My overheating journey never ends

[DirtDonk]

And I've seen worse upper hose orientations and they still worked. The bends are there, but they're smooth and have a pretty mellow radius.

What I do see however are uncoated headers it looks like?
If so, I would do anything I could to wrap them. I know not everyone likes wraps, but if those are stainless then keeping the heat in with a wrap is not going to be the end of the tubes any time soon. Lots of people run it with good luck.

I know the headers themselves don't necessarily add heat to the coolant. But they can't be helping!

Another thing you can get away with is a higher pressure cap.
The RD radiator has a recommendation, and I'll check to be sure, but I think it's 16psi. AS discussed earlier, the higher pressure merely raises the boiling point of the coolant. Not something in itself that would help you lower the temps. But again, if even a slight amount of the extra temps at slower speeds are due to hot spots inside the block casting, then the higher coolant pressure could indeed help.

I thought you said you had a high-flow water pump already? Flowkooler as well? Is it just painted? Looks different, but maybe it's the angle or the lighting.

What are the pulley measurements again?

Paul

 

[DirtDonk]

Oh, and what is the rest of the exhaust doing? How is it run and is it right next to any trans cooler lines, or anything else important?

Paul

 

[mduenas]

And I've seen worse upper hose orientations and they still worked. The bends are there, but they're smooth and have a pretty mellow radius.

What I do see however are uncoated headers it looks like?
If so, I would do anything I could to wrap them. I know not everyone likes wraps, but if those are stainless then keeping the heat in with a wrap is not going to be the end of the tubes any time soon. Lots of people run it with good luck.

I know the headers themselves don't necessarily add heat to the coolant. But they can't be helping!

Another thing you can get away with is a higher pressure cap.
The RD radiator has a recommendation, and I'll check to be sure, but I think it's 16psi. AS discussed earlier, the higher pressure merely raises the boiling point of the coolant. Not something in itself that would help you lower the temps. But again, if even a slight amount of the extra temps at slower speeds are due to hot spots inside the block casting, then the higher coolant pressure could indeed help.

I thought you said you had a high-flow water pump already? Flowkooler as well? Is it just painted? Looks different, but maybe it's the angle or the lighting.

What are the pulley measurements again?

Paul

I thought about wrapping the headers, but, I wrapped my motorcycle and it didn’t seem to cut the heat THAT much. But I am willing to do anything to make it work.

Do you have recommendations on what I should do with my hoses? I am going to try a fill on the top hose for sure.

I do not have a high flow water pump, it is a stock pump. The pulleys are 5.5 I believe, will double check when I get home. I have a FlowKooler thermostat. Is a 16lbs cap good? I went with 13psi as it was recommended by ford and nothing higher, from what I remember reading.

The passenger exhaust runs right next to my transmission. I don’t know where else to route it

 

[nvrstuk]

Not doubting what Paul said about flex fans but like the other poster said and like I have seen in the past a flex fan is supposed to pull more air at idle but that does not mean that they do not straighten out at 700 rpm and are pretty much worthless under a 1000 rpm...

he could be cooling just fine at cruise because the air is just getting pushed through the radiator due to him traveling down the road at 25 to 45 miles an hour meaning the fan is spinning and doing nothing..

Every Bronco that we have tried this twst can hold a rag or a piece of cardboard against the grill at idle. Every one we've tried does that so that's not much of a test...
Hard to imagine that the engine is heat soaking from exhaust heat n the 2 minites he sits at a stoplight..

Pull the hood, this should help to see it its airflow...might just have too much static pressure on the fan without tbe assistance of the Bronco moving to help air out of the engine compartment

 

[jw0747]

x2 get rid of the flex fan in favor of a solid blade like this:

https://www.wildhorses4x4.com/product/Steel_Blade_Fan_Standard_Rotation_18in/Bronco_Cooling_Fans

if 18" won't fit get a 17" from Summit.

 

[DirtDonk]

Could just be different versions of the flex fans doing their thing too. Some may be designed to specifically stay curved until higher rpm levels, while others smooth out sooner.

I've seen other vehicles that could not pull a tissue up to their radiators at idle (exaggeration, but not by much!) so maybe you're right that all that volume of air he's seeing with that test is not enough.

Definitely pull the hood at some point. Gotta pinpoint the air flow issue if it's just hot air staying under the hood.
It could still be coolant flow too of course, but I still say there's a reason so many people used to pull their hoods off on the trail.
Kind of a pain of course, and I understand why you wouldn't want to do it unless you have to md. But at this point you've done 99% of the other things!

Maybe that would point to the headers again, and reducing their output might be just enough to bring it back under the limit.

