Coolant System Additives and Cooling Issues, Help.

[Steve Wood]

DPOK....as I tried to indicate, the primary function of RMI-25 is not a cleaner. It will put soft deposits into solution but it will not remove hard crusted deposits. It is not intended to. Anything capable of removing such will also destroy the radiator.

Not sure how you do your math but a quart is 32 ozs and you use 8 oz per radiator. That is four doses, not three.

It is the creme de la creme but it is not a miracle drug.

 

[Fuzzy]

Is 8 ounces the correct amount of RMI-25 to put in the system? The bottle says 8 oz per 5 gal of system capacity. The manual states we have a 12 quart or 3 gal cooling water capacity, so I add 5 oz to the system after draining and flushing. Does the system actually have more capacity which would require more RMI-25?

 

[Steve Wood]

I always use 8 but I see no reason you cannot use 5. I just loaned someone my quart bottle yesterday so I cannot go read the exact words but I recall it as you say it.

 

[jsta6]

Steve/Nick,

My 87GN quickly hits 220 when in traffic.

I do not know what kind of radiator that I have. I can't remember, but I thought the previous owner said that I had a HD four row. The fans that I have are a dual fan setup from I think a ford taurus.

Should I take it to a rad shop and have it professionally checked/flushed out? Or should I just flush it myself and try some RMI25? Also, will putting a fan in front (in front of the condensor and my trainy cooler) help at all?

TIA

 

[Steve Wood]

Shawn, it is hard to offer an opinion without really looking at it so you will have to do the looking. It's hot enuf in Houston for me right now, I don't need to visit the Fort!

1. What temperature does it run at on a hot day going 70 mph down the freeway? Is is down around 170-175?

2. Does it have all the baffling around the front of the radiator? There should be a felt piece on each side of the radiator that extends forward and then another piece that is attached to the bottom of the grill and goes back to the bottom of the radiator support. The purpose of these three pieces is to force the air that goes thru the radiator to come thru the grill. If the bottom piece is missing, the car, when in traffic, may pull the hot air rising off the pavement up and thru the radiator rather than somewhat cooler air thru the grill.

3. Take the radiator cap off and drain some water out of the system so you can see the end of the radiator core. Are the tubes (openings) coming out of the core open or do they have deposits clogging the ends?

Count the number of tube openings from rear to front in a row. Are there two, three, or four? This is what we mean by three row or four row, etc.

Four row (or five row) radiators are a lousy investment. They provide very little additional cooling at speed and may actually run hotter at idle. Why?

a. by the time the air passes thru the front of the radiator and reaches the rear, it has been heated up by the tubes it has passed over so the air temperature is much closer to the water temp in the radiator and does not remove much heat.

b. The tube width is more narrow (in order to get the core to fit within the side tanks) and it is oval in shape. We are talking brass/copper not aluminium. Therefore, the fin bonding occurs over a smaller area and the fin is less efficient in picking up heat for transfer purposes. Brass/copper is better at heat transfer than aluminium but the oval shape creates surface problems that increase as the tubes grow smaller. Aluminium has a worse coefficient but the tubes are rectangular and provide more contact to the fin bond.

c. The core is more tangled up with fins and air has a harder time passing thru it and when sitting still, the fan struggles harder to get pulled thru the core and that is the reason it can run hotter. Better four row cores have no more than 14 fins per inch and some may have 12. It is a competition between having a lot of fins per inch to transfer more heat and having enuf space between the fins to allow air to actually flow thru in order to pick up the heat off the existing fins so the heat moved to the fins can be dissipated.

d. Smaller tubes stop up easier with coolant silicate deposits and mineralization from the water if distilled is not used.

4. check the voltage to the fans and be sure it is close to battery voltage when the engine is idling.


In my experience, thermostats tend to either work or not work. I doubt that is your problem.

If the core is clogged up, professional cleaning (rodding out) is a waste of money in my opinion. Yeah, yeah, yeah, I know that people have been rodding out radiators for 75 years. I still think it is a waste of money. I would replace it with a modern h/d three row core from Nick.

If it is a four row core and has more than 14 fins per inch, I would replace it with the same.

If it is missing baffling, replace it.

If it is clogged up with crud, RMI-25 is not the cure. It won't hurt but it probably won't make much of an improvement. It's not made for that problem and neither is anything else.

If the radiator appears to be unclogged, has 4 rows or 3, has 14 fins per inch or less if four rows, the bottom part of the radiator feels as hot as the top part after it has been run, the baffling is in place, etc., you can try distilled water and rmi-25 and NO antifreeze during the summer to see if that won't cool is down a bit. Antifreeze is not a good transferrer of heat.

