Cooling issues, could use some advice

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UOP

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Not an Abody, obviously, but maybe some of you guys can help me with persistant cooling problems ever since I put my car on the road.

Not trying to write a novel here but I'm out of ideas. My first setup was a 22x19 (core alone is larger than old radiator) 2 core aluminum radiator with your typical Flex-A-Lite 16" fan and it barely kept up. Anything over 90 degrees outside I was constantly checking the temp gauge and I had to make absolutely sure to never get stuck in traffic because it was sure to overheat. I completely boxed the entire area in front of the radiator and that made it ok when moving over 40 mph, but even then it ran above 200 degrees. Forget it on a 100+ degree day, it took highway speeds to keep it cool. Believe it or not I made it through Drag Week '12 this way, but was fortunate it was cool that week.

Last year I decided to revamp the whole system, cutting the car to install the biggest radiator that would fit between the frame rails, a 27x20 2 row double pass FSR radiator. I also installed new waterpump, thermostat, and installed a Lincoln Mark VIII 2 speed fan that's supposed to flow over 4000 cfm that covers the entire core. I thought I had it in the bag, but again once it gets hot outside, so does the motor. Running the fan on high in 100 degree heat still runs the gauge up to 210+ and I even had to stop in traffic once last year and open the hood to keep it from overheating. Embarassing. Again I've boxed the front to catch as much air as possible but it won't run at the 185 degree thermstat setting unless it's 75 degrees or less.

With the new setup it's ok running down the highway, but once I stop or get stuck in slow traffic, I'm getting nervous. Any ideas? I've tried all the water wetter additives, my headers are ceramic coated (used to be wrapped and almost ruined them), and the front of the radiator is sealed from the engine compartment. I don't particuarly want to cut hoes in my custom one-off hood but if that's what it takes then so be it.

One more thing, as I was writing this I remembered I don't have the heater lines hooked up. Could that be part of what's causing my problem? The heater core in the car leaks but maybe I could loop them? Heck, I'd even run the lines through a large trans cooler in the wheel well if that would help. I just need to get this under control before it gets hot again.

Appreciate it.
 
I run block hugger headers, could the heat from them being so close to the block cause the problem?


This is driving me nuts. I run around with a few Dakota guys and they don't have any problems at all with that thin little factory core. Heck one of them runs 180 degrees no problem with no fan but some 16" universal fan. It's set up as a pusher and has a 3/4" gap between it and the core so I would think a good amount of air escapes out the side.

I just don't get it.
 
are the headers coated?

Maybe look into waterless fluids like Evans NPG + Coolant. They are allow the engine to run at higher temps with almost no increase in pressure of the cooling system. The fluid has a higher boiling point then water so i doesn't make steam that pressurizes the cooling system.

It is a little expensive but can be run for 30 years.

[ame="http://www.youtube.com/watch?v=VkNz-ANfUkc"]http://www.youtube.com/watch?v=VkNz-ANfUkc[/ame]
 
So is this in your Mazda body?

Any picture of in front and behind the radiator?

I'm thinking MP sized (18"? diameter) viscous mechanical fan with complete fan shroud. Did your first 16" flex fan run a complete shroud?

Next would be to check pulley ratios if they are not all together as a system 100% confirmed stock.
 
I'm not a fan of flex fans. I would trash that and go with a good old 7 blade fan.

Next, you have to make sure that the airflow is going THROUGH the radiator and not AROUND it.

There are a few things that you can do to help this:

1. Get a good fan shroud. The shroud is important to help the fan pull the air through the radiator fins.

2. There is a critical spec that they use to measure the amount of "overlap" between the fan and shroud when they design cooling systems. It's acronym is FOOS (no, not Chip Foose), it stands for "Fan Out Of Shroud". Like I first said, it is how much of the fan is overlapping with the shroud. A good starting point is 50%. Which means half of the depth of fan is covered by the shroud.

3. Next make sure that there are no gaps for the air to go AROUND the fan and/or shroud. check for gaps between the fan and shroud, and gaps between the radiator and front mounting wall. If there are, fill them with foam, or flat rubber "sheets" so as to cover the gaps and prevent any air from going AROUND the radiator and shroud and direct it THROUGH the radiator and shroud. The radiator will not be able to cool to its full potential if you can't get all of the air to go through it.

Also make sure that you have enough grille area for the radiator. Many grilles can be restrictive. The original Grand Cherokee, had 8 openings in the front grille. They changed that to 7 bigger openings somewhere between 94 and 96, (I can't remember the exact year, but I wanna say 95). The change increased front end air flow by 10% which was needed to help the A/C performance. The original system had almost 425 psi "head pressure" (pressure through the condenser) when the maximum spec was 450 psi. The new grille helped lower the head pressure approximately 25 psi so they weren't running so close to the maximum head pressure.

