Cooling issues

viper red cj-7

viper red cj-7

Well-Known Member
Joined
Apr 5, 2005
Location
charlotte
Hey all,
Looking for guidance. I'm not a mechanic, so keep that in mind!

Mustang 302 (88) into my CJ. I can't seem to keep temps down at all. Wife and I just took ~25 minute ride- temps creeped up north of 230 degrees.
Motor is basically stock- not hopped up at all.

What I've done.
Dual fan with Flex lite controller. The controller is supposed to come on ~165-170 at 1/2 speed which I'm pretty sure it does, then at 10% above that, it's supposed to come on at 100%

Had my PS cooler changed from mount on radiator (flat cooler) to what you see in the pic by Winch.
Had winch control box moved to under hood
Recently replaced thermostat (165 degree), new high flow water pump, radiator was pulled to fix small crack (was welded / brazed), pressure tested and put back in..

My thoughts:
Is the 165 deg thermostat appropriate? Should it be 185/190?
Was told to put a shroud (?) around my K&N air filter to block the heat
I could put some dimple die (?) holes in my inner fenders
I really don't want to poke holes in the hood of the CJ. I know I can get a bolt in louver set from GR / PSC or whoever, but really want that as last resort
Thoughts on aluminum radiator?

What am I missing??

thanks!
 

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I'm assuming you don't have any symptoms of a head gasket.

If not, I'd start by hard wiring the fans (remove the controller as a problem source) and re-check your timing.

I'm not a fan of your fan system, and 230+ temps creeping won't be fixed by some louvers or holes in the fenders.
 
The winch is blocking some air, but it looks like there's a gap between the fans and the radiator. If so, it's not pulling air through the radaitor like it should.
 
Croatan_Kid said:
The winch is blocking some air, but it looks like there's a gap between the fans and the radiator. If so, it's not pulling air through the radaitor like it should.
Click to expand...
This. That shroud has a rubber seal to seat to the radiator but it's floating in air. It's sucking air around the radiator instead of through. That's first step... then ...has the temp been an issue since motor swap or did it used to cool and new problem?
Depending on year of 5.0 there are multi direction water pumps. If you have a mismatched pump and belt circuit it won't cool.
 
Ron may be on to something, with the water pumps. But I do see the seal, which seems not to be against the radiator. But with the size of the double fans, I wouldn't think it that big a deal. The 165* thermostat, may be too Low, & letting the water circulate too fast especially with the high flow pump. Not letting the water cool enough in the radiator. 180* or even 190* might make all the difference. start with simple things & work up. Like sealing the fan-to-radiator, be sure the pump is rotating correctly, thermostat.
Side note; a shorter top hose, would be less interference with the Air Filter.
 
rodney eppes said:
The 165* thermostat, may be too Low, & letting the water circulate too fast especially with the high flow pump. Not letting the water cool enough in the radiator.
Click to expand...

That's a myth that has been debunked many times.

A proper shroud is essential.

As far as electric fans, they can cool the most impressive engines but you have to get the right ones. Not the cheap shit that's sold in parts store. For a lower budget, it;'s really hard to beat a 2sp Volvo fan with its factory relay.
 
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I would check your timing first makes sure its correct, this tends to make these motors heat up quickly. As for the thermostats a 180 seems top be the best bet in most cases, unless its a factory ford efi then some of the computers like the 195.

I would look next at your fan/ radiator setup, The cheaper electric fans tend to not pull enough CFMs when they are presented with a load AKA a radiator to pull through. But either with a mechanical fan or electric fan make sure the fan is actually pulling air through the radiator. Air in this case is like electricity and will pull from the path of least resistance.

If you decide to go mechanical fan setup, switch the front dress out to the explore serpentine setup. Has the closest to the block fan setup that ford ever made including the aftermarket. It has a massive 16" clutch fan that moves a lot of air. It will also get you a 4 g alternator so more amps is always nice. This setup cools 427 small blocks in broncos all day long.
 
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Timing is a good thing to check, but I'd juuuuust about lay a C note on that gap between the fans and radiator being the majority of the issue. Provided that those fans pull enough CFM to suffice even if they're sealed up.
 
Thanks for all the feedback.

I'll start with checking the timing and fill the gap between the electric fans and radiator. What would you put in there? Foam, rubber gasket ?? I'll try that and give it a run. The fans are from Flex a lite- I spoke to them before I purchased and that's what they recommended..(FWIW)...
I may jump to 180 deg thermostat after that....
Ron- how would I tell which direction the pump is flowing vs what it's supposed to be flowing? it's an 1988 5.0....
Bebop- no symptoms that I can tell. As for the holes, I wasn't really thing thinking of improving the cooling, more so to remove the hot air out of it...(spitballing here)..

I'm not sure about changing it all out for mechanical- guess I'd have to do some research on parts....
 
Has this motor in this vehicle ever ran cool?

Is this a new more swap and it's always been hot since motor swap?

Other than temp, how is the power . Is it running smooth and good?
 
What he said. Some bent sheet metal or aluminum would be fine. Doesn't necessarily have to have a rubber seal between the fans and radiator, just enough to force it to pull air through the radiator and not around it.
 
A fan shroud. I can't begin to tell you how important a fan shroud is. In your case, filling that gap would be equivalent to a fan shroud I suppose.

Also, someone mentioned a Volvo fan. Yes.
 
I swapped a GM 5.7 into a 92 Wrangler and found a early Dodge Dart radiator fit well and had the outlets on the correct sides. Summer came and it would get pretty warm to the point it made me nervous.