That is about all I can think of at the minute other than an overdrive pulley for the water pump to make it move a bit more water at idle...but, normally, that should not be needed. I would think you would have to have a long sit in traffic on a hot day to exceed 200 degs. Oh, I think R134a AC conversions may make them run about 10 degs hotter.

Now, if you have a fricking front mount like me, it is the subject for a different conversation not to mention a CAS three PASS (not row) radiator and dual fans.

 

[jsta6]

Wow. Thanks Steve.

I will definately check all of that out.

That is some GREAT information. I can definately use it. I hope that other members can to.

I still have R-12 AC and stock intercooler.

What about using a fan in the front of the car? In front of the condensor and my external trainy cooler?

Also, how can I test my fan relays? I just got a new delay relay, and I hear it working, so I know that it works. But what about the other two? How do we test the low and high relays?

TIA!!!

 

[Steve Wood]

A fan in the front tends to become an obstruction at higher speeds. It should not be needed.

I am not sure how to help you on the fan relays because I don't know how the dual fans are wired in on yours. I have dual Spals and I wired one to the low speed relay and one to the high speed relay so I would not over load a relay at fan kick on when current draw was high.

Do both of your fans run all the time? Or, does one come on when the car warms up and the other one come on when you turn on the AC?

With factor wiring, the low speed relay is the one that has a brown wire to one post of the relay, two dark green wires on another post, two red wires on the third post, and a black/red wire on the fourth. In theory, the black/red would have gone to the resistor on the factory fan. This wire should have voltage on it when the coolant temperature reaches whatever is the fan turn on temp programmed into the chip. That is the factory wiring for the stock fan. If you were to ground one of the dark green wires when the key is in the run position, the fan should run.....again, I note that this is the original wiring.


The high speed relay was the one that had a brown wire going to one post on the relay, a dark green/yellow wire going to another post, a red wire to another post, and a black/pink wire which went directly to the original fan motor instead of going thru the resistor. The black/pink wire should be hot when the ac is on. The fan could be made to run on high speed when the key was on by grounding the dark green/yellow wire. It runs to the coolant fan temperature sensor on the drivers side front top of the intake.

Again, I note this was the factory wiring. It would be helpful to see how the dual fans are wired on yours and then we would know what to check.

If they both run all the time and there is no resistor used, then they would appear ok. On the other hand, if they are both wired into the same relay, they might be getting only 12 volts or so when the alternator is putting out 14 and the fans would be running slower than they should. That is the reason I told you to check the voltage at the fans.

 

[dpok69]

Hey, your right Steve. It is 4 doses. I considered it three doses cause the first dose is supposed to be emptied out after a month of use to get rid off loosened deposits. Should have put that down for newcomers reading this.

The only reason i wrote that it may remove hardened deposits is cause in previous searches on RMI, i have read that RMI can produce leaks in badly corroded cores from the cleaning action. So i figured it was removing the crusties. I guess i may have figured wrong. It was worth a shot, before getting a new core for me, since my car does not usually go over 200 deg. On highway speeds on a hot 90 deg day, my temps are around 184. Usually in traffic i am 10 deg hotter.

 

[Steve Wood]

That ain't too bad....it's obviously clogged somewhat but you are not to the danger zone yet...regular cars would have a 195 thermostat and it seems to me that the factory chip did not run the fan til it was over 200. Been so long that I am not sure of the number.

 

[The Radius Kid]

Originally posted by Steve Wood
There is no comparison between RMI-25 and Water Wetter other than the fact that both contain a surfactant.

Water Wetter has very little lubricant in it and besides allowing rust to form, it will hasten the demise of the water pump when used with pure water.

RMI-25 has the surfactant plus a strong lubricant package, some cleaner, and, when used with antifreeze, prevents the deposits that precipitate out of antifreeze and clog the radiator tubes. It was developed for long haul truckers that don't want to have to replace their cooling systems frequently.

I suspect a couple of drops of Cascade dish washing soap would work about as well as Water Wetter.

Hmm.That RMI sounds a lot like the stuff I dumped in the rad yesterday[it was a neat purple colour].The head honcho at the local Detroit/Allison/Cat tells me he uses it in his personal vehicle.
Apparently it;
1.Prevents corrosion
2.Cleans the cooling system
3.Lubricates
4.Prevents surface boiling on hot spots in the cooling system.
My pint bottle[16 oz.] cost $9 Canadian and treats up to 4 gallons[4 oz. per gallon of the green stuff,and you can use it with the Dexcool if you want to]
*BTW*,it's called Power Cool 3000.
I think I have to try some of the TranSynd fluid on my next trans rebuild[real soon,I just pooched 2nd last night. That's what you get for showing off.Never did like that Trans Go shift kit.It sucked all the way through 2 rebuilds.Never ever worked right]

 

[dpok69]

Okay, today was 90+ degrees.

