Overheating wowes that make no sense - help!!!

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AUS_Duster

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Hi guys. I have a 71 Duster with a 100 mile 440. it has a Mopar prule cam and 10:1 comp.·

It was overheating with the old clutch fan and 26" original radiator. So i diched the lot!

I now have a new 440 Source housing and pump, 182 degree thermostat, a brand new 26" aluminium radtiator with twin thermo fans set to come on at 185 degrees. It running 33 degrees timing. It also has a seperate transmission cooler.

It is overheating and i dont knbow why. At 50 mph @ 2000 rpm the temp climbs up to 205-210 and just keep going to 215 and boils. I have veaired my spped and RPM to see if it gets coller if i go slower or faster. It doesnt seem to matter.

I am at my wits end.... I am tired of looking at the car too scraed to drive it in case it overheats - which it always does. Today it did it and the temp outside was only 75 degress.

Any suggestions???????????????
 
If it's overheating at 50 mph, it's not the fans or airflow through the radiator. You don't even need a fan at 50 mph.

Must be a flow (which could include air pockets) or a tuning issue.

Block could be full of crap. Coolant flow speed. Machining.

Yank out the thermostat and test it. Pan of hot water and a thermometer see if or at what temp it opens. That's something free and easy you can start with.
 
I have checked the thermstat and its ok. Block might be the cause but how blocked can a block get?
 
Ever heard of block fill. It the crap people pour in the block that they use to go racing with. Goes down the track and then shut it off Ive seen it done a lot (not my thing, I like to drive to and from the track). That or it didnt get tanked and cleaned before being rebuilt
 
mixed matched pulleys and water pump can cause overheating problems
if the water pump moves the coolant to fast, it doesnt have enough time in the radiator to cool off,
if the water pump is flowing to slowly the coolant isn't removing the heat from the engine fast enough
I have also had overheating problems when using electric fans, or a stock fan with a broken shroud
 
It was supposedly hot tanked. I bought it off ebay but I have a dyno video and the print outs so i have no reason to think it was a poor build.
 
I am using a 440 source pulley set so i wouldnt think they would be over/under driven. Although I am not 100% sure.
 
tuning can cause an engine to run hot, and as 1970Duster said if the block has been filled it is only usable as a race motor
 
Did you SEE the water pump? Inspect, consider a different pump

Are you sure your temp gauge is correct?

Are you sure the cap is holding pressure?

Air trapped in the block is NOT a big deal on these old engines. People are always suggesting drilling bleed holes in the stat. That's OK, but all you really need to do is yank one heater hose loose or a plug--you want the highest place you can get that is still UNDER the stat, fill until it comes out that point, then go from there

Timing--you sure your timing marks are OK? Bear in mind that a stocker that's cruisin with vacuum adavance runs out into the 50-50's degrees. I'd try running more advance. Mechanical only, about 40 is all you can push, I'd think.

And---how's your fuel? In this day and age........................

Last, get a chemical check (can't remember the name) at a rad shop for a seeping head gasket. It doesn't take but a small seep you might not be "aware" of to inject hot gas into the coolant, and cause puking out the cap.
 
First off, 215 ain't boiling. Not under pressure. What cap are you runnin? 16 pound? I forget the formula but it's like 3 degrees for every one psi. If that's right, that raises the boiling point to 260. If you're boiling at 215, I bet your radiator cap isn't holding pressure.
 
Thanks guys for your help. There are a few ideas there - i think ill start with the 440 source pump housing and the cap!

Cheers!!!
 
Did you install a bottom hose with a spring inside. High flow pump can suck the hose flat and cause overheating issues.
 
daredevil said:
Did you install a bottom hose with a spring inside. High flow pump can suck the hose flat and cause overheating issues.
Click to expand...
X2...... I sold a Beach Boys style 67' belvedere wagon with a slant six to buddy because of an overheating issue for cheap !
Right after we made the deal we popped the hood to have a look at the Leaning Tower of Power and while I was revin' the motor he says "hey that lower hose is collapsing when you rev it" ? and I'm like you gotta be bullsh*ttin' me , I just sold a car because of a $5 radiator hose ?

So take double D's advise and check dat' hose !!!
 
If the lower hose collapses, it MOST OFTEN is not a hose problem, but rather a restriction, like a plugged radiator. Someone mentioned you might have "block fill."

Friend of mine once had some heads exchanged, and the "new" heads had loose crap in 'em. Plugged the bottom of the rad. You could rev the engine--a 383--and it would suck the hose so hard it would BEND THE BOTTOM OF THE RADIATOR TANK
 
67Dart273 said:
If the lower hose collapses, it MOST OFTEN is not a hose problem, but rather a restriction, like a plugged radiator. Someone mentioned you might have "block fill."

Friend of mine once had some heads exchanged, and the "new" heads had loose crap in 'em. Plugged the bottom of the rad. You could rev the engine--a 383--and it would suck the hose so hard it would BEND THE BOTTOM OF THE RADIATOR TANK
Click to expand...

On my old belvedere wagon the spring had rusted away and my buddy just took a spring from a different hose and placed it in the slants radiator hose ? Problem solved .
The cooling system had good flow as observed in the tank with radiator cap removed .
 
crossram383 said:
On my old belvedere wagon the spring had rusted away and my buddy just took a spring from a different hose and placed it in the slants radiator hose ? Problem solved .
The cooling system had good flow as observed in the tank with radiator cap removed .
Click to expand...

You are missing the point. If nothing is clogged, you should not even need a spring. The pressure cap will expand the hose enough to keep it open. What's sucking it shut is what's important. In the case I posted, it damn near tore the bottom fitting right out of the tank.
 
Iwas just throwin it out there. Its nice when its something simple. Start with the easiest things first.
 
I have had the waterpump with a impeller that was loose on the shaft causing the shaft to freewheel during speed (impeller moving less or not at all) but would Idle fine. Took about a year to figure that one out in a 66 Valiant. The up side of this is I gave the owner $16 bucks for the car. Good luck and please let us know your findings.
 
My 69 bee with a 383 had alot of over heating issues. Turned out to be sediment in the bottom of the block. Didn't seem like much when I flushed it out but it was enough to restrict flow. I just pulled the hoses and thermostat and flushed it with a garden hose from the top and bottom. Problem solved for me.
 
a leaky radiator cap can cause all kinds of heating issues too, seems trivial but the pressure has to be held in the system to keet it from "boiling" ie (filling up your overflow tank)...test or get a new cap, flush the block....then the others advice about a head gasket may be the culprit..i agree the fan isn't it if the cars moving at 50 mph..new rad takes the blame away from it...so just take it a step at a time. good luck!
 
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