Hello!

My car is a late 2014 2.0 Tdi Vrs, engine code CUPA and 6-speed manual gearbox. Mileage at the moment is 210k km.

Yesterday i noticed that my cars temperature gauge wouldn't reach the 90 degree mark. It was +5-7 Celsius outside when driving.

I had just the day before yesterday removed a "windguard" from the lower grille in the front bumber. The windguard helps to get to operating temp faster and keep the engine warm during winter time here in Finland, i dont use the cars auxiliary heater/webasto when driving, only before starting the car when its minus degrees outside for like 15-30 mins.

Ok, so today i took a drive and connected my Obd11 to the car and followed the coolant temperature while driving around. I was driving for 60-90 km/h for like 20 minutes and the coolant temp wouldn't rise over 70-71 Celsius according to live data in Obd11, the cars temp gauge read about 80-83 at the same time.

I then went off to motorway and accelerated hard a couple times from 100-140 km/h and also drove in the motorway for maybe 10 minutes with a constant 120 km/h, Obd11 showed that temp wouldn't rise over 75 Celsius and the cars temp gauge was reading 90 Celsius, just in the middle of the temp gauge. The maxidot display showed that oil temp was 87-93 Celsius when driving in the motorway.

I also put the heater on max temp and full blow from the top vents, the air was warm but not hot. The temp gauge and obd11 readings would drop by a few degrees this point, but would come up after putting the heater setting back to 22 Celsius and Auto-mode blowing.

The outside temperature was also this day 5-7 Celsius when driving around.

Do I have a faulty thermostat/stuck open, a faulty coolant temp sensor or something else? Or is it a normal operating temp for 2.0 Tdi when its early Spring outside temperatures here in Finland.

Searching the web says that normal coolant temp is 75-105 Celsius, but i would have thought that if the car is Ok, it would reach about 90 Celsius real temp in normal driving when ambient temp is over 0 Celsius.

The cars coolant level is ok and I have replaced my coolant bottle with the version that doesn't have the silicate-bag in it. I also don't loose coolant.

Is there something wrong with my car or is this normal temps this time of the year?

Thank you!

I would recommend with replacing the thermostat first

Thanks for the reply.

I have watched videos and read from the web instructions how to change the thermostat and coolant temp sensor.

They dont seem to be hard to replace, but the coolant bleeding process is pretty akward in this engine type.

I have Obd11 but dont know if I can bleed it right with it?

Any other suggestions for the possible fault?

And tips for bleeding the coolant system?

And what I really want to know is my cars behaviour and the coolant temps normal before I go changing parts?

2 minutes ago, Jo88Mak said:

And what I really want to know is my cars behaviour and the coolant temps normal before I go changing parts?

I would say no, even on a 10 mile run my 1.8TSI reaches nearly 100C, and over 90C on a 5 mile run. Like already said I would change the thermostat as your first step.

Ok, thanks for the reply.

So you are saying that your petrol car reaches over 90C after a 5 mile run, even in colder weather like 0-5 degree Celsius?

Petrols do run warmer and also warm faster, yes?

1 hour ago, Jo88Mak said:

Ok, thanks for the reply.

So you are saying that your petrol car reaches over 90C after a 5 mile run, even in colder weather like 0-5 degree Celsius?

Petrols do run warmer and also warm faster, yes?

That is true. Not directly comparable unless you have got a poster with same engine.

I would really like to hear from fellow diesel owners what kind of coolant temps they are getting in chilly weather?

Im holding back on buying new parts, because still dont know for sure is my car faulty or not. The upper and lower grilles are pretty open in Vrs and when its cold weather, it cools the engine for sure with the cold air blowing.

I have had this car for 2 years now and the two winters that have been, i have used a windguard in the lower grille and that helps to keep the engine warm below 0 Celsius.

Theres only one thermostat and its a mechanical one not electric, so no fault codes coming from that one either i would think.

Also the coolant temp sensor when read with Obd11 live data, shows in my opinion reasonable readings even though they differ from the cars temp meter by showing 5-10 Celsius lower readings when the needle starts to rise from 50 Celsius. I would think that if this was broken it wouldnt show nothing or off the scale readings, also there would be a fault code registered.

Both parts are original from the factory. Am I correct that a faulty thermostat would fail so that its spring gets weak or breaks so that it stays open completely or partially?

1.6 TDI here. Gets up to 90c on the gauge no matter what the outside temp is. What the actual temp is I've no idea as I don't have OBD11 monitoring it.

TDI vRS and My coolant temps are fairly low and i have a big turbo upgrade. In colder weather can take 20 mins to get to temp (90). I have a full DPF/EGR/CAT delete becasue the DPF was kicking the engine fan on even on short journeys.

When it gets to 90 it stays there though and doesnt move at all.

I suggest that if you want your TDI to warm up quicker, you can go down one of two routes:

1) Get a Wabesto preheater installed. If you retrofit a genuine install, you can get the preheater to be timed and kick in 30 mins before you head off.

2) Have a look at Kopachek / SuperSkoda - https://www.kopacek.com/skoda/octavia-iii/octavia-iii-winter-grille-cover-in-great-oem-design-ki-r-glossy-black - this will fit the front of your car, but replacing the front grill is an absolute ars* of a job to do because getting out the existing grill is almost nye-on impossible without breaking the lugs of the grill. That option would work if you have two bonnets - a summer one and a winter one.

Thank you all for the feedback.

Im going to monitor the temps for a moment and when the weather gets warmer if the car doesnt seem to get to the normal operating temp, im going to change the thermostat.

Btw has anyone flushed your coolant system and completely changed from G13 to G12 Evo-coolant?