The new Shelby Mustang GT500 with 662 HP does not have any "webbing" in the grille because they need all of that area for front end cooling, any ribs in the grille will restrict the airflow. They eliminated all of the "webbing/ribs" from the earlier models because they need all of the airflow that they can get. Ford realizes that they will have to eat some warranty for rocks getting through the front end and damaging the cooling fins/tubes on the condenser, but have to do it for proper cooling performance.

I cringe when I see cars driving around where people change the grilles from stock and use aftermarket or block some of the airflow with cardboard etc. If those changes restrict the airflow through the front end and the car/truck overheats, the OEM will not warranty any failures from overheating as they were modified from what was originally designed and proven with testing before ever being released to the public. Part of the testing includes parking the car less than 1 foot from a wall at the Phoenix proving grounds during summer and letting it idle for over an hour while monitoring the temperatures and pressures in the cooling system and A/C system. They also test them while pulling a 5000 lb trailer with the A/C on max through Death Valley where there are signs warning you to turn off your A/C to prevent overheating. This is a very stressful test for your A/C and cooling system.

Good luck, I hope some of this helps you.
 
Sorry for the delayed response, but hopefully this answers a few of your questions.


So is this in your Mazda body?

Any picture of in front and behind the radiator?

I'm thinking MP sized (18"? diameter) viscous mechanical fan with complete fan shroud. Did your first 16" flex fan run a complete shroud?

Next would be to check pulley ratios if they are not all together as a system 100% confirmed stock.

Running a mechanical fan isn't an option.

Here is a picture of my radiator/fan setup. There isn't a rubber seal between the shroud. One thing to note is I did have to shorten the shroud by 1/2" to make enough room to clear the crank pulley.

photobucket-18964-1378578000785_zpse675b7fe.jpg


photobucket-33216-1378577738969_zps7743f299.jpg


As for the pulleys, I'm running a crank pulley from a 70's smallblock and water pump pulley from an 80's truck.



I'm not a fan of flex fans. I would trash that and go with a good old 7 blade fan.

Next, you have to make sure that the airflow is going THROUGH the radiator and not AROUND it.

There are a few things that you can do to help this:

1. Get a good fan shroud. The shroud is important to help the fan pull the air through the radiator fins.

2. There is a critical spec that they use to measure the amount of "overlap" between the fan and shroud when they design cooling systems. It's acronym is FOOS (no, not Chip Foose), it stands for "Fan Out Of Shroud". Like I first said, it is how much of the fan is overlapping with the shroud. A good starting point is 50%. Which means half of the depth of fan is covered by the shroud.

3. Next make sure that there are no gaps for the air to go AROUND the fan and/or shroud. check for gaps between the fan and shroud, and gaps between the radiator and front mounting wall. If there are, fill them with foam, or flat rubber "sheets" so as to cover the gaps and prevent any air from going AROUND the radiator and shroud and direct it THROUGH the radiator and shroud. The radiator will not be able to cool to its full potential if you can't get all of the air to go through it.

Also make sure that you have enough grille area for the radiator. Many grilles can be restrictive. The original Grand Cherokee, had 8 openings in the front grille. They changed that to 7 bigger openings somewhere between 94 and 96, (I can't remember the exact year, but I wanna say 95). The change increased front end air flow by 10% which was needed to help the A/C performance. The original system had almost 425 psi "head pressure" (pressure through the condenser) when the maximum spec was 450 psi. The new grille helped lower the head pressure approximately 25 psi so they weren't running so close to the maximum head pressure.

The new Shelby Mustang GT500 with 662 HP does not have any "webbing" in the grille because they need all of that area for front end cooling, any ribs in the grille will restrict the airflow. They eliminated all of the "webbing/ribs" from the earlier models because they need all of the airflow that they can get. Ford realizes that they will have to eat some warranty for rocks getting through the front end and damaging the cooling fins/tubes on the condenser, but have to do it for proper cooling performance.

I cringe when I see cars driving around where people change the grilles from stock and use aftermarket or block some of the airflow with cardboard etc. If those changes restrict the airflow through the front end and the car/truck overheats, the OEM will not warranty any failures from overheating as they were modified from what was originally designed and proven with testing before ever being released to the public. Part of the testing includes parking the car less than 1 foot from a wall at the Phoenix proving grounds during summer and letting it idle for over an hour while monitoring the temperatures and pressures in the cooling system and A/C system. They also test them while pulling a 5000 lb trailer with the A/C on max through Death Valley where there are signs warning you to turn off your A/C to prevent overheating. This is a very stressful test for your A/C and cooling system.

Good luck, I hope some of this helps you.


