Could this be anything but a headgasket problem?

[s1ngletracker]

So I just put about 2000 miles on my 170k mile basically stock 93 TSi in the last week or so, driving out to colorado and utah. It was a lot of fun and I really love taking it on long trips. It has been pretty reliable to this point.

The problem came up in the heat of the day, both on the way out and back. in the 90+ degree heat and scorching direct sunlight, after having driven about 4 hours, with the AC on constantly (econ mode), and under a decent amount of load going about 80 mph, the temp started to climb.


At first it was just a bit, but it would get to the point eventually that it would start to get too high for comfort so I'd either scale back the speed or shut the A/C off and then it'd be fine.

As soon as the sun got lower in the sky and the temp cooled off a few degrees, the problem disappeared. Also worth noting is that every time I popped the hood when the car was hot, I'd hear a gurgling from the thermostat/radiator cap area. While I was out there, i replaced both, sound didn't go away. No visible external leaking.

If you've read this far, I imagine this problem won't be a big deal to me unless it gets a lot worse, as I typically don't drive it for more than 4 hours at a heavy load in a lot of heat... but it is still unnerving.

Brainstorm:
-Water pump? I hear they don't really start to go incrementally, they just totally fail. I could be wrong. I haven't replaced it, it may have been in the life of the car at some point.
-Coolant looks nasty, gonna flush it.
-Any other gaskets that could be failing?
-Could bent fins on the radiator cause this? The lower front fins on the radiator are all pretty folded.
-Don't think it is a radiator fan issue, when I'd slow it down and idle, the temp would go back down. Fans work fine.

other ideas?

Thanks in advance!

[311evo]

I could see it being any one of a few different things.

Could be headgasket. Especially if your coolent was oober black.
Water pump, maybe.

Have you tried a different thermostat for shits and gigs?

[93gtpeater]

I would say flush the coolant for sure. And mabe try a new t stat.

[CarPsyco84]

Your saturating the Radiator with heat, and can't shed it fast enough. Obviously fresh coolant might help. But might be time for a new radiator. That gurgling sound is the coolant starting to boil. I wouldn't worry about the head gasket just yet, but it is possable that its leaking, but unless its pushing coolant out of the engine I doubt it.

[s1ngletracker]

yes, i mentioned that I put in a new thermostat, gasket, and rad cap while I was out there.

[s1ngletracker]

Originally Posted by CarPsyco84

Your saturating the Radiator with heat, and can't shed it fast enough. Obviously fresh coolant might help. But might be time for a new radiator. That gurgling sound is the coolant starting to boil. I wouldn't worry about the head gasket just yet, but it is possable that its leaking, but unless its pushing coolant out of the engine I doubt it.

The car isn't smoking at all, no signs of coolant in the oil. I need to get a better look at the coolant to see if there is oil in it. No signs of external leakage.

I might just get a new radiator, mines' fins are so bent It wouldn't surprise me much if that is causing issues.

[CarPsyco84]

Sometimes with leaking head gaskets, they just leak combustion gas into the coolant passage, though usually not unless you are full throttle does it leak, at least till the gasket is blown. If fluids start mixing theres pieces of the gasket missing at that point.

[viridionplague]

in that situation i would grab a nice aluminum radiator and flush out the system good, as well as a new t-stat.

also if you start the car when its cold. pull the radiator cap off. and see if it constantly bubbles/gurgles. if its constantly doing that, it would be a sign of a bad head gasket.

[s1ngletracker]

I haven't noticed coolant pushing out much - as in, the resovoir overflowing. But when I replaced the Tstat (again, yes, I did do that) I started it with the cap off to let it bleed, and the coolant was expanding a lot and actually pouring out of the hole. Is that bad?

The car does seem to be using coolant though. I have to keep topping it off.

[1ViciousGSX]

Hammer on it under boost and if you smell coolant, it's 99% your head gasket.

[s1ngletracker]

never smelled it, or saw smoke, and I definitely hammered it at a few points.

update, just went out and started it with the rad cap off, and after a while coolant was just streaming slowly out the cap hole onto the ground. That doesn't seem right to me. Can someone confirm this? Or is it expected due to expansion of the liquid?

HOWEVER... after the 1100 mile journey yesterday, it didn't appear to burn much, if any coolant. Just seems that the headgasket may be bad and pushing air bubbles into the cooling system.

[CarPsyco84]

If the coolant is ending up in the overflow its probably the head gasket, otherwise its probably a leak. My car doesn't smoke or stink... still fills up the overflow when you thrash on it though.

[Spikesoftail]

Check the front of your radiator for blockage, Very common to have cotton wood seeds plugging the front for the radiator, causing issues like this. If your car has A/C make sure you look between the radiator and the condensor. Gurgling noise could just be coolant boiling in the engine, or your coolant is low and there is air in the system

[s1ngletracker]

blah. Well I guess I'll look into a good flush and a new radiator. Anyone have suggestions for techniques for thoroughly flushing?

[1ViciousGSX]

BG products. There is no substitute.

[s1ngletracker]

should I just get one of those little flush kits that plumb a T into a heater hose?

[Spikesoftail]

Yup, flush it both ways a few times till its all clear water coming through

[s1ngletracker]

'both ways' - what do you mean by this? details