Hi Guys, looking for some information from the Kodiaq community. Specifically the 2.0 TDI owners.

Owned the Kodiaq since new (2018) Tropical Cairns Australia.

Mechanical Engineer by trade, so very familiar with cooling systems, thermostats, water pumps, old engines, new engines etc.

As expected, towing a heavy load up the mountain range leads to elevated cooling system temperatures (not into overtemp) until good airflow and flat ground is restored.

At this point the cooling system is at full flow capacity, whatever heat is extracted from the radiator is where the engine temp will settle. So some increase in engine cooling system temperature is expected and also observed.

Other than towing a trailer up the range, the temperature needle always sits right in the middle where it should. HOWEVER....

 

A while ago, I noticed that while sitting at the traffic lights (quite a cool morning, only about 12Km down the road from home and this was the first drive of the day) not towing anything, only driving up a very small hill, the water temperature all of a sudden began to rise quite quickly.  I proceeded to drive at the green light, all the time temperatures increased until overtemp warning sounded only about 200m down the road. Within about 2 - 5 seconds, the warning went away, temperatures dropped back to their normal indication and no abnormal indications for the rest of the day.

Following this strange occurrence, I reported this to my service center, who proceeded to find nothing (as expected).

This strange behavior repeated itself many times after that (other than the first overtemp warning, there have been no instances of it reaching the red zone on the gauge), always with the same outcome, "no faults found, cooling system operating normally".

Even stranger, I would observe the engine water temperature to increase while driving along straight flat ground with no obstructions to the airflow (like when closely following a truck), then decrease back to normal again with no change in engine load, vehicle speed etc.

This persisted for about a year, and its now been quite some time since it has repeated the strange temperature spikes.

 

Then about 3 months ago, funnily enough, in our winter (18 Deg C) I noticed that it took significantly longer for the engine to achieve normal operating temperature.

It used to take maybe 1.5 Km down the road, and the temperature needle is bang in the middle where it should be.

Now it takes over 10 Km for the engine to be at a stable operating temperature. Once normal operating temps are acheived, it behaves very normal with no temperature fluctuations.

 

After doing a fair amount of Googling the subject, Ive got a fair idea of what the problem is, however I cant prove it to the service center who continues to find no fault with the system as it is "functioning normally and no fault codes were logged"

In my opinion, based on DR Google, the problem lies with the water pump design. From what I understand, the cooling system temperature is no longer regulated by a bi-metallic spring thermostat, however it is regulated by a sleeve in the water pump which is actuated by the engine management computer. It appears from what i have read, that there are plenty of others out there who have had the water pump replaced due to the sleeve sticking and therefore not properly controlling the temperature anymore.

In my case, I believe that it is not closing properly, allowing water to flow when it shouldnt during the warm up process.

I have even gone to the trouble of downloading a workshop manual so I can do some diagnosing, however the manual seems to be quite light on how long it should take to acheive normal operating temperatures. Also I dont have a vehicle diagnostics tester so that makes it pretty difficult to do certain things.

If there is anyone out there with the same experience, could you please share.

 

If there is anyone interested who owns a 2.0 TDI, would you be able to record the time it takes to achieve normal operating temperatures from a cold engine?

Ideally just while idling in the driveway, however, I guess distance travelled would also suffice.

 

2 hours ago, Klippmann said:

In my opinion, based on DR Google, the problem lies with the water pump design. From what I understand, the cooling system temperature is no longer regulated by a bi-metallic spring thermostat, however it is regulated by a sleeve in the water pump which is actuated by the engine management computer. It appears from what i have read, that there are plenty of others out there who have had the water pump replaced due to the sleeve sticking and therefore not properly controlling the temperature anymore.

In my case, I believe that it is not closing properly, allowing water to flow when it shouldnt during the warm up process.

Agreed, and this issue is well documented in these very fora.

http://briskoda.net/forums/topic/479313-overheating

 

http://briskoda.net/forums/topic/489018-dsg-thermostat-replacement

 

http://briskoda.net/forums/topic/498456-sudden-over-temperature-warning

 

Next time you get the on dash warning grab a video and present it to your service centre. This proves the fault exists and the ball is then in their court.

 

It's an extremely common issue across the VAG range and one I'm surprised your service centre isn't already familiar with.

When I told the local 3rd party VW service guy (Volkstech in Bundoora) down here that I'd bought a Kodiaq he said "I'll see you when we replace the water pump under warranty".

 

 

1 hour ago, silver1011 said:

Next time you get the on dash warning grab a video and present it to your service centre. This proves the fault exists and the ball is then in their court.

 

It's an extremely common issue across the VAG range and one I'm surprised your service centre isn't already familiar with.

Thanks for the input. As stated in my post, other than the first overtemp notification, its never gotten that hot again, and now it doesn't fluctuate, it just takes forever to reach normal operating temperatures. I spent quite a many drive with the camera in hand to try and capture the moment.

The problem is my service center is not very switched on...... 😞 i have to explain everything 3 times, then get passed onto the next person etc.....then they still get it wrong. Im looking for information that they simply cannot explain away with "no fault codes found, system operating normally" Such as a normal warm up time when idling.

