[Quago]

Hello! New day another problem with this car.
Noticed this yesterday while towing my boat, I could see the gauge go from 90 down to 70 when slowing down to take a turn, then dropped even more while accelerating after the turn.
Engine coolant temp read 68-73c 73 being 90 at gauge and 68 being 68 at gauge
Oil temp 83-85c
It does not behave like this while driving in town where the temps are good.
Im looking for someone who had this problem and can tell me what it was before throwing parts on it.

Edit: it reaches 85c then starts rapidly dropping to 70 to pretty much stay there. Hm open thermostat?

 

[Black Grouse]

The Touareg's temperature gauge is artificially managed - if you use VCDS or Scangauge plugged in to the OBD port and read the actual sensor values they can be very different - during the warm-up phase the gauge will show 90 when the sensor has only reached 60-70 - so you can't rely on the gauge for diagnostic purposes.

Your fault could be faulty thermostat or faulty gauge - but you need to know the actual sensor values to do the diagnosis.

 

[Quago]

The Touareg's temperature gauge is artificially managed - if you use VCDS or Scangauge plugged in to the OBD port and read the actual sensor values they can be very different - during the warm-up phase the gauge will show 90 when the sensor has only reached 60-70 - so you can't rely on the gauge for diagnostic purposes.

Your fault could be faulty thermostat or faulty gauge - but you need to know the actual sensor values to do the diagnosis.

I checked obdeleven, the gauge called 'Engine coolant temp'. I monitored this from cold start, the gauge in the car shows 90 when that shows 70.
The obdeleven gauge climbed to 85c then rapidly dropped to around 70 and it never raised above 73 after that.

 

[adidas]

Thermostats.

 

[SaVAGeSoot]

What engine are you talking about? You could have 2 or 3 CTS. Need to look at multiple things to isolate the problem or failed component.

 

[voortreger]

My v8 had strange temperature readings that disappeared after a new water pump and thermostat.

 

[Quago]

What engine are you talking about? You could have 2 or 3 CTS. Need to look at multiple things to isolate the problem or failed component.

The CRCA engine

 

[Quago]

Thermostats.

Thank you.

 

[SaVAGeSoot]

The CRCA engine

I have to look it up, but that sounds like the 2nd gen, so similar to our CNRBs, meaning that you'll have 3. Monitor all 3 plus the oil temp and rad fan to see what it reveals. Has the coolant system been correctly filled and bled?

 

[PRY4SNO]

Has the coolant system been correctly filled and bled?

Air pocket was the first thing that came to mind.

Monitoring the delta between the sensors and the gauge is also crucial before loading up the parts cannon.

 

[Quago]

I have to look it up, but that sounds like the 2nd gen, so similar to our CNRBs, meaning that you'll have 3. Monitor all 3 plus the oil temp and rad fan to see what it reveals. Has the coolant system been correctly filled and bled?

I have had this car since december and done like 4000km, ive not even opened the coolant reservoir and the level is the same, ill check all the cts tomorrow omw to work.

 

[Quago]

Update: i drove the car hard this morning while monitoring the temps and they all looked good... 92-98c engine outlet coolant temp
Oil temp 90-101 depending on the driving
Then just cruised for a while. The problem seems to have disappeared for now 🤔

 

[SaVAGeSoot]

Well done on not doing anything that was suggested.

 

[Quago]

The crca engine right?

Yes

 

[Quago]

Well done on not doing anything that was suggested.

Thank you, but I did, I could not see anything off?

 

[Quago]

Okay now everything is off again, this is the stuff i can read with obdeleven

 

[SaVAGeSoot]

I repeat.....

Monitor all 3 plus the oil temp and rad fan to see what it reveals.

Ideally, you should be logging the data, since you can't spot anything, and you're not showing us anything....
Also, whatever limitations ODBeleven has are irrelevant to the troubleshooting... either figure out how to do it with what you have, or get what you need... or start throwing parts at it.

 

[Quago]

I repeat.....

Ideally, you should be logging the data, since you can't spot anything, and you're not showing us anything....
Also, whatever limitations ODBeleven has are irrelevant to the troubleshooting... either figure out how to do it with what you have, or get what you need... or start throwing parts at it.

The only thing i can see is that the thermostat opens at 70c, coolant temp.

The only way to get it to dont do this is to drive the car hard to get The engine oil to 85+c then everything to work as normal. This seems like a sensor problem to me? Im sorry i dont got the right stuff to monitor this.. obdeleven is what i have at the moment.

 

[Quago]

Thermostats.

I have one in the oil filter housing and one next to the waterpump, correct?

 

[SaVAGeSoot]

You're not getting it.
Unless you're able to look at\monitor all the sensors your engine has, you're not isolating the problem.
Do you understand that your have 3 CTS?
Have you looked at 3 different CTS to compare what they are reading, and to use that information in conjunction with what the rad fan is doing, and what the oil temp is?