GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

Rapid coolant loss

oreozzy

New member
Location
Australia
Hi everyone,

MK7 Golf Alltrack 2016.
Got a warning about a month ago with low coolant, so topped up with some demineralised water I had at home. Couple weeks after I get a red warning saying check coolant. Top up again with demin water (can't find Purple VW coolant around, only Red or Green). Week later it needs topping up again.
Now it's emptying the expansion bottle after a couple hours.
I can't see any visible leaks looking down from the top, and I can't get underneath to look up.
I've booked in for it's 60k km (40k mile) service in 7 days, and it's out of warrantee by just under 4 months. I'm currently waiting for someone at my local dealer service department to give me a call back about getting some coolant, and ask them the same one I'm about to ask you:

Is it worth topping up with genuine coolant, knowing it will vanish immediately. Or keep topping up with demin water until next Tuesday when it gets looked at properly?
I'm in Queensland Australia in summer (currently 36c/97f) , so not overly worried about the anti-freeze properties of coolant, but I know it's still not good not using it at all.
My engine doesn't appear to be overheating, and the infotainment says it never goes over 90c/194f, although the oil does get to around 105c/221f.

P.S. My thermostat housing was replaced last service under warrantee due to small leak around 8 or 9 months ago.

Thanks in advance, I'm not very mechanically minded, and don't want a dead Golf.
 

Jovian

Drag Racing Champion
Location
Denver, CO
Car(s)
2016 VW GTI
I would get the thermostat housing checked again, most dealers warranty their work for 1 year so you want to get it looked at before that expires.
 

OldVWFan

Go Kart Champion
Location
NW Arkansas
Car(s)
17 GTI Sport
If you do not see any coolant on the floor under the car, then check the floor boards inside in case the heater core has developed a leak, and do as Jovian suggests, and also take off the oil fill cap to see if a white froth can be seen, a possible indication of water in the oil. Maybe the oil/water exchanger has developed a leak although it should go oil to water based on the pressure of the two systems.
 

oreozzy

New member
Location
Australia
I would get the thermostat housing checked again, most dealers warranty their work for 1 year so you want to get it looked at before that expires.
Thanks Jovian, I will definitely raise that with them thank you.

If you do not see any coolant on the floor under the car, then check the floor boards inside in case the heater core has developed a leak, and do as Jovian suggests, and also take off the oil fill cap to see if a white froth can be seen, a possible indication of water in the oil. Maybe the oil/water exchanger has developed a leak although it should go oil to water based on the pressure of the two systems.
I will go take a look at that soon, thanks OldVWFan. What do you mean by the floor boards?
 

OldVWFan

Go Kart Champion
Location
NW Arkansas
Car(s)
17 GTI Sport
Thanks Jovian, I will definitely raise that with them thank you.


I will go take a look at that soon, thanks OldVWFan. What do you mean by the floor boards?
Inside the car under the carpet on both the passenger and driver side. If the heater core is leaking water will be under the carpet and the carpet could feel damp. Hope this helps.
 

oreozzy

New member
Location
Australia
Inside the car under the carpet on both the passenger and driver side. If the heater core is leaking water will be under the carpet and the carpet could feel damp. Hope this helps.
The carpets appear to be dry, would that only show after driving, or after it has cooled?
While checking the oil cap (no frothing), I did see the pan under the engine is darker in places, I can't tell with this lighting if it is water/coolant or not (I believe it would be though).
 

OldVWFan

Go Kart Champion
Location
NW Arkansas
Car(s)
17 GTI Sport
If the carpets are dry then that is good. If the heater core was leaking I believe that it would show at any time. I do not know if the valve allowing hot coolant to the heater core is before it or after, in any case a dry carpet is good. As to the dark streaks on the oil pan, might say the thermostat housing is failing again so take it back to the same dealer and have the check it.
 

oreozzy

New member
Location
Australia
Thanks OldVWFan. I have it booked in for Tuesday the 11th with the same dealer.
As for getting around in the meantime, would you recommend getting coolant, or can I get away with just topping up with demin water until then? I work 2 jobs daily, so approx 80km (50miles) each day.
 

OldVWFan

Go Kart Champion
Location
NW Arkansas
Car(s)
17 GTI Sport
Since it losing so much I would stay with a the demin water, carry a couple of liters or more with you and watch the coolant temp gauge.
 

oreozzy

New member
Location
Australia
Looks like it's the water pump. Dealer said they've contacted Volkswagen HQ to see about getting it replaced under warranty (I'm about 4 months out), should hear back in a week or so.
 

OldVWFan

Go Kart Champion
Location
NW Arkansas
Car(s)
17 GTI Sport
If this part was replaced only 8 to 9 months ago then as Jovian says then it should be covered again under warranty. I hope this is the case for you. Argue if they say different.
 

Carlosfandang0

Autocross Newbie
Location
UK
Car(s)
2016 3Dr GTi DSG CSG
If this part was replaced only 8 to 9 months ago then as Jovian says then it should be covered again under warranty. I hope this is the case for you. Argue if they say different.
Yes, it should have a 12 month parts warranty.
 
Top