98 V70 NA antifreeze question

Post by **98v70dad** » 23 Jul 2015, 09:33

My radiator has 50/50 mix of Volvo blue antifreeze and distilled water and its about 2 cups (at most) low after replacing the coolant temperature sending unit. I want to top it off. The radiator, the heater core and all the hoses are new. Would it be better to add two cups of water or two cups of a prestone (generic yellow/green) 50/50 mix that I have and is already open. The extra cup of water probably doesn't affect the boiling/freezing point of the mix much. 56/44 water/antifreeze instead of 50/50.

I don't want to buy another bottle of antifreeze to add to my stash of the 3 bottles I already own unless I have to. The prestone stuff claims to be compatible with everything.

Post by **cn90** » 23 Jul 2015, 10:18

50-50 Prestone green is what I have been using for years on my Volvo.
Don't worry about it.

Post by **mecheng** » 23 Jul 2015, 10:28

I would not mix coolants. Sure the green stuff says it compatible with everything, but that is impossible as there must be some compromise. I switched to only the Volvo blue as if you do some reading it has specific chemistry for these engines. So if you want to save some bucks, if the boiling/freezing point is okay then add some water or get the Volvo blue.

You will get varrying opinions, so you need to do what you feel is right. When I used the Green on my Honda, the water pump started leaking. I switched back to the Honda coolant and the leaked stopped as it must have re-swelled the rubber gasket.

Post by **abscate** » 23 Jul 2015, 10:30

Top off with water. Tap water is fine if your tap water isn't crazy hard with minerals (if you don't use a water softener at home, its fine.)The mix would be fine too.

Post by **98v70dad** » 23 Jul 2015, 12:21

cn90 wrote:50-50 Prestone green is what I have been using for years on my Volvo.
Don't worry about it.

I'm not worried about it, just wanted to hear other people's input. I knew that the opinions would be all over the map.

My point was that I have everything in the cooling system just about as good as it gets and sticking the prestone in with the volvo fluid sort of contaminates it. However, my gut feeling is that mixing them wont have any appreciable affect and and would lean towards doing this versus diluting whats already in there. Its really hot here in Atlanta in the summer so I don't want to affect the boiling temp of the mix in an appreciably negative way by adding more water.

I'm looking at picking the best of two less than optimum choices. I'm not going to shell out 20 dollars for another gallon of volvo coolant to top up two cups even though that's the obvious best thing to do.

Post by **erikv11** » 23 Jul 2015, 12:38

I would either use water or buy a bottle of Zerex G-05 (very close to the Volvo formulation, but not a whole lot cheaper) or a bottle of the Volvo coolant. I wouldn't mix different coolant chemistries just in principle. I agree water will be just fine.

Post by **FLXC90** » 23 Jul 2015, 14:55

The differences in chemistry don't really affect so much the anti-boil, or anti-freeze qualities of the fluids, they are usually preferred because of lubricating and anti-corrosion properties tailored to the metallurgy of the branded engines. I remember seeing pictures of VW TDi motors eaten up inside running "Green Death"

and I experienced gasket breakdown and engine failure when added tap water contaminated GM DexCool in a minivan. The old formula green stuff was formulated in the days of iron block and head engines, and the OEMs specify based on the alloys in their motors and the gasket materials they use. (And I'm sure, agreements and contracts with chemical companies!)

Post by **cn90** » 23 Jul 2015, 21:47

Actually Prestone antifreeze is compatible with Volvo coolant. I have mixed them for 25 years, zero issues.

If you want to be kosher (and make Volvo a tiny bit richer), then stick to Volvo coolant.
If you don't care about Volvo coolant, then use Prestone.

Post by **98v70dad** » 12 Aug 2015, 16:43

I ended up buying a small container of Pentofrost NF and gave my really old Prestone to a friend. He put it in his hoopty and was very appreciative. I didn't mention that the bottles of Prestone were given to me for free and were at least 5 years old. I don't know if they have a shelf life but usually anything with chemicals in it does. I mentioned the issue of shelf life to my friend and he didn't care about it. He said that his hoopty leaks enough that he wasn't concerned about it.

I was surprised that the local Advance Auto Parts had Petosin antifreeze, especially in the 1.5 liter bottles. Now I have some left over for top ups if I need it.

Anyhow thanks for the advice everyone.