# Low coolant light and coolant loss



## IbsFt (Dec 15, 2018)

Does anyone know when the low coolant light is supposed to come on relative to the minimum level line?

Our Tig's level went from just below the min level line to just above the tube connection on the bottom in three months. No signs of external dripping. Low coolant light never came on. Dealer says they pressure checked it for 15 minutes and found no leaks. They never answered why the low coolant light wasn't on. They gave the standard "cold weather" non answer for the level drop, ignoring that they were told the level drop has been consistent since August when I first noticed it was at the min line and for sure it has been going on before that since the car was likely at or above the full line when it left the dealership. Seems like a lot of evaporation if it's not a leak somewhere. 

Do you guys have to regularly have to add small amounts of coolant to keep it at the full level?


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## sp4c3m4nsp1ff17 (Feb 6, 2008)

Yes I have to periodically add coolant as well. Mine is an '18 and last year they had a recall for a connector to the coolant reservoir which could allow coolant to leak out and go up the wiring harness. My connector was replaced and I thought that would solve my coolant loss issue - no dice. No clue where it is going!


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## jjr57 (Sep 17, 2018)

You should both check your water pumps and thermostat housings. They are not easy to see from above and you really should remove the belly pans and look up from below the engine. If you see dried coolant on the front of the block then it's either one, or both, of those leaking. It's a relatively 'known' issue with these engines and it seems to carry on for years. You would think they would have figured it out by now - apparently not.


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## BSM (Jul 4, 2020)

The electrodes on the coolant level sensor are quite visible through the coolant reservoir opening. If the coolant isn’t touching the electrodes, you should have a warning lamp.


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## IbsFt (Dec 15, 2018)

Thanks for the info guys. Some searching about coolant leaks a while back brought up the coolant bottle/connector issue as well as the water pump. Also the thermostat housing as a common VW leak point, though I don't know if that applies to this engine. I pulled the connector back then to check for leakage and it was fine. One of the main reasons to buy the Tig was so I didn't have to work on it for at least 6 years! So much for that naiveté. :banghead: I guess its time to get underneath the darn thing.

I wish VW put out an acceptable coolant consumption number, like they do with oil. It would probably be ridiculously high, but at least it would be a starting point.


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## GTINC (Jan 28, 2005)

IbsFt said:


> Thanks for the info guys. Some searching about coolant leaks a while back brought up the coolant bottle/connector issue as well as the water pump. Also the thermostat housing as a common VW leak point, though I don't know if that applies to this engine. I pulled the connector back then to check for leakage and it was fine. One of the main reasons to buy the Tig was so I didn't have to work on it for at least 6 years! So much for that naiveté. :banghead: I guess its time to get underneath the darn thing.
> 
> I wish VW put out an acceptable coolant consumption number, like they do with oil. It would probably be ridiculously high, but at least it would be a starting point.


Why not just top up the coolant and move on. Virtually every water cooled vehicle made will need a top up, usually in the fall/early winter.


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## Smokebomb1! (Mar 12, 2019)

*Coolant levels*

I also don't like crawling under cars.But this is good advice on being diligent and observant on the fluid levels and warnings that are on these cars.Winters coming so hopefully no one has issues.That 6 year,72,000 warrenty kind of lulls us into thinking nothings gonna happen.Back in the 5,000 mile days,your car was inspected more frequently in the shop.Now 10,000,this makes me believe that the owner has to do more investigations. Get some coolant,oil and windshield washer.Check often,add a bit as needed.Document carefully, in case you need to warrenty.When the light comes on,its sometimes a expensive problem.You don't want to be stranded.When you return from a drive,pop the hood,inspect,sometimes you can see,hear or even smell leaks.I also take part in oil analysis, like a blood test at the doctors, it alerts you sooner.These cars are expensive,complicated.Lots of little things an owner can learn and do to keep them running well.


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## PZ (May 9, 2002)

Coolant should not drop in a sealed system. There could be an air pocket from the factory that could allow coolant level to drop, but it's very rare and it would happen after 1-2 drive cycles. You should be able to go at least a year if not multiple years before you need to add coolant to a newer car.


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## GTINC (Jan 28, 2005)

PZ said:


> Coolant should not drop in a sealed system.....


Automotive cooling systems are NOT sealed! The system has a pressure cap. Just as batteries are not sealed.


