EVANS NPG COOLANT (http://evanscooling.com/main21.htm)

...time to service my cooling system and thinking about replacing my coolant with the NPG+ coolant. has anybody tried this before?

Teamrx8 as i remember has done NPG.

cool, hopefully he chimes in soon =)

I wouldn't recommend it for normal street use, not worth the cost and hassle except for racing where everything costs and is a hassle, nothing to see here so move along ... :hahano:

if you do it anyways then you need NPG-R for the RX-8 radiator, the viscosity of the other NPG coolants are higher than standard coolant and intended for open-channel racing radiators

I haven't had any issues with it. The coolant system doesn't boil over anymore after running the engine hard for long periods like it did prior. Getting the system flushed of water-based coolant and ready for the NPG is a pain. You'll have to flush it at least twice with a lower cost PG type coolant such as Sierra, which you're simply pouring down the drain, before you put the high $ NPG in. If anyone ever pours water or non-PG coolant in it then you have to start over. Nobody local carried the Sierra coolant. I ordered in online from Ace Hardware and they shipped it to the local store for pickup. Side benefit is that it doesn't freeze over, but it will turn into a thick slurry at -10 degF or lower

...thanks! NPG-R it is. so, you used Sierra instead of the prep fluid? I do all the mx in my car/s so I'm not worried about anybody else touching it. it might seem expensive but still cheaper than replacing the single row calsonic radiator with a 2 row.

the prep fluid is $28/gallon plus shipping, you'll need quite a few gallons to drain and flush twice

you can get a 6 gal pack of Sierra coolant for $11/gal from Ace Hardware, shipping is free if you have it sent to the local store and pick it up there

http://www.acehardware.com/product/index.jsp?productId=1295821&cp=1254883.1255098.1303981&parentPage=family&searchId=1303981

there's also a plug on the left lower side of the engine center housing to fully drain the block, it's not called out in the mazda service literature anywhere, there's a thread where we discussed it and took some pics, draining the radiator only won't even get half the volume out, you have to drain the radiator and then the block to get it fully drained

thanks! very helpful info!!!

Also going to do NPG-R or npg+

DJ how is it working out for you?

Teamrx8, would you still recommend the NPG-R because of the Viscosity 2.0cp @ 212°F or would the NPG+ Viscosity 2.3cp @ 212°F be okay.

I ask because NPG only recommends the R for racing applications but + is recommended for all gas applications.

be aware that you'll be running a higher water temp (or shall i say coolant temp) due to this stuff being 100% propylene glycol.

and remember to switch to a low pressure coolant cap as this is more like a lubricant. it absorbs engine heat, but doesn't "boil" like water does, creating a high pressure in the cooling system and a need for a pressure cap to bleed vapors.

i haven't gotten the chance to personally use this product yet, but i can see the pros of using this product over the long haul from a cost effective standpoint... as it IS pretty much maintainance-free... ( anyone can chime in on this coolant servicing if i'm wrong)

am i missing some info regarding this product?

higher coolant temps but lower block pressure, more heat absorbant (both pro and con of its design), doesn't boil over,requires a lower pressure cap( unsure of recommended psi) and environmentally friendly.

but a huge PITA to change over to.

I hear for everyday street use 100%water with water wetter is the best!

I hear for everyday street use 100%water with water wetter is the best!

There have been several people that have compaired 100%water with water wetter, 70/30, 50/50, 30/70 and every other combination and they have found that the stock mix works best with the RX8. 60/40 I think.

2 year thread revival, for sec I thought dj was back.

^damn didnt' even notice that!

I use NPG+ in my FD RX-7 with no pressure cap. Have been running it over 2 yrs, daily driver, several track days and auto-x and drag racing too. Never had any overheating whatsoever.

I flushed the system with Sierra first, daily driving the car with pure sierra for a few days then did the same with 2 gallons prep fluid. NPG+ after that.

I use NPG+ in my FD RX-7 with no pressure cap. Have been running it over 2 yrs, daily driver, several track days and auto-x and drag racing too. Never had any overheating whatsoever.

I flushed the system with Sierra first, daily driving the car with pure sierra for a few days then did the same with 2 gallons prep fluid. NPG+ after that.

