Ireland 

Unless you're driving down the M1 in third gear, or Vmax, that's not normal. 

 

There's an issue with the inbuilt silica bags that burst. It sounds like yours has, shown by your black header tank before you replaced it. My (non expert) opinion is that the silica has blocked some coolant channels in the engine which is preventing even cooling of the oil. Because some are unblocked, the rad is still maintaining coolant at 90, but it's not getting to all of the block, hence the higher oil temperatures. 

Do you have a VAG specialist near you?

Yes definitely sounds like silica bags has burst, main dealer are quite expensive, so was hoping to know where the main issue is and sort at local garage. Will have to bite the bullet and book it in to main dealer!

Thanks for suggestion though.

1 hour ago, Patent said:

My (non expert) opinion is that the silica has blocked some coolant channels in the engine which is preventing even cooling of the oil. Because some are unblocked, the rad is still maintaining coolant at 90, but it's not getting to all of the block, hence the higher oil temperatures. 

 

Glad you said non expert.

 

The engine oil is the primary engine coolant, it takes combustion heat directly from the underside of the pistons, it also takes heat from all the bearing surfaces, all of this is heat that will therefore not need to be removed by the water cooling system.

 

It is not cooled by the water circulating in the coolant channels in the engine block, it is cooled (and heated) by the water to oil heat exchanger part of the oil filter housing.

 

The only reason that this heat exchanger can help raise the temperature of the oil from a cold start is the clever VAG water circulatory system during the warm up phase with the sliding sleeve water pump and auxiliary coolant pump(s) on a more basic engine the oil will get hot before and quicker than the coolant and those equipped with an oil cooler would also have a thermostat to prevent the coolant from cooling the hotter oil during the warm up.

 

Nobody has yet mentioned that the water temperature guage will show a rock steady indicated 90°c for any temperature between 70°c and 110°c.

 

My oil temperature regularly exceeds 120°c when I am towing, I would not expect it to do so cruising at the NSL during moderate temperatures.

 

I would compare the maxidot indicated oil temperatures with a measured temperature using a probe down the dipstick tube, I would want to be sure that I could trust the indicated reading before doing anything else, I know for sure that I cannot trust the water temperature guage reading.

 

It is indeed possible that the silkat crystals have partially blocked the radiator (they wont have blocked the engine water jacket) and that both the oil and water temperatures are too high as a consequence.

Edited 25 March, 20224 yr by J.R.

Thanks J.R for reply, I def have a blockage of radiator as I only have hot air working on driver side if car the passenger side is not getting hot. So is a radiator partial blockage all my problem?

12 hours ago, Bob3 said:

Thanks J.R for reply, I def have a blockage of radiator as I only have hot air working on driver side if car the passenger side is not getting hot. So is a radiator partial blockage all my problem?

There is only a single radiator that does the entire cabin called a heater matrix, it will constantly be hot.

 

the thing that determines temperature for 1/2/3 zone climate is blend flaps which mix the hot and cold air as requested, 1 for each zone. A blend motor or flap could be stuck causing it 

13 hours ago, J.R. said:

Glad you said non expert.

 

The engine oil is the primary engine coolant, it takes combustion heat directly from the underside of the pistons, it also takes heat from all the bearing surfaces, all of this is heat that will therefore not need to be removed by the water cooling system.

 

It is not cooled by the water circulating in the coolant channels in the engine block, it is cooled (and heated) by the water to oil heat exchanger part of the oil filter housing.

 

The only reason that this heat exchanger can help raise the temperature of the oil from a cold start is the clever VAG water circulatory system during the warm up phase with the sliding sleeve water pump and auxiliary coolant pump(s) on a more basic engine the oil will get hot before and quicker than the coolant and those equipped with an oil cooler would also have a thermostat to prevent the coolant from cooling the hotter oil during the warm up.

 

Nobody has yet mentioned that the water temperature guage will show a rock steady indicated 90°c for any temperature between 70°c and 110°c.

 

My oil temperature regularly exceeds 120°c when I am towing, I would not expect it to do so cruising at the NSL during moderate temperatures.

 

I would compare the maxidot indicated oil temperatures with a measured temperature using a probe down the dipstick tube, I would want to be sure that I could trust the indicated reading before doing anything else, I know for sure that I cannot trust the water temperature guage reading.