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## gerardrjj (Sep 4, 2014)

PZ said:


> Coolant should not drop in a sealed system. There could be an air pocket from the factory that could allow coolant level to drop, but it's very rare and it would happen after 1-2 drive cycles. You should be able to go at least a year if not multiple years before you need to add coolant to a newer car.


THIS!

Engine coolant an air conditioning refrigerant are not expected to leave the system under normal operating situations, low levels indicate a fault somewhere.
Unfortunately my experience with dealership repair techs is they are either lazy, not well trained or not very experienced. Getting them to understand, never mind find or actually fix an issue can be tedious. I'm sure some are great, but it's not generally been my experience.

In the case of coolant I would monitor it. Take a photo weekly with the engine at operating temp, car in the same position and the camera in the same relative location/angle so you can show them a continuous decreasing of the level. The engine being at operating temp _should_ counter any claims of ambient temperature changes causing this.


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## GTINC (Jan 28, 2005)

gerardrjj said:


> THIS!
> 
> Engine coolant an air conditioning refrigerant are not expected to leave the system under normal operating situations, low levels indicate a fault somewhere......


Wrong! The engine cooling system is not sealed and will naturally loose coolant.


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## IbsFt (Dec 15, 2018)

Smokebomb1! said:


> I also don't like crawling under cars.But this is good advice on being diligent and observant on the fluid levels and warnings that are on these cars.Winters coming so hopefully no one has issues.That 6 year,72,000 warrenty kind of lulls us into thinking nothings gonna happen.Back in the 5,000 mile days,your car was inspected more frequently in the shop.Now 10,000,this makes me believe that the owner has to do more investigations. Get some coolant,oil and windshield washer.Check often,add a bit as needed.Document carefully, in case you need to warrenty.When the light comes on,its sometimes a expensive problem.You don't want to be stranded.When you return from a drive,pop the hood,inspect,sometimes you can see,hear or even smell leaks.I also take part in oil analysis, like a blood test at the doctors, it alerts you sooner.These cars are expensive,complicated.Lots of little things an owner can learn and do to keep them running well.


All good points, I used to enjoy all of it, but most of the fun has gone out of it anymore. Once the warranty runs out our vehicles don't ever go back to the dealer (that may change now that everything is a module that has to be programmed to the vin by the dealer). I still have 4 other old cars to maintain / repair. The brand new VW was supposed to lighten the load, not add to it, lol. 



gerardrjj said:


> THIS!
> 
> Engine coolant an air conditioning refrigerant are not expected to leave the system under normal operating situations, low levels indicate a fault somewhere.
> Unfortunately my experience with dealership repair techs is they are either lazy, not well trained or not very experienced. Getting them to understand, never mind find or actually fix an issue can be tedious. I'm sure some are great, but it's not generally been my experience.
> ...


Agreed that the car should not consume coolant, but I am open to (hoping for?) a logical explanation on how these high HP per liter overworked little engines can lose coolant so I don't have to chase it down. I've taken pictures cold in the morning and am considering an oil analysts. Hot is tough since its the wife's car and she typically gets home before me. It is clearly dropping over time so that shouldn't be an issue to prove. Years ago a coworker's car had a tiny leak from one of the head bolts which the dealer couldn't find. We found by pressure testing it for hours with the valve covers off. Not something I'd expect the VW dealer to do under warranty unless the leak was more severe and they had eliminated every other possibility for the source of the leak. Its still frustrating though.


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## GTINC (Jan 28, 2005)

IbsFt said:


> ....Agreed that the car should not consume coolant, but I am open to (hoping for?) a logical explanation on how these high HP per liter overworked little engines can lose coolant so I don't have to chase it down......


Just like every other vehicle on the market for the last 10 decades, it will loose coolant via the pressure cap vent.


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## sp4c3m4nsp1ff17 (Feb 6, 2008)

I've been seeing drops of coolant under my car and pulled the skid plate today while changing the oil. I saw some coolant on the bottom of the A/C compressor as well as the front passenger side of the oil pan - I couldn't see anything coming from the water pump area specifically. I'll be calling the service department as this appears to be getting worse. I'm at around 27k miles.

Pics -


http://imgur.com/a/e4RrRLJ


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## PZ (May 9, 2002)

GTINC said:


> Wrong! The engine cooling system is not sealed and will naturally loose coolant.


 Wrong. It is sealed to the pressure of the cap. The only way for the cap to vent coolant is for the car to boil the coolant. If that's happening, there is something wrong with the car.