?

How many km do you do from a cold start in winter with 18*oC ambient before the Oil gets to an indicated 90*oC?

 

The issue with your car needs addressing whatever they might say.  That will most likely replacing of a part. 

 

Warm up time when Idling is not something that matters really. It is started and driving and how soon.

The Ambient temp etc. you talk of for winter has not much in common with much of the UK.

 

Your cold start warm up time for the coolant with a 'Cold Start' at 18*oC winter ambient temp would be many people in the UK's Summer temperature.

More towards 0*oC might be a winter temperature to start off at. 

7 hours ago, Klippmann said:

Thanks for the input. As stated in my post, other than the first overtemp notification, its never gotten that hot again, and now it doesn't fluctuate, it just takes forever to reach normal operating temperatures. I spent quite a many drive with the camera in hand to try and capture the moment.

The problem is my service center is not very switched on...... 😞 i have to explain everything 3 times, then get passed onto the next person etc.....then they still get it wrong. Im looking for information that they simply cannot explain away with "no fault codes found, system operating normally" Such as a normal warm up time when idling.

Sounds like the shield in your water pump has jammed in the open position.  If they jam in the closed position, the engine overheats quite quickly.

I wouldn't have thought there would be a fault code associated with it, because the problem is mechanical.  Electrically, the actuator that moves the shield will have received a signal from the computer that tells it to do so, and would be a short or open circuit, so the onboard diagnostics would have no reason to suspect anything was wrong.

Avocet, this is exactly what I suspect, however I have no way of proving it...... and yes, the diagnostics would have no clue that there is an issue. This is why Im looking for information from other 2.0 TDI owners as to how long a 'normal' warm up is.

Went out in it this evening. Ambient temperature 11.5 degrees C.   Rural area, single track roads with hills, relatively light throttle openings.  From startup, it took 6.5 minutes for the gauge to first reach normal, and 3.4 miles (average speed 31 MPH).  There was a lot of standing water on the road though.

This was my water pump (left) taken from a 2.0 TDI 150, despite reduced water pump efficiency there was no overheating issues but I don't tow and the car is never driven hard. RHS is new one

Edited 1 October, 20223 yr by SuperbTWM

13 hours ago, Avocet said:

Went out in it this evening. Ambient temperature 11.5 degrees C.   Rural area, single track roads with hills, relatively light throttle openings.  From startup, it took 6.5 minutes for the gauge to first reach normal, and 3.4 miles (average speed 31 MPH).  There was a lot of standing water on the road though.

Thank you!

The first person who actually answered the question!

Thanks also for the other very relevant info.

 

Good input from everyone else though.

 

3 hours ago, SuperbTWM said:

This was my water pump (left) taken from a 2.0 TDI 150, despite reduced water pump efficiency there was no overheating issues but I don't tow and the car is never driven hard. RHS is new one

Thanks! Why was the water pump changed?

On 25/09/2022 at 05:32, Klippmann said:

From what I understand, the cooling system temperature is no longer regulated by a bi-metallic spring thermostat, however it is regulated by a sleeve in the water pump which is actuated by the engine management computer.

 

On 25/09/2022 at 07:55, KenONeill said:

Agreed, and this issue is well documented in these very fora.

 

The above is incorrect, water temperature is still regulated by a wax capsule thermostat, more than one in the case of a DSG vehicle, the sliding sleeve prevents circulation to provide a faster warm up for emissions and quicker cabin heating response, there is an additional electric water pump to circulate the water through the heater and I think the EGR cooler during the warm up phase when the sleeve is deployed.

 

I think everybody is correct in the diagnosis of a sticking impellor sleeve or its actuator but if you have a DSG vehicle you should also look at the DSG thermostat which will be cheaper and easier to replace.

 

You should also be aware that the temperature guage is software driven with an algorithm that means it will show a rock steady 90°c at any temperature between 70° and 110°, thats a guesstimate it might be +/- 10 or 15°c, whatever it is there is no point watching the guage like a hawk to see small temperature fluctuations, they simply do not register, it will sit at 90°c or drop sinificantly above or below it when the threshold is exceeded.

7 hours ago, Klippmann said:

Thanks! Why was the water pump changed?

 

Not only was the sleeve stuck it had gotten misaligned and was rubbing on the impellor slightly making a noise on tickover. I ran the car with the aux. belt off to narrow down the noise but it persisted so i knew it had to be some component of the timing belt

7 hours ago, J.R. said:

 

 

The above is incorrect, water temperature is still regulated by a wax capsule thermostat, more than one in the case of a DSG vehicle, the sliding sleeve prevents circulation to provide a faster warm up for emissions and quicker cabin heating response, there is an additional electric water pump to circulate the water through the heater and I think the EGR cooler during the warm up phase when the sleeve is deployed.

 

I think everybody is correct in the diagnosis of a sticking impellor sleeve or its actuator but if you have a DSG vehicle you should also look at the DSG thermostat which will be cheaper and easier to replace.

