Hello,

I'm a true rookie trying to take on some basic do-it-yourself maintenance with help of my haynes manual.

I'm curious as to the consequences of mixing fluids specifically: coolant and brake and manual transmission fluid. It says right on the coolant cap "do not mix fluids"... is this so the dealers can make tons by charging you through the roof or is it legitimate... if so I suppose I'll need to do a flush.

Also, which tranny fluid should I be using for my manual transmission.

Any advice would be much appreciated.

Thanks,
Mike

The coolant cap refers to not mixing anti-freeze types. Americans, Japanese, and Europeans have each had their own approach and used some slightly different chemistry in their vehicles. Volvo blue follows other European brands. There are some new formulations in today's cars (Ford has one for which there is not yet an aftermarket substitute). Mixing types may reduce corrosion protect or boiling point, but all are water based. Generally, a minor flush with clear water and refill with the proper mix of an acceptable product, even if not the specified product, is all that's usually needed.

Mixing a petroleum or water based fluid into the brake system; that is a COMPLETELY different story. It would require immediate flushing and very likely extensive replacement of components with soft sealing parts.

Many fluids are not only made for certain uses, but your car require that certain specifications are met or exceeded. Not all brake fluid, engine oil, etc is interchangeable based on the label name. In other words, you need to know the right type of fluids for your car, and pay attention to which filler cap is for which fluid.

Hi Rookie,
We were all like you not long ago. Live and learn.
Mixing fluids between brands is OK, but not fluid types.

The brake fluid should be flushed every 2 years, the factory says DOT 4+.

The antifreeze should also be flushed every 2 years. If it uses antifreeze, you need to find out what is causing the loss. For a "top up", find some that is good with alluminum alloy engine blocks. I get a gallon from the dealer for a lot of bucks, but that is good for 2 years.

Tranny fluid is gear oil. Only about 2 quarts or so. Available at all auto stores. Try to flush it with synthetic. The flush should be around 100K or less.

Make friends with the Volvo dealers parts people, that way you can ask really dumb questions and they won't mind. Like, what kind of tranny oil does the shop use.

Klaus
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The more I learn, the more I forget. So why learn?