I use the Prestone green anti-freeze mixed 50/50 and have for many years. I have always tried to change at 2 year intervals. I have a Summer and Winter 940 and wonder if I need to change as often as I do. My Winter car will be coming to life in the next month and has only 9K miles on it in the last 2 years and I am wondering if it is really necessary to change anti-freeze? Is there a time/mileage formula for changing anti-freeze?
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Mine:5-940s running, 1-740, 2-940 parts, dtrs:3-940s running

What about original brass heater cores?

your schedule's correct but the coolant is wrong. zerex g05 is what volvo says to use. it has no phosphates to react with the aluminum in the head. phosphate will leach out and in some cases, will clog the radiator. good luck, chuck.

hi pork- have a gallon of go5 which has been on my for a 4 years. 92 245 has clear green antifreeze in it. no issues with coolant. has always used green. thinking of doing a flush this fall and putting in the go5 this time. will it cause leaks as some have told me? thanks tons oldduke

Good info. Chuck and Porkface

I read on the 700/900 FAQs Coolant Recommendations, if I am understanding it correctly, that Silicates protect solder in the coolant system radiator and heater coils and that low or no phosphates is necessary to protect the Aluminum in the radiators and the heads (mine is a 940 with aluminum head and cast iron block, B230 engine).

I have a bit of a dilemma here. My daughters and my wife and I have 7 940s running and 3 of them have aftermarket brass (and solder) radiators CWF brand. I wonder if I should continue using the Prestone Green antifreeze in the brass radiators since the silicates should protect the solder from being leached out? After reading the replies, I will be changing the antifreeze in cars with Aluminum radiators to Zerex G05 since it has low silicates (don't need the solder protection) and is phosphate free.

Does this sound like a good plan or does the Zerex G05 have enough silicates to keep the solder from being leached out?

Thanks.
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Mine:5-940s running, 1-740, 2-940 parts, dtrs:3-940s running

only an anecdote, no hard info available.

used to work for a guy who, years ago, worked for volvo na. his last responsibility was test the ac in miami for the new 760 we got in 83.

some dealers in the 70s were returning b27 engines for leaking coolant from the block, like the 92-93 960s did later on. turned out, they were using the typical ethylene glycol that EVERYONE used and sold-no such thing as special coolant. it was reacting to the aluminum blocks and thinning the metal, causing the leak. nj studied this and found those that used zerex coolant had no issues. i have no idea if it was g05. i was at the dealer in the 70s, but not long enough to see this occur.

when volvo used the vw diesel in 80, vw specified the coolant and volvo went across the board for all engines. probably a reaction to past experience and minimizing part numbers. brass rads were still being used until about 85 or so and i don't recall problems with them leaking because of g05.

understand that mercedes has used g05 since the 70s and bmw a similar 1-g48. good luck, chuck.

Chuck is right.

It is my understanding either Volvo or Zerex g05 are the correct antifreezes to use in most older Volvo's. Meaning the ones with aluminum heads and/or aluminum blocks (used it in both my 240 and 850). The really old iron head/block cars are probably okay with most any antifreeze.

I do believe Volvo switched antifreeze composition with its newer cars??

I've been on your schedule for 30+ years. All my street cars get all fluids other than oil changed on a two year interval - coolant, PS, brake, tranny, rearend (or transaxle). I have no idea what the pros/cons are. But I think it extends the life of the components that have the fluid in them -- and it makes me feel better. Besides - when I'm underneath doing that stuff I'm more likely to see/find other stuff.