In researching coolant requirements for my aunt's Toyota, I read some disturbing info on coolant and the consequences of using the wrong type.

I currently have Zerex G-5 in my 84 240 based on previous positive reports. Also recall past posts that it's basically the same stuff that Volvo, MB and other European mfgrs recommend.

The worrisome portion I just read in a Toyota forum basically said that the HOAT technology used in the G-5 coolant shouldn't be used in OLDER vehicles with copper/brass/lead rads and heater cores. HOAT type coolants are optimized for newer aluminum rads and heater cores. Being that our older Volvos use iron, copper, and aluminum in the cooling system, I'm not sure what to make of this.

As luck would have it, I just replaced my old radiator (with a new Nissens all metal type) after it developed a leak at the side tank seam somewhere. This, less then a year after switching to the G-5. Since I really didn't know how old the rad was, I just assumed it was time for a new rad. Now I'm second guessing my decision to use the G-5 coolant in the new Nissens. I've also been getting a tiny whiff of a coolant smell in the cabin off for the past 6 months and hope the heater core isn't developing a leak.

Has anyone else used the Zerex G-5 long-term to evaluate its performance?