PSA for those with a tune, keep an eye on your coolant!

[HurrayFive]

Wanted to give a heads up after my experience. The S3 has been tuned since March of 2015, 17K miles in that time frame (car is at 19K total).

Last week I was headed home from a car wash and the dash lit up with the equivalent of an overheat, "Shut engine off immediately, check coolant level." Stock, the coolant is supposed to be a "for life" system, never requiring maintenance.

Pulled over, sure enough, overflow tank was below the "min" marker. Let the car cool down for a bit and was able to make it home in overdrive, message came back on just as I got home.

Me thinks that two summers of Arizona heat + my occasional lead foot caused the coolant to boil a few times due to the extra heat from the tune.

Interesting enough, I had just read an article the week before where the Quattro team said one of the reasons they abandoned the Quattro 420 concept (our engine with 420HP) was because the integrated exhaust manifold generated too much heat at that power level and would have to be replaced.

Our G13 coolant boils at 228F with a 50/50 water mix, not a lot of room for extra heat with an internal manifold. Anyway, filled the overflow tank back up with a 50/50 mix of Pentosin Pentafrost E (G13 rated) and distilled water, car has been fine since, no leaks, no consumption, no white smoke from the exhaust at any time.

Something anyone running increased power is likely going to have to watch over the long haul!

[kewe24]

Just an fyi, that is normal. There is a TSB for this issue. Basically the coolant system has an air pocket from the factory and the TSB states that this can happen even at 15k miles. So you shouldn't worry and just top it off.

[HurrayFive]

Just an fyi, that is normal. There is a TSB for this issue. Basically the coolant system has an air pocket from the factory and the TSB states that this can happen even at 15k miles. So you shouldn't worry and just top it off.

Yup, know the TSB, that happened just before the car was tuned at 2K miles, lost half the overflow tank, dealer explained the issue then. This has occurred since, factory voids and system air pockets aren't an issue once they're filled.

[will13k7]

My car drinks more coolant than oil!

[INYAUDI]

Anyone know if the coolant boiling off will produce that distinctive smell? I smell it getting out of my car after a hard drive. No visible leaks anywhere otherwise I wouldn't ask

Follow my build on Instagram: @towknee603

[HurrayFive]

Anyone know if the coolant boiling off will produce that distinctive smell? I smell it getting out of my car after a hard drive. No visible leaks anywhere otherwise I wouldn't ask

Follow my build on Instagram: @towknee603

Very hot coolant does have a distinctive smell, it's not uncommon after a hard drive, even stock. Doesn't necessarily mean it's boiling though.

The only trouble with coolant flash boiling inside the coolant channels is that it can cause cavitation (microscopic holes) that eventually leads to corrosion if it happens frequently enough. Might be a limiting factor to the maximum amount of power these engines can make over the long term. I recently downgraded to APR's "low output" file (375HP/360TQ) in an effort to extend the life of my stock DSG clutch pack, will be interesting to see if I still lose coolant over time.

[INYAUDI]

Alright thanks HurrayFive, good to know

Follow my build on Instagram: @towknee603

[A20V200]

Yep, mine has been "sipping" coolant since stage 2 GIAC too. I just top it off and its good for a couple months.

[S3Danny]

My car loses coolant slowly as well, but it did it before being tuned too. I thought I read a while back about some cars weeping coolant out of the water pump from the factory. I've only topped it off three times in 35,000 miles so it's no big deal so far.

[Anonymous User]

Topping off coolant is not just a tuned car concern, all of the a3/s3 needs top offs and some leak from the water pump area.

[Baggio]

Mine was at the minimum line when the engine was cold. I topped it off to the top line.