Still running close to hot

[tampabronco]

Replaced the corroded radiator with a new one, added a fan shroud, new hoses and still running 200 with a 180 thermomstat. The sensor seems to be working correctly

Guessing the water pump is bad....

 

[blubuckaroo]

I don't think I have ever seen a water pump cause overheating, unless it leaks.

What's the history with the car? Has it always overheated on you?
The reason for my questions is to eliminate that a previous owner may have put a head gasket on backwards. It's more common than you might think. Some think that both head gaskets need to be assembled "pretty side up" and then end up running hot.

 

[tampabronco]

It's recently started running hot

Everything else is new but the pump. There was lots of rust in the system so I'm just guessing at this point

 

[BUCKWILD]

So 200 is not bad, 220 is still ok, i would not worry to much if is constant 200 it will be ok. some more info on your engine will help with diag but i wouldnt sweat 200

 

[spap]

I have seen the impeller on water pumps pretty rusted to the point of not having all the fins on them. If it’s been there for awhile just replace it, one less things to worry about. If the radiator was so rusted you had to replace seems like they just ran water through the system and not coolant
Running 200 now wait till the weather gets hot

 

[DirtDonk]

The sensor seems to be working correctly

What does "seems to be" mean? have you verified 100% that the gauge is reading the exact temperature (or at least within five degrees) of reality by comparing with a known good gauge and sender? Or at the very least using an infrared thermometer, or basting thermometer in the filler neck?

Guessing the water pump is bad....

Possible, but kind of a long shot as blu was saying. I've seen them cause trouble, but by that time they were so far gone that the impellers were half worn down.
However, if you did not check yours while it was apart, it's possible you missed a dying impeller from rusting off to almost nothing. Rust is a killer sometimes.

Just how bad was the rust? If bad enough it can actually effect the heat transfer to the coolant as well. Not just from the surface coating itself, but by disrupting the flow in critical areas.
If there is any doubt, I would run some Thermo-Cure (by Evapo-Rust) through it for a week or more and then re-flush the system. Before you just throw another part at it.

It's also possible that your pump was just a very poor design if it was a more modern aftermarket (cheap Chinese) replacement. But doubtful even that would be enough to cause your issue. Just not out of the question either.
It would take a pretty piss-poor design, since they've been making even cheap ones perform just fine for getting pretty close to 100 years now.
Any cheap replacement should work if it's got a decent impeller, but I'm a fan of Flowkooler long before I started selling them, so whenever I have a pump off I just go big bucks and buy what I feel is the good stuff.

Other issues can be ignition timing and overall tune, ignition quality, carburetor jetting, choke not functioning properly, defective or under-performing thermostat, wrong size pulleys,hard use under hard conditions (is this an automatic trans, with big tires and stock gearing by any chance?) and probably a few other things.
Definitely not just the few things you've replaced, but they can contribute.
We've found that in general a Bronco that is having a very consistent and repeatable condition of running even just slightly hot is not going to be cured by adding a shroud. It takes other things working properly too.
But a shroud is always a good thing anyway, so even though it was not your issue in this case, it's better that you have one on there now.

Good luck.

Paul

 

[DirtDonk]

Oh, and what radiator did you use, and what fan setup are you running? Fans can make a big difference if they're not stock.

I also forgot to mention another important aspect. Your new engine.
Just how new is it, and what was done to it?
Is it still under 1000 miles on the rebuild? Is it over-bored? Is it cammed now?
These are extremely important points to take into account.

And I think it was already asked, but was it acting like this before the rebuild? If so then a problem with the build is less likely, but still not out of the running yet.

Paul

 

[tampabronco]

It's an 11 year old reman w/ 11000 miles. The motor was blown when I bought it. It always hovered around 180 and hot GA summers it would creep up to 200 when I doling at a drive through. The old heater core was full of rust crud and heater valve was rusty mess so I replaced both.

It's the water pump that was installed on the motor 11 years ago. It's not wabbly or leaking. I'm going to test the sensors ago. I should have just replaced the water pump when I had it broken down

 

[Mikesimp70]

Replaced the corroded radiator with a new one, added a fan shroud, new hoses and still running 200 with a 180 thermomstat. The sensor seems to be working correctly

Guessing the water pump is bad....

I run 197-204 regardless of time of year. 105 outside or 35, I am between 197-204.

I run a motorcraft 195 degree thermostat.