Paul

 

[DirtDonk]

Oh, and along the lines of what nvrstk was saying, and what we were talking about earlier about Hayden brand in general. That fan you have is definitely NOT looking like a stock type heavy duty replacement fan that everyone is recommending.

It definitely looks like a flex-fan. And while it might be perfectly good, it's not the one that the others are recommending.

Paul

 

[gr8scott]

I'm pretty sure he got this fan:
https://www.summitracing.com/parts/hda-3718

x2 get rid of the flex fan in favor of a solid blade like this:

https://www.wildhorses4x4.com/product/Steel_Blade_Fan_Standard_Rotation_18in/Bronco_Cooling_Fans

That's the fan I run. It isn't even set up right (not deep enough into the shroud) but it keeps my engine cool. But then again,
I'm not driving stop-and-go in LA traffic. Someday I'll add a spacer.

 

[mduenas]

I'm pretty sure he got this fan:
https://www.summitracing.com/parts/hda-3718



That's the fan I run. It isn't even set up right (not deep enough into the shroud) but it keeps my engine cool. But then again,
I'm not driving stop-and-go in LA traffic. Someday I'll add a spacer.

That’s the exact fan I have. Looks like I’ll try the other one and see! Trial and error I guess.

 

[mduenas]

Oh, and along the lines of what nvrstk was saying, and what we were talking about earlier about Hayden brand in general. That fan you have is definitely NOT looking like a stock type heavy duty replacement fan that everyone is recommending.

It definitely looks like a flex-fan. And while it might be perfectly good, it's not the one that the others are recommending.

Paul

Going to try the wild horses fan and then, if that doesn’t work, hood is coming off. So the 18-“ rigid fan will pull more air than what I have?

 

[Broncobowsher]

I have a 13psi radiator cap, what should I get for the hose fill?

Put the 13 on the hose fill
Put a 16 on the radiator.

 

[mduenas]

Will this work? As I won’t have to pay high shipping. https://www.oreillyauto.com/detail/...ba/flex-a-lite-18-inch-fan-blade/1618/4315388

 

[nvrstuk]

You will hear the difference

 

[DirtDonk]

...So the 18-“ rigid fan will pull more air than what I have?

I don't know to be honest. But I would think so at least at some speeds.

Your fan is the same diameter, and may even have the same characteristics in some other ways too. Other than it looks like your blades are perhaps thinner (consistent with it being a flex fan of course) so may not be capable of pulling as much air.

But I just don't know because I've never tested Fan A and Fan B compared to Fan C.
As you've heard, some here are using the fan you already have, and not having the heating issue you are. Others could never get their flex fans to work and had better luck with the rigid fans. But without knowing whether or not those flex fan users had the same fan as you, it's just speculation at this point.

Paul

 

[DirtDonk]

I thought about wrapping the headers, but, I wrapped my motorcycle and it didn’t seem to cut the heat THAT much. But I am willing to do anything to make it work.

Well, that's not really apples to apples. Your motorcycle's header tubes were not buried under a hood and sandwiched between body parts and engine parts and other bits too.
Or were yours on a street bike under body work too? If so I would have thought the wrap would be a good thing.
You still have 8 tubes under your hood though, compared to probably 2 or 4 on your bike? Maybe that's enough of a difference to make doing it again worthwhile.

I'm kind of surprised you didn't see a difference, but not sure what to make of that either. Most people report big changes.
And when you watch the episode of (I forget the name) on youtube about testing headers of different size primary tubes, they had some bare metal and some ceramic coated. When they walked into the dyno room after a run on coated headers the room was pretty cool. But on the bare headers they could hardly stand it for the heat.
Just watched that today in fact. Fun stuff.

I do not have a high flow water pump, it is a stock pump. The pulleys are 5.5 I believe, will double check when I get home.

Seems about stock diameter then I think. Somewhere between 5" and 6" if I remember.
If the water pump pulley is smaller than the crank pulley though, you have a little bit of overdrive. That would be a good thing at this point.
If it's the same, then no matter what size they are they're pretty much running at stock speed.

I have a FlowKooler thermostat.

It's what I've run and it worked great.

Is a 16lbs cap good? I went with 13psi as it was recommended by ford and nothing higher, from what I remember reading.

That's because the stores are mostly going to know what works with stock stuff. Your radiator is rated for more pressure now, so as long as all of your clamps and hoses and heater core are in good shape, the 16psi rating is fine and will give you more headroom for boil-over.
And with any luck, more pressure inside the system will mean more even heating/cooling within the system.

