• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

440 Running Warm - Why

Yes, but the stat is not your problem. I really think you need to look at that radiator, I bet that's the culprit.
 
Radiator, fan type, fan spacing from radiator, lower hose collapsing. Could be any, or all, past the thermostat. Easily decided by the way the cooling system is set-up.
Why don't you try without a thermostat, for a run, or two, and see what it does. Not going to say it will cool the system down, but might tell you if you have other problems.

In the day, used to run without a thermostat, if a heating problem was in play. Sometimes, the dang thing would run too cold.
Look at the overall picture, to find out what's going on...including the higher RPMs.
 
miller said:
Radiator, fan type, fan spacing from radiator, lower hose collapsing. Could be any, or all, past the thermostat. Easily decided by the way the cooling system is set-up.
Why don't you try without a thermostat, for a run, or two, and see what it does. Not going to say it will cool the system down, but might tell you if you have other problems.

In the day, used to run without a thermostat, if a heating problem was in play. Sometimes, the dang thing would run too cold.
Look at the overall picture, to find out what's going on...including the higher RPMs.
Click to expand...
When someone has been through all the hair pulling, wasted money on ineffective parts, all that jazz chasing down a problem, you want to help anyone else who then is going through it after you.
I sure did. Been there.
I wound up addressing every contributor in the cooling system and wound up with one that uses partly factory parts and whole lot that isn't remotely factory.
180 SuperStat with holes drilled for "burping" trapped air, massively efficient Griffin aluminum radiator, factory shroud, generic 18" directly driven fan, spring in lower hose to keep it from collapsing, 8 impeller water pump, it ALL got addressed.
Overkill? Sure, but you know what? The results aren't overly dramatic; the engine still is capable of getting close to 200F in hot weather stuck in standstill traffic.
Bottom line is these 440's are capable of making a massive amount of heat, probably a result of the design of the engine to begin with.
 
moparedtn said:
Straight