Cooling problems continue

[nickeboy]

Hey CB gurus,
I am having a frustrating time with my Bronco overheating. Im in Socal and on hot days at a stoplight, my temp gauge is getting up towards 220 before I shut her down. I am running a 302, C4, edelbrock 650 carb, headers, full fan shroud, 6 blade fan etc. I recently bought a Ron Davis radiator and its better, but not much. It still cant keep up at idle. I have a 160* thermostat and am being told to try a Stant thermostat at 160*. I cant imagine this would make a difference.
So, should I try no Themostat, a 180*, new water pump (not very old). Not sure what to try next.

 

[bronconut73]

Be sure you do not have an air pocket in the system.
I have heard parking it on a steep incline with the radiator cap off/loose.

Most Broncos have air flow issues. I would look into that first.

Many have found 195 degree T-Stat keeps theirs cooler.
Temp stays more consistent.

 

[Steve83]

The thermostat has nothing to do with engine cooling - it's only there to help the engine warm up sooner. Put a 195°F t-stat in, and leave it until you have reason to think it needs replacement.

"Overheating" ruins an engine. If your engine runs the next day, it didn't overheat. 220°F is high, but it's not TOO high. Exactly how & where are you measuring this temperature?

 

[jckkys]

The 195 is what Ford specified and has worked well for me. But then it's only gone over 115 a few times here in Tucson, this summer. What are the ambient temperatures when this happens? Socal has little meaning. My cousin who lives on Coronado Island rarely sees the 80's but El Centro makes Phx seem cool. Both are Socal cities. The OE 7 blade fan is the best I know of and the high density brass radiator is a little better than aluminum.
Another thought, is heated air that has passed through the radiator can be pulled through again when the truck isn't moving. The baffles and air damns in new vehicles address this. I'm looking at adapting some of these techniques for EB applications.

 

[langester]

Just a thought, from my experience. Have you verified your gauge is working correctly? My gauge in my truck was showing hot all the time. Had the radiator cleaned, new water pump , thermostat, no change. After all that I checked the temp with an infrared temp gun and it the gauge was off by 30 degrees.
Hope it helps, good luck with your project.

 

[Steve83]

The baffles and air damns in new vehicles address this. I'm looking at adapting some of these techniques for EB applications.

I did that to Frank's '75 (with A/C), and it ran just like a modern vehicle, even on hot days. Since it was his only vehicle for a decade, it had to run right every day, and get him to work on-time in a clean suit.

.

 

[Slowleak]

I had a six blade fan on mine and when air temps were around 90 mine would get up around 220 at idle with a/c on. I experimented with different fans and a smaller pulley. The six blade fan did not pull enough air. It was a stock 17 inch fan. I have a stock 3 core radiator with a/c condenser in front of it.

I did some testing on mine with different fans. I measured max airflow at idle, with the meter up against my condenser, using various fans and a smaller pulley. Here's what I got.

Six blade 17 in. stock fan, stock pulley - 492 ft/min
Six blade 17 in. nylon flex fan from Summit, stock pulley - 708 ft/min
Seven blade 18 in. stock flex fan, 5.4in pulley - 846 ft/min

The bigger fan gave me a 72% increase in airflow at idle. It will now idle at 185-190 with the a/c on all day long in 90+ degree heat. I also measured my evaporator coil temp. With A/c on max I'm getting 19-24 degree readings at idle. That's a big improvement for the A/c as well.

I would suggest finding a better fan and possibly swapping to a smaller pulley to get more airflow at idle.

 

[nickeboy]

All of these help. I will get a 195. Next I'll try a different fan blade. When I use the infrared gun, should I point it at the thermostat housing?
I'm in Temecula, so summer months are anywhere from 90 to 105.

 

[spap]

Harbor freight has cheap laser thermometers. It would be good to get a real reading of temp and start from there. The radiator cap is an important too but since you have the new radiator you prob have a new cap

 

[SteveL]

Back when mine was a daily driver in LA traffic I would throw a bottler of water wetter in it. It won't fix a cooling problem but found it helped run a little cooler in traffic. Running no stat will make it heat up under load at higher rpm. I ran into that going up to the local mountain. The stat helps slow the water thru the radiator helping it cool before going back to the motor.

