Car not reaching running temp? :(

[Asahi]

Recently replaced the coolant flange at the rear of the engine and hose to the heater and filled up with new coolant if that could have anything to do with it. I've tried bleeding the system twice to see if that helps.

Basically the car used to get to 90c on the gauge and stay there. Now it only starts to climb in temp if I drive the car, idling barely moves it.

This morning I drove to work then drove in circles round the car park to bring the temp up close to 90c as I could. When parked it drops more. The Gauge shows abit below 90c and VCDS ranges between 75c - 80c max

Heres some images of the gauge and my reading from VCDS that I had running while driving.

I'm not sure how to diagnose it exactly and what to replace first

Click for Link to photos

 

[pauldazzle]

Stuck Thermostat. Replace with a genuine part not aftermarket.

 

[Asahi]

Stuck Thermostat. Replace with a genuine part not aftermarket.

Ooops, before posting I ordered a Thermostat for collection with ECP, was around £5 with discount. the brand is Circoli, I used this brand for the waterpump when I did the cambelt and no issues so far touch wood. Do you reckon I should cancel the ECP and go Dealership? I'm shelling out quite alot right now for the car and just trying to get it through the MOT this month, (worried about emissions).

Link to part: https://www.eurocarparts.com/p/circoli-thermostat-209660160

 

[Stickystuff]

There’s no issues using a brand new aftermarket thermostat. And the Circoli aren’t too bad a brand so use what you’ve ordered and fit that.

I had it on my A3 where it would get up to temperature on the drive of in slow moving traffic but would go down to 60 ° when driving at anything above 35-40. Mine was stuck open it could be that yours is stuck closed along with not allowing an airlock through if it has one still


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[Asahi]

Went to ECP picked up new thermostat, removed OEM Audi one from car. Put both in a pan of water 90-100c Audi one opened fine alot quicker and also shut alot quicker than the ECP one. I assume this is good as it's meant to start opening at 87c and fully open at 102c.

Turns out the ECP one wouldn't even fit properly into the fitting and turn so just put OEM one back in. All is the same.

Can I assume now that the thermostat is fine as it opened okay in the pan.

Dealership want £32 for new thermostat when I called !!

Circoli on left - OEM Audi on right

 

[Asahi]

There’s no issues using a brand new aftermarket thermostat. And the Circoli aren’t too bad a brand so use what you’ve ordered and fit that.

I had it on my A3 where it would get up to temperature on the drive of in slow moving traffic but would go down to 60 ° when driving at anything above 35-40. Mine was stuck open it could be that yours is stuck closed along with not allowing an airlock through if it has one still


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Just a note, not sure if you know why this might be but mine doesn't even hit 90c on idle.

 

[Gazwould]

Wahler thermostat , genuine housing with Meyle CTS is working very well for me .

Thermostat was the issue but renew CTS whilst coolant is drained down a bit .

Circoli has a poor reputation .

 

[Asahi]

Wahler thermostat , genuine housing with Meyle CTS is working very well for me .

Thermostat was the issue but renew CTS whilst coolant is drained down a bit .

Circoli has a poor reputation .

Is CTS Coolant Temperature Sensor, the green 4pin thing at back of engine?

Where did you purchase your thermostat and sensor from?. Audi quoted me. £42 for a sensor !.

I put in oem.thermostat again and topped it up as I need the car to drive currently

 

[Stickystuff]

The temperature sensor is a common fault among the VAG group of cats this age that could be why it’s not getting up to temperature on the dash.


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[pauldazzle]

I've owned a few VAG TDI's that struggled to get up to & maintain 90C in the Winter months. Would be fine during the Summer though so I wouldn't worry about it if you have TDI.

 

[Asahi]

I've owned a few VAG TDI's that struggled to get up to & maintain 90C in the Winter months. Would be fine during the Summer though so I wouldn't worry about it if you have TDI.

