I went to NAPA to buy GO5 Zerex and ...

Post by **JimBee** » 01 Oct 2010, 16:49

the clerk there energetically talked me out of it. I thought people on this forum agreed it's the best/original and should be used in the '93 850. So I didn't buy any until looking further into it. He said if I only want a phosphate-free antifreeze, NAPA has its own brand, but that's not the best thing to use, either, in the 850. Part of the reason was it's a long life coolant and leaving it in that long will cause harm to sensitive parts. He said, use the green stuff, Prestone (which by the way NAPA has on rebate special through October). So, my coolant right now is tap water and want to get some coolant in there soon. WHICH ONE SHOULD I USE?

Also, the NAPA guy did sell me some "15 minute flush/cleaner" which he said he has used for years. Is that a good thing to run in your cooling system? Or just flush it with water?

FCPEURO · Post by **FCPEURO** » 01 Oct 2010, 17:29

I would just flush the system with water. I was never a fan of "cleaners" in the cooling system.

Post by **JDS60R** » 01 Oct 2010, 18:07

use the Volvo coolant - the NAPA guy was wrong. Prestone hasn't made the green antifreeze with high levels of silicate in a while.
Today almost all of the brand have are Ethlyene glycol , diethelyne glycol and 2 EHA

Post by **JimBee** » 01 Oct 2010, 19:05

JDS60R: do you mean coolant with Volvo's name on it or the Zerex brand that people here talked about—I thought as a similar product to Volvo's own house brand, or actually the same product which presumably is made by some other manufacturer.

Post by **confused_al** » 01 Oct 2010, 20:52

JDS60R wrote:Prestone hasn't made the green antifreeze with high levels of silicate in a while

Boy, that green $*#@ is bad. On my newly acquired 96 platinum wagon, I found corrosion everywhere with the green stuff, in t-stat housing, coolant hoses...
After flushed the coolant, I still have nightmares about the corrosion in the block. BTW, does anyone know a good clean method?

Post by **JDS60R** » 01 Oct 2010, 22:29

I meant the Volvo branded coolant. Its made in NJ . Zerex G-05 is a HOAT but is not chemically the same as the Volvo stuff.

Post by **JDS60R** » 01 Oct 2010, 22:37

Al - don't laugh at the solution - that corrosion is is silicate drop out from leaving it in too long. Its similar to lots of hard water stains. I have some strong chemicals to release it but I have seen success with Cascade dishwasher gel and water. It has to be for a dishwasher so it doesn't foam up. Get whichever formula is best on hard water spots.

We tried it late one night after all of the off the shelf stuff didn't work. We let it sit and work for a few hours and then flushed it out several times with distilled water. It wasn't perfect but it did do a heck of a good job. Once refilled with proper coolant/water mix it cooled quite well. We had the thermostat out during the process as it was a new one the owner put in a week prior and was testing out properly. I offered to replace it without a labor charge but the owner decided this is where he wanted to save a few dollars. In this case it turned out fine.

Post by **JimBee** » 01 Oct 2010, 22:54

This seems like good analysis. I"ve owned my '93 850 for two years and except for vapor leakage at the top of my heater core (just replaced that) have maintained a perfect temp reading and in that time only topped up the reservoir about a pint. I drained it the other day and the green stuff in there was quite dirty. So I assume there's stuff accumulated throughout the system. Right now, it's full of tap water and I've run it about 20 miles on that. Again, temp is at 3:00 o'clock.

How much Cascade should be added? Can it be left in for a while to complete a good scrubbing? What happens if a couple of good fresh water flushes don't get it all out?

How often should the Volvo coolant be changed?
Thanks to all respondents; this is truly helpful!

Post by **confused_al** » 02 Oct 2010, 07:05

JDS60R wrote:Al - don't laugh at the solution - that corrosion is is silicate drop out from leaving it in too long. Its similar to lots of hard water stains. I have some strong chemicals to release it but I have seen success with Cascade dishwasher gel and water. It has to be for a dishwasher so it doesn't foam up. Get whichever formula is best on hard water spots.

Thats an ingenious solution! I'll try that as soon as I get her back running...Thanks John.

JimBee wrote:How often should the Volvo coolant be changed?

Every 2 years, I think.

Post by **JDS60R** » 02 Oct 2010, 09:29

After 2 flushes you will have it all out. If there is any left it will not hurt you. Just like your dishes it is meant to rinse clean the first time. If you are still nervous then do a flush and fill after a few months. Just like me you find you didn't need it . ( But it can't hurt and I slept better. )

Should you let it sit for a while -Oh yes - with visible deposits you need to let it run for a bit (1 hour)and then sit for a few hours. The motion of the fluid causes some light agitation and helps bring the deposits down . Sitting lets it work chemically. Be overly generous with flushing the rad. I take off both hoses and run a garden hose to it until I am sure its clean. As the water drips out the bottom you don't have to worry about the quality (mineral deposits) in the water. I do the same for the heater core but many fear the o rings and it is still fine without it. If you are nervous you can flush with a garden hose and then flush twice with distilled. Distilled goes on sale periodically and I keep some handy. At 88 cents per gallon keeping 15 or so on hand it is an easy expense to handle. Your system will only let out 1.5 -2 gallons per drain .

If the corrosion didn't all come out then do it again - and with a stronger mix. I put quite a bit in - probably enough to do 5 or more loads of dishes. I think I use about a quarter of a bottle. The lemon scent is nice.

The Volvo fluid has shown some silicate depletion in 3 years. It can go longer but I prefer the 3 year change. Following the 3 year rule ( was 2 years max for the old green heavy silicate fluids) I have seen many cars with 100-400K miles that have original rads and no visible corrosion. Hoses are toast every 4 years unless using Gates ECD which can go 8 years.

The low level of silicates in the Volvo fluid are repairing minor damage to your engine and rad. Over time the amount depletes (used for repair) and then you should replace the fluid mixture. No need to flush or use a cleaner . Just drain and refill every 3 years with Volvo antifreeze and distilled water.

PS- Take a gallon of your local distilled water and boil a cup of it in a pan until gone. Some distilled waters are of poor quality. You want one that leaves no visible deposits. If there are no deposits in the pan you can expect the same will be left in your cooling system. It was helpful to me to agree which pan/pot I would be using with my fiancé. I used a scratched Teflon one as its dark and the deposits show well.

On an extremely rare occasion with a horribly neglected coolant system I have seen the removal of deposits from the rad or heater core allow it to leak. Not from it being hurt by the cascade -just that it was seeping and the remove of the junk that clogged the hole allowed the leak to speed up. In these cases a core or rad was around the corner anyway.

If you want to see the effect of cascade on aluminum take a small piece and soak it in a mixture over night ( keep the metal submersed ) You will find its quite safe on the aluminum - similar to the way it cleans your aluminum pots.