SR20 Coolant.

[Mikester]

First of all, please don't post if you don't have any FIRST-PERSON experience or some other kind of credible fact(s) to present.

My whole time in Okinawa, I ran regular, green Prestone antifreeze... Prolly about 70/30 or 80/20 mix with distilled water. Avg coolant temp was 64-66C... 67-70C with the AC blasting in Okinawa traffic. Never had an issue.

This time around, I decided to go with 2gal of 50/50 DexCool; topped off with distilled water & a bottle of Water-Wetter- NOT because DexCool is any cheaper or anything like that; just thought I'd give it a try for S & G. So far, I've noticed my avg driving temps are in the neighborhood of 68-70C in the summer heat. I wonder if I should drain some out & add more distilled water & Water-Wetter to bring the temps down a tad- or is there some KNOWN, WELL-DOCUMENTED reason why I should just drain the DexCool out altogether & go back to the green stuff? I know that distilled water and WW is the ultimate combo; but it gets well below freezing here and I will drive the car on the few clear days we get.

I did some searching and found a bunch of "DexCool is crap" posts- mostly by 21-22yr old kids who probably are the 13th or 14th owners of their raggety SR's... so I am hoping somebody who actually knows can point me in the right direction.

My setup is a fresh, clean, full bottom-to-top rebuild...

Cooling-wise I have:

Koyo rad
Nismo cap
Nismo thermo
Samco hoses
GKtech clutch fan w/OEM shroud
New water pump
full bumper-to-core support cooling plate




OH- Also running an oil cooler behind the FMIC now; as well as aftermarket cams & slightly more compression... Could the few degree rise in coolant temps simply be because of the added goodies?

Thanks in advance~

Mike

[godsmack]

Right now I'm running 1 gal of dex-cool and the rest topped off with distilled water and water wetter. Just sitting still and I don't need my second e-fan to kick in. Running 66*C in traffic.

Once winter hits again I'll probably go to more of a 50/50 mix though.

[oni jake]

You're in St. Louis right now? I would recommend Distilled Water + Water Wetter and that's it. During the cold winter months, which is really roughly 2-4 months down there, you drain the coolant all together and park it. (Assuming you don't drive this car during the winter months)


DEX-Cool is mainly crap because it eats away at gaskets not designed for it. If you absolutely want to run anti-freeze stick with the good ol' fashion green poison.


Info from Wikipedia, feel free to check these out yourself:

Certain cars are built with organic acid technology (OAT) antifreeze (e.g., DEX-COOL[18]), or with a hybrid organic acid technology (HOAT) formulation (e.g., Zerex G-05),[19] both of which are claimed to have an extended service life of five years or 240,000 km (150,000 mi).
DEX-COOL specifically has caused controversy. Litigation has linked it with intake manifold gasket failures in General Motors' (GM's) 3.1L and 3.4L engines, and with other failures in 3.8L and 4.3L engines. One of the anti-corrosion components presented as Sodium or Potassium 2-ethylhexanoate and Ethylhexanoic acid is incompatible with Nylon 6,6 and Silicone rubber, and is known as Plasticizer. Class action lawsuits were registered in several states, and in Canada,[20] to address some of these claims. The first of these to reach a decision was in Missouri where a settlement was announced early in December 2007.[21] Late in March 2008, GM agreed to compensate complainants in the remaining 49 states.[22] GM (Motors Liquidation Company) filed for bankruptcy in 2009, which tied up the outstanding claims until a court determines who gets paid.[23]
According to the DEX-COOL manufacturer, "mixing a 'green' [non-OAT] coolant with DEX-COOL reduces the batch's change interval to 2 years or 30,000 miles, but will otherwise cause no damage to the engine."[24] DEX-COOL antifreeze uses two inhibitors: sebacate and 2-EHA (2-ethylhexanoic acid), the latter which works well with the hard water found in the US, but is a plasticizer which can cause gaskets to leak.[16]
According to internal GM documents,[citation needed] the ultimate culprit appears to be operating vehicles for long periods of time with low coolant levels. The low coolant is caused by pressure caps that fail in the open position. (The new caps and recovery bottles were introduced at the same time as DEX-COOL). This exposes hot engine components to air and vapors, causing corrosion and contamination of the coolant with iron oxide particles, which in turn can aggravate the pressure cap problem as contamination holds the caps open permanently.[25]
Honda and Toyota's new extended life coolant use OAT with sebacate but without the 2-EHA. Some added phosphates provide protection while the OAT builds up.[16] Honda specifically excludes 2-EHA from their formulas.
Typically OAT antifreeze contains an orange dye to differentiate it from the conventional glycol-based coolants (green or yellow). Some of the newer OAT coolants claim to be compatible with all types of OAT and glycol-based coolants; these are typically green or yellow in color (for a table of colors, see[15]).

