first early bronco.... cooling problems.

[Illinois73]

Hello everyone. Im new to the community and wanted to introduce myself and ask for some help with the cooling system on my first EB.After owning 78/79 broncos and pick ups for the last 16 yrs i finally got a EB i always wanted. Bought my 73 from arkansas about 5 yrs ago. All orig. pretty clean and just worn out. Put it in storage for 3.5 yrs while i finished other projects. 18 months ago i finally pulled it out just to get to know it and tinker with it. well u guys know how that goes. replaced 302 with FI 5.0, rebuilt c4 ,fuel system, axles, wiring,suspension and cooling system. Finally got it up and running and after a few short idiling sessions checking fluids and what not i let it run a bit longer and temp started to rise and hit 230. let it cool and it did it again. thought maybe t-stat was bad out of box so i replaced it with 192 from ford. Still did same thing. Its got flow cooler pump, ron davis radiator, stock type shroud and bcb 17in. narrow blade fan. motor is has stock internals and stock pulleys. used infared gun and shot water neck and cylinder heads and gauge seemed pretty close. inlet to rad is reading 100 degrees hotter than leaving side. Its like im not getting flow. Ran it with cap off and didnt see much flow when t-stat opened. Its killing me not to drive it after all this time. Any help would be appreciated. thanks

 

[bronco-billy-66]

Are you running V belts? Are you running a standard rotation waterpump/fan?

 

[NicksTrix]

fan sucking air through the grill?
welcome to the site.

 

[broncnaz]

Welcome
Do you have anymore info on the engine? has it ever been rebuilt? other history on it? I'd double check that you have the correct fan.
I'd ditch that flowcooler pump and just get a stock water pump for your engine. I know several people that actually had engines run hotter with them. The bronco cooling system is small to small for a high flow water pump IMO.

 

[Illinois73]

Thanks for the welcome. Running serp.system. reverse rotation pump and fan put paper up to grill and sticks to it. Finally drove it around the block the other day and temp went up quickly to 230.

 

[Illinois73]

Not rebuilt but good running used engine i got and had a good friend reseal everything when he was slow from work and i was swamped.Asked about head gaskets being on wrong. said he was very careful of the water pass.lining up. Hope hes rite. pulled pump and took look pump then got a ford racing stock .flow pump today from summit. its exactly the same casting, impeller, everything except flowcooler put a round plate on the impeller. dont see how its high volume over the stock replacement. so similar i dont know if its worth trying. just got off phone with jason at BCB. Fan seems rite. hes stumped. seems like somethings blocked with the way the inlet side to radiator is so cool but yet motor is screaming hot.

 

[rsharpnm]

Sounds like you've done all the diagnosing you can do... I'd suggest trying another water pump for giggles, and making sure the rotation is right for the engine. If that doesn't work... I'm stumped. You may have to check those dang head gaskets.

 

[broncnaz]

X2 Hate to say it but it may be those head gaskets.
basically that little plate on the impeler is all that makes it high flow you can do it to any water pump for about $10

 

[bronco-billy-66]

X's 2 on the head gasket being on wrong...Bummer

 

[Illinois73]

Trying to think this out. If head gaskets are on wrong, pump is still gona circulate coolant just not through passages surrounding the cylinders causing it to overheat. So the fact that the inlet and outlet are a 100 degrees different may be right but coolant isnt getting where it needs to go. The driver side rad. tank (inlet to pump) being as cold as it is still has me confused. what radiator can cool 100 degrees from inlet to outlet?

 

[77BRONKOTN]

Air pockets are notorious in our trucks. If you take the stat back out drill holes in it let air weep past it while it's not open.

Coolant mix?

 

[JWMcCrary]

I'm thinking head gasket on backwards also. The part where he says he was careful to line up water ports is a red flag, he should be installing based on how they are marked, front goes to front. I have experienced head gasket on wrong and it gets hot quick and builds a lot of pressure.

 

[Justafordguy]

It may be the head gaskets but I'm thinking thermostat in backwards? If your sure it's in right maybe take it out and boil it in a pot on the stove to make sure it's opening. I don't think any radiator is going to drop the temp 100 degrees, they just aren't that efficient. Sounds like you aren't getting any water flow.

 

[Illinois73]

yea t-stats in right and i did boil it both times ive had it out and it opened and closed with in range. id say open was about 1/4 to 3/8 when fully open. waterflow is definitely what i was thinking thats why i was gona try another pump before i tear into the head gaskets. But after all the gasket replys im really starting to wonder. never had a problem like this on any of my previous rigs. very frustrating.

 

[Justafordguy]

Maybe try it without the thermostat? Can you see water flow with the radiator cap off?

 

[rustbucket]

100* difference is too much. Hell, that makes it room temperature down here is MS! Are you sure the t-stat is on right? Something must be restricting flow.

 

[Rox Crusher]

Welcome
I'd ditch that flowcooler pump and just get a stock water pump for your engine. I know several people that actually had engines run hotter with them. The bronco cooling system is small to small for a high flow water pump IMO.

I recently took my FlowKooler pump and replaced it with stock one form parts store.

Suddenly my engine was running 15 degree cooler.

 

[Slim]

Is the RD radiator new or older? If older is it clogged with mud, dirt, leaves, etc? Maybe pull the both radiator hoses and verify there is no shop rags, debris, tools, etc accidentally clogging or misplace while engine rebuilding.

 

[Illinois73]

Maybe try it without the thermostat? Can you see water flow with the radiator cap off?

Havent tried it without therm yet. Did run with cap off and flow was there but very little at just above idle. Thats why i pulled pump cause seemed like it wasnt flowing.

 

[Illinois73]

Is the RD radiator new or older? If older is it clogged with mud, dirt, leaves, etc? Maybe pull the both radiator hoses and verify there is no shop rags, debris, tools, etc accidentally clogging or misplace while engine rebuilding.

Rad is new as is everything else. everything is apart right now. i flushed rad- free flowing. checked hoses- all clear. gona replace flowcooler pump with stock style pump and reassemble everything this weekend and give it another go. let you guys know what happens. If its doin the same thing i'm gona have to pull the heads. What else could be left?