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General Information => Troubleshooting => Topic started by: Matteo on November 28, 2008, 02:34:03 pm

Title: When to change coolant
Post by: Matteo on November 28, 2008, 02:34:03 pm

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?

Title: When to change coolant
Post by: clbanman on November 28, 2008, 04:17:17 pm

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.

Title: When to change coolant
Post by: Smokey Eddy on November 28, 2008, 05:14:45 pm

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?)

Title: When to change coolant
Post by: clbanman on November 28, 2008, 06:13:25 pm

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.

Title: When to change coolant
Post by: Smokey Eddy on November 28, 2008, 06:25:30 pm

Wow way longer than i thought! Good to know!  :D

Title: When to change coolant
Post by: GV2001 on November 29, 2008, 02:35:22 pm

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.

Title: When to change coolant
Post by: Vincent Waldon on November 29, 2008, 04:06:38 pm

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:

Title: When to change coolant
Post by: Matteo on December 01, 2008, 12:41:45 pm

I believe what the chemist was refering to was blowby contaminating oil, and through the head seal eventually or potentially contaminating the antifreeze...