 

You should also be aware that the temperature guage is software driven with an algorithm that means it will show a rock steady 90°c at any temperature between 70° and 110°, thats a guesstimate it might be +/- 10 or 15°c, whatever it is there is no point watching the guage like a hawk to see small temperature fluctuations, they simply do not register, it will sit at 90°c or drop sinificantly above or below it when the threshold is exceeded.

Now thats some good information! Thanks heaps.

With reference to the algorithm displaying temperature, this explains quite a few things.

 

Yes, this is a DSG and I completely agree with replacing the thermostat first due to ease and cost of replacement. However, this vehicle is still under warranty for another year, and while it is under warranty, I cant touch anything myself without upsetting the service centre who will deal with any warrany claims. And I certainly wont get my money refunded if I take it to a third party and ask them to replace the thermostat in order to troubleshoot a problem that will most likely end up with the water pump being replaced.

 

I guess my issue is this, I know there is a problem because since the overheating issues which fixed themselves, it doesnt behave the way it used to..... how can I convince the service center that there is in fact a problem with the cooling system when they take a 10 minute look at it and tell me "There are no fault codes and the system appears to be functioning normally."

On 01/10/2022 at 16:37, J.R. said:

 

 

The above is incorrect, water temperature is still regulated by a wax capsule thermostat, more than one in the case of a DSG vehicle, the sliding sleeve prevents circulation to provide a faster warm up for emissions and quicker cabin heating response, there is an additional electric water pump to circulate the water through the heater and I think the EGR cooler during the warm up phase when the sleeve is deployed.

 

I think everybody is correct in the diagnosis of a sticking impellor sleeve or its actuator but if you have a DSG vehicle you should also look at the DSG thermostat which will be cheaper and easier to replace.

 

You should also be aware that the temperature guage is software driven with an algorithm that means it will show a rock steady 90°c at any temperature between 70° and 110°, thats a guesstimate it might be +/- 10 or 15°c, whatever it is there is no point watching the guage like a hawk to see small temperature fluctuations, they simply do not register, it will sit at 90°c or drop sinificantly above or below it when the threshold is exceeded.

That's interesting!  Two thermostats in the DSG?!  How does that work, please?  (I'm interested because ours is a DSG).

Simple answer is I dont know, I have never had a DSG but have often read of the second DSG stat on here, hopefully others will explain what it does as I would be guessing or Googling and as I rail at others that do that to sound knowledgeable I prefer to state my ignorance.

1 hour ago, Avocet said:

That's interesting!  Two thermostats in the DSG?!  How does that work, please?  (I'm interested because ours is a DSG).

 

The simple answer is you need to control the temperature of the gearbox just the same as you do the engine.

8 hours ago, SuperbTWM said:

 

The simple answer is you need to control the temperature of the gearbox just the same as you do the engine.

Ah, OK, so it's an oil thermostat?  Or is the DSG box water cooled?

There are many more threads since this one for anyone wanting to learn more.

A Guide.

http://briskoda.net/forums/topic/445467-dsg-equipped-cars-second-thermostat

 

34 minutes ago, roottoot said:

There are many more threads since this one for anyone wanting to learn more.

A Guide.

http://briskoda.net/forums/topic/445467-dsg-equipped-cars-second-thermostat

 

Thanks.  So anything with a DSG box has a water-to-oil transmission cooler with a thermostat?

7 hours ago, Avocet said:

Thanks.  So anything with a DSG box has a water-to-oil transmission cooler with a thermostat?

 

I'm not 100% but engines under 2.0 which have the dry cutch might not need the water/oil cooler so won't have the additional stat. I'm pretty confident everything with a wet clutch will have the oil cooler.

On 01/10/2022 at 16:37, J.R. said:

 

 

..You should also be aware that the temperature guage is software driven with an algorithm that means it will show a rock steady 90°c at any temperature between 70° and 110°, thats a guesstimate it might be +/- 10 or 15°c, whatever it is there is no point watching the guage like a hawk to see small temperature fluctuations, they simply do not register, it will sit at 90°c or drop sinificantly above or below it when the threshold is exceeded.

 

Sorry, just coming back to this, because a couple of things today, made me question it!

1.  When starting from cold, the gauge creeps up, bit-by-bit as the engine warms up.  I'd have thought that if it was a "managed" reading that just read 90 for any temperature between 70 and 110, it would jump from 70 to 90 as t warms up - but it doesn't!  The gauge just carries on 75, 80, 85, 90 as it warms up.

2.  I towed a significant weight for the first time today.  About 1.5 tons, on the motorway.  At one point  (see separate thread, 'cause I'm puzzled about this!), it started overheating.  The gauge went past 90, 92, 95, 97 (ish), 100, (ish) and so on.  Max temperature was about 112, briefly.  Reducing speed brought the temperature back down, but again, the gauge move gradually.

All good observations, I will look at your other thread re the overheating, I have towed large frontage storage trailers loaded with probably double that for 500 mile trips and the temperature guage has never risen, oil temperature has reached 115°c perhaps more a few times though.

 

The only way we will know for sure what the difference is between indicated and actual coolant temperature is to run VCDS while driving, something I will not do as i only have vision in one eye and very rarely do I have passengers, certainly not the sort to be happy comparing data fields with a computer on their lap.