[Mikester]

^^Thanks... Will prolly go ahead and keep the DexCool, but drain out another gallon or more & add more distilled water & WW...

May give it a year or 2 (only 3,000mi or less lol) and swap out. Unless there is more info for me to ingest

[TheRealSy90]

I'm honestly surprised your car even hits operating temperature. I'm running the oem shroud and clutch fan, a koyorad, 1 bottle of water wetter and the rest distilled water. It is way hotter down here in AZ and my temp sits at the bottom of the gauge all the time.

When I lived in Boise I was still running just distilled water and 1 bottle of water wetter even during the winter where it got well below freezing. My car was parked outside and it never froze the block or anything. I drove it during the winter without "anti freeze" with no problems.

[KendallH]

Originally Posted by TheRealSy90

I'm honestly surprised your car even hits operating temperature. I'm running the oem shroud and clutch fan, a koyorad, 1 bottle of water wetter and the rest distilled water. It is way hotter down here in AZ and my temp sits at the bottom of the gauge all the time.

When I lived in Boise I was still running just distilled water and 1 bottle of water wetter even during the winter where it got well below freezing. My car was parked outside and it never froze the block or anything. I drove it during the winter without "anti freeze" with no problems.

Do you not have a thermostat?

[Mikester]

Originally Posted by TheRealSy90

I'm honestly surprised your car even hits operating temperature. I'm running the oem shroud and clutch fan, a koyorad, 1 bottle of water wetter and the rest distilled water. It is way hotter down here in AZ and my temp sits at the bottom of the gauge all the time.

When I lived in Boise I was still running just distilled water and 1 bottle of water wetter even during the winter where it got well below freezing. My car was parked outside and it never froze the block or anything. I drove it during the winter without "anti freeze" with no problems.

It hits operating temp just fine... 68-70C is 'cool' but not ridiculous... but I want my temps back down to 64-66 where I like them.

Here in St. Louis, the temps get silly hot & the humidity is retarded (which I love) in the summer... Gonna drain some of the mix out & add more water & WW then report back. It cooled down to 79 today, and my temps never got over 68 on the freeway... which is fine w/me lol

[fliprayzin240sx]

Personally, I dont ever run straight distilled water and just WW. You need some coolant to help lubricate the water pump bearing. Honestly, I think where your car is at is good. My car always runs better closer to 80* than it would sitting at 70* on both my SR and RB.

[SD_Kouki]

Isn't dex intended for GM cars only?

I heard that stuff is poison for Japanese cars and after a while you'll start finding chunks and globs if you ever do a coolant flush.

[inopsey]

Originally Posted by fliprayzin240sx

Personally, I dont ever run straight distilled water and just WW. You need some coolant to help lubricate the water pump bearing. Honestly, I think where your car is at is good. My car always runs better closer to 80* than it would sitting at 70* on both my SR and RB.

+1 these engines are not designed to operate at 65c for any length of time. the purpose of the colder thermostat is not to run the car that cold but for race applications where your trying to lower 100c water temps 10-20c. you are damaging your engine operating it at those temps.

[Mikester]

Originally Posted by inopsey

+1 these engines are not designed to operate at 65c for any length of time. the purpose of the colder thermostat is not to run the car that cold but for race applications where your trying to lower 100c water temps 10-20c. you are damaging your engine operating it at those temps.

