Coolant Goo


I recently went to look at a 2003 Beetle TDI to purchase. While doing my pre-drive inspection I checked the coolant overflow. I looked inside and noticed that the coolant was an orange/red with white bubbles on top. The coolant did not smell like fuel. However, at the neck of the coolant filler I found a goo the consistency of gelatin (before it dissolves in water), and mixed with it was what looked like small metal shavings.

Any ideas on what might be wrong?


Could be they were mixing their coolant with tap water. That could cause the goo to form due to a reaction with the trace elements in the tap water & the chemicals in the coolant. Bet a radiator flush at a dealership would fix it.
That said: If you’ve got any qualms about buying the car, trust your gut & walk away.


like the monty python movie said…

run away, run away


I would suspect a leaking head gasket. As was said, get away from this deal as fast as you can.

The coolant in that car should be pink, and no other color.  If it is not, there is a problem.

The coolant in that car should be pink, and no other color.  If it is not, there is a problem.


It’s possible there’s an internal leak (head, intake) and some sealer was put in as a temporary fix. I would walk away from this car. I would ask for an explanation, but take what the dealer says with a grain of salt.

Before I got my 2000 Blazer I test drove another one in 2003. They have a history of intake gasket leaks and coolant contamination. I came back the next day with the deposit. I didn’t check the radiator before the test drive because the engine was hot. When I opened the radiator cap there was a layer of black goo about a 1/2" thick inside the cap. The service manager told me with a straigt face that this was normal. Needless to say I didn’t buy that Blazer or return to that dealer.

Ed B.


Silicate is used in many coolants and will gel if the pH of the coolant goes off as it ages. I don’t know if silicates are used in VW-spec coolant, but I doubt it. Everyone seems to have gone to low or no silicate composition. It is very likely that either someone put the wrong coolant in there and neglected it, or, less likely, someone put the right coolant in there and neglected it.

Since silicates can damage seals and other stuff in cooling systems not designed for them. This could be a huge problem.

What about the metal shavings? Don’t some stop-leaks contain them? OTOH, maybe the water pump impeller is falling apart.

In the words of Jefferson Starship, " Run run run run runaway." or the Talking Heads Run run run run run run run away.

Are these TDIs really all that desirable a vehicle anyway? I understand that reliablilty is sub-par and repairs are expensive. That is not a good combination.


I agree with VDC. This is a very possible sign of a breeched headgasket. Run away.


It’s my understanding that the required antifreeze for the TDI is VW’s pink G12 antifreeze. Other formulations can be used, but the system is supposed to be flushed first. It’s possible that someone mixed the wrong type of antifreeze or added some of that stop-leak junk to the system. I don’t know about the “shavings,” it could actually be metal from the engine or something that was included in a stop-leak product.

If you are interested in the car, definitely have it checked out by an independent shop or a dealer. It sounds like it will need a coolant system flush at a minimum, so plan on spending at least a few $100 if you decide to buy it. I would avoid it if there is any evidence of a head or head gasket leak, but I don’t think that’s a known problem with this engine. I would also be concerned if some idiot put stop-leak in the system.

I know a few folks who have been very happy with this engine, but you want to make sure you find the right one.