Mike

 

[DirtDonk]

It's an 11 year old reman w/ 11000 miles. The motor was blown when I bought it.

The old heater core was full of rust crud and heater valve was rusty mess so I replaced both.

Well the good news then is that at least when that was done the engine block was not a rusty mess. If you de-rusted the rest of the system back then, I'd say rust was not an issue.
But since you just recently replaced those other items, it's very possible that the engine block has at least some minor rust buildup. Perhaps naturally, or perhaps just as residue from the other older items passed through the cooling system.
If just passing through, then the basic flush you gave it all when swapping the parts should have cleaned it up. However if it was really built up, or if it was created more recently, then the engine should still be flushed I would say.
Cheap insurance just to make sure that no unknown buildup of rust is still in the system.

It always hovered around 180 and hot GA summers it would creep up to 200 when I doling at a drive through.

Good. Sounds like it's run pretty well.
But I would still check the timing. Even with electronic ignitions it can change (thought not very often) but if it's an old distributor there's not telling how much wear and tear have changed the timing.
Best to check and maybe even give it a good tune up. We're spoiled these days with 100,000+ spark plug changes, but with our old stuff it's not out of line for things to change in that 11,000 miles.

It's the water pump that was installed on the motor 11 years ago. It's not wabbly or leaking. I'm going to test the sensors ago. I should have just replaced the water pump when I had it broken down

Most likely yes, but it's not out of line to expect to get another long life out of an old component. But yes, changing it would have saved you a lot of trouble even if the pump is not the heating issue.
But with the rust description, it's not out of line to at least pull it off and inspect it. But at this stage and age in it's life, if you're going to go to the labor of pulling it off, then yes I'd say replacing it is your best option.

With all the potential rusty, gritty coolant running through the system over the years, it's not out of the realm of possibilities that the pump impeller has been damaged. Like said, it's not a common issue, but it does happen. So you can't ignore the possibility.
Very interested to see the old one when you get it off. It might still be good, but it would be almost a relief to see it's been ground down to a stump!

Did anyone watch the recent episode of one of the Power Block shows where they opened up an engine that was working and staying relatively cool and found an old shop rag wadded up in the water pump? Wow, what a mess!

Good luck.

Paul

 

[maverickconner]

Just a thought, if your running a 195 thermostat, try the 180.

Also lots of issues with rust and corrosion blockage. If it starts overheating, be concerned that the passage side rear block to head flow chamber is clogged. It happens frequently without putting in a rear crossflow on the intake manifold. If you pull the right head off you would see the rear channel would be totally clogged.

 

[Rustytruck]

pull the thermostat they are not all created equal I prefer a Robert Shaw High performance thermostat they are fully open at rated temperature. make sure your idle speed isnt set too low. use a 16 lb pressure cap to push boil over point up and make sure you use a coolant recovery tank and fill the radiator full. Block air openings around the radiator so air is forced in through the radiator and hot air is not sucked in around the radiator. the factory 7 blade fan is best.

 

[Timmy390]

Thermostats have a “rated” temperature such as 180F or 195F
This is the temperature the thermostat will start to open, give or take 3 degrees
The thermostat fully open about 15-20 degrees above its rated temperature

Tim

 

[bronconut73]

I'm sure everyone is tired of me saying this...
But that 96 to 01 Explorer Serpentine swap cured many issues for me including running hot.


For 20+ years my rig ran hot but didn't overheat.
I have multiple temp gauges to verify that my Autometer gauges are accurate.
In central Florida summer heat during afternoon traffic it would get up to 235 to 240 degrees. Never completely over heated or puked coolant but just too hot for me.
I began a 15 year mission to get it to run a little cooler in traffic. I'm okay with 200+ degrees but 240 is just too much for me.
I did all of the stuff we do/did in years past.
4 core Duff rad,
Brassworks water pump (Flowkooler wasn't around yet),
Real small BC water pump pulley,
Real big BC crank pulley,
Added an electric fan,
Added an electric fan and hd mech. fan,
Stock style shroud,
Pulled tranny fluid from rad,
And on and on and on...

Although I'm sure it all helped incrementally but not a big enough change to give me a cushion of grace regarding over heating in summer time traffic.

I know it's a big step to take on the Explorer Serpentine swap....And I took a year to acquire parts and the brackets from Sandmann here on CB but I am sure glad I did. Cured so many issues and now I barely can crack 200 degrees with a 195 t-stat. Real hard-core mudding got me up to a whopping 212 one day. I am pleased.