Cool, thanks. When I switch over I am replacing the water pump, radiator and the 3- hoses all at the same time. I will probably just use the sierra to help flush it, along witht he help of an air hose to get the heater core drained. Of course use the engine drain plug too.

be aware that you'll be running a higher water temp (or shall i say coolant temp) due to this stuff being 100% propylene glycol.

it's not 100% PG

I emailed Evans requesting their NPG+ MSDS and they emailed it back to me. I attached Sierra's also for comparison. Keep in mind that NPG and NPG-R are different from NPG+.

Summary of ingredients:

Sierra:
Propylene Glycol 94-96 %wt
Water 3 %wt
Proprietary Additives 1-3 %wt

Evans NPG+:
Ethylene Glycol 66–70 %wt
Propylene Glycol %wt not specified
Water %wt not specified but from Evans webpage info it should be <3 %wt
Proprietary Corrosion Inhibitor Package <2 %wt

We could possibly make our own by mixing 30% Sierra with 70% of a good quality pure EG-based coolant...

For those that use either NPG+ or NPGR, did you change the opening temperature of the thermostat? What coolant temperatures are you seeing? Did you alter the fan engagement temperature? Is the OEM coolant pump adequate for safe use with either of these coolants, or does an aftermarket coolant pump like the Remedy need to go in first?

With either NPGR or NPG+, just how high can we allow coolant temperatures to rise without the thermal expansion of the various parts becoming a problem (back when I drove an FB, I was warned that overheating would result in crushing the rotor housings; but I don't know if that's true or just an urban legend)? I'd ideally like to even out the engine temperatures as much as I can for best reliability and getting as complete combustion as is feasible with our engine's geometry.

I received the following reply from Evans Cooling regarding my query of whether to use NPG+ or NPGR:

From: Tom Gondal [mailto:tech@evanscooling.com]
Sent: Wednesday, October 07, 2009 10:43 AM
To: XXXXXXXX@optonline.net
Subject: RE: NPG+ or NPGR?

Lane........we have customers with just your situation, that is, running
a basically a stock motor. You can use our NPG+ with no problems. I
personally use it in my wifes stock Dodge Stratus. It's been in for over
5 years now and there are no problems. The stock radiators in the newer
cars are usually one row of 1" tube, which gives enough flow capability
for the cooling with NPG+.
The NPG-R is also good for 5 years as of now not every other
year....Tom

-----Original Message-----
From: XXXXXXXX@optonline.net
Sent: Wednesday, October 07, 2009 8:19 AM
To: tech@evanscooling.com
Subject: NPG+ or NPGR?
Importance: High

I'm sorry to bother you; but I'm afraid I'm still struggling to make a
determination as to which Evans coolant would be best suited for my
daily driven Mazda RX-8.

I understand that if I go with NPGR, I will have to replace the coolant
every other year. On the other hand, I am uncertain whether the OEM
radiator in the RX-8 is free-flowing and of large enough tube design to
be compatible with NPG+. I would very much like your honest assessment,
and if we're not certain, which product would be better to allow a
margin for error. The coolant pump on my RX-8 is also the OEM design,
and I have not modified the pulleys to alter the rotating speed from
stock, in case any of that has any bearing.

I am very much enamored of your product, ever since I first read about
your original coolant and saw it in action on your GT-class Camaro some
20 years ago and am hoping to convert over to either NPG+ or NPGR next
week when I am off from work.

Thanks and Regards,
Lane Lombardia

i used npg+ but decided that i didn't like it. and since i live in cali and like to track my car as chance arise... i've changed it out to NPGR.

and since vvhen did you have to change out npgR every 5yrs?

i thought both npg+ and NPGR are both maintenance-free... so almost for the life of the car....did something change?
remember, vvater is not used in conjuction to the coolant. so as long as moisture is kept out... it should be fine as advertised. and it really is only because corrosion from vvater that coolant needs to be flushed.

at any rate, let me knovv if something has changed for the npgR. and just ahead and use npgR if you are never gonna see belovv -10 degrees.

