Back-flushing cooling system on 86 22rec

[mini-wini-dan]

I just inquired about back-flushing my cooling system and my mechanic discouraged this if it is not showing signs of overheating. He feels the age of the cooling system may have weak areas that will be degraded by this process. Anyone had experience with this era toyota cooling system back flushing.

This vehicle always runs under the half way mark on the gauge. Maybe I should well enough alone but I am heading for the southwest in August which will be hot.

[fred heath]

My mh is a 1978 with the 20R. Flushing and cleaning was the first thing I did. That was about 14k miles ago.

I bought the Prestone "flush and fill kit) at Walmart. Followed the directions including the optional rust and scale remover. Refilled with new antifreeze. Temp. gage also has never gone above 1/2 (before or after). I'm not sure what your mechanic is concerned about unless it's the rubber hoses. Better to find out now than later. I changed all my hoses at the same time I did the cleaning.

[mini-wini-dan]

Thanks Fred for your info and I will look into such an option.

[Boots]

I just inquired about back-flushing my cooling system and my mechanic discouraged this if it is not showing signs of overheating. He feels the age of the cooling system may have weak areas that will be degraded by this process. Anyone had experience with this era toyota cooling system back flushing.

This vehicle always runs under the half way mark on the gauge. Maybe I should well enough alone but I am heading for the southwest in August which will be hot.

Hi Dan

I think in this instance your mechanic may be correct. I had an RE22 engine and it was invincible - this is a commercial truck engine (which always seem to be called on to do more) and my experience in driving in all conditions, including desert areas and steep mountains the engine never overheated. This, I suspect to a oversized radiator and likely an oversized water pump. I always changed out my radiator fluid every two years, whether I needed it or not and I suggest Toyota's Red Antifreeze (yes it is more expensive, but so is replacing an antique water pump). I always flushed the radiator and engine before every change. Never had a problem.

Brian

[mini-wini-dan]

Thanks Brian,

I will flush and use the red antifreeze and I noticed today the temperatures in the southwest are as high as 117 degrees. We will be there in about a month.

[sdboltdude]

I'm planning on doing a flush on mine & was going to use one of the Prestone flush kits

I have never flushed radiator are these good kits?

[waiter]

I've used the two part powder stuff in the past.

drain and fill with water.

The acid stuff goes in first, its circulated hot for several minutes, then drained.

Refill with water and add the neutralizer stuff. circulated hot, then drain.

Refill with water for a rinse, circulate, drain,

Then refill with antifreeze/water mix.

I'm not sure how effective it was,

I believe the chemistry is that the antifreeze ionizes, and its these ionized molecules that are corrosive, I remember we had this problem in heat exchangers we used at a power plant, changed from ethylene glycol to propylene glycol to reduce the problem.

Change antifreeze every couple years is the recommended solution.

John Mc

88 Dolphin 4 Auto