bigdongsr94

trying to find anyone running low pressure coolant. It is waterless and is kept under 7PSI yet cools better even with less pressure ( or it is suppose to). Well it seems to me it might save a cooling seal and i thought there were a few running this.

Icemark

How are you going to get proper flow for cooling with low pressure???

What's the point??? Cooling seals on a rotary blow because the motor was not maintained, not from too much pressure.

Dak

Are you talking about the Evans NPG stuff? Do a search or post in the Rotary Performance section. I believe there are some guys in there who are using it.

jackhild59

iTrader: (7)

It wont fix a coolant seal. It won't prevent a coolant seal from going out.

However-

I am using it, for about 5 weeks now. I was plagued by my cooling overflow gaining a little coolant each time I drove. I did the coolant seal test, didn't get any bubbles. When I poured the coolant back from the overflow into the radiator, the amount was just right. Good engine compression, cooling system passed pressure test, new mazda pressure cap, new thermostat. The engine never overheated. After 5-6 drives, the tank was full and the low coolant alarm went off. This became real risk to someday overheat the engine and was a major pain in the butt.

I researched the Evans on this board, particularly the 3-gen threads. There are lots of threads with several successful users that are in very hot weather climates. Some are even running at track days. These threads quickly become quite combative. Some people say they are using Evans with no issues, lots of benefits. Others (haters?) pound the many supposed reasons why the NPG systems cannot work. When confronted with the reality pf practical success, they frequently criticize the Evans NPG as hocus pocus, overpriced marketing hoo-haw.

So, I changed to the Evans NPG+. I put in a new generic radiator cap that I gutted. I turned it into a $7 0-psi cap. The overflow tank is now just an expansion tank.

I have driven in 85* days with the A/C on 85 mph+ extended on the highway. I have driven in town, lots of stop and go, a/c on. No high temps, no loss of coolant. No problems yet. After about 1000 miles or so, I am beginning to become comfortable with the situation.

Truly hot weather is just around the corner. It remains to be seen how this system will work in the summer in Dallas, TX.

Now it is time for the haters to tell me why it cannot work, how I should fix my car and solve my cooling problem ad nauseum.

Your experience may vary; So may mine going forward. I consider this to be a successful start to this experiment. The jury is still out.

Icemark

Glad you have started testing, but have you been monitoring the Oil temps as well? An increase in oil temps when using the low pressure system would show you a real world example of if it works.

My concern on these systems is an inacurate water temp reading. The stock water temp sender is designed for high flow coolant, yet with a low flow system is it really reading correctly. Sure its reading correctly at the sender, but my concern is that with a low flow system where the sender is might be colder (or hotter) than the overall coolant temp.

That is why any coolant modification like that should be also closely monitored on the oil temp (which will really show what temp the engine is working at).

hIGGI

iTrader: (7)

Described situation looks like coolant seal starting to go. It might not be loosing any combustion pressure into cooling system at idle or in normal driving situations, but once u start beating on it or boosting, it will push water out. I happened to deal with some cars with this problem. Without boost, you could have been driving for months without any coolant loss, however, after half hour of boosting, you would have overflow tank full.

bigdongsr94

I actually wasnt wanting to use this because I was worried about a coolant seal that was an after thought. My main reason for the question is just the overall affects of the low pressure coolant. I understand heat tranfer a little and I understand why there are haters of the low pressure coolant. I have a custom radiator setup that comprimises the radiator airflow. Thats why I am looking for better coolant alternatives. This was not advertising, I actually found the coolant in the shop I work at. So its free to use and I think I will try it. I dont believe the gauge is tricked by low pressure coolant. A reason for this is the gauge will actually work in a vacuum environment. I will however monitor my oil temp gauge. Thanks for that tip it does make sense. Also note these gauges are aftermarket not factory.

jackhild59

iTrader: (7)

That is an excellent suggestion. I have been intending to add an oil temp gauge to my car for a while. This gives me a good excuse.

I will not have a baseline for before the coolant change so what is an approximate oil temp (range) when the coolant is up to operating temp for highway driving, 60 mph on an 85* day?

Question: I understand that the S5 coolant temp gauge is generally poorly regarded, but why would it be less accurate with low pressure in the cooling system? Nothing has changed except the pressure. The coolant flow should be the same. What am I missing?

Thanks!

jackhild59

iTrader: (7)

It might very well be the seal starting to go. I have no other symptoms, so hopefully not.

I do drive the **** out of it on occasion: 8000 rpm = reason to own rotary! I redline the engine at *least* once EVERY time I drive it. I have put nearly 10,000 miles on the car in the last 12 mos, so it is not a fragile garage queen. Cars are made to be driven, rotaries included.

Also, being N/A I have no boost.

In my situation I played around and watched it closely. Every time I warmed the car, a little more coolant stayed in the tank. I played with a Slant radiator cap, the kind with the pressure release lever. If I pulled up into my driveway, raised the hood and popped the slant cap 5 minutes later, the coolant was always drawn back into the radiator. It was just too damn inconvenient. Also the lever could not be left up and the hood lowered. So the hood was *always* up on my car. What a pain. So I am trying the NPG+ and so far so good. I don't think it is for everyone, and it may not be for me, either. I would have never tried it if I could have solved my issue by other means.