The lifetime for the NPG and NPG+ and every other year for NPGR is all from http://www.evanscooling.com/coolants/

From their site, regarding NPGR:
It is recommended to change the coolant at the end of the race season for racing or every other year for street driven vehicles with a maximum life of three years.

Based on the information from their own web site, I wrote to them to ask for clarification. What I posted was my email and the reply of Tom from Evans Cooling. The only changes I made were removing two asterisks that somehow got there when I copied over the email into the forum posting, and Xing over my email address.

According to Tom, they recommend swapping out NPGR ever 5 years, though they have not updated their site to state this yet. I included Tom's email address in the posting, so if anyone has any questions about his recommendation regarding their products, please feel free to drop him a line.

To get optimum results with NPG+ or NPGR, would it be desirable to use a higher temperature thermostat and to set the on and off temperatures for the fan higher?

I could see the potential for some power advantage by delaying the fan from coming on but have no idea how much the fan draws.

From the SCCA GT class car I saw them campaigning back some twenty years ago and a conversation I had with one of their team at Pocono Raceway, I remember that one of the advantages of them using a high coolant temperature was that it increased the temperature differential between the ambient air temperature and the coolant temperature. They said this increased heat rejection from the radiator to the surrounding air, so they were able to get away with less airflow through the radiator for a given amount of heat rejection (bear in mind, this was with a piston engine and is also my recollection of a conversation two decades ago that I had with them in the pits at Pocono). I was driving an FB at the time, and since it was very new technology back then, I wasn't brave enough to give it a try.

I use NPG+ in my FD RX-7 with no pressure cap. Have been running it over 2 yrs, daily driver, several track days and auto-x and drag racing too. Never had any overheating whatsoever.

I flushed the system with Sierra first, daily driving the car with pure sierra for a few days then did the same with 2 gallons prep fluid. NPG+ after that.

Where did you get your zero pressure cap, or did you mean that you don't run any cap at all? Does anyone make a zero or low pressure radiator cap for the RX-8 or should I plan on gutting my OEM one? I will be doing the conversion next week and am trying to sew up all the details beforehand.

Where did you get your zero pressure cap, or did you mean that you don't run any cap at all? Does anyone make a zero or low pressure radiator cap for the RX-8 or should I plan on gutting my OEM one? I will be doing the conversion next week and am trying to sew up all the details beforehand.

I removed the rubber gasket under the cap, leaves a very small gap between the reservoir opening and the pressure spring on the cap, this lets the pressure escape easily resulting in a very low (if not zero) pressure cooling system.

Evans Cooling told me to keep and use the OE pressure cap (unmodified) with the NPG-R

Evans Cooling told me to keep and use the OE pressure cap (unmodified) with the NPG-R

Do you use the stock thermostat, one hotter, or one cooler?

LONGPATH:

it seems like all of us get different info and recommendations on the use of NPG+/NPGr...

i've researched/read as thoroghly on the product beforehand as vvell... and i remember somevvhere a commercial diesel truck has ran on the npg vvell over 100k+... the example is somevvhere on their site.

but anyvvho.... i think it vvas also tom i spoke to over the phone, and i believe caroline.

to the point... tom only recommends replacement of npg+/R if vehicle has accumulated enough atmosphere moisture over a period of time. and i asked if this is the case for a california car... in vvhich he advised that it isn't really necessary and just use it for its intended purpose as vvater/moisture is the only reason for replacement to prevent corrosion.

all he advised is that ABSOLUTELY no h2o gets in there. and its also OK to use oem pressure cap/thermostat.

trust me... the process is a bitch. i sent in 2 samples that failed the test and he eventually told me to just boil the coolant until all bubbles are gone.

but my cooling system novv is virtually vvater and contamination-free! (except for the vent tube)

so is there really another reason to need a replacement every 5yrs? i don't really see one, but if there is, then i'd like to be cautioned...

longpath,

if you'd like, u can try to get a dead cap out of an old rx-7 (FC) as they use a dead cap on the upper hose iirc. but as stated earlier... oem is ok. thermostat too...

and i believe u are in a cold state... so the recommended 5yrs replacement may apply if enough moisture gets accumulated over time to fail the "refractometer"??? test. (forgot the equipment name)

not sure on team rx-8's location, but some truth may be for daily cars not needing this. its just sooo easy for dealers to mess it up during service, and the moisture problem for cars that live in cold climates... i'm lucky this is a california car that is gonna see this products benefits, track miles or not. i'm happy vvith NPGR if it does turn out not needing much maintainence over the long haul and performs like it should...

