Slow Occasional Coolant loss over 5 month, some questions.

Jun 15, 2024
19
1
I've posted this a comment on different thread but didn't want to distract had a few extra thoughts on it.

I've a 2016 1.8tsi FR DSG Estate on 68k.
I'm noticing that I'm loosing a bit of coolant over time. I bought the car June from a as a part ex from a PSA/Vauxhall/KGM (Non VAG) dealership, and was it was serviced when I bought it, Sparkplugs/Oil/Coolant etc. I got a 3 year extended warranty on purchase too, mostly due to mild concern on the DSG being not super reliable.

Since then I have have topped coolant up twice possibly 3 times from around/below minimum. neither times the coolant light has come on, mostly either noticed while tinkering/installing mods/routine checks, just new car stuff etc.

1st time around August before a week's camping trip in the lakes from above min.
2nd, end of September before going Rustival 2 (400mile round trip), maybe from half way.
3rd. most recently this Wednesday from below the Minimum.

I've driven around of 3500 miles since I've bought it. And trying to figure out the cause.

I haven't noticed any white smoke from the rear, only the usual on the more recent cold morning starts, but I'm positive I've had people flash me from behind after a few hard pulls getting up to speed on 60 roads, and coming off motorway slip roads. I was thinking it's the coolant tank/cap, as it's the most common/easy to change part. And noticed a bit of red/pink liquid near the tanks overflow wep/chute, a bit a go but not a massive enough to concern me. Can't smell anything burning. I did see steam coming out after one time, but that was after some really bad rain and having to drive through lots of small sections of slightly flooded roads no deeper than 3-4 inches/8-10cm so put it down to that.

All the pipes look good inside the engine bay, but could have some more buried I can't see. It's a stock tune, but I've got a Ram-Air Turbo Elbow, Silicone Intake Hose and panel filler. Pikey R600 Air collector mod, with extra oem blanking plate from the Golf R. Purely for the improved induction sound/turbo noises. When I fitted the turbo elbow I did notice a bit of oil in the stock elbow but again it was just a small bit, probably from the PCV tube on top of the elbow. I also hasn't lost any major amounts of oil. Maybe 500ml

It's sometimes smells little warm after a longer, more spicy drive. But aside from what I assumed is the exhaust cooling "ticks" and the sound of the water pump running for a bit after engine shut off, I can't find anything. Equal heat is coming from both side of the vents so I don't think it's the heater matrix.

I know the coolant tank/cap can be some of the causes. And it's a cheap fix.

Another comment on a different post said it could be the thermostat housing being plastic and being less than ideal with cracks.

While browsing for inspiration for engine dress up kits and billet mods/upgrades on tuners/suppliers websites, I've seen other mods for things like 034 Motorsport - Billet Coolant Vent Union, and knowing the VAG fondness for plastic engine parts wondered if there's anything else that could be causing coolant loss without it being head gasket, (no white foam) or obviously spit hose.

I know I've got the extended warranty to do work if needed, but I'd like to narrow it down before taking it somewhere and putting a claim in. But I can't be arsed doing all that if the fix is easy/cheap like a new coolant cap tank or that 034 union vent. I fixed the DSG Park Selector switch myself. I'm not looking to go for a tune either at the moment due to warranty and the gearbox being the power limit and I'm enjoying the car as is, just want to help it with better parts for longevity, VAG plastics and possibly a front resonator delete for improved exhaust sound and DSG noises.

TL : DR
3500miles Mixed driving in ~5 months and topped up coolant 2-3 times (1.5L?), maybe 0.5L oil I know its within tolerance. Am I being a little paranoid.
 
Nov 25, 2024
1
0
Hi did this ever get fixed? I'm having the exact same issue similar mileage my current thoughts are it's the thermostat causing it to overheat. I've had the waterpump replaced as that needed replacing however it still has maintained the issue.
 
Jun 15, 2024
19
1
Hi did this ever get fixed? I'm having the exact same issue similar mileage my current thoughts are it's the thermostat causing it to overheat. I've had the waterpump replaced as that needed replacing however it still has maintained the issue.
I'd actually forgotten about this. I never actually did anything about it, other than kept an eye on the levels and it stayed pretty much the same level. It might have dropped a little bit and I'd added a bit extra coolant, but I don't recall if I have since I last made this post. But it wasn't excessive. ADHD for you.

Don't know if it's because the weather has been a lot colder, most of my driving in that time was no more than 10-15mile (20/30mins) at a time with light mixed traffic. With it being so cold (particularly Nov-Jan) my oil temps where usually only just getting to 80-90c by the time I'd reached my destination.

Now it's warming up and I've a few longer drivers coming up, I'll keep a closer eye on it.

I'm still planning on doing that billet coolant connected, and swap the coolant tank as a precaution anyway, being a known issue.
 

nd-photo.nl

Active Member
Mar 6, 2012
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The Netherlands
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I replaced the nipple not too long ago on my 2.0 TFSI. Mine was still intact, and the O-ring was also "ok", but Im happy this is done for peace of mind.

