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Don't be fooled by aftermarket cooling systems

696pack

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PLEASE MAKE THIS A STICKY.

I have posted most of this previously and thought it was a sticky but can’t find it so here goes again.

We see so many posts with people having cooling problems that have added aftermarket radiators and electric fans thinking they are improving things.

Don’t try to reinvent the wheel.

The standard H.D. factory cooling system should be fine for cars with 600 h.p. This system consists of 26” radiator with fan shroud and clutch fan. The clutch fan disengages when not needed saving the power robbing of the fan and basically free wheels.

Make sure your fan is placed properly about 1” inside the fan shroud. Some of the original cooling systems have some rubber or foam sealing around any air gaps around the shroud and radiator, if yours doesn’t it is a good idea to do so. Simple closed cell foam tape will work. This system was created by factory engineers and WORKS. Why? Because the shroud encompasses the entire back side of the radiator cooling area and creates a vortex with the fan in its proper place sucking the hot air off of the radiator from all surfaces of the radiator. Electric cooling fans are their own obstruction in this path of air. Don’t be confused by the fact that newer cars have electric cooling fans and work. Again that is a factory engineered system for a specific vehicle.

Another common mistake is using an aftermarket “high performance” water pump. The factory standard pump is usually fine and at the most you may want to use the factory pump that was designed for an A/C equipped car. If memory serves me correctly I believe that pump actually moves the coolant through the system SLOWER. Why? Because it has more time for the radiator to pull the heat out of the hot water. Most of the “high performance” water pumps move the water through the radiator too fast and does not give it enough time to remove the heat.

Thermostats are another problem. Some people that don’t understand their purpose will use a 160 degree unit thinking it will make the car run cooler. The 160 degree opens at that temp. but that doesn’t mean it is going to keep the temp. there. The factory suggested T-stat for our old cars is a 195. That is because your engine is designed to operate more effciently at that temp. On newer cars it is a 205 because of pollution control and a hotter engine burns more hydrocarbon than a cooler engine.

Timing is another issue for cooling. Especially with todays poor fuel. If you are running too much advance and your engine is predetonating (pinging that is not always autible) it will create addtional heat in the cumbustion chamber and may also cause you to burn valves or a hole in the pistons. This addition heat makes your cooling system work harder and may not suffeciently cool the engine. It can also cause starter bind (hard or slow staring wnen the engine is hot. This is caused by the starter expanding from the heat and being too tight. If your car was factory equipped with a heat sheild make sure you use one. If you have added headers and one or more of the tubes are close to the starter wrap those tubes with some type of fire retardant insulation material. DO NOT wrap the starter as it will eventually absorb the heat and then hold it there.
 
thank you for that....thats pretty much what myself and everyone has been telling him. im not sure which post but there have been too many to keep track of.

LESS IS MORE GUYS.........
 
Well I would have followed that advice but I wanted a 3 row 26" shinny metal box up front :) although I'm not having cooling problems you are right about the factory had it dialed in why change it?

And were I live it was cheaper to get that then have the factory one re-cored, which I still have by the way :) not giving that up for nuttin haha
 
Thanks 696pack,
That IS a GREAT sticky ! The factory engineers knew what they were doing. REMEMBER: The aftermarket industry wants "WE the public" to buy their products! I have seen many experts "dumbfounded" and thoroughly baffeled by overheating. I had a 67 H.O. GTO that would always run hot. It too had heat soak and the car would not re-start. (another story)
I feel for John as he is totally frustrated. And as "we" post replys and rebuttals it can sometimes cause individuals to become agitated and again frustrated. Hell, he's talking about selling his car. That is drastic. After spending time in the Navy, then College and now some projects on his MOPAR and he can not get it dialed it in. A cool-down period is much needed. (NO PUN intended) I feel sorry for him and this situation.
"Super-bee_ski"
 
Amen brother they spent tons of dollars in the day to figure this out...
 
I agree with much of the first post in this thread, except this:

The factory suggested T-stat for our old cars is a 195.
Actually, the correct and generally recommended thermostat temperature is 180° for non-CAP vehicles through '67; starting in the late '60s higher-temperature thermostats (185°, 190°, 195°, and even 200°) start showing up in the FPCs as part of an effort to clean up exhaust emissions -- higher coolant temperature means more complete combustion because of less quenchout, therefore less unburned hydrocarbons and less carbon monoxide in the exhaust. But higher combustion chamber temperatures also mean more oxides of nitrogen in the exhaust, so starting in '71 the factory began backing down on thermostat temp (from 190° to 185°, for example; specifics depending on engine size and configuration). But then in '73, valve-controlled exhaust gas recirculation came along as a very effective NOx control strategy, and so thermostat temps started climbing again -- up to 195° pretty much across the board by '74.

Generally, and within reason, higher coolant temperature is better for engine operation (more efficient = more power from any given amount of fuel burned) and wear (less of it) and oil life (longer) and exhaust emissions (cleaner except for NOx).

But higher-temp thermostats cause higher underhood temperatures at idle and after shutdown. Zero problem if you have a properly designed fuel injection system, but most of us don't. Carburetors and open fuel systems like ours don't get along well with elevated underhood temperatures. You get percolation with resultant lousy idle and bitchy hot restarts -- this started being a problem when the 195° thermostats became factory equipment in the early mid '70s, and it's even a bigger problem with today's gasolines which are formulated around the assumption of a closed high-pressure fuel injection system, not an open low-pressure carbureted system.