Originally the OE t-stat, but I now have the lower Mazmart one

it doesn't get much drier than where I'm at, but again it's not something I'd recommend to just anyone due to all the factors involved. My '05 with under 8 k miles has only been to the stealership once, and that was many years ago.

Just for clarification......does the water " boil out" of the coolant?

IE...I live in one of the wettest climates in NA......will I have problems keeping the water out?

only if you have an open system, which then also allows moisture to get back in

the overflow/surge tank has to be vented to the atmosphere, so there is always the risk of some exposure to moisure over time, the amount would have to be pretty small though, just change it every year or two should be fine, no way would I try to go five years, that's dumb regardless of whether it has moisture contact or not

I have yet to modify the pressure cap; but I was thinking that in order (since I do indeed live in a cold wet part of NA) to take advantage of the assets available to me (engine heat, unmodified pressure cap, etc.) I'd turn the cap to the vent position when the engine was cold right before starting up, then, using an oven mitt or something similar, turn it to the fully closed position after I arrive. Mind you, this is just my thinking and I have yet to try it as I've been home taking care of my daughter since the day after I completed the conversion.

I sent the following query to Evans' tech mailbox today:
I completed the conversion last Wednesday, disconnecting and blowing out
the contents of the heater core, using the block drain, and draining the
radiator in my 2004 Mazda RX-8. I've also run the engine with the OEM
pressure cap in the vent position in stop and go traffic to drive the
coolant temperatures above 215F (carefully closing it with a thermal
mitt when I arrived at my destination); but I don't have a refractometer
and my NPG+ didn't come with test strips. I've started looking into
getting a Brix scale refractometer so I can check the mixture; but they
seem to range from $24 to over $300 and I am not certain what to look
for.

I live in Stamford, CT, and it's obviously the rainy season, so I am
concerned about atmospheric moisture contaminating my coolant; but am
not sure if this is really an issue or not (for all I know, any humidity
might just boil off). I have also considered turning the OEM cap to the
vent position when the engine is cool, prior to starting it up, and then
turning it to the fully closed position using a thermal mitt when I
arrive in order to prevent humidity in the air from contaminating my
coolant. I might be overreacting, so I wanted to know what you do with
daily drivers in the more humid areas of North America.

I have contemplated placing an electrically operated valve in the
overflow tank vent line so that the valve would be open when the engine
is running and would close when I shut the engine down; but I am not
certain if there really is any need for something like this.

Most of the people that I have communicated with who are using Evans
coolant are located in drier climes than I am located in, and they seem
to have conflicting opinions about whether the OEM pressure cap, a low
pressure cap, or a zero pressure cap is ideal.

I am presently looking into whether there are any higher than standard
thermostats available for my car as well as I would like to take full
advantage of the NPG+ cooling my car's engine; but it seems I have to do
some more research before I will be able to locate such a thermostat
(all of the 3rd party thermostats I've found for my car are set for a
lower temperature, the opposite of what I am trying to find).

Any clarification you can give me on any of these points is greatly
appreciated.

Thanks and Regards,
Lane Lombardia

I then got the following reply:
Lane.............first thing is you are overthinking this conversion.
Don't change the cap, leave the stock pressure cap on the system and
always tighten it up. Most all the "tuner" cars have a pressure side
cooling system and if you go changing the cap to a lower pressure, you
will open the cap and push all the coolant out of the radiator into the
overflow. Leave the t-stat alone as well, no need to go to a hotter one.
On all stock conversions we tell the customer, JUST DO THE
CHANGEOVER>>>>>>>LEAVE EVERYTHING ELSE ALONE.
We sell refractometers for our coolant for $69.95, but you can send
me a sample and I will test it free of charge and get back to you with
the results. I need about an ounce in a screw lid bottle, tape the lid
on and put it in a baggy. Then send it to me with your name and phone
number where I can reach you during the day, or an email address.