My overheating journey never ends

[mduenas]

I’ve made so many posts on this and everyone has been so helpful. Long story short I can’t get my truck to stop overheating. I put a 195 FlowKooler thermostat in. I have a rebuilt 302 with a fitech. I also have ac, and power steering.

I put a Ron Davis radiator in, a Hayden 7 blade flex fan in, and taped up my shroud with aluminum tape. As it was hacked to death to accommodate for my 1 inch body lift. I tried to fit the full circle shroud from wild horses and the steel shroud, no go. They both hit my pulleys or my fan was too deep inside the shroud (more of a combination of those 2) my fan sits about 3/4 from my radiator and 1/4” from my crank pulley. I have a new water pump and gauges.

I keep reading about shroud extension straps, but I can’t find any online, and I am having trouble visualizing them. I want to get a new shroud that is intact and see if that helps. My truck stays cold when moving. But once I idle it starts to creep about 1 degree ever 5-10 seconds. I move it drops, and fast.

I am getting enough sucking through the radiator fins to hold cardboard to my grill. But maybe that’s still Not enough. I’m going to pull the thermostat and see if it is stuck closed or staying open. Heater works great and I very diligently burped every bubble out.

In fact when I got all the air out, the truck idled for over an hour and didn’t even get up to operating temperature. Now the last few days, the temps climbs at every stop light. I drive in LA traffic. So I desperately am trying to find a solution. I’m hoping a new shroud. And another thermostat soled this issue.

I have posted this a few times, here my previous threads:
http://classicbroncos.com/forums/showthread.php?t=286069
http://classicbroncos.com/forums/showthread.php?t=286943
http://classicbroncos.com/forums/showthread.php?t=286727
http://classicbroncos.com/forums/showthread.php?t=287090

 

[labuski]

sounds like a thermostat issue. You didnt put it in backwards did you?

also did you burp it by keeping your rig at an incline?

 

[mduenas]

sounds like a thermostat issue. You didnt put it in backwards did you?

also did you burp it by keeping your rig at an incline?

I am 100% positive it is not in backwards, I feel maybe it is a faulty one i received. Yeah, I burped it on an incline. I ordered a new thermostat so I’ll swap again. And see if that clears it up.

 

[englewoodcowboy]

It might be an air entrapment under the hood as well. Does it over heat if you have the hood open?

 

[1strodeo]

you can easily test the thermostat on the stove with a pot and meat thermometer...test the new one too before install

 

[charlie6976]

What are your over heating temperatures?

 

[Eoth]

You mention that it is a rebuilt "302". Is it a 70's v-belt setup, 5.0 serpentine or a "mix-and-match" combination? It sounds like you have beat the fan, radiator, and thermostat to death. Last part of the equation is the actual circulation of coolant.... How confident are you in the correct direction of your water pump?

 

[mduenas]

It might be an air entrapment under the hood as well. Does it over heat if you have the hood open?

When I burped the coolant my hood was open and I couldn’t get past 167 unless I blocked flow to the radiator. It was good driving for about a week. But never did reach operating temp, then started to climb the next day. So may very well be hot air, but seems that would have been happening all along? I’m not familiar with hot air being trapped, so this would be new territory for me.

 

[mduenas]

What are your over heating temperatures?

Hitting 230 if I get stuck at a few stop lights.

 

[mduenas]

You mention that it is a rebuilt "302". Is it a 70's v-belt setup, 5.0 serpentine or a "mix-and-match" combination? It sounds like you have beat the fan, radiator, and thermostat to death. Last part of the equation is the actual circulation of coolant.... How confident are you in the correct direction of your water pump?

It is a 1974 v belt setup. I am extremely confident the flow the of the water pump is correct. Had another person triple check with me.

 

[Broncobowsher]

Cools as speed, so there is enough waterflow and the radiator is good.
Gets hot at idle is a sign you have an airflow issue.

Drive it, get it warm, go home, keep it running. It should be getting hot at idle by all accounts. Water the radiator with the hood closed. Just a misting spray across the grill. Cool the core of the radiator only. Temp drop? No, there is a bubble blocking flow. Yes, airflow isn't enough to cool the core.

 

[mduenas]

On my drive in a ton of traffic this am, it’s a little cooler out, and I got 187 at the highest, currently sits around 180. I’m perplexed

 

[tatersalad]

I had the same issue on my first engine. I tried everything and never could solve it. It had an aluminum Edelbrock water pump on it. I always thought that the water was wasn't sitting in the radiator long enough to cool down once the stat opened. I had a 4 core copper rad and always thought that an aluminum or triple pass would have helped. The oil pump shaft snapped on that engine and that solved its overheating issue lol. Put a 351W with efi and it's all good now. ��

 

[Rustytruck]

3 things happen when you stop in traffic. Fan speed slows down, water pump slows down and your automatic transmission fluid heats up and slows down. For a test try increasing your in gear idle speed a little.

How is the cooling system for your transmission plumbed?

If you test your thermostat check at what temperature it starts to open and at what temperature it reaches fully open. I would also check the temperature in the radiator and compare it against what your using to read temperature in the truck. When cold open the radiator cap and put the thermometer in the coolant and start the truck compare what the thermometer reads and what it shows on the dash or what ever gauge you use. as the coolant warms up check and compare. when you see good coolant flow what temperature is the thermometer and you gauges. If you find the 2 reading are off make sure you temperature sensor in the intake isnt using and thread sealants that will interrupt a good ground path.

I am assuming that even though the temperature reaches 230 F your not popping the radiator cap and boiling the coolant? What pressure radiator cap are you using?

 

[nickeboy]

I had the same issues with my Bronco. I, like you tried everything. The one thing that seemed to make the biggest difference for me, was keeping the hot air from recirculating. I made cardboard cutouts for top and bottom of the radiator. Just like this

https://www.wildhorses4x4.com/product/Stainless-Air-Dam-with-Built-in-Tool-Tray/newproducts-EB

It made a world of difference so, I bought it from Wild Horses. Next I want to get the mesh air dams for the inner fenders and probably a fiberglass hood with airflow to get more heat out.

 

[Timmy390]

On my drive in a ton of traffic this am, it’s a little cooler out, and I got 187 at the highest, currently sits around 180. I’m perplexed

Were you running the A/C?

Define "cooler out"

How hot is it getting when it's "overheating"? Mine runs 210ish all the time in he summer.

Isn't that Ron Davis Radiator thicker and more dense than stock?

Just thinking thicker and more dense with an A/C coil in from of it would equal low air flow.

Tim

 

[hucklburry rev2]

The question that goes through my mind was the engine rebuilt? Head gaskets on correctly? I don't know if that fits the symptoms of overheating at idle but not driving, just thought I'd ask

 

[BoureeOne]

Are you running a fan clutch? Had an F250 that I chased a sitting at red lights over heating issue. Finally realized the fan clutch was bad.

 

[Nevadasmith]

Have you checked the temp gauge??? Are you sure it is overheating? I just replaced my factory temp gauge. The old on died in the meantime I was using a cheap AutoZone mechanical, it read 200f when I was ideling my non contact thermometer, and a contact one on my multi meter but agreed it was 170f, then new gauge I put in the factory cluster, reads 175f ..... I've seen gauges off 30* before, and my temp gauge reads 150f on the highway and climbs rapidly while I'm ideling...... Just something to double check????

 

[DirtDonk]

We're just re-hashing all the same things as before it sounds like.
Maybe you should tie this into your other threads instead of starting another one. I know it's good to get fresh ideas, but it's also good to be able to go back over what was already thrown into the ring to make sure we're not duplicating the effort.

I don't remember if you said you confirmed the gauge readings or not.
I doubt it's a thermostat issue, because it reacts so quickly to going faster. Does it also cool down just from reving up the engine but not moving?
I doubt that it's a thermostat issue also because it does not heat up when you have the hood open. That's a classic air flow issue. Not even coolant flow, just air flow.

If you can pull a piece of cardboard up to the front of the radiator at idle, you're pulling enough air for most engines to run cool.
Sounds to me like a tuning issue. Have you advanced the timing a few degrees just to see what's going on? I know we talked about it before, but I don't remember what you said you did.
If you're having issues with pinging at the higher timing advance settings, disconnect the vacuum advance temporarily and see if that helps.

How old is the distributor? That one of the new parts you mentioned?

Maybe at least post links to any other discussion threads you have going on to make it easier to reference what's already been done.

Thanks

Paul