Do i have to change the coolant to G12 Evo because i dont have the expansion bottle that contains the silica bag anymore?

My timing belt+water pump was changed 2020 with 125k km on the dash, thats when a lot of coolant was changed to new, but not all i think.

Coolant should be changed every five years - especially if you have removed the Silica teabag. I know that some 2015 cars were odd with having to have G13, but basically G12Evo will work up/down from G12-> G13 so you should be good to just use that setup.

8 minutes ago, varaderoguy said:

I suggest that if you want your TDI to warm up quicker, you can go down one of two routes:

1) Get a Wabesto preheater installed. If you retrofit a genuine install, you can get the preheater to be timed and kick in 30 mins before you head off.

2) Have a look at Kopachek / SuperSkoda - https://www.kopacek.com/skoda/octavia-iii/octavia-iii-winter-grille-cover-in-great-oem-design-ki-r-glossy-black - this will fit the front of your car, but replacing the front grill is an absolute ars* of a job to do because getting out the existing grill is almost nye-on impossible without breaking the lugs of the grill. That option would work if you have two bonnets - a summer one and a winter one.

Hi.

I wrote in the first post that i have a factory webasto in the car that I use when the ambient temp is below 0 Celsius.

And I also have a windguard installed in the lower grille also when its below 0 Celsius.

What I was wondering is, that if its normal for the car to get to operating temp when the ambient is like 5-8 Celsius, in the descripted manner that I wrote in the first post...starting from cold without any preheating and without the windguard.

1 minute ago, varaderoguy said:

Coolant should be changed every five years - especially if you have removed the Silica teabag. I know that some 2015 cars were odd with having to have G13, but basically G12Evo will work up/down from G12-> G13 so you should be good to just use that setup.

Maybe the G13 was used in the Euro5 diesels, i have the CUPA-version of 2.0 Tdi.

Heres a bulletin by North America Volkswagen that I found from the web.

MC-10170208-0001.pdf

Okay - applogies - I did find your brief reference to having a Wabasto heater; it wasn't standard in your year, hence why I asked or suggested it.

I'm not entirely sure why you wouldn't use the preheating system if its already installed in your car - its consumption is fairly minimal and why you wouldn't have the frost protection.

Anyhow; this that aside; if the ambiant temperture is constantly low, you might want to see if you can find a themostat that opens at a lower temperature, but that is quite an extreme solution and you should need to replace it for the summer (when it warmer).

1 minute ago, Jo88Mak said:

Maybe the G13 was used in the Euro5 diesels, i have the CUPA-version of 2.0 Tdi.

No - G13 was still present until 2017/2018. It was removed from sale as it wasn't environmentally friendly, and eventually replaced by G12evo (which if you go to VAG, they will sell you G12ebvo as a part replacement for G13 coolant)

2 minutes ago, varaderoguy said:

No - G13 was still present until 2017/2018. It was removed from sale as it wasn't environmentally friendly, and eventually replaced by G12evo (which if you go to VAG, they will sell you G12ebvo as a part replacement for G13 coolant)

Ok, thanks for the info.

4 minutes ago, varaderoguy said:

Okay - applogies - I did find your brief reference to having a Wabasto heater; it wasn't standard in your year, hence why I asked or suggested it.

I'm not entirely sure why you wouldn't use the preheating system if its already installed in your car - its consumption is fairly minimal and why you wouldn't have the frost protection.

Anyhow; this that aside; if the ambiant temperture is constantly low, you might want to see if you can find a themostat that opens at a lower temperature, but that is quite an extreme solution and you should need to replace it for the summer (when it warmer).

I am using webasto and windguard when its below 0 Celsius. I have just noticed that on a longer trip with the windguard in the lower grille installed the oil temp in the maxidot would get as high as 110 Celsius. Is this too high oil temp, if you drive like 2-3 hours straight.

Without the windguard the oil temp stays at 90-93 max below 0 Celsius ambient.

2 hours ago, Jo88Mak said:

I have just noticed that on a longer trip with the windguard in the lower grille installed the oil temp in the maxidot would get as high as 110 Celsius. Is this too high oil temp

Its an optimal oil temperature.

2 hours ago, Jo88Mak said:

Is this too high oil temp, if you drive like 2-3 hours straight.

Its hot; you wouldn't want it to go any higher. I would remove the windguard when it get warmer (above 8-10C)

Up to a constant 125°c is fine with occasional higher demand peaks.

Oil has to reach the temperature where it can boil off condensation.

So if water boils at 100C then the oil temp is best to be little bit over that 100C mark to get rid off condensation.

So when its colder weather and the oil wouldnt get over 90 without the windguard in place, is not good because the condensation doesnt boil off. Thats also a good reason to keep the windguard in place, engine gets to temp faster, stays warmer easier, oil stays good and fuel consumption and emissiona are better also.

Yes. That's generally true also. One of the reasons why you can get a lot of water contamination in oil on short trip vehicles.

Hi, I have 2015 2.0 TDI CUNA and I live in Finland. In 20 minute highway trip it easily reaches 90 C with/without wind mask & with/without Webasto. Seems you have some issues.

You could try how the hose to radiator feels after 30 minutes of webasto use before you start the car. If it is obviliously faulty it will be warm. Does not necessarily mean the thermostat is OK if the hose is cold since it also can open early ie. at 75 C which is more likely to be reached during driving.

So if the OBD says the temperature is 75 C you could also try the radiator hose after driving since the thermostat should not be open. Be careful with the fan and your fingers.

Oil temps seem normal tho, might be the sensor.

Also, faulty thermostat usually causes webasto to seem heat weaker than before, have you noticed this?