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Yearly Coolant Flush?

VFilms

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Back in the day, when I was young and worked on these MOPARS (mid '60s to early '70s), we would flush the cooling systems yearly. I remember the coolant always being a bit 'rusty'. Looking at the FSM is says to flush annually. It also states to use 1 gallon of coolant and fill the rest with water. Given the advances in coolant chemistry is it still necessary to flush the system each year, and with what percentage of coolant/water?
 
Long standing 50-50%. Yes technology has come far.Some guys like the water less coolant.
Annually I would do a sample check and if it starts to look bad,change. Now a days 5 years seems normal. Anything old like my 33 year old truck I have it gets pretty rusty looking even after a good flush.But who knows if it was ever changed before I got it.
A good clean block to start with is the way to go.
 
I don't believe a yearly flush is necessary,,, IF your coolant is clear and clean. A dose of a good rust inhibitor now and then (follow directions on bottle) sure wouldn't hurt hurt. Mix enough water with the a-freeze to get 20 deg below the max low temp in your area,,,,Ed
 
I run 50/50 and should probably flush my two again. I can't remember when I did it last. I do add a can of conditioner every year or two though. That freshens up the water pump lube and anti corrosive qualities in the mix.
 
The new purple Mopar antifreeze is a 10yr 100,000 mi coolant and helps with aluminum corrosion for the newer engines. I threw it in my 68 500" stroker with the aluminum heads figured it couldn't hurt. It was 18 bucks a gallon my cost, but hey after 9G worth of parts I figured what the hell why not hah! The older red stuff before that was a 5yr 50,000mi coolant and then the green **** is probably good for a few years as well.
 
Went through my POLY a last year - bigger bore, hotter cam (thanks Gary P.) and the engine just went back in the car with no fluids. As soon as the NE winter leaves (could be July around here) I plan to fire it up. Thanks to all for the help.
 
I run 50/50 and should probably flush my two again. I can't remember when I did it last. I do add a can of conditioner every year or two though. That freshens up the water pump lube and anti corrosive qualities in the mix.

Out of curiosity, what "conditioner" fo you use and what are its ingredients? Bear in mind that water pumps do not require a "lube" as the shaft bearings are sealed and pre lubricated by the bearing manufacturers. However, the anti corrosion inhibitor component is a good idea but depends on the chemistry of coolant....ethylene glycol, Dexcool (and its derivatives), and propylene glycol and of course the Evans Coolant proponents.
BOB RENTON
 
I shoot for about 40% glycol/60% water.
I've never seen it less than -15 deg. F here and my cars in a garage/barn so they would never see that temperature.
Besides, I'm really cheap.
 
Out of curiosity, what "conditioner" fo you use and what are its ingredients? Bear in mind that water pumps do not require a "lube" as the shaft bearings are sealed and pre lubricated by the bearing manufacturers. However, the anti corrosion inhibitor component is a good idea but depends on the chemistry of coolant....ethylene glycol, Dexcool (and its derivatives), and propylene glycol and of course the Evans Coolant proponents.
BOB RENTON
I used this Prestone product. https://www.amazon.com/Prestone-Sup...42ddc&pd_rd_wg=pVd9b&pd_rd_i=B07GQ5XC8M&psc=1
 
I flushed mine in 2016. First time since 1988 !!!! VERY little rust even on the FULL flush. Still using the SAME water pump !!! Radiator I had in the car still in nice condition as well .
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If you can access AND get them out, you'd be amazed at the crap that comes out of the water jacket drain plugs.
 
If you can access AND get them out, you'd be amazed at the crap that comes out of the water jacket drain plugs.
Exactly. Most blocks, if they are still original, have foundry sand to the bottom of the expansion plugs. It look me a couple hours on the engine stand to get mine cleaned out. I have a ling screwdriver (24"+) that got in and loosened all the muck up.
 
Just out of habit I do a drain and coolant refill every other year on all my vehicles. No flush. Just drain approximately 1 gallon and fresh coolant replacement.
Gold universal coolant in my newer cars and conventional green in the older cars. Mix is 50 50 with reverse osmosis water.
 
Probably overkill, but I am with Billcm. Drain and refill every other year - 50/50 coolant and distilled water.
 
I think back in the day nobody used distilled water to mix with the antifreeze, so then it was a good idea to do it yearly. My Dad had a 58 Plymouth and always used house tap water. Then as the radiator got clogged he had to use screw on hose clamps for preventing leaks because cooling wasn't efficient anymore.
 
Here’s a somewhat related tip...
The stuff that goes in my boiler for my heating system is grievously expensive. Dowfrost.
Someone came up with the idea of just running automotive antifreeze. DON’T DO IT!
The way a boiler heats the fluid and the way a car heats it are different. In a house boiler the antifreeze becomes more acidic, eating your stuff despite anti corrosion additives. It’s not about dissimilar metals or anything like that, it has to do with the way the fluid is heated going through the boiler. Conceivably you could PH test and neutralize it every year, or you could just buy Dowfrost and sleep easy.
It happened to me.
I managed to find a guy who could get me wholesale Dowfrost. Much, much better.
 
The two cars I own get just the radiators drained every other year.
Refill with fresh anti freeze , never had a problem.
Been doing this for 20 yrs
 
Thanks Toolman for the link on the Prestone,
I have looked for something like that at the local parts stores,but they don't carry any.
Counter people don't even know what I'm talking about most of the time.
Recently have been using a product made by HyperLube that I like.
 
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