Losing antifreeze

[NSTDI]

Has a few issues with my 2015 TDI, have extended warranty and parts ordered for my ac/heater- doors sticking, sometimes only heat on drivers side, ac fine on passenger side. Sometimes ac works fine on both sides, but no heat at all. Also, lower control arm bushings shot, parts ordered Friday past for these issues, plus missing antifreeze.

Last week in addition to the above issues, I got a red light telling me my antifreeze was low, I was on my way home and checked my oil temp- it was 104C while driving 80/90kph so I kept driving. When I got home, my overflow tank was bone dry.
I filed it and a few hundred kms later, it was down below minimum, I topped it up again and a few days later I had my dealer apt for the above issues and it was low again. No leaks on my garage floor or anywhere visible around the engine compartment. The dealer checked it out, found nothing but added dye to the antifreeze. Just checked it now, below minimum again in maybe 200 or so km’s.

I’ll be taking it back to the dealer, it now has 132,786kms, had only phase 1 emissions done, I have about a year left on the extended warranty I bought. I bought it new off the lot June 2017, have not had many problems at all up to now.

What are the possible options for where my antifreeze has disappeared to?
Oil looks perfect, antifreeze looks good too. I did a flush about 2 years ago using my shop vac.

 

[oilhammer]

You can pressure test it when it is cold, see if you can find any leaks. The cooling system is absurdly complicated, and there are little pieces in places that are hard to see.

What also happens is the little vent lines can clog up, and cause a steam pocket which will cause hot spots and the coolant just boils away and pushes out the cap vent, especially on cars that have had heater core issues. Once they get low, it gets worse.

 

[NSTDI]

That sounds complicated.

 

[740GLE]

You bought an extended warranty for a 2015?

I wonder if there is a pin hole leak in the EGR cooler that only happens when fully warmed up?

 

[NSTDI]

When I bought the car new in 2017, I bought the vw extended warranty, 7 years, pretty much bumper to bumper, 200,000kms. I used to drive 40,000 a year but I retired.

 

[oilhammer]

It isn't complicated to check the vent hose(s). It has three or four steam vent points, I forget how many exactly and do not have one here to look. But, if you start at the coolant bottle, and go from there. I know there is one that tees in atop the engine, then one I think that tees in at a radiator hose, then ultimately ends up back at the heater core upper outlet on the firewall. I cannot remember if there is a fourth one that goes to the end of the head or not.

But anyway, if you remove that vent hose assembly, and make sure it is all clean and able to flow. Some of them have a little restrictor in the hose, usually where it passes over the timing belt cover. That's where they can really get clogged up and you need to blow them clean with compressed shop air.

 

[NSTDI]

I noticed when topping up the G13 antifreeze that the dealer used a green not a pink antifreeze. They told me they used a green G13- didn’t know they made green. Also wondered why they would make green, I assumed it was pink so there would be less likelihood of putting the wrong stuff in the radiator.

 

[06bluebeetletdi]

Ive never seen green vw coolant, always pink. Was it a vw dealer?

 

[NSTDI]

Yes.

 

[oilhammer]

Volkswagen has never, ever, used a green coolant. The first water cooled models used a yellowish color, then they switched to the blue G11, then around 1996-7 they started with the pink G12.

 

[NSTDI]

That’s what i thought. I kept a copy of my question and answer text for future possible needs.

Is all this “special “ antifreeze stuff a lot of crap? Has anyone used all purpose Prestone green formula and had something really bad happen? Considering all the bad things that are happening with the pink crap.

 

[oilhammer]

More an issue that there are different chemistry requirements, and they are not all compatible. I'm not really sure G12 is to blame, so much as the lame EGR cooler setup coupled with a very small heater core matrix.

I'll be honest with you, the CKRA engine is really unlikely to never let the coolant go very long without some need for opening up the system. The CVCA seems better, but not without its issues (the vent tube I mentioned above).

 

[two passat man]

Check the oil cooler on the front of engine. My 13 Passat was slowly loosing and that’s where it was coming from.

 

[oilhammer]

NSTDI was asking about his '15.... different engine than a '13.

