuck in traffic, it starts to rise. Get it out onto a 70mph stretch and it's back to 90C again.

But in slow, uphill driving it gets above 95C (but not quite 100). Both fans are running and the thermostat is recent - so back to the garage that fitted it I suppose.

Would a CTS fault show upon VCDS?

Yours seems like it could be genuine reading, temperature rising when load is higher or oncoming air speed lower.

When my stat failed recently the indicated temp climbed to 100deg plus as you would expect. However, when putting vcds on at home and starting the car, on one occasion the indicated temp showed a steady 95 when vcds show it steadily climbing to 100deg plus. I didn't manage to sort out why there was a discrepancy but it did occur on two occasions when I was trying to see if vcds could reveal any other defect. E.g pump or CTS failure. The stat is stamped as "87deg" so that is obviously when it should open and get the extra cooling of the radiator. The electric fan seemed to kick in at or around 97deg - a fact I ascertained when waiting for the engine to cool down when nursing the car back home after the stat failure. I.e. It would stop working when the temp fell below this as indicated on the dash instrument.

Nothing on the VCDS scan, but I've not seen this behaviour before - the gauge usually sits at a very constant 90C. The pump and thermostat were replaced when the belt was done earlier this year, so if it's either of those, then it's a warranty job.

My suspicions are that it could be due to a sub-optimal pump that isn't coping with the slow speeds and extra load.

Booked in on Monday.

I fell your pain ..hope that it works out ok , gets sorted ok and not to much ££.

Had mine done now ...so will see how it goes.

good luck with yours