That's good to know, before this I've only owned Ford cars. Yeah I have a 2004 A4 Avant Sport 130 1.9tdi AVF engine. Bought it at around 200k, at 211k now.

 

[Asahi]

The temperature sensor is a common fault among the VAG group of cats this age that could be why it’s not getting up to temperature on the dash.

Is it worth buying one other than genuine for £40 odd pounds?

First result on eBay is cheap, has sold over 3300 and seller has 100% feedback. Seems too good? Unsure whether temp sensor is okay via pattern parts.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/171011609447

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[Gazwould]

I've owned a few VAG TDI's that struggled to get up to & maintain 90C in the Winter months. Would be fine during the Summer though so I wouldn't worry about it if you have TDI.

That's what I used to think , even more so with the EGR disabled .

How wrong was I , new culprit thermostat and it's a rocket to 90 ° .

 

[AudiNutta]

Ooops, before posting I ordered a Thermostat for collection with ECP, was around £5 with discount. the brand is Circoli, I used this brand for the waterpump when I did the cambelt and no issues so far touch wood. Do you reckon I should cancel the ECP and go Dealership? I'm shelling out quite alot right now for the car and just trying to get it through the MOT this month, (worried about emissions).

Link to part: https://www.eurocarparts.com/p/circoli-thermostat-209660160

Cancel this, I did exactly the same as you and then read the reviews!!

OEM is only around £20, I compared the 2 and the construction is different and strength difference in springs is huge.

Don’t make the mistakes I’ve made, certain things need to be genuine.. engine mounts and thermostats are two of them haha! Same with your sensor, if you buy one just buy genuine... why buy a cheap one, save £20 but have to do the same job again in 6 months time and coolant isn’t cheap if you drain it all.

 

[AudiNutta]

Went to ECP picked up new thermostat, removed OEM Audi one from car. Put both in a pan of water 90-100c Audi one opened fine alot quicker and also shut alot quicker than the ECP one. I assume this is good as it's meant to start opening at 87c and fully open at 102c.

Turns out the ECP one wouldn't even fit properly into the fitting and turn so just put OEM one back in. All is the same.

Can I assume now that the thermostat is fine as it opened okay in the pan.

Dealership want £32 for new thermostat when I called !!

Circoli on left - OEM Audi on right
View attachment 194013

Still change it for OEM! I tested mine and it was opening very early, it took a lot longer for the new one to open and close.. a good thing! When I tested it, it had me worried because the new one just didn’t seem to be working it was so delayed to open.

The original was opening too early and over-cooling the engine, fitted the new one and it is perfect now.

 

[Gazwould]

Is CTS Coolant Temperature Sensor, the green 4pin thing at back of engine?

Where did you purchase your thermostat and sensor from?. Audi quoted me. £42 for a sensor !.

I put in oem.thermostat again and topped it up as I need the car to drive currently

Thermostat a local mechanic had a few in stock as common issue , it's a Borg Warner boxed Wahler .

At first I bought a Meyle CTS from a local motor factor but they don't contain a new Onion ring and clip , Murray's Direct , do .

 

[sandis pēlmanis]

Recently replaced the coolant flange at the rear of the engine and hose to the heater and filled up with new coolant if that could have anything to do with it. I've tried bleeding the system twice to see if that helps.

Basically the car used to get to 90c on the gauge and stay there. Now it only starts to climb in temp if I drive the car, idling barely moves it.

This morning I drove to work then drove in circles round the car park to bring the temp up close to 90c as I could. When parked it drops more. The Gauge shows abit below 90c and VCDS ranges between 75c - 80c max

Heres some images of the gauge and my reading from VCDS that I had running while driving.