So that needs to weigh into your choice of thermostat temperature. A 180° thermostat means less fuel-related start-and-idle aggravation. You can use a 195° thermostat, but it will tend to cause and/or aggravate hot-start/hot-idle issues -- this is the reality of running yesterday's car on today's gasoline. 160° or no thermostat at all is never the correct choice.

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A very good article with detailed information on how thermostats work (and how they don't work despite common "knowledge" about it) is here.

I have done a good bit of experimentation with waterless coolant, and I like it a lot; I now run it in all my cars. No corrosion (because no water), operates at atmospheric pressure (because no steam because no water), therefore much reduced stress on radiator seams, water pump seals, gasket junctions, hoses, heater core, etc, but with higher boiling point than any water-mix coolant operating at elevated pressure. More info here, here, and here.
 
Great post! I believe John, like everyone can get at times was merely frustrated from spending countless hours on a problem with no resolution. I could not agree more that he should just step back, take a breather, and regroup. I believe all posts on thermostat temps are great here, but for the Un-informed I would like to say this. The Direct Connection engine technical manual states the BEST thermostat to run in a high performance "big block" application is a 160* thermostat. It also was not revised in the newer Mopar Performance engine manuals so it is still a standing statement. For everyone that doesn't run this thermostat, the engine at idle runs around 180-185* for a reference and can only keep the 160* temperature while driving (in my application). With a 180* thermostat, you can see temperatures above 200* at idle before the engine has a chance for cool down, or higher idle operating temperatures. I would not run a 195* thermostat in my car, it just seems to not be a sound choice with a high horsepower application but could possibly be a great choice for a factory build. It's all personal preference, but I believe the best choice varies for each individual build.
 
You guys rock and are correct within your applications and I love old school methods.
Please allow me to add that I have had very good performance from Griffin 2x1.5 core aluminum radiators combined with aftermarket hi-flow water pump and hi-flow 160 degree stat on 500+ cid engines for the street
I never saw an electric fan that cooled are well as a good old mechanical fan with a factory shroud
 
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Good read.
Here is a picture of the FACTORY sticker on the core support of my original 1964 Plymouth Sport Fury. It clearly states to use a 180 degree thermostat. Just my .02 cents.
Roger
 
Some systems have different designs then what came from the factory.I have NO room for a puller fan:eusa_think:
 

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So what is the thought on thermo controled electric waterpumps and electric fans after engine shut down
 
Another tip is to run a 50/50 mix with distilled water. No minerals means no corrosion. My trucks, 92 and 97, both with over 260,000 miles have their original radiators and are as clean as can be. I had a few cars with over 300K and real clean cooling systems.
 
Just try running that engine over 250° and see what happens will not make any difference if the coolant boils at 375°.
 
Dont be fooled by aftermarket cooling sy

Not sure if this is the place to stick this, move it if it is not please I have a 95 Ranger XLT and I want to put an electric radiator fan, and remove the crank fan. Im not a super mechanic and I dont have a lot of tools, so I am looking for a bolt on aftermarket cooling fan that is electric and dead simple to hook up and install, or easy within and hour to install for my mechanic if needed. Any suggestions? Thanks, Drach
 
Just try running that engine over 250° and see what happens will not make any difference if the coolant boils at 375°.

Agreed! but try overheating with a 50/50 mix and see what happens when your hoses or radiator blow out lol the point of the 375° boiling point is that unlike water which will boil starting at 250 Evan's will not so while you're blowing out hoses and pumps Evans will be just cruising along :) Hopefully that helps the understanding a bit.
 
This is a very interesting and enjoyable thread. Although I always use an 26inch aluminum 3 core rad and make my own custom fan shrouds with a few small half moons cut out and little flaps of rubber riveted over them. I use two 12 inch spawl hp fans 3200cfm per fan so 6400cfm I'm not complaining. 50/50 mix never had any of my builds have a problem. Oh and 180* t stats
 
I leave my electric fan and electric pump on when drag racing. Run starts at 140 1/4 mile 180 back to pits 220 no stat
 
Gentlemen,
I agree and at the same time disagree, with 696pack's premise re coolong systems. I refer to the EXCELLENT artice in the April 2016 issue of MOPAR ACTION magazine with regard to the alumium radiator controversy that always seems to be discussed and the type of coolant to use. The article is written by Rich Ehrenberg, a member of SAE (Society of Automotive Engineers), explains in detail the differences in materials of construction, heat transfer characteristics (specific heat of the coolant), radiator design, manufacturing methods, etc. I firmly believe in his postulations and i am going to purchase the Griffin radiator noted for my '70 GTX V code 4-speed car. I will be purchasing the Griffin # 5-00004 (26" wide 2 row 1 1/2" wide tubes, aluminum construction) NO AUTO TRANS OIL COOLER. The cost is appox $650 + shipping. My suggestion is to READ the article....do not go on the word of someone with no engineering training (ie, the next door's neighbor's brother-in-laws cousin's friend).
I also disagree with premise that water pump characteristics (gallons per minute and circulating pressure and rate) are OK. Velocity (higher the better 20-30 ft/second) is the major component (along with heat exchanger surface area, read tube size and fins per inch, on the air side) are the 2 most important factors on heat transfer ability, combined with the specific heat of the coolant. Beside a slight decrease in weight (copper brass soldered construction vs aluminum furnace brazed) for my money, the article makes perfect sense. I'm sure that there will be differences of opinion. But this, of course, my opinion.
Regards,
RJ RENTON
 
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