1970 Ford Bronco 302 - Radiator Replacement

[tonytony9]

Hi Everyone,


I am new to the Bronco world with my recent purchase of a 1970 Ford Bronco 302 w/ 3 speed manual. So far, I have been enjoying my experience on the forum and have received a lot of helpful feedback. I have been working on cars most of my life, although, I definitely consider myself an amateur eager to learn.

I am looking for any tips or advice on installing a new radiator. Current radiator is cracked at the overflow tube and loosing coolant. PO supplied a Tom's Offroad Working Man #6370 in the box that I would like to get installed this week. Since the Bronxo did not come stock with an overflow tank, is there a way to retro fit one to this system?

Any tips, advice on flushing the system, recommended coolant (assuming just a 50/50 mix from autoparts store), general process. Links to existing threads.

Need to buy a new radiator cap, I am assuming its a 13lb. Also, considering buying new bracket bushings from Tom's. Hoses look new.

On all of my drives, 55 mile max drive, temperature on the gauge sat between 120 and 170 and has consistently sat between those the past few weeks of ownership. I have had to top off the coolant once or twice.

https://tomsoffroad.com/parts/66-77-ford-bronco-3-core-aluminum-radiator

Thank you!

 

[gnpenning]

IF your gauge is correct you are running way to cool. If you have a IR temp gun double check your gauge reading.

You need to be checking your thermostat if it has one and you can put it in a pan and heat up for opening temp. Really not hard to do.

Do you have a fan shroud?

I would flush the cooling system while you have it down. Make sure to get the heater core.

Do you have a functional heater valve?

Now is a good time to go over everything coolant related

You can add a over flow tank if your choice. A popular one is the coolant and washer bottle combo. Ford used on trucks etc. The vendors and junkyards have them.

 

[tonytony9]

IF your gauge is correct you are running way to cool. If you have a IR temp gun double check your gauge reading.

You need to be checking your thermostat if it has one and you can put it in a pan and heat up for opening temp. Really not hard to do.

Do you have a fan shroud?

I would flush the cooling system while you have it down. Make sure to get the heater core.

Do you have a functional heater valve?

Now is a good time to go over everything coolant related

You can add a over flow tank if your choice. A popular one is the coolant and washer bottle combo. Ford used on trucks etc. The vendors and junkyards have them.

Good checks, planning on all. Thank you. What temp should it be running at?

I need to check which thermostat I have. Not sure which temp it is. I do believe I have a fan shroud.

 

[gnpenning]

The red sticker saying "caution fan" is attached to your shroud.

Can't tell you what temp it should be running with out knowing what temp your thermostat is.

Most modern vehicles are in the 195° range. With a good cooling system that should work well. Motors like a warmer temp to a point.

 

[bulletpruf]

It would be helpful to know where you live and what temps you're driving in. Are you in Key West? Anchorage? Somewhere in between?

Also, is this all highway driving?

Whatever the case, it does sound low. I wonder if you have a 160 degree thermostat installed or maybe no thermostat at all. One of the problems with an engine running too cool is that it doesn't warm up enough to get rid of the sludge that forms internally, so that can have a detrimental effect over time.

I also agree with using a laser temp gun (maybe $10 at Amazon?) to verify what you're seeing on your gauge.

As far as the radiator swap goes, should be an easy job - drain coolant, remove radiator, install new radiator, fill with coolant. It's been a while since I did a radiator swap, so I don't recall how difficult it is to remove the fan or the shroud, but one will have to be removed to get this done. 50/50 green coolant from the auto parts store will be fine.

 

[DirtDonk]

When doing any maintenance on any cooling system part, I always fill it with 100% water first.
That way, if anything leaks, or if you need to remove something to redo it, not only are you not out the extra money for the antifreeze, but you’re not out the time it takes to clean up the big ugly mess!

 

[tonytony9]

It would be helpful to know where you live and what temps you're driving in. Are you in Key West? Anchorage? Somewhere in between?

Also, is this all highway driving?

Whatever the case, it does sound low. I wonder if you have a 160 degree thermostat installed or maybe no thermostat at all. One of the problems with an engine running too cool is that it doesn't warm up enough to get rid of the sludge that forms internally, so that can have a detrimental effect over time.

I also agree with using a laser temp gun (maybe $10 at Amazon?) to verify what you're seeing on your gauge.

As far as the radiator swap goes, should be an easy job - drain coolant, remove radiator, install new radiator, fill with coolant. It's been a while since I did a radiator swap, so I don't recall how difficult it is to remove the fan or the shroud, but one will have to be removed to get this done. 50/50 green coolant from the auto parts store will be fine.