Grill area is definitely something I'm lacking, there really isn't any. I've done some things to help direct air through the core, and it works ok running down the road, but still could use some improvement. These puctures are when I originally tried boxing in the front of the core and have since sealed it up much better.

photobucket-39432-1374209321973_zps7dbf986d.jpg


photobucket-41277-1374209366429_zps6daef23f.jpg


Frontal area. I've thought about cutting out the center bar in the grill, or :gulp:, install a body kit bumper with a larger opening for an intercooler.
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one thing that comes to mind is that the top of the radiator is lower than the top of the engines coolant passage, I don't know why I am thinking this could be a problem but I just read something in either hot rod or car craft where they fixed a guys overheating problems and this was one of the main issues. I cant remember how they fixed the problem (maybe with some sort of tank mounted higher up). So, if someone out there can remember this article, please refresh my poor memory....On a side note, I had a Belvedere that used to run hot all the time, well one day the core plug started to leak, it was then that I found out that the block was full of crud because the previous owner had never used any type of anti-freeze. I yanked the engine, pulled out all the core plugs and cleaned out the crud with a clothes hanger and running water, replaced the plugs. After that, the engine ran so cool that it would barely get into the heat range, and this was down in Florida where it gets hot.
 
I figured I throw this out there since many people over look it ... Have you bled your cooling system ??
 
The fact that it runs cooler at speed tells me there's not enough air or not enough water flow or both at low speed.

I'm not familiar with magnum / LA all my stuff "stays LA" You don't have some mismatch with magnum timing cover / LA pump or vice versa?

Any chance the block is effed up, IE dirty or epoxy filled?

Have you checked (hold at high med, med high, and high RPM) that the bottom hose is not pulling shut?

I don't know how many stats you've tired, I would try another.

Have you tried just pulling the hood clear off on a hot day to see what happens?

My gut thinks frontal grill opening is not the problem

It might be the fan is not doing as well as you think.

I don't think the heater hoses are the trouble, but you could throw a marble or something in the hose to plug the flow.

Too bad you are having trouble. That's a cool concept.
 
Just a thought a buddy of mine has a 70 Nova pro street car and he had the same problem come to find out he had wired the fan in reverse of the way the blades were made to turn might try reversing the fan wires just a thought
 
I think the grill could use work for more air in. Like hemidart said, make sure the blades are on the right way and wired correctly. I know that some flex-a-lite electric fans come as pushers so you have to reverse the wires AND the blades.

Also try to remove the thermostat and put just an open restrictor in with about a 3/4" hole in it. You need some restriction or else the water will not cool in the rad.

I'm not familiar either with water pumps on LA vs magnum, but it there a chance you're turning the water pump the wrong way? Small block fords changed when they went to a serpentine belt and it rode smooth side of belt on pulley therefore turning it counterclockwise. Guys would put a newer motor in but use their old pulleys and run into lots of issues.
 
The hardest part for the cooling system is when the engine is running and the car isn't moving. The lack of airflow through the front end makes it difficult to cool. That's why they do the test where they park the front ends within 1 foot of a wall outside in Phoenix and idle for at least an hour to prove the design.


Lack of airflow through the front end/grilles makes it very difficult. It puts a heavy load on the cooling system. Without enough airflow through the front end, it is difficult to keep cool.

Any way to open up the grille opening? Or put an electric "pusher" fan in front of the radiator to help get air through it?
 
Is there a spring in the lower radiator hose to keep it from collapsing?

I installed a flow cooler water pump, increases flow 30-40%

FLOW COOLER adds extra veins and anti cavity plate to the stock water pump blades.

What kind of pulleys are you using. Stock, under drive or overdrive?

Put march pulleys on mine and they sent under drive plus had a 6 blade water pump for an AC car, wrong thing to do.

So changed to the stock dia. pulley to increase flow.

Factory Chrysler AC cars used a 6 blade water pump to slow flow and then speed up the fan with larger pulley to provide more air flow. Non air cars used 8 blade pump.

I know exactly what you are fighting and very frustrating.

It has all helped but still not there. Have a BE COOL aluminum radiator that I think is for a B Body and it just doesn't fit right.

Good luck
 
Lots of ideas, I like it.

Running stock pullies on an LA timing cover and water pump. It's a 6 vane if I remember correctly.

New, at cooling system upgrade, T-stat (185)

If I open the hood it won't overheat idling, and will recover faster.

I never checked the lower hose but will as soon as it's on the road again from having the rear end rebuilt. Never thought of that.