I'm not sure how to diagnose it exactly and what to replace first

Click for Link to photos

Diesel engine in the idle don't get the job temperature like gasoline engines..... My 1,9 tdi gets the 90C temperature only in driving condition.... After +-8km in summer and much more in winter when is minus degrees..... And I have fitted a new thermostat (mahle)

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[Asahi]

Thanks for all the replies guys, really helpful. I think OEM is the safest betb will cost around £70 for the thermostat and CTS from my Audi dealership so I'll leave it until after my MOT this month.

The spring difference was massive, the circoli was so weak.

 

[Stickystuff]

There’s nothing wrong with aftermarket parts as long as you go for OE quality parts.
A lot of them are made for the manufacturers.

Of course that said going genuine gives you the best peace of mind. At the end of the day it’s what you can afford to spend. But if your aftermarket CTS fails within 6 months that’s something that can happen with genuine. Faulty sensors aren’t only an aftermarket thing and they shouldn’t fail that soon.


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[AudiNutta]

Thanks for all the replies guys, really helpful. I think OEM is the safest betb will cost around £70 for the thermostat and CTS from my Audi dealership so I'll leave it until after my MOT this month.

The spring difference was massive, the circoli was so weak.

Get your parts from TPS. As Audi told me, they can’t even buy the parts as cheap as TPS sell them!

They are a good few quid cheaper.

 

[Asahi]

Get your parts from TPS. As Audi told me, they can’t even buy the parts as cheap as TPS sell them!

They are a good few quid cheaper.

Never heard of TPS, I'll have to find one near me and check them out, thank you!

 

[Stickystuff]

Trade parts specialist. They don’t actually sell to the general public but you can use Usually get parts from them anyway.

But their prices are the same as main dealers so just make sure you ask for discount


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[boffin486]

I just bought one from BuyCarParts.co.uk for mine. Make EPS, I presume thats an OK brand? Its a thermostat & housing combined part - a reasonable cost of £20.52 delivered. Just another job lined up for the old bus......

 

[AudiNutta]

Never heard of TPS, I'll have to find one near me and check them out, thank you!

https://tps.trade/

They have them dotted around everywhere. As above, they aren’t supposed to serve the public.. if they ask your just private trade and I’ve never been refused.

Trade parts specialist. They don’t actually sell to the general public but you can use Usually get parts from them anyway.

But their prices are the same as main dealers so just make sure you ask for discount


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Correct they aren’t supposed to, but as they told me it’s paying customers they’re turning away so providing you accept the trade sales basis it’s not an issue.

They don’t charge the same as dealers though. Audi told me specifically that they can’t even buy the parts themselves for the price I pay TPS. He said that Milton Keynes VAG obviously pay TPS to distribute their parts nationwide, that’s the cheapest way of getting them. If Audi order parts they order from Milton Keynes not TPS, so there are 2 lots of profit on their parts before they even sell them. The parts guy told me if they sold for what I could get parts for from TPS, they would be making a loss.

TPS also have great deals on, if you get a combination of service items you will find they discount things like diesel filters etc by circa 50% or so. Can get 5L of Quantum oil sub £20.

 

[Asahi]

Just a quick update in case it helps diagnose.

Just finished a 40minute odd drive whilst running VCDS next to me monitoring the coolant temp.

When the temp gauge was on 70c (the line inbetween 50 and 90?) VCDS read 71c so I assumed that the temp sensor was okay although alot of people say the gauge in inaccurate.

The temp came close to 90c on the gauge either when I was driving hard uphill or when I slowed down to 20mph say or stopped at traffic lights.

Coolant temp on VCDS averaged 78c the entire drive. Highest it reached was 81c and thats when the dial was bang middle. Temp graph showed a pretty consistent temp.

Link to Photos

 

[pauldazzle]

CTS is ok if it tally's with VCDS.
A lot of VW Passat TDI owners used to block off the front grill in winter to keep temps up, I had a PD 130 Bora that wouldn't get up to temp in winter months, but blocking off the front grill worked.

