Coolant Bubbles

[vault415]

I just changed my thermostat a couple of days ago because I was logging high coolant temps (220-230) in DSMLink (which I'm still logging, but I haven't changed the cap yet so it could still be that).
To refill and burb the system I parked the car on an incline with the front end pointed uphill and put a funnel in the fill hole, then started filling the system. I noticed that there were the usual big bubbles coming up from time to time, but also that at all times there were little champagne like bubbles coming to the top. There weren't enough bubbles to make foam on top of the water/coolant in the funnel, but it was a steady stream of tiny bubbles that rose to the top.
Is this indicative of a blown head gasket? I always hear and read that foamy coolant is bad news, but have never seen what it actually looks like.

 

[Catoboli]

was your car running while you refilled the coolant?

 

[RiceKiller_TSi]

I would think it would be better to have the car flat while burping the coolant system. Why? Because the air bubbles will want to rise to the high (front) end of the car and remain trapped there. Just my guess.

 

[vault415]

Yeah the car was running and I left it running for 15 minutes so that it warmed everything up.

I put it on a hill because I read a bunch of posts that said you want it on an incline so that the bubbles in the heater core and anywhere else will be lower than the fill hole, so they will be forced out of the system. I've also burped it on level ground more than once, and I still get the little champagne bubbles.

 

[Catoboli]

do the little bubles continue as long as the car is running or do they eventualy stop

 

[mramc3]

bad headgasket - probably not. but check to see what your coolant looks like. maybe a possible radiator flush is in store. This way you can look at whats going through your system. Also, check the oil, possible mocha colored oil is a sure way to know that you have a mixture of oil and coolant.

RADIATOR (corrected) cap - this is the first thing you should have change at least immediately. If you have a non-pressurized system and your starting too gargle, not only are you asking for that bubbly mess, but you can be warping your other coolant hoses. Warped hoses = cracks.

This is all from my experience with my tsi. hope this information helps.
-Jeff

 

[vault415]

The bubblescontinue the entire time that the engine is running.

I haven't replaced either the coolant cap or the oil cap, so I'll try that. Why would I have to replace the oil cap? Just curious because I hadn't read anything about the oil cap being linked to the coolant but anything is possible. What psi is the cap rated for?

I just changed the oil and it doesn't look milkey or like it's mixed with any coolant.

After re-reading the last post I see that you meant coolant cap. Thank you!

 

[Catoboli]

u said the bubles are colored, is it like a colored liquid bubling up ie oil or are the bubles air...

 

[vault415]

They look like air. Just like beer bubbles but about half the size and they're not colored as far as I can tell.

 

[jmadison]

Lots of bubbles at idle can just be the air moving out of the system after a recharge, but if they persist like you say they are then check your oil to see if you have water/coolent in it. If so that could be bad news , blown head gasket.

 

[FireyIce01]

do a compression test. If the head gasket is just starting to leak into a water jacket, the oil could be perfectly fine and you'll never know. If your car is still running high coolant temps, I'd suspect that the head gasket is your culprit, but a compression test is a sure way to find out.

 

[vault415]

Ok, I'll try to do a compression test tonight and see how that comes out. Thank you all for your help!

 

[mramc3]

Hmm. fine bubbles you say? I am concerned about what would cause a fizz like that? Considering the chemical mixture involved with just coolant alone. I would think a coolant flush is in store. You should drain the radiator just to see what other fluids are getting mixed with your coolant. Anything other than the bright green would help us to see whats going on. Look at the consistency along with color. And you can flush out and clean your radiator lines while your at it

and yes.. sorry i meant radiator cap. WTF