The big thing that ya'll mentioned a couple of times is if the block is full of crap. This is very possible. The was picked up from a junkyard and I freshened it up with new rings and bearings to go in another project, but I changed directions so the motor sat for a year before ever running. I still didn't have the RX7 yet but wanted to run it so I built a test stand and broke it in on that. The problem, and where I really think I messed up, was after the motor was pulled off the test stand I never drained the block, so 50/50 coolant sat in it for about 6-8 months before finally being installed in the car. Total NEWB mistake, I know.

When I first got it going I had a heck of a time with the coolant, it turned into something that resembled foamy diarhea. Really nasty stuff with all kinds of junk floating around. It got to the point where I was flushing it every other week to get it cleaned out and after probably a dozen times the coolant started to actually stay green.

When doing my upgrade last year I figured part of the problem was the radiator was probably clogged and not functioning properly. The coolant still gets a little rusty since during the summer I just run water with Purple Ice (due to track racing a lot) but it doesn't seem to have lots of junk floating around in it anymore. I wonder what I would find if I pulled the freeze plugs in the side of the block. It woud be a total PITA but worth it if there was a really good chance my cooling issues would be solved.

Something to think about for sure.
 
obviously not getting enough air flow at idle/traffic speeds. 7 blade steel clutch Fan should be half in/out of full shroud. You can get a 4 core rad...alum from champion at a cheap price. Antifreeze at 50/50. Non alum rad , cap should be 14to 16 lbs. Alum...24 lbs.
 
...

If I open the hood it won't overheat idling, and will recover faster......

Reading all your other comments and no reading this, it seems your grille opening is just not big enough to feed your radiator.

Just like how 69 Dodge Daytona's tend to overheat at idle and low speeds. Same cooling system everthing is on a 69 Dodge Charger that does not overheat. The Daytona just has a smaller grille opening.

Open up this grille squares. Maybe redirect the brake duct cutouts to feed the air box. And you liceanse plate is blocking the main grille opening. Doesn't seem like much, but in your case everthing counts. This would be a start.
 

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From your description on the block issues, the "diarhea" coolant etc... sounds like it could be a big part of your problem.
 
Meet-Joe-"Dart";1970358178 said:
From your description on the block issues, the "diarhea" coolant etc... sounds like it could be a big part of your problem.
I,ll second that...With all the improvements you,ve done to your cooling system and still having issues.I,d say the block needs to be hot tanked to get rid of any crud/blockage.Who knows what was used/dumped in it before you got it?JMO
 
I've found that my car ran a lot cooler with my hood off. I made a big improvement by sealing the hood to the radiator support. I used foam rubber from the Home Depot. Still gets hot in traffic if I sit idling a long time but it's a vast improvement. Just thought I'd throw that out there. Good Luck
 
A couple of things come to my mind:

1) Are you sure of the timing marks really being TDC when indicated. A LOT of over-heating issues can be traced back to the wrong ignition timing.

2) Are you sure of the temp gauge? Just because it's a name brand doesn't mean it's right. Buy a real temperature gauge from some place like mcmaster.com, where the % error is specified, and compare it's readings to your gauge.

3a) I know that it sounds like the wrong direction, but what happens if you go to a higher temp t-stat? More than once I've seen this move cure the problem.

3b) High flow or std flow t-stat? If high flow, dump it. Go with the std flow version. The std. flow t-stat is a bigger restriction, which is what you want, it will raise the coolant pressure in the block above the cap value which makes it harder for the coolant to boil in the localized hot spots. Once the coolant has changed to steam it's a lot, lot harder to cool the engine.

3c) While you're messing with t-stats, are you drilling a small hole in it/them to bleed air out while filling the system? If not, do so. 1/8" or smaller. On engines where I can I rotate the t-stat to put the hole as high as I can get.

4) The radiator cap absolutely has to be at the highest point in the system. '60's era Corvettes had surge tanks due to having a cooling system layout very similar to yours. Strongly suggest putting a very high pressure cap on the radiator, putting a surge tank in the hot side heater core hose, and placing the tank in the engine bay where it's cap will be higher than any other part of the coolant system.
Also: If you can figure out a way to do it, modify the cap on the radiator to allow coolant into the overflow hose bib on the radiator's neck. Route a hose from there over to the top of the surge tank. This will make the system self-bleeding. 80's era VW Rabbits are one potential JY donor for the surge tank and there's likely others as well.

5) Water pump; how new is it, and where did it come from? I once had an over-heating problem with a car that had *just* had it's pump replaced before I bought it. I tried everything and the last thing left was the pump. I put a Stewart Components water pump on it and the problem went away. I've since quit buying electrical or cooling system parts from the national chain stores. In the long run they don't save you money or time.
 
Maybe you could setup a second water temp gauge out the radiator exit for clues?
 
Easy to check the grille opening...........yank that front end stuff all off (ya, ugly!!) and drive it for awhile
 
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