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## gerardrjj (Sep 4, 2014)

GTINC said:


> Wrong! The engine cooling system is not sealed and will naturally loose coolant.


It is sealed unless it goes over pressure then it can vent. If the system were not sealed it could not pressurize to raise the boiling point of the liquid.
If it were not sealed you'd be adding water every few days from evaporation alone.


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## sp4c3m4nsp1ff17 (Feb 6, 2008)

Just heard from the service department - leaking thermostat housing. 

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## jonese (Jun 21, 2020)

VW/Audi and their leaking cooling systems. Nothing changes.....


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## gerardrjj (Sep 4, 2014)

jonese said:


> VW/Audi and their leaking cooling systems. Nothing changes.....


I guess people have different experiences. I've owned five VW/Audi vehicles. The only one that ever consumed coolant had a blown head gasket(used '88 Cabrio). Gasket replaced = consumption stopped. These car model years range from '82 through '18.


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## SpoolPls (Dec 1, 2014)

I was really hoping they had figured the thermostat housing out for the 2nd gen Tiguan...not feeling so great about that now. It's been replaced twice on my 15' Golf R and I haven't even hit 70k miles.


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## sp4c3m4nsp1ff17 (Feb 6, 2008)

Plot twist - dealer called today and said once they got the intake manifold off (boy am I glad this is under warranty) the leak is actually coming from the oil cooler, not the thermostat housing after all.

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## blueimp (Sep 5, 2019)

well everything is water cooled these days (including intake charge, throttle bodies, exhaust, hybrid EV components). in short. everything can and will eventually leak lol.


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## duvs182 (Aug 5, 2009)

I got low level warning in 2019 winter with my 2018 Tiguan...called dealer and said it was normal in cold weather ( coolant dilatation cold/hot temp ). So I added coolant ( about 4-5 oz ) After that I had a recall to change coolant connector and bottle....was thinking it'll fix this coolant issues but needed to add 2 oz this summer because level was low....now 2020 winter I have again low coolant warning. Seem like this Tiguan eat some coolant. Adding about 5 oz by year. My old 2203 Jetta 2003 1.8T did that about 4 times with G12 coolant in 17 years but never twice a year. Checked under engine and there is no leak at all ...did someone noticed leak somewhere...seem like this Tiguan consumes coolant ...not good ...


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## IbsFt (Dec 15, 2018)

duvs182 said:


> I got low level warning in 2019 winter with my 2018 Tiguan...called dealer and said it was normal in cold weather ( coolant dilatation cold/hot temp ). So I added coolant ( about 4-5 oz ) After that I had a recall to change coolant connector and bottle....was thinking it'll fix this coolant issues but needed to add 2 oz this summer because level was low....now 2020 winter I have again low coolant warning. Seem like this Tiguan eat some coolant. Adding about 5 oz by year. My old 2203 Jetta 2003 1.8T did that about 4 times with G12 coolant in 17 years but never twice a year. Checked under engine and there is no leak at all ...did someone noticed leak somewhere...seem like this Tiguan consumes coolant ...not good ...


Great info, thank you. If it is true that is normal for these engines consume some coolant, then one would think it would be consistent across the all the Tigs and a “typical” consumption range could be generated. I’ll keep watching ours and measure how much coolant needs to be added over time.


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## IbsFt (Dec 15, 2018)

sp4c3m4nsp1ff17 said:


> Plot twist - dealer called today and said once they got the intake manifold off (boy am I glad this is under warranty) the leak is actually coming from the oil cooler, not the thermostat housing after all.


Has your Tig stop consuming coolant since the repair?

I finally did some rough volume measurements. Max to Min line is approximately 8 oz of coolant. The level to fully expose the electrodes is way down near the bottom of the reservoir and looks to be about 18 oz below the max line.

Assuming our Tig wasn't overfilled at the factory it consumed roughly 16 oz in about 21,000 miles equaling 1 oz lost every 1,300 miles or so. It is still going down. When the dealer did the pressure check they overfilled it so there wasn't a good reference point to quantify the loss until the level reached the max line, which happened just recently. Now to see if continues to drop at the same rate.


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## sp4c3m4nsp1ff17 (Feb 6, 2008)

IbsFt said:


> Has your Tig stop consuming coolant since the repair?


Correct - no coolant loss since they replaced that oil cooler gasket


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