 

[buffa98]

Check the oil cooler on the front of engine. My 13 Passat was slowly loosing and that’s where it was coming from.

I "loaned" my 2013 to my son, First job out of college, had plan to pay off student loans first, didnt want him to have a car payment etc,etc. He called me to tell me that the coolant light was on, no big deal I thought. He topped it off, 100 miles later it was empty again. It wound up being the oilcooler, oil filter housing, and I cant recall what teh other part was. The way these engines need to be torn apart to replace a $500 part is crazy.

 

[RSH]

When my 2013 was loosing coolant it was difficult to find the leak until pressure testing the cooling system, then it was obvious, the water pump would piss itself under pressure. Of course since it would have to come apart then the timming belt and tensioner and rollers were replaced as well.

 

[NSTDI]

So they couldn’t find any evidence of a leak with the dye, they added more dye and asked me to drive it some more,
I did some highway driving yesterday, the oil temperature on the MFI system ran about 10C higher than usual. Running at 100-125kph, oil is usually 95-100C, yesterday it was 105-110C running for about 80kms. The temperature gauge was locked at 90C as usual.

I didn’t get home until too late to check antifreeze and oil level, will do that this morning.
What could cause this spike in oil temperature?

 

[NSTDI]

Oil level and antifreeze level both full.

one odd thing, the antifreeze container had 3 layers of colour of the antifreeze, pink on bottom, clear in the middle, and green on top. It was like that before the highway drive, so the antifreeze is not being circulated, it just leaves the overflow as needed?

Time to take it in for a pressure test, not sure if they did that.

 

[NSTDI]

Took it in , they checked for leaks with the dye, none, asked me to keep driving it. No explanation for the high oil temperatures, it hit 114c/237F yesterday.

No AC/heater parts (currently have no heat), no LCA bushings).

I said my car is basically not trustworthy to drive, we have a heat wave here this week, AC could start pumping out heat anytime or if it gets cold, I have no heat. Missing antifreeze has to be disappearing inside the engine somewhere and they’ve been looking for it now since June 9. I have an extended warranty, it should be fixed. They said they have nothing they can do.

I asked nicely for someone to yell at, after saying all this is unacceptable, was given the 1-800 number for customer service.

I’ve driven a VW since June 1998, same dealer, have driven them over 1,000,000 kms, I guess that doesn’t count?

 

[NSTDI]

The green I am told was the dye they use.

I’ve got the GM at the dealership trying to help.

 

[Tom in PT]

I wonder if your cooling system is so clogged with crud from G13 and 10 years of regens that the oil cooler might be functioning far below designed efficiency. You say you have no heat. That means a clogged heater core - and the glycerine clogs don' exist only there. Maybe you can get the dealer to replace the heater core, oil cooler and maybe even the radiator too since that is probably clogged to some degree. After you get this sorted out consider a Kerma tune, extended warranty be damned.

 

[NSTDI]

Was on the highway today, it went to 117c twice= 243F.

My problem with heat seems to be failed doors/motors, when I had heat in May, it’s on full bore on my side of the dual zone only and it’s happened while on AC, AC fine on passenger side. It reset itself to working normal AC, but no heat since about June 1.

I bought the car new in June 2017, so 6 years of regens.

If the antifreeze is getting cooked off in the exhaust, would the def be eliminating the odour? I’m not smelling that odour.

 

[Tom in PT]

Well, your "no heat" situation could be due to failed doors too, not just the clogged heater core. If your car went into service in 2013 its been 10 years, regenerting the DPF periodically the whole time. When that happens, the exhaust gas temperature goes through the roof to something like 1100 degrees F in order to burn off the soot accumulating in the DPF. The way the coolant is circulated through the engine means that the coolant is also heated to a high temperature during regeneration, enough to affect the integrity of the G13 coolant and cause glycerine in the coolant to separate out (or so the theory goes, lots of posts on that here), clogging the heater core. You will not smell any coolant in the exhaust during regen since there is no injection of coolant into exhaust, just injection of the urea (adblue), and since you are not smelling anything unusual you probably are not losing coolant via the head gasket (especially if your oil looks normal, black oil, no "milkshake"). Do you have a scan tool that monitors how many miles you are going between regens? A post-dieselgate fix '13 will go something like 200-250 miles between regens. If yours are happening a lot more frequently, like every 60-100 miles, there are other issues lurking here possibly a clogged DPF. Eventually codes will pop op, like "no start in 250 miles" and a CEL.