 

[Asahi]

CTS is ok if it tally's with VCDS.
A lot of VW Passat TDI owners used to block off the front grill in winter to keep temps up, I had a PD 130 Bora that wouldn't get up to temp in winter months, but blocking off the front grill worked.

I'll give that a go cheers. Never thought I'd have this issue aha usually it's the other way round.

 

[Mike B]

I would try and get a better stat.I have read before that these are slow to warm up but should then be able to hold at 90.After all they are designed for a lot colder countries than ours.Blanking the rad off is an old trick but you need to be careful that it doesn't overheat

 

[Gazwould]

CTS is ok if it tally's with VCDS.
A lot of VW Passat TDI owners used to block off the front grill in winter to keep temps up, I had a PD 130 Bora that wouldn't get up to temp in winter months, but blocking off the front grill worked.

Simply not required if everything is working as it should , this morning my Passat AVF got to 90° C on the gauge in 9 minutes / 4 miles , the first minute was at idle clearing the windscreen .

 

[sandis pēlmanis]

Simply not required if everything is working as it should , this morning my Passat AVF got to 90° C on the gauge in 9 minutes / 4 miles , the first minute was at idle clearing the windscreen .

Outside temperature?

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[Gazwould]

6°C .

 

[Gazwould]

Bit quicker this morning at 7° , 3 miles and 8 minutes .

In summer it must be 2 miles / 7 minutes .

This is with the egr disabled !

 

[sandis pēlmanis]

Bit quicker this morning at 7° , 3 miles and 8 minutes .

In summer it must be 2 miles / 7 minutes .

This is with the egr disabled !

Some 1,9tdi has the job temperature problems caused by the belt driwen fan clutch ... It gets old and stucks ... Drives the fan all the time..... (termo clatch)

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[Asahi]

Simply not required if everything is working as it should , this morning my Passat AVF got to 90° C on the gauge in 9 minutes / 4 miles , the first minute was at idle clearing the windscreen .

I tried blocking the radiator with a panel covered it entirely. Did 45 min drive, A & B roads. Temp gauge was similar as before in this post but fan was on I noticed.

Also something I should note, after a 40 odd minute drive I can slowly take the coolant cap off straight away with no issues. I know this is a big no no but I took proper safety precautions but it opens fine, no blowout. Coolant level is not dropping and no leaks. Is this normal for this car?

 

[Mike B]

Complete blanking is risky that's why the fan was running.The rad was probably nearly as hot as the engine.After 40 mins the cap should be under pressure and it wouldn't be advisable to even loosen it until it had cooled down.I still think the stat isn't right.Are you getting good early heat from the heater now its frosty?My 2.5tdi is after 10 mins.

 

[stevey83]

Id still say thermostat

 

[sandis pēlmanis]

Complete blanking is risky that's why the fan was running.The rad was probably nearly as hot as the engine.After 40 mins the cap should be under pressure and it wouldn't be advisable to even loosen it until it had cooled down.I still think the stat isn't right.Are you getting good early heat from the heater now its frosty?My 2.5tdi is after 10 mins.

If the temperature gauge show not more then 90 or 95 degrees there is no risk to overheat the engine

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[Turkster]

I've not read all the replies but for what its worth, buy and use Genuine Audi Parts for jobs like this as ECP and GSF parts will only but come back and bite you in the **** later, there is a reason why they cost more money, you get nowt 4 nowt !

 

[Turkster]

I tried blocking the radiator with a panel covered it entirely. Did 45 min drive, A & B roads. Temp gauge was similar as before in this post but fan was on I noticed.

Also something I should note, after a 40 odd minute drive I can slowly take the coolant cap off straight away with no issues. I know this is a big no no but I took proper safety precautions but it opens fine, no blowout. Coolant level is not dropping and no leaks. Is this normal for this car?

Seriously, are you looking to destroy your motor ? Do you not think Audi Tested your car's performance in -20 degrees before they put them out for sale in 2001 ?

 

[Marky007]

Update or just replace thermostat