 

[blubuckaroo]

Hey CB gurus,
I am having a frustrating time with my Bronco overheating. Im in Socal and on hot days at a stoplight, my temp gauge is getting up towards 220 before I shut her down. I am running a 302, C4, edelbrock 650 carb, headers, full fan shroud, 6 blade fan etc. I recently bought a Ron Davis radiator and its better, but not much. It still cant keep up at idle. I have a 160* thermostat and am being told to try a Stant thermostat at 160*. I cant imagine this would make a difference.
So, should I try no Themostat, a 180*, new water pump (not very old). Not sure what to try next.

When I still had my C4 tranny, I found it important to find that happy spot to set the idle. 600 RPM in gear is correct.
Too slow, and you're not moving enough air and coolant.
Too fast and the torque converter is trying to hook-up, and that creates lots of heat.

Another thing that helps is a good fan. The OEM six blade just wouldn't hack it for mine. The best is the OEM seven blade flex fan that came with the "Super Cooling" option.
I've found a good substitute for that one too. The manufacturer doesn't recommend using it on engines over 250 cubic inches but neither Hayden or Summit could answer why. There were several testimonials that claim to use it on bigger motors with good results. Anyway, it works great on mine, moves tons of air, and best of all, it doesn't have that drone that some fans have.
https://www.summitracing.com/parts/HDA-3718

 

[yakelys69]

Check your timing & look at plugs

 

[yakelys69]

never mind double post

 

[nickeboy]

Great Update!

I took langlester's advice and picked up an IR thermometer for $30. It turns out my gauge is off by roughly 30 degrees. AWESOME

SO... It turns out that I bought a $700 radiator for nothing. So if you need a good aluminum radiator, I will be selling my old one soon. LOL

On the bright side, I think I should be good to make Bronco Daze this year.

Thanks for all the help.

 

[jckkys]

I did a wine tasting tour in Temecula. It's a beautiful area. Keeping your EB cool, should be no problem there.

 

[Steve83]

When I use the infrared gun, should I point it at the thermostat housing?

Point it where coolant is FLOWING at the top front of the intake. If the t-stat is closed (or if you're not sure), open the heater valve (if equipped) and aim for the heater outlet at the intake manifold. Not on the rubber hose; on the metal.

...slow the water thru the radiator helping it cool...

That's a myth.

 

[sykanr0ng]

The stat helps slow the water thru the radiator helping it cool before going back to the motor.

That's a myth.

Myth.
If the coolant is staying longer in the radiator then the coolant is also staying in the engine block longer and getting even hotter, which means more heat to remove from it when it finally gets to the radiator.

 

[DirtDonk]

The thermostat isn't so much "slowing" the coolant down, as it is creating a higher pressure behind it to get more even cooling around the water jacket.
Not just a function of higher pressures raising the boiling point. But the higher pressures keeping liquid at the hottest spots even when they would liked to have boiled into gas long before the overall engine temps rose to the boiling point. If they ever did.

So did you verify temperatures at different points too nickeboy? Just to be sure?
Will you try to fix the gauge issue, or just leave it and remember that it's reading high?

Either way, glad you got it figured out.

Paul

 

[73azbronco]

I've long suspected most overheating claims could or are bad gauges. Think about it, most who claim to be running hot, do they actually boil over?

 

[DirtDonk]

Most don't. But that's not necessarily a good indicator either. Since when under the typical 13lbs of cap-rated pressure, plus the mix of anti-freeze to water, the actual boiling-over point is a lot higher than the point that most of us are ready to turn the engine off and wait.

If the system loses pressure, or you have the cap "popped" for whatever reason (like so slow down a leak for instance) or in an older vehicle the system just isn't rated for high pressures, the 220 that people often see would likely be into the boiling point.

I'm sure it still happens now and then. But for most of the stories of overheating that I've read about in the Bronco world over the years, actual boil-over is a rare occurrence.
I bet as often as any defective or insufficient performance from a part, the engine tune and/or an improperly reading gauge are many times at the core of the issue.

Glad that's all it was this time.

Paul