tmak26b

Hey guys, I just changed my coolant. They have about 50000 highway miles on it (1 year old). it came out to be light brown color with a lot of black dirt in it. Is that normal for worn coolant?

Mark S

iTrader: (1)

NO

Icemark

no... something is disolving and/or it has been way too long sich was last changed

Grimlock

50,000 miles dude, i think your supposed to change it every 12,000 miles or every yr. which ever comes 1st! 50,000 is way to long to go with out a coolant flush. put some good stuff in there! i changed mine after a yr. worth of driving and about 20,000 miles (i let it go to long) and the old stuff that came out was spotless like i had just put it in--made me feel good about my motor

tmak26b

I changed it 3 times since I boguht my car, always look like this color when I change it. I use prestone and distill water

Grimlock

did your car ever overheat?

Amur_

Throw some Red's Water Wetter in your new coolant mix, too. A definite must-have with a rotary. There was a post in here with a great description of it... and I have a copy! Read this if you're not already familiar with the stufff...
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Does it really work?
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Does it work? I cannot give a conclusive answer to that question. But I like "Water Wetter" and have been using it in all of my cars for many years now.
What I can say with conviction is that the person who wrote Redline's Technical Information brochure on "Water Wetter" knew what he or she was talking about. I have a Ph.D. in Heat Transfer and have taken a graduate course in Boiling and Condensation. Based on my training I can say that Redline's explanation of their product makes good scientific sense.

First we must dispel a common misconception: "Water Wetter" is not designed to lower your car's bulk coolant temperature. So if you put it in your E30 M3 hoping to see lower operational coolant temp's, then you will probably be disappointed.

"Water Wetter" is designed to reduce hot spots in your cylinder head. It does this by reducing the build-up of water vapor in any superheated areas. The bad thing about having hot spots in your cylinder head (read combustion chamber) is that they can promote pre-ignition - definitely a bad thing. This harks back to Smokey Yunick's theory of "soft combustion chambers". Any sharp edges in your combustion chamber (around valve seats for example) may tend to get very hot (even red hot) during operation. These areas of the combustion chamber can then form local hot spots in the cooling passages. Thus, even though your bulk coolant temperature is well below its boiling point (i.e. your gauge reads just fine), there may be localized boiling in some regions of the coolant tract.

This localized boiling can cause a layer of water vapor to form over the hot spot. This vapor forms an insulative blanket and prevents heat from leaving this area, thus making the hot spot even worse. But reducing the surface tension of the water makes it easier for vapor bubbles to leave the surface of the cylinder head and allows the bubbles to convect heat away from the area. Something that changes the surface tension of a liquid is called a "surfactant". It does not take very much surfactant to significantly change the surface tension of water. Hence, you do not need to add very much "Water Wetter" in order for it to do its job.

An additional benefit of using "Water Wetter" (in conjunction with 100% water) in you cooling system is that water has an extremely high heat capacity. Thus a gallon of 100% water can carry more heat away from you engine than an equivalent gallon of 50/50 water and coolant. Water also has a high thermal conductivity which increases the convection of heat away from the coolant passage walls and into the free stream of the liquid flowing through the passages.

"Water Wetter" does not increase the boiling point of water. Standard automotive coolant does increase the boiling point of the mixture above that of 100% water. But remember that if your cooling system is operating properly, it should never get hot enough to boil (I mean BOIL, not just localized boiling). Raising the boiling point of the coolant in passenger cars is primarily a safety measure, so that if the cooling system is over stressed (climbing a hill on a hot day with AC on), it will not boil over. On performance cars the primary duty of the cooling system is to keep the engine in its optimum temperature range. This is best accomplished with 100% water, because its high heat capacity makes it very efficient at transferring heat.

Performance cars often run relatively high cooling system pressures. This also raises the boiling point of the coolant . But the high system pressure is not used to avoid boiling so much as to allow the engine to operate at a higher temperature for reasons of efficiency. A higher cooling system bulk temperature also allows the use of a smaller radiator (there is a greater driving force to transfer heat from the coolant to the free stream air). Take a look at the E30 M3's "tiny" radiator and you will see what I mean.
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ttyl,
Amur_

tmak26b

Nope never overheated my car even in traffic and a/c on. I wil verify it again this year with a water temperature gauge

Grimlock

i cant remember where it might have been on here but somewhere i read that the chemicals in the water wetter can disolve the seals in a rotary engine. i dunno if is accurate but i remember reading it somewhere!

tmak26b

Yes, no water wetter for me. I dont want my water seal to go byebye

Amur_

Here's the thread (or one of 'em):

https://www.rx7club.com/forum/showth...t=wetter+seals

While it is suggested that Red's does damage, no one seems to have any proof of that... I'll poke around some more...

ttyl,
Amur_

tmak26b

Use it at your own risk as always

PraxRX7

I have only ever overheated my car once, and I stopped and let the car idle as soon as it happened.

I was driving on a hot day at full boost (for about 30-50 seconds) with the A/C on and there was tar on the road that was emmitting MASSIVE amounts of heat at the radiator level...well needless to say, massive heat problem, gauge skyrocketed.

From then on I replace my coolant every year (after storage) or every 10,000 kilometers (6500 miles ish).

I am also upgrading to a Fluidyne Radiator this year (and probably going to change my oil cooler as well).

When it comes to radiators/heatsinks, the bigger the better.

fc3s.org

I challenge anyone to provide PROOF that it does any such sort of damage to a rotary engine. I disassembled a rotary that we used in the Project 86 (after I ran out of gas on a hard turn on the track under boost ) since it was blown, and we had used water wetter in it since we installed it. There was absolutely NO SIGN OF ANYTHING ABNORMAL with the seals or any other related portion of the engine. I also use it in my 91 vert and there have been ZERO signs of any sort of problem. Matter of fact I have only had good experiences with it. I will be doing a Fluidyne AL radiator upgrade Thursday, so I will be inspecting the radiator for any signs of anything, but I am sure it will be as all the other evidence that I have seen, and things will be just fine. All those people on the race track wouldn't use it if it were so bad for rotaries.

Amur_

It has been mentioned in another thread that using a heavier oil (I say heavier cuz I've been using 5W30 year-round 'til now) also helps to carry heat away from the engine...
I'm considering using 10W30 for my next oil change, whcich will probably be end of May/early June... I've got to take cold starts first thing in the morning into account. It'll be around only +5C then. We'll see.

ttyl,
Amur_

Grimlock

cool, someone with 1st hand experience with it! how many miles did the engine have and was it drivin everyday???

fc3s.org

About 35K miles, and when it was driven, it was driven as hard as I could drive it. That also included 2 trips to Phx AZ to drag race =) It was driven at least 3-4 times a week.