George, IMO you are doing more harm than good with your procedure. Its not really the ethylene glycol that breaks down in the cooling system, its the corrosion inhibitors that get used up. Used up corrosion inhibitors don’t do any harm, they just stop doing what they are supposed to do.
A simple drain and refill is all you need. You need to drain both the block and the radiator, then refill with new. The little remaining old stuff is harmless. But running straight water in a cooling system with aluminum is very harmful. Under those conditions, especially using tap water that may have some chlorine and salt in it for even one day will cause a lot of corrosion inside your engine and radiator.
I have been very happy with the Peak universal for many years also. There was just too much controversy over the Dex and other varieties and tried the Peak in a few highly abused fleet vehicles and was pleased with the total lack of problems so I just drain and fill everything every 3 years using the Peak. Others seem to have experimented and found similar success with other products, though.
@RodKnox it seems to me you’re taking a step back with the Peak, because you’re doing a drain and refill every 3 years.
With the Dexcool, you’re supposed to do a drain and refill every 5 years.
Where is the savings?
In my opinion, the guys that have problem with the Dexcool are the ones that aren’t changing it at all and have plugged radiators, heater cores, etc. after 10 or 15 years.
I think a problem with coolant is the way it’s marketed. Many people are under the impression that it’s a “lifetime” fluid. And then they complain when their neglected coolant system starts having problems. This is by no means limited to Dexcool or GM.
I always just drained the radiator and used 50\50 rainwater and antifreeze to refill,recently I just use universal premix-kinda lazy I guess,but it works for me-Kevin
I’ve used Peak, and kept it in the system for 5+ years. It was on sale at the time. I’ve also used Prestone orange and Prestone yellow. I guess the only reason that I haven’t used Zerex universal was that it wasn’t on sale when I needed it.
Thanks to all for your good comments. Just to clarify, my method always ends ups with a 50/50 mixture in the engine. The reason I only drain the coolant when the engine is cold is to prevent any possible metal warping that might occur if the coolant is all drained out but some of the engine parts are still hot. That seems like it could be a bad situation. I run with a diluted mixture for 2 or 3 days is all. Then I refill with enough pure Prestone to bring it up to 50/50 (based upon the engine coolant capacity). I always test it again a couple of days after I do the refill. If it isn’t 50/50 , I drain some coolant out and add straight Prestone until it shows 50/50 after several days of driving. Usually I can get it spot on the first time though. I wonder, do you think driving with diluted coolant or pure water for just 2-3 days causes significant corrosion? I’ve always assumed a few days of running pure water would not cause problems. And it has the upside of never draining the coolant when the engine is warm. And at least w/my 20 year old Corolla, at 200k, this method hasn’t seemed to cause any problems.
My 99 RAV4 is still on the original factory coolant, with no problems. I’m sure that’s not a record. Anybody got any amazing long-time/high-mileage tales involving coolant, oil, or whatever?
Ooops, I didn’t mean to say I add a 50/50 mixture. When I’ve done the drain-outs several times over the courswe of 2-3 days, there is mostly just water in there, so the final step, I add 100% Prestone, measure it out for 1/2 the cooling system capacity, to create a 50/50 mixture.
You can do it that way if you want, but I won’t do it that way nor would I recommend that anyone else follow those procedures either, I would not want to be responsible for the resulting damage. I believe a simple drain and refill done in a timely manner is the safest and best way to protect the cooling system.
I had a friend with her own Toyota Corolla – this one an early 80’s carb’d engine – and she never changed the oil or the oil filter once in the life of the car. Which was going on 20 years when she told me this surprising fact. She said she simply added a quart of oil when it was low, 2 or 3 times a year. She never washed it either. Her theory is the rain should do the washing for her. She babied it when she drove it, and the engine never gave her any problems as far as I know. But the paint – that’s another story! The paint job was a total disaster. Oh, she never cleaned the inside either. Nobody would ever ride w/her. lol …
I think there are probably a lot of stories like that, where people never change their oil, just add when it gets low. So I doubt her story is a record. But one person here said they got over 650K on the original clutch. I think that may be close to a record.
Re the 3 year drain and fill, most of my work was on fleet vehicles that accumulated 30,000 to 120,000 miles each year. Often repairs required draining and that re-set the clock. But after 3 years coolant would be replaced. What became normal for me is quite unusual for most and I often forget that. For drop in work if the radiator flues had any visible accumulation of residue or the coolant was not bright I recommended a drain and fill.
@keith, do you mean running pure water in a cooling system for only 2-3 days would do damage? You may well be right, but this seems unlikely to me. it seems like it would take several months at least before there’d be any measurable damage from running pure water (provided the freezing part isn’t an issue.) I wonder, is there any evidence one way or the other?
Take a piece of aluminum foil and put into a glass of water for a few days. Heat the water up if you can, say by putting the glass into an oven set to 180F for a few hours each day. Better use Pyrex for that.
Great idea for an experiment @Keith. I think there needs to be a control too, with a 50/50 mix, to compare against. I think it best to do that part outside rather than in the house. Do you think if I simmered both – one with tap water and one with 50/50 – in a pot with a campstove outside (instead of an oven) that it would be am equally good experiment?
hmmm … come to think of it, I sort of have done this experiment as I have an old aluminum cooking pot I use to pastuerize my compost for indoor plants. 180 F is the temp I use for this. I don’t recall seeing any degradation of the pot, and I’ve done this several times a year for 15 years or more. And before I relagated that aluminum pot for compost use, I boiled water in it for coffee for 10 years before that. I wonder, is an aluminum cooking pot comparable to an aluminum head?
Still, I’ll do this experiment with the aluminum foil you suggest. Seems interesting.