Edit- I just realized NSTDI has a '13 and a '15 and the '15 is the one on the fritz, I was directing the comments to the '13 since I have one. The '15 has a different cooling system and may have different characteristics such as period between regens.

 

[watatrp]

I just added the Kerma tune recently. My regens had been happening around every 250 miles. Now they are happening just short of every 500 miles.

 

[NSTDI]

Yes , the 13 left me in the buyback.

My question is I’ve lost about 1-2 liters of g13 coolant, where could it have gone? Since the 2 pressure tests and dye has not shown up any leak of coolant anywhere, where did it go? Oil is perfect, no milk, so no coolant going there. So where? If somehow it’s ended up in the exhaust and is getting cooked off, you can usually smell the coolant, would you smell coolant cooking off in a def diesel?

 

[NSTDI]

Intercooler?

 

[eugene89us]

I don't have much experience with MY2015, but on 2014 Passat, the coolant kept disappearing slowly and had to be topped off every so often without any evidence of leak. When I would drain coolant and use Venturi effect vacuum fill device, once I would close off the system from Venturi side, the vacuum would not hold, it would slowly come up in pressure. Once I did the timing belt job, I noted streaks of coolant residue along the path of the timing belt. The water pump was leaking and TB spreading it around the area, just not enough to cause any signs. Since TB job, the coolant level has remained rock solid. I cannot extrapolate my 2014 experience to your 2015 Passat, but I would certainly make sure that the coolant pump is working (possibly replace with non-electronic version as suggested by others) and verify thermostat is operating properly. Thermostat is meant to have a high and wide opening range well above water boiling point. If those do not solve problem, I wonder if something is wrong with the radiator? In my case, when car is warmed up, the upper radiator hose is piping hot while the lower is barely warm. Temps always stayed below 100C. They like around 98C to 101C at most.

 

[oilhammer]

You could have a very small loss over a period of time and not really have any good evidence of where it was going. If it isn't an external leak, then it has to be internal.

The CVCA's cooling system is ridiculously complicated. Lots of places to leak, but sooner or later it should be leaving some pink stains somewhere if it was.

You could have a tiny pinhole of a leak in the EGR cooler (which sits INSIDE the DPF/catalyst assembly, it literally slips in the end of it), in the intercooler, or some micro fissure (Ford term) in a casting somewhere and have it very slowly burn away during a certain period of the heat cycle and never really be able to tell where it is going.

You could also have a blockage in one of the steam vent hoses (I mentioned above, evidently this was ignored) that could cause hot spots in the cooling system which will turn it to steam, which will allow it to slowly vent out the cap as a normal pressure release function.

 

[NSTDI]

Thanks OH, I wasn’t ignoring your advice it’s just giving a dealer advice “from the internet “ is not well received. You kind of have to feed it to them slowly

They will deal with this under the dieselgate warranty, once I get a cel or another low coolant light, I’ll get a loaner/rental. Once they have the car in the shop and I have a rental, I’ll make some of your suggestions.

Still no progress on the heat/ac doors or LCA bushings, back order. They may do aftermarket on the bushings.

I’ll update this when I know more, thanks.

 

[RSH]

I see you had the cooling system pressure checked and no external leaks were found.
When your car overheats do the fans run at high speed, does the coolant resovoir overflow, causing coolant loss.

Common overheating causes:
Water pump insuffient flow, variable flow function not working, diverter stuck, bad solenoid or wiring.
Fans not working
Thermostat not opening
Bad coolant resovoir cap
Bad coolant resovoir
Air pockets in cooling system
Heater core passages clogged/plugged
Radiator airflow blocked
Radiator coolant passages
Coolant mix incorrect
Coolant breakdown
Most of the above can be checked relatively easily, I would assume your dealer would have performed those checks, maybe not.
More extreme overheating cause, exhaust leaking into coolant
Does your car have any EGR codes.