The passenger exhaust runs right next to my transmission. I don’t know where else to route it

No problem. It's what we all run into, but if it's too close then yes, that's when you can have problems. Then it's adding heat needlessly to the trans fluid. Same if the cooling lines are running too close. Those pipes get pretty hot.
But I was only throwing that out there to put it in your mind to keep an eye on stuff like that and think about it when you're laying under there scratching your head at what the problem is.
At lower rpm it's not really throwing a ton of heat into the transmission. But it's not completely insignificant either. At idle it's a lot less than it would be at highway speeds.
Then again, at idle the fan wash is maybe not enough to keep what heat there is away from important things.
So many things to factor in...

Basically though, if you have more than an inch of clearance between the exhaust and anything important, while not perfect it should be ok. Probably will allow enough air flow between.
More is better of course, but there is some leeway here too.

Paul

 

[Slowleak]

I don’t think it will pull more air unless you have so much back pressure under the hood that the current blades are flattening out at idle. If it runs cool with the hood up then that may be the issue.

Each blade moves a certain amount of air per revolution. 7 blades will move more than 6 if everything else is equal. The seven blade fan also has the blades unevenly spaced which reduces noise.

I tested a 17inch 6 blade rigid fan. I would expect the 18inch rigid fan to pull more than the 17inch fan I tested, but less than the 18 inch seven blade flex fan in normal conditions.

If you want to do some accurate tests, spend $20 on an anemometer to check the airflow thru the grill. Also check the water temp at the radiator inlet and outlet with an infrared thermometer. Do your checks with the current fan blade, and then with the new one....

 

[DirtDonk]

I just re-read this looking for more timing clues and cues. Now I have another question.

When I advanced a 1/4" turn I didn't notice a difference in driving, and temp seemed to be around the same. When I went 1/4" more I was certain I was hearing knocking, I could very well be crazy.

Maybe not crazy. But maybe....;D
What did it sound like and when did it happen? Maybe the EFI unit is running things too lean (or rich?) and you were hearing a ping or knock after all. Maybe it has to have time to figure it out, or maybe something else is going on.

What cylinder heads do you have? Are they stock.
Just as an aside, when I experimented with timing on my stock original '71 302 I ran it from 6 to 20 degrees BTDC. Knowing that 20 was too high, I still wanted to see how it ran because I've had other engines that ran best at 18 degrees base timing advance.
It never knocked or pinged. It fell on it's face of course, and had a real hard time revving up and felt rough and smoked a lot. But it did not knock.
That's likely due to a combination of the combustion chamber's design in addition to the carb tuning.
Maybe your EFI is changing the mixture in such a way as to ping at a much lower rpm under load.
But did you idle it for awhile and it still got hot?

If so, and you went a full 1/2" rotation of the distributor, then I guess I can get off of the whole retarded timing kick I'm on and concentrate elsewhere for once.
But it sure would be nice to know if your timing marks are accurate. Then I could get some sleep at night!

Throttle response felt better, but I also felt like I smelt an oil smell out of my exhaust, although I could be looking into it to much.

Crisper throttle response is a typical result of advancing the timing. And if the timing was too far advanced you could have smelled smoke out of the exhaust. Combination of things, including unburned fuel because the timing was so early it was not getting it's whole bang in the cylinder.
Same for too retarded, but in a different way.

Could your timing be higher than 11 degrees indicated?
Does your starter ever turn over slowly like it's struggling to crank the engine? When it's been idling and getting hot, is it ever hard to start up after turning it off? Or do you let it fully cool before you try to start it again?
Ok, so I could not quite get completely off the timing kick after all!

Maybe the next time it starts getting hot, turn it off for five minutes and then fire it up again. If it turns over slowly you may have too much timing.

Just another thing to think about.%)

Paul

 

[blubuckaroo]

The shroud to blade clearance here is way too much.
You have a shroud problem.

 

[mduenas]

The shroud to blade clearance here is way too much.
You have a shroud problem.

The top is where I have a slightly larger gap, maybe an inch? He sides and bottom is half an inch. The bottom of the shroud is cut out a little to allow for my body lift. I wanted to get another shroud, but could not figure out how to hang it lower. I do not have access to a welder. I tried 2 different shrouds. Any advice? I have a 1” body lift. And if it’s not the shroud, at least I’ll have a nicer looking one.

 

[blubuckaroo]

The top is where I have a slightly larger gap, maybe an inch? He sides and bottom is half an inch. The bottom of the shroud is cut out a little to allow for my body lift. I wanted to get another shroud, but could not figure out how to hang it lower. I do not have access to a welder. I tried 2 different shrouds. Any advice? I have a 1” body lift. And if it’s not the shroud, at least I’ll have a nicer looking one.

Is that one of the steel shrouds made for a body lift?
I ordered one recently for a 1" to 2" body lift and the fan hole was oval rather than round. the hole was way too tall. I was concerned that the fan clearance would loose too much efficiency.
I guess it would have made a fine fan guard though.%)