I ordered one from Aliexpress for about 5 euro. Build quality is very good and fitment is 100%

AP1GczOqTlFRvi9p4jCDQmeLfjKhX1mXmyAKuEHfEVYgkfJBf-Q6WcwWTgHDd76HCCy0la5wS5rQWycIVmlJ96diCJyrFLYUB9nKRloElK5whmvAMWjfSZr24kvB70sp7ADuSNL9KSErSzZ9RG9mcUSssjVShg=w1920-h1080-s-no-gm


AP1GczNAeWvDgVhhoRvTf9Bicv8zBfSh4pkxHKzKdsF0W9Np7UIRWzkMwnCuZCUNf1SHTq5oxcHwVZmvDCr-_4EWSEN-GoSHzCgwBNFNAAf-z5ABgR5rox1vFCzZex4b8QZZgihC-fMtSDzoS-lTa13RgR2IAw=w1920-h1080-s-no-gm
 

RichieXR2

Active Member
Feb 8, 2025
17
20
I replaced the nipple not too long ago on my 2.0 TFSI. Mine was still intact, and the O-ring was also "ok", but Im happy this is done for peace of mind.

I ordered one from Aliexpress for about 5 euro. Build quality is very good and fitment is 100%

AP1GczOqTlFRvi9p4jCDQmeLfjKhX1mXmyAKuEHfEVYgkfJBf-Q6WcwWTgHDd76HCCy0la5wS5rQWycIVmlJ96diCJyrFLYUB9nKRloElK5whmvAMWjfSZr24kvB70sp7ADuSNL9KSErSzZ9RG9mcUSssjVShg=w1920-h1080-s-no-gm


AP1GczNAeWvDgVhhoRvTf9Bicv8zBfSh4pkxHKzKdsF0W9Np7UIRWzkMwnCuZCUNf1SHTq5oxcHwVZmvDCr-_4EWSEN-GoSHzCgwBNFNAAf-z5ABgR5rox1vFCzZex4b8QZZgihC-fMtSDzoS-lTa13RgR2IAw=w1920-h1080-s-no-gm
That’s pretty cool actually as I was looking at buying the 034 one at £30 odd.

I’ve bought a bottle of uv dye to try and find my possible coolant leak, the car had a new water pump fitted under warranty so could be it needing bled or a leak, who knows.
 

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Jun 15, 2024
19
1
That’s pretty cool actually as I was looking at buying the 034 one at £30 odd.

I’ve bought a bottle of uv dye to try and find my possible coolant leak, the car had a new water pump fitted under warranty so could be it needing bled or a leak, who knows.
Well I have an update.

After I bought a new expansion tank cap it didn't fix the issue. I thought sod it and just get the 034 Billet barb I was going to anyway. I live fairly close to Awesome GTi so just called in on the way to work the other day and I fitted it this morning.
Took off the original one and it looked intact from the top but after removed it I noticed the bottom flange had blown off the plastic one and rubber O Ring and lower part where missing. Fortunately the heads designed so that it's got a cup to sit on and both parts where just inside the hole. I managed to fish them out with a long pick. Hopefully that's the last of the coolant issues now.
Probably will replace the Coolant tank for the non scila bag one just to be on the safe side.
 

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RUM4MO

Active Member
Jun 4, 2008
8,040
1,097
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I'd think that if you still have the original G13 coolant in your system, that you should now consider changing it for G12eco IF you are getting rid of the "MIT SILIKAT" reservoir.

One other thing, my older daughter has owned a May 2019 SEAT Leon Cupra from new, and it does "use" a small volume of its G13 over time, every time at service time it needs topping up from roughly just above MIN to mid way between MIN and MAX. I have been a bit lax/lazy and have just topped it up using straight G13 - and after 4 years of doing that I've discovered that the freezing point/%age of the coolant remaining in the reservoir is lot higher than the original 50% - I did not expect that, I had thought that in normal use, there was a gradual "flow through" of the system coolant through that reservoir and so the increase in %age would be very very low/little! So, when I next have that car at our home, I intend to "recover" as much of that higher "strength" coolant from the reservoir, measure it's %age, do some sums, add distilled water into the recovered coolant, then load the correct volume of coolant back into the reservoir - that will help to return the %age to what it was initially AND hopefully leave me with a small volume of 50/50 mix coolant that can be used the next time that car needs topping up!

Despite me reading that owners of VAG indie workshops have never spotted any burst Silicate pouches - yet, I'd rather force my older daughter to play safe and push me enough cash to cover replacing her 2019 Cupra's reservoir with a later version that doesn't have any Silicate - ie for use with G12eco at initial fill, and replace the G13 coolant with G12evo.

Edited to correct G12eco to G12evo which is the correct name as pointed out by @nd-photo.nl - sorry my error, I don't like it when people use the wrong product names either!
 
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