When going down the road it shouldn’t be an air flow problem if all is well. In my case the radiator just wasn’t capable of removing enough heat. A call to Valeo and a new 4 core radiator of the same size and style totally fixed the issue.

FTR, I was running an electric fan as well.
 
I'd like to see that Debunk article, because I've personally debunked that article. Just like So many articles, studies, & radiator specialist state a 2 row will cool just as well as a 3 or 4 row. So, I guess it depends on your setup. What works for some don't work for all.
 
rodney eppes said:
I'd like to see that Debunk article, because I've personally debunked that article. Just like So many articles, studies, & radiator specialist state a 2 row will cool just as well as a 3 or 4 row. So, I guess it depends on your setup. What works for some don't work for all.
Click to expand...


flowkoolerwaterpumps.com

Doesn't coolant need more time in the radiator to cool?

No. But a lot of people still think so. We have come up with some explanations for the Doubting Thomas. Debunking the I Can Have It Both Ways Theory The water has to have "time to cool" argument is perhaps the most common one we hear. In a closed loop system if you keep the fluid in the heat...
flowkoolerwaterpumps.com flowkoolerwaterpumps.com

Here are 2 well known names talking about it.

More info:

Watercooling Myths Exposed - Overclockers

Nice compilation of common misconceptions - Greenman100 (Tim Elmore)
www.overclockers.com www.overclockers.com

www.cycleworld.com

A Liquid-Cooling Motorhead Myth

Kevin Cameron dispels another motorhead myth—this time about liquid-cooling and how quickly heat transfers.
www.cycleworld.com www.cycleworld.com

Last one, from the very prominent Billavista :

 
rodney eppes said:
I'd like to see that Debunk article, because I've personally debunked that article. Just like So many articles, studies, & radiator specialist state a 2 row will cool just as well as a 3 or 4 row. So, I guess it depends on your setup. What works for some don't work for all.
Click to expand...
No this isnt accurate. Physics works the same for everyone.

Now there can be variables that someone doesnt understand at play that they miss.

A key example of that would be someone buys a brand new thermostat that is bad or they damage during installation. Vehicle still overheats. They go back and buy a new T stat with a higher rating. This one isnt bad or damaged and it works.
Then that person draws the wrong conclusion that a higher tstat is better and spreads the story.

On top of what @Bebop linked I could write a book on cooling that most dont understand. People want easy platitudes not thorough understanding.

Just like your 2 row versus 3 or 4 row example.
Its isnt universal. There are many variables here such s the size of the cores, the arrangement of the passes and the material. I could easily design a 2 row that cools better than a 4 row I design, or a 4 row that cools better than a 2 row just by changing those variables. Again people see the simple 2 vs 4 and they understand that so they spout it off. Then companies see that and take advantage of it by marketing cheaper solutions just to increase sales.

If you really want to dive into this Ill be glad to post a wall of text tonight that explains it.
But in very very short. If you keep water int eh radiator "longer" in theory, that also means the rest of the system is in the block longer. So even if you could cool the water in the radiator more, you would also heat the water in the block more and would therefor cause the entering water into the radiator to be a higher initial temp than if you just cycled it faster.
The faact that temp delta and rate of change is exponential actually makes that last argument moot because it isnt even at play, I'm just saying if you COULD correct for that it STILL wouldnt work.

I'm sure @CasterTroy has some awesome experience with industrial cooling such as CRAC and cold row/hot row and how this all fits in,
 
Ron said:
If you really want to dive into this Ill be glad to post a wall of text tonight that explains it.
Click to expand...

Yes please !

Taken from the links I posted above :

Myth: Water must slow down to fully absorb heat.

Reality: In a closed loop, a given water molecule actually spends the same amount of time in the radiator, no matter how fast it is moving, as long as the water is indeed moving.
If this is a difficult concept to understand, think about a race car on a track. If the track is one mile (5280 ft) long and the car is driving at 60 mph, the car will spend about one second in a 100 ft stretch. Think of the 100 ft stretch as the radiator.
If the speed is doubled, the car only spends ½ a second in the 100 ft section, but it passes through that same section twice a minute, so it spends a total of one second in the 100 ft section per minute.
 
Bebop said:
Yes please !

Taken from the links I posted above :

Myth: Water must slow down to fully absorb heat.

Reality: In a closed loop, a given water molecule actually spends the same amount of time in the radiator, no matter how fast it is moving, as long as the water is indeed moving.
If this is a difficult concept to understand, think about a race car on a track. If the track is one mile (5280 ft) long and the car is driving at 60 mph, the car will spend about one second in a 100 ft stretch. Think of the 100 ft stretch as the radiator.
If the speed is doubled, the car only spends ½ a second in the 100 ft section, but it passes through that same section twice a minute, so it spends a total of one second in the 100 ft section per minute.
Click to expand...
To be clear I am agreeing with you.

The caveat is, in SOME cooling applications (Im thinking industrial and equipment not any auto Ive ever encounterd) the thermostat can be a full stop where flow is prevented, (in which case the water isnt indded moving as stated above) and there is a bypass where jacket water is re-circed until reaching "operating" temp and then and only then will any (new) fluid enter the radiator.
 
Viciously curious about this because I just installed a flowkooler water pump in my 4.0 and it is running warmer than before. I have installed a dozen 4.0 water pumps over the years too.

edit: ambient temp today was 60 deg and engine coolant temps were avg 210
 
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