Coolant blown out from expansion bottle

Kel8117

Member
Joined
Feb 8, 2021
Location
UK
TDI
VW Golf MK7 GT TDI
THANK YOU tdi club for this thread.!!!

I bought my Son his first car. VW golf 2013 Highline 2.0 TDi Bluemotion second hand as a private sale. After his first longer drive on the freeway he pulled up to his mates house for a couple of hours and when he got back in he got the low coolant warning. He couldn't see any obvious leaks so he topped up with distilled water. Used the car again around town for the weekend and we kept checking the fluid levels which was ok. A week or so later the coolant dropped again much like all the others in the forum. ( at this stage I hadn't found this forum thread unfortunately) I took the car to the local mechanic to do a pressure test on the cooling system - perfect - no drop. Car ran again for another week and it did the same thing. I took the car to a specialist Audi service center (non Audi). They checked the car over and pressure tested it again. They had it for a week and it didn't have a blow out. At this time my son found this forum and we read almost every page. Over the weekend I emailed the mechanic and pointed them to this forum and suggested the Heater matrix is the likely cause. I spoke to them on Monday morning when they opened and they were un-convinced and suggested the problem was the EGR cooler. I disagreed with them and asked them to do a back-flush of the heater matrix and entire cooling system. They did this as requested and I picked up the car a day later. ( $330 later)
Of course a couple of days later the same Blow out occurred. I was convinced (95%) that the heater matrix was partially blocked. I ordered a new heater matrix from the local Radiator repair place ( about $300). Saturday morning I installed it ( followed the YouTube video above). Eventually got the matrix out of the car and of course the new part I had was the wrong size and part number for my car, and the shop was now closed for the weekend! Had to re install the old Matrix because I was away for work the next week and my son need his car.

So the following weekend I had the correct heater matrix for the car in my hand. Removed the old heater matrix for the second time ( only took 1 hr the second time) and installed the new one.

Before installing new one I compared the flow by blowing with my mouth through the matrix. The new one was completely un-restricted. When I blew through the original one there was significant back pressure and the was a lot of water gurgling sounds coming from within. I cut the end off the old unit later and I could see many of the cores were blocked up. 100% - this was definitely the fault. Some of the guys here on the forum point to the DPF regeneration as the trigger for the Blow out - 100% this was the same for me.

My Son has since done over 1000km and there has been no coolant blow outs since. We had to do a tiny top up after the first run as the air was still bleeding or from the new Matrix.

I could have easily been sucked into replacing the ERG cooler and spending $1000's more without a solution.

Thanks again for everyone's contributions!
Glad you stuck to your guns. I had all those symptoms and was given the same brush off by many repair garages, despite sending them this forum. All seemed adamant it was the water pump or head gasket! I had some really sound information from @ shocks (thank you) on this forum about managing the situation on my return from Europe in the car, until I could get the heater matrix replaced. I did 4 months ago and I haven’t had an issue since! I will add that my blowouts were more frequent and prevalent during the warmer weather, but still, I’ve had nothing at all since the matrix was replaced! Local garage replaced for £380.
 

GolfSW98

Well-known member
Joined
Feb 8, 2021
Location
Texas
TDI
2015 GSW TDI
Got really paranoid about that silica packet, took it out. Turkey baster'd the expansion tank and added fresh G13.
 

gertiethegolf

New member
Joined
Apr 28, 2022
Location
Melbourne VIC
TDI
2014 Golf Highline 110TDI
Hi all!
I am legit freaking out over this thread. I have a 2014 VW Golf 110TDI 102,000km which suddenly started experiencing exactly the same issues described here..
Coolant bursting out the overflow, no overheating, only doing it every couple of weeks, only after freeway driving, passing pressure tests, slight exhaust fumes, none of the normal head gasket symptoms (everyone kept suspecting the HG but my gut said it wasn't) - the works. We did the waterpump change, replaced bottle replaced cap with no luck. This has been going on for about 3 months, 3 mechanics have looked at it and left scratching their heads. I was on the verge of cutting my losses and selling her but I love this car so much and was shattered at the idea of having to let her go. Then I stumbled upon this... Before I call my mechanic with the update - is there anything else I can do to further prove my suspicions of the Heater Matrix?
 

anniebanani

New member
Joined
May 17, 2022
Location
Adelaide
TDI
2014 Golf Highline 110TDI
Hi @gertiethegolf, Do you have any update? Mine is EXACTLY the same story! I can't believe how much the same it is...

Started losing coolant fairly regularly around 6 months ago, mainly after freeway driving. Got progressively worse. Have had the EGR cooler replaced - still losing coolant, new waterpump - still losing coolant. This last episode saw the car in the workshop for 58 days - thank god they gave me a loan car FOC! Replaced the throttle body cooler something? (located at the front of the engine). They tested it before returning it - boom! still losing coolant. They removed the new, refitted the original and charged me for labour only. They've pressure tested it and it's fine. They've been in touch with VW. There's no sign it's the HG (no usual symptoms). Now they've pretty much given up on it I think. I get the feeling they never want to see it again......... BUT interestingly, they had it so long that by the time I picked it up the weather was cooler and I noticed that I have gurgling behind the dash and almost no heater. Apparently there's a RH flap fault in the AC which they say is what's causing the lack of heat. I'm no mechanic but I can't help thinking the issues are related so after hours of searching I've come up with this tread and I'm freaking out too!

We posed the heater matrix question to the workshop who said the lack of heat is likely the heater flap fault and they're reluctant to keep trying different things. They've suggested I take it to a VW dealer, which I'm reluctant to do.

It also sounds like @gertiethegolf and I own the same car! So if you've had an update, or if anyone else is experiencing the same, I'd love to know. I'm determined not to give up on this - I'm also determined not to mess with the HG etc. unless we absolutely know it's that and so far no one is convinced it is!
 

gertiethegolf

New member
Joined
Apr 28, 2022
Location
Melbourne VIC
TDI
2014 Golf Highline 110TDI
@anniebanani hi! So I showed this thread to my mechanic who was mind blown haha. A week ago today I got him to bypass the heater core so we can see if the pattern changes. We noticed bubbling noises when we got home from picking it up and it lost some coolant (went below min) but this time it wasn't sprayed everywhere and it didn't completely drain out. Topped it up again and it dropped again after another freeway drive but once again, it only dropped to just ABOVE the min and held it there. We've topped it up again and it was fine over the weekend but only done local driving which it never plays up on local drives. We've got 3 more big freeway drives this week so I will report back in a week and let you know how I go... I don't think I'm out of the woods yet! Crazy how common of an issue it is with VWs yet no mechanic nor VW are aware to know how to fix it straight off.
 
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