Was checking some things here and there the other day while replacing fuel filter, PCV valve and air filter. Noticed the coolant had a sort of glazed doughnut look ... a sort of shiny, almost crystalline film on top. What's up with that? It doesn't look oily or lumpy. Aside from the glaze, it's a nice new, pretty (for coolant) green.

 

Normal? Silicate deposit?

 

Nothing to be concerned about? Bad? VERY Bad? :-\

 

Thanks, in advance, for any ideas.

 

P.S. I drained and filled the coolant about 8 months ago.

First with Genuine Subaru coolant. Two days later, my mecahnic did the timing belt and oil pump seals and had to remove the rad to get to everything and he replaced the coolant yet again. (2 hours on a Saturday wasted ... ) Not sure what he used. I would have made him replace it with the Subie stuff I'd put in there the first place, but I was moving out of town and had way too many other things on my mind, so there it still sits today.

I think the answer could be in your post: Mixed coolant types.

 

Most coolant packing mentions that you should not mix this product with anything else. For once you can trust the company. They aren't writting that in order to force you into buying only their product, but because mixing coolant types can cause them to turn to glop very quickly.

 

I hate to be the bringer of lousy news, but you need to drain the system again, flush it thoroughly with clean water, and then fill with coolant again.

 

I did a write-up that you will find if you search for "coolant replacement", I believe I have found a sure-fire and fairly simple way of re-filling without the air pockets!

I think the answer could be in your post: Mixed coolant types.

 

Most coolant packing mentions that you should not mix this product with anything else. For once you can trust the company. They aren't writting that in order to force you into buying only their product, but because mixing coolant types can cause them to turn to glop very quickly.

 

I hate to be the bringer of lousy news, but you need to drain the system again, flush it thoroughly with clean water, and then fill with coolant again.

 

I did a write-up that you will find if you search for "coolant replacement", I believe I have found a sure-fire and fairly simple way of re-filling without the air pockets!

Thanks. Would you recommend one of those chemical flush/cleaners? Or would just a clean water flush do the trick?

uuuuuuuuummmmmmmmmmmmm Doughnuts....

Only use the chemical stuff if you suspect that the cooling system is blocked, or if you can see rust inside the radiator.

 

Otherwise stick with clean tap water. If you flush every time you change the coolant, you should never need to do the chemical flush.