What exactly is getting damaged?

[fliprayzin240sx]

Originally Posted by Mikester

What exactly is getting damaged?

Well, not necessarily damaged, more like added wear and tear on the rings. Then if the engine stays cool, oil may not be getting up to temp. Cold oil doesnt lubricate well. You want your operating oil temp to get up to 80*-90*C

[Mikester]

Interesting... So even though I can watch my oil pressure start high & then work it's way down to 2-3 bars when driving & 1-1.5bar at idle that doesn't necessarily mean its at the proper temp?

Had no idea that running 27*F too cool would have such an effect.

[fliprayzin240sx]

Originally Posted by Mikester

Interesting... So even though I can watch my oil pressure start high & then work it's way down to 2-3 bars when driving & 1-1.5bar at idle that doesn't necessarily mean its at the proper temp?

Had no idea that running 27*F too cool would have such an effect.

I thought you had an oil temp gauge in oki? Good rule of thumb, you want it somewhere between 80-115* ish. Once it gets up to 120-125* thats when oil starts cooking and starts breaking down.

[codyace]

Woah man, waaaaaayyyyyy too cold of operating temps. Atop of that, the computer does not even recognize that the car is 'up to operating temp' with it being that low, which puts you in an area of the tune that is designed to warm the car up though timing and added fueling.

You want it to be up to the thermostat opening level and to keep it right around there.


Coolant wise, I use water/water wetter/and some antifreeze for it's rust inhibiting properties.

[Mikester]

Ray, I just have oil pressure & boost gauges.

Cody- My thermo opens at 62*C so if I'm running at 64-66, I should be good yea?

Also, it's tuned for the lower temps... or is that not possible?

[fliprayzin240sx]

Originally Posted by Mikester

Ray, I just have oil pressure & boost gauges.

Cody- My thermo opens at 62*C so if I'm running at 64-66, I should be good yea?

Also, it's tuned for the lower temps... or is that not possible?

I'm pretty sure it can be done on the PFC with dataloggit. You cant without it.

[e1_griego]

You can at least get to the warm-up tables with the commander.

[cotbu]

Originally Posted by codyace

Woah man, waaaaaayyyyyy too cold of operating temps. Atop of that, the computer does not even recognize that the car is 'up to operating temp' with it being that low, which puts you in an area of the tune that is designed to warm the car up though timing and added fueling.

You want it to be up to the thermostat opening level and to keep it right around there.


Coolant wise, I use water/water wetter/and some antifreeze for it's rust inhibiting properties.

Been watching this thread!
Glad somebody said it, instead of me!

Normally you need to hit 80c at least once, to go into closed loop. 78c the check starts then 80c, if everything is copacetic closed loop occurs.

Mike, if you are tuned for lower temps? Then you should at least know what they are. You can watch the commander at operating temp(?) for the 02 sensor voltage to go crazy, fluctuating more than 10x in 5sec iirc.

[Mikester]

^^cotbu, I don't run an O2 sensor; I keep the signal turned off and the port bunged shut. Even though I'm almost certain it was tuned for the lower operating temps in Okinawa, I will be sure to inquire when it goes in for the final tune next week or the week after.

I'm pretty sure it goes into closed-loop b/c the idle is high (2000rpm-ish) at startup, then settles right around 900-1000 after warming her up. Also, right at startup it drives really poochy, but it's very responsive when warm... I know that's prolly a noob thing to say, but I know little/nothing about the nuances of actual tuning.

Would there be any other way using the Commander that I can verify that it goes into closed loop?

[cotbu]

If your 02 sensor is turned off then there's your answer.
You could have been tuned open loop, though? Or Maybe the wb is simulating the 02 signal?
The ecu uses the 02 sensor for feedback, keeping you close to 14.7afr in closed loop.
Without the signal you are not in closed loop.
Idle speed is a whole other category, you can go into closed loop at 2000rpm, but why would anyone want to do that??!

[Mikester]

Oh I think I get it...

So why would it run like a dream when all warmed up if the Power FC doesn't change modes? Not saying that in a doubtful way... but in a respectful wanting to know way.