 

It is indeed possible that the silkat crystals have partially blocked the radiator (they wont have blocked the engine water jacket) and that both the oil and water temperatures are too high as a consequence.

This was beautiful to read, spot on information and covers everything perfectly.

 

cars often run much hotter than 90, just the gauge will only ever show 90 to prevent people from panicking, a coolant gauge is not a direct connection and hasn’t been for years!

 

spot on about oil being the main coolant too and the thermostat’less engines nowadays.

 

I think most people here are looking into it too much and trying to find a problem that isn’t there.

oil is not gonna sit at 90/100 degrees, it will fluctuate depending on a lot of factors.

My first vehicle with the fiddled water temperature guage was my 2001 Octavia, my chauffeur pal I bought it from commented on how rock steady the coolant temp was, I was used to seeing the minor variations according to engine loading, ambient temp, radiator airflow and the hysteresis of the thermostat, I saw none of that on the Octavia.

 

I'm ashamed to say that it took 5 years for the penny to drop, I don't feel too bad now seeing that after 2 decades it still hasn't dropped for many on here!!!!

I have to drive to Helsinki Wednesday. I will try to set things up that I can log oil temp. Should be about -5C at start and be below freezing most of the way down. Lightly loaded and with limits at 80 / 100km/h that should give a decent indication of how fast temp goes up and where it gets to. I will see if I can log ambient, coolant and oil temps. 

@ApertureS you have VCDS too, no? Could you do the same for a short trip of say 10-15miles at reasonable speeds and post the results? Would be good to see what a higher ambient does. I expect to be towing in the summer 1700kgs of caravan for a while, will attempt to log that too. 

 

 . Bret

So, a log is attached from the first 15-20 mins of the trip down yesterday. You can see ambient was around -7. Aux heating was on for over 20 minutes before getting in the car; load doesn't seem to make much difference to heating speeds. Note also that oil lags way behind coolant. First few minutes is town driving, then onto the motorway, slowing for roadworks and then back to cruise clicked in.

 

This was made with some excel magic (mainly the formatting of numbers) and Carport's logging. I note with interest that the speed is the correct GPS speed, not what the speedometer says. 

 

 

Edited 31 March, 20224 yr by brettikivi

Greetings.

 

I bought a 2017/18 superb 2.0TDI 110KW in november - 230k km atm (brought from the NL) and am also experiencing oil temperature problems - also twice now - 6000km after oil change, the "check oil level" has lighted up and showing minimal oil levels when I check with the rod (no leakage has been found during service).

 

Temp ranges from 92°C while idleing (a week ago it rose to 103°C tho while being idle for 30 min) up to 117°C while driving 90km/h in a snow storm (even the coolant temp rose to 110°C then but that was probably because that coolant froze a month later when it was -20°C outside). Have had the coolant fluid purged and changed twice after that (second time was because I had the engine belt and waterpump changed). Oil temp hasn't gone above 112°C after that.

 

Reading here it seems its not that high but it is still troubleing because I'm getting a stable 105°C on highways 90km/h on D7 with just me in the car and no extra load - even when there is -10°C outside + also...where does the oil dissapear to...

 

And when there is strong frontal wind with snow coming at the car then the oil temp even rises to 108°C while driving 50km/h - like its blocking the cooling system?

 

Also one wierd thing is that when the dpf filter fires up then the oil temp quickly drops to 90°C...shouldn't the filter burning rise not lower the temp?

 

If anyone has any thoughts, I would be happy to hear them. Thank you for your time.

Hi Bob,

 

i am Facing same situation Engine oil temperature goes 124deg C and coolant temperature sits at 90 Deg C .above 124

deg c coolant coming out from

coolant tank .

 

Have your vehicle recovered from

this problem please let me

know the actions taken 

 

thanks 

On 26/03/2022 at 03:35, Bob3 said:

Thanks J.R for reply, I def have a blockage of radiator as I only have hot air working on driver side if car the passenger side is not getting hot. So is a radiator partial blockage all my problem?

Hi Bob3 can you please confirm if you got resolution of the problem and what action has been taken as I am facing same issue