100% Water as Coolant
 

So I'm looking to buy my first RX7, its a 1988 T2. The car is in pretty good condition, but it has one or two issues.

The one that worries me the most is that it looks like the current owner has been using 100% water for his coolant. From what I understand, this can cause corrosion in the aluminium engine housings.

Assuming its been like this for 3 years (how long he's owned it for), will that cause any major problems, or should it be ok?

Thanks for the help guys!

I'd wonder Why the guy has been running Water as coolant?..is the car overheating alot?Has it overheated?..is he Cheap?..If the engine is OK,then Flush the Coolant system out,and put in a good 50/50 mix of coolant and Distilled water(not Tap water).

100% water
 

Exactly, If the water he was using was not distilled then it could cause problems. Flush and if that does not work, Radiator Upgrade :naughty:

If the previous owner has been using distilled water (and thus purish H20) then there should be no worries. Using an ethylene glycol mixture depresses the boiling point of water in a mixture. If the car was in an extremely cold climate then the glycol helps fight freezing. Aluminum shouldn't react to a de-ionized (distilled) water, so the cooling channels should be ok. If tap water was used then worry.

Hope this helped.

V/r

Matt

100% tap water + 3 Years = Epic Fail
100% Distilled water + 3 Years = Fail

The reason why some racers run 100% H20 is because it has better cooling property's then 50/50 mix does, a 50/50 mix cuts the amount of heat that the coolant can pull out in one pass, while H20 is (just about) the max heat transfer you can get.

The Distilled water water will not really hurt the Aluminum Housing as much as it will hurt the Iron.

Like the people said, flush it really well, then add a coolant cleaner, then flush again, then add 50/50 mix.

Ive been having great luck with the "red" antifreeze that have SCA's for diesels. Since the RX is a high revving engine, and a mix of metals, I figured if its strong enough for a diesel, the rotary should be happy.... 5 years not a drop of coolant lost, 83 GSL with 89k on it and other than the radiator and hoses, the WP is original

The biggest reason to use coolant/anti-freeze in a complex metal engine (where more than one metal) is for the anti corrosion properties.

When you mix metals such as Aluminum alloys and Iron, you get electrolysis between the metals and typically the iron items experience a much higher wear than other metals. Water pump impellers for example can rot all the way through in worst case, or pit badly in best case (usually resulting in a much lower cavitation level than otherwise expected). Cavatation in a rotary motor can result in radically reduced cooling capacity.

Running 100% with some redline waterwetter should not be as bad. The waterwetter is suppose to help lubricate stuff.

water cools better than AF, hence why some folks run it. Difference between 50/50 and water is about 25 degrees F when it comes to moderate tracking... there is no way to tell if you are fucked or not. Aluminum does not rust. Some of you must be thinking of Iron, Fe, which rusts. I'm not sure where y'all got the impression Al does.. but I won't ask.

-Bart

no one said the aluminum was rustingb but it is going to degrade under the described conditions
the thing I'd worry most about is the water pump, it hasn't been properly lubricated for 3 years and lord only knows what shape the impeller is in

water pumps are cheap. engines are not :(