My car on the highway stayed around 190 and in stop and go traffic it reached 208 deg. This is without the A/C on and front mount transmission cooler.

Cruise BLM's are around 140-145 with no knock under boost. I plan to raise the fuel pressure up, right now its at 30psi with vac on. Running lean as i do, may be contributing to more heat in the engine.

2 weeks earlier i did a back flush by teeing in the heater hose with a prestone backflush kit. This enables you to attach a gardern house right to your engine to completely flush out the system with clean water.

The water that came out was brown, and there was ALOT of foam also. As someone mentioned earlier, the foam could have been caused by me using the prestone radiator flush. The rad still has hard crusties. (its almost like metal)

Right now my rad fluid is the normal color. I will probably replace the core with a high effieciency one if i see my temps going over 210 with the A/C on (right now my A/C is putting out hot air, so i ghotta fix that also)

 

[Steve Wood]

Sounds like it is new core time.

 

[jsta6]

Well, I had the $$$ to buy a new core/radiator exchange from Nick; but I had to spend it on something else

So necessity becomes the mother of invention...

1. My stock air dams behind the grill that are supposed to force the air in to the radiator were going all over the place. I used nylon ties/cable ties/zip strips or whatever you want to call them to tie all the dams together to keep the air from getting away.

2. The previous owner had replaced the stock fan with a dual fan setup. The problem here was that the dual fans had no "shroud". The fans were close to the radiator, but since there was no shroud, they were pulling a lot of air from around the radiator, instead of through it. Instead of making a shroud or buying new fans, I put the stock fan back on. Since there is still a 1/2 - 3/4 inch gap between the stock fan and the radiator, I used weather strip (actually, I went to home depot and the best thing that they had was the rubber strip that goes on the bottom of garage doors; it fit "perfect") around the fan shroud so that the fan would be forced to pull air through the radiator. "WARNING"; be sure that no weather strip interferes with the fan. I trimmed mine perfect, but when I put the fan in, some of the weather strip on the bottom got pushed up and interferred with the fan.

3. I drained my radiator, and it looked awesome!!! It looked like new. No crust or crud at all!!! (the previous owner used distilled water). I am going to clean it out and use RMI from now on.

RESULTS:
Well, today it ran 30* cooler. (I swear it!!!). Today was kinda overcast, so I will report back when it is more sunny outside.

Thank you to Steve and Nick who are two really great guys!!!

In summation:
1. Make sure that your factory air dams behind the grill and in front of the condensor are in place and forcing air into the condensor.
2. Make sure that your fan is pulling air through the radiator. Use weatherstrip, but be careful.
3. People in south florida do not need to use anti-freeze. Use RMI and distilled water instead.

 

[jsta6]

...trying to share some ideas...

radiator air deflector:
http://personal.atl.bellsouth.net/mia/s/h/shawnco/projects/radiator air deflector/RAD.htm

radiator fan seal:
http://personal.atl.bellsouth.net/mia/s/h/shawnco/projects/radiator seal/RAD.htm

intercooler scoop:
http://personal.atl.bellsouth.net/mia/s/h/shawnco/projects/scoop/intercooler scoop.htm

 

[BLACKHAWK38]

Originally posted by GS70350
OK Guys, i got some questions for ya. I am having some cooling system problems, where when i sit in traffic, at lights iin the daytime, 90 deg. +, my coolant temperature will rise to about 180, maybe even higher, unless i get up to speed, about 45 mph, for about 1 minute, and it cools back down to about 165 by then. when i turn on the high speed fan, it will also bring down the temps, but not as quickly, it usually runs around 170 in town, which is when the low speed fan setting kicks in. NOW, I have found some things that look to be missing on my car, such as a under the radiator air deflector of some sort, to keep hot air from rising from the ground to the radiator, or to keep air from the grille from going under the radiator, also, im missing deflectors on the side of the grille, to channel air to the radiator, and im missing a deflector above the radiator on the header panel, which looks like there used to be one there, connected to studs in the header panel and some bolt holes in the radiator support. Where can i get these and will they help any? alot of air could go up and over the radiator from the looks of it. Another thing, is, coolant additives, like, redline water wetter, and RMI-25. or that pro-blend stuff that cools by 28*, and is 1 gallon. What works, and how well does it work. i tried the redline stuff, and havent noticed a bit of difference in coolant temperature. not a bit. im puttin on a front mount, so i need all the cooling help i can get. thanks guys,

oh and 1 more thing, if my radiator is about 2 inches low on coolant from the top of the radiator when not flowing, will this cause it? thanks