I read here that oil and antifreeze is key to long engine life. Recently I spoke with a chemist for the auto industry that shed some light on this for me. He said the result of blow by converts the water portion of the anti-freeze mix combines with the blowby and forms a corrosive mix that eats away at internals and seals. I'm sure this is not new to most of you.
My question is:
How often do I change the antifreeze? Should I do it based on miles rather than time?
How exactly is blowby supposed to come in contact with coolant? I'm not quite following that one. Unless your cooling system is defective it should be a sealed system.
I also fail to see (in my mind) where the coolant comes in contact with combustion?
I have to buy a new head because that was happening. If that's happening changing the coolant is the least of your troubles.
I'd say every 6 months if you have a perfect working engine? no real reason. Just seems like a resonable amount of time to spend 15$ for some new coolant.
If not, when ever you see discolouration. That could also mean to change the head gasket (or you have other problems to contend with?)
To answer the original question, the traditional reply is 1-2 years. The newer extended life coolants are supposed to go up to 5 years.
Wow way longer than i thought! Good to know!
Using VW G-12 antifreeze you can run it a long time. My 2001 Golf with 198K miles still has the original antifreeze. The only "new" G-12 was after the timing belt changes. The last TB change was done 2 months ago and when I removed the water pump there was no rust and the antifreeze looked just like the stuff I added from a new jug.
The only cardinal rule is to never mix any other antifreeze with the VW stuff. If you do it will turn to a substance that looks like mud.
Yeah, VW rates G12 as "lifetime"... and it's designed to change colour if for any reason it loses its effectiveness or gets contaminated... with, say, Prestone :wink:
I believe what the chemist was refering to was blowby contaminating oil, and through the head seal eventually or potentially contaminating the antifreeze...