The red sticker saying "caution fan" is attached to your shroud.

Can't tell you what temp it should be running with out knowing what temp your thermostat is.

Most modern vehicles are in the 195° range. With a good cooling system that should work well. Motors like a warmer temp to a point.

When doing any maintenance on any cooling system part, I always fill it with 100% water first.
That way, if anything leaks, or if you need to remove something to redo it, not only are you not out the extra money for the antifreeze, but you’re not out the time it takes to clean up the big ugly mess!

Great advice all around. I am not sure if or which thermostat temp I have. I will get an IR to see if gauge is accurate. I think I am going to go down the route of having my stock radiator rebuilt/fixed based on advice from other threads. I put some jb weld on the overflow tube temporarily so that my coolant is not spraying on my battery.

I am also considering having my water pump replaced (plus thermostat if its incorrect) and then rebuilding the heater box (new core, new heater valve, new heater blower)

 

[BroncoJimbo]

I believe repop overflow tanks are available from the usual suspects. You don't need a special t-stat but avoid getting one that is too cool. Mine is a 180* and works fine in the GA heat. A new water pump is a good idea. Buy a quality one (Flowkooler, Weiand) since it's a job you don't want to do twice.

 

[DirtDonk]

Speaking of not doing it twice… How many miles on the engine?
Has the timing chain ever been replaced? Yes, that question is leading down that rabbit hole that we all fall into sometimes.
If you are that close, and your engine has 100,000 miles on it, my feeling is you might as well just go in and replace the timing chain.
I did it once on an engine that had only 40,000 miles on the timing chain.
The engine itself had about 140, but I figured I was in there anyway, parts were only 25 bucks, and my labor came cheap.
So I spent the extra time and did it.

 

[tonytony9]

Speaking of not doing it twice… How many miles on the engine?
Has the timing chain ever been replaced? Yes, that question is leading down that rabbit hole that we all fall into sometimes.
If you are that close, and your engine has 100,000 miles on it, my feeling is you might as well just go in and replace the timing chain.
I did it once on an engine that had only 40,000 miles on the timing chain.
The engine itself had about 140, but I figured I was in there anyway, parts were only 25 bucks, and my labor came cheap.
So I spent the extra time and did it.

Oh man don't push me...but this is a good idea. Mileage, lets assume the conservative assumption that the timing chain probably could use the work.

Forgot to mention, my Bronco will mostly be in an environment between 30-90 F on average. However, might spend a portion of its life in Florida. Either way, I want a proper cooling system that will prolong the usability and keep my engine safe.

Would you all agree, rebuild rather than replace with the Tom's radiator PO gave me?

I believe repop overflow tanks are available from the usual suspects. You don't need a special t-stat but avoid getting one that is too cool. Mine is a 180* and works fine in the GA heat. A new water pump is a good idea. Buy a quality one (Flowkooler, Weiand) since it's a job you don't want to do twice.

Thank you, I will check out these brands.

 

[DirtDonk]

Oh man don't push me...but this is a good idea. Mileage, lets assume the conservative assumption that the timing chain probably could use the work.

Just so you know, the Cloyes double roller timing chain that I replaced at about 40K, was shockingly loose and sloppy compared to when it was new.
I was already going to replace it, but that just cemented it for me. Made me feel better about my decision!

Forgot to mention, my Bronco will mostly be in an environment between 30-90 F on average. However, might spend a portion of its life in Florida. Either way, I want a proper cooling system that will prolong the usability and keep my engine safe.

You’re on the right track. Any pump will get the job done, but there’s nothing wrong with using this opportunity to spend a little more and upgrade to one of those recommended previously.
Any of the performance pumps that utilize a better impeller design will benefit you in the long run. More flow volume, more flow pressure, and less horsepower used. All good things.
You may not see it run cooler than the thermostat temperature, but if it overheats, it won’t be due to the pump!

Would you all agree, rebuild rather than replace with the Tom's radiator PO gave me?

I can’t see a negative either way, other than cost.
If you already have a new radiator, I would at least utilize it now and then consider having your original refurbished at your leisure.
I suppose It’s possible that the original was made to higher standards than any of the modern stuff, but it’s also possible for a new radiator to be very good and give good service.
Your choice at this point.

 

[tonytony9]

Just so you know, the Cloyes double roller timing chain that I replaced at about 40K, was shockingly loose and sloppy compared to when it was new.
I was already going to replace it, but that just cemented it for me. Made me feel better about my decision!

You’re on the right track. Any pump will get the job done, but there’s nothing wrong with using this opportunity to spend a little more and upgrade to one of those recommended previously.
Any of the performance pumps that utilize a better impeller design will benefit you in the long run. More flow volume, more flow pressure, and less horsepower used. All good things.
You may not see it run cooler than the thermostat temperature, but if it overheats, it won’t be due to the pump!

I can’t see a negative either way, other than cost.
If you already have a new radiator, I would at least utilize it now and then consider having your original refurbished at your leisure.
I suppose It’s possible that the original was made to higher standards than any of the modern stuff, but it’s also possible for a new radiator to be very good and give good service.
Your choice at this point.

Thanks will check out the pump recs. Would rather spend up to spend once. Any recs for a thermostat? I assume I should be looking for a 190 F.

 

[DirtDonk]

That's what I would use, rather than the 180. The 180 for a minimum, but 190 preferred.
Actually, they're typically rated more in the 192 to 195 range if I'm not mistaken, but close enough for government work.
I don't remember any reports of vehicles over heating in hot weather just for the use of the higher temp rated thermostats. Just that they allow the engine to warm up to a better/higher operating range under normal conditions.
So as long as everything is working as intended, the higher temp for the happier engine. Usually...

Paul

 

[tonytony9]

That's what I would use, rather than the 180. The 180 for a minimum, but 190 preferred.
Actually, they're typically rated more in the 192 to 195 range if I'm not mistaken, but close enough for government work.
I don't remember any reports of vehicles over heating in hot weather just for the use of the higher temp rated thermostats. Just that they allow the engine to warm up to a better/higher operating range under normal conditions.
So as long as everything is working as intended, the higher temp for the happier engine. Usually...

Paul

Thanks for your advice. I believe I am just going to go with a Motorcraft thermostat, unless there are better brands. I guess Auto Parts store will carry.

 

[DirtDonk]

I like the Robertshaw, full flow type myself, but they’re not on every shelf. And they’re not 100% needed, just nice to have.
But unfortunately, with the quality of parts these days, I wouldn’t install any auto parts store stuff unless I tested it on the stove first.
Put it in a pot of water and make sure it does it’s thing at the prescribed temperature.
If it was an old Chevy engine, I’d say don’t bother. But changing a thermostat on our engines is just awkward enough to make it a pain. So I say always test them first.
No matter what brand.

 

[tonytony9]

I like the Robertshaw, full flow type myself, but they’re not on every shelf. And they’re not 100% needed, just nice to have.
But unfortunately, with the quality of parts these days, I wouldn’t install any auto parts store stuff unless I tested it on the stove first.
Put it in a pot of water and make sure it does it’s thing at the prescribed temperature.
If it was an old Chevy engine, I’d say don’t bother. But changing a thermostat on our engines is just awkward enough to make it a pain. So I say always test them first.
No matter what brand.

Makes sense, and easy enough. Went to Harbor Freight picked up the laser thermostat. Tried to grab readings on a few spots. This is after a 20 minute drive, engine still running. This matches up with my dashboard gauge reading, just about 170 little under. Ive never seen it run below or above that temp on any drive. Unless of course it was warming up. I have not been stuck in traffic and this is also driving in about 50 degree weather, lowest probably high 30s.

 

[DirtDonk]

That’s actually the best news so far! The fact that your gauge is reading correctly, is a great sign.

 

[m_m70]

That's about where mine runs in the cooler months and around 190 when it warms up in the summer.

 

[tonytony9]

That’s actually the best news so far! The fact that your gauge is reading correctly, is a great sign.

Which way does the RobertShaw Thermostat attach to the housing? Different design than I am used to seeing, typically, I would want to drill a little breather hole on the top, and face the spring into the intake manifold. This way, the plate which opens is facing the housing. I would use a bit of RTV on both sides of the paper gasket, a little RTV on the thermostat so it holds onto the housing when I attached it to the housing. Same procedure for the RobertShaw, minus drilling a breather hole? I am planning on doing this today. Will grab the Shaw if available, otherwise one from the AutoParts store and will install after I test on the stove.

The original Robertshaw 330 series hi flow thermostats

Why Robertshaw? Because we make a hi flow pump and its unique three port construction or "balanced sleeve" design equalizes the system pressures above and below the thermostat’s moving valve. Therefore the thermostat is pressure balanced and will respond to system temperatures only. No other...

flowkoolerwaterpumps.com

That's about where mine runs in the cooler months and around 190 when it warms up in the summer.

Thats interesting and good to now I am not the only one. I am still going to open up the housing and check it out. No idea what PO had or does not have in there. Housing looks new.

 

[m_m70]

I am still going to open up the housing and check it out. No idea what PO had or does not have in there. Housing looks new.

smart