Coolant 101


Hello all,

can you guys explain to me in layman's terms why the Coolant manufacturers recommend 70/30 coolant/water for max heat protection and most of you guys recommend differently??
I am obviously trying to find out what is best ie. RMI 25, Water Wetter, 50/50 etc but I just wanted to UNDERSTAND why.

Thanks alot for your time.

if you go on to nick micale's web site (see sig) he has a small video on RMI as well as a few write ups on RMI 25 this should help better your understanding of that product.

hope that helps a bit
I am installing a brand new GM radiator, hoses, etc and I am going to also install some RMI 25. Can you leave this stuff in your cooling system indefinately? I also bought some Redline Water Wetter what is the general consensus on this stuff?
Been There

Oh my goodness! About 2 years ago my GN ran at 210 degrees in summer traffic, that was with a 165 degree thermostat! Now she runs 165 degrees in the same traffic. I've done more research into cooling systems than most ASE certified mechanics! Let me shot a few ideas your way;
1. The local library, the book? Cooling system basics, it's very fascinating.
2. The local library again, why? Any videos you can check out on auto cooling systems.
3. Arizona GN on this board, he lives in the desert with a Turbo Buick. Talk about heat!
If you're a lazy slob like me and don't feel like doing research I'll give you a quick run down of my current setup.

- Aluminum radiator with plastic end tanks. It's sold as a replacement radiator for the 87 Buick regal V-8 with air. Make sure you specify, "Aluminum with plastic end tanks". Cost $125
- External stacked plate tranny cooler. The radiator only has oil cooler provisitions for one cooler. Your TR has 2, one for the oil and one for the tranny. Cost $35
- Distilled water only. Cost $3
- RMI-25 as per the instructions. Cost $25
- Ramchargers dual fans. Cost $80
- If you don't have one get a 165 degree thermostat. Cost $10
- Just enough anti-freeze for your particular situation. I live in Tampa Florida so I don't use any at all. Why? It's a long story, but basically it's because anti-freeze was never designed to be coolant. You'll discover that if you do some research.
Your grand total would be $278.

I'm not saying that this is the gospel truth, just sharing my own adventures. - BB
distilled water=free

If you've got a dehumidifier, just use that. As far as radiator water, it's as good as distilled and it's FREE! Mine makes gallons and gallons a week. No minerals.....just a few bugs but you can strain them out.:D
It's a long story, but basically it's because anti-freeze was never designed to be coolant
I like that! And water, of course, was designed to be a coolant? As suggested, read up all you can find. But be careful of reading things on the internet. For example, if you read the blurbs on Red Line's web site, they will all say wonderful things about Red Line products. I wonder why? But it's also true of Evan's NPG, another "designed" coolant. There are publications by the SAE, for example, that are "brand neutral", and will give you the pros and cons of running most common coolant mixtures. Water, for example, is terribly corrosive, without something like the RMI to protect the metal parts. Water also boils more easily than the glycols, so there is a potential for hot spots around the exhaust valves where steam collects. But water is not as bad as ethylene glycol for damaging bearings if you blow a head gasket. So read up on all the pros and cons, or maybe you could just go and see what GM is using the new Corvette, or Chryser in the Crossfire. But be careful, because the coolants sometimes don't mix well.
Originally posted by Ormand
So read up on all the pros and cons, or maybe you could just go and see what GM is using the new Corvette, or Chryser in the Crossfire.

That'll just tell you what the bean counters are saying. They have the final vote, after cost analyse.

While Evans hypes his product the info seems good. Especially the Buick modifications, they mention.
Re: Been There

Originally posted by Buick Beginner
.....- RMI-25 as per the instructions. Cost $25 -..................

All good info, but our cost is $27 including shipping, BUT that is for a quart, 4 treatments!:cool:

Comment on Redline Waterwetter - if used with only water it will go corrosive and remove solder from the radiator. It does not contain other additives like RMI. This is not to bash the product, but our experience with it years ago before we found and used RMI-25.

Also, RMI-25 has been found to work well with Dex Cool.

To answer the original question, plain water is one of the best fluids for heat transfer, antifreeze is not as good.

Water in a 15 psi system will boil about 250 deg, a 50/50 mix of a/f and water will boil at 265, neither of which we want our cars near.:)

Another reason to use only water [and RMI] is it will not immediately kill your bearings if it mixes with oil, like antifreeze does in case ahead gaasket blows.:(

For the record, this a really old thread (Jan 2004). I did alot of research and talked to alot of very knowledgable people and eventually bought RMI25 (thanks Nick).


Originally posted by strikeeagle
Distilled water costs less than a buck a gallon at Wal-Mart and elsewhere - and no bugs.

I was kidding about the bugs. It's clean, and at my house, it's plentiful. I'd rather spend the money on gas.....or beer.:D
This is like a discussion of religion. Many believe things without basis in science, and go with those beliefs. Fortunately, they don't hurt anything, unlike some religious fanatics. It is often mentioned that the engine "shouldn't" see temps above the boiling point. Those who mention this won't explain how you car run an IC engine if the peak temp anywhere in the engine is 250 degrees F. The temp in the combustion chamber will be near 2000 degrees, the exhaust valves will reach more than 1000, the surface of the combustion chamber will reach 1000. Heat transfer is such that there WILL be hot spots, and they WILL be near the heat sources, like the exhaust ports. Even though the "bulk" temperature of the coolant may be only 160 or 170, that is, to most thinking people, NOT the highest coolant temp anywhere in the engine. So, you can run Evans NPG, or other coolant with higher boiling point, and give yourself a little margin against hot spots, or you can run pure water, and pray to the RMI gods. By the way, the bean counters carry more weight at the low end of the auto spectrum, less at the Corvette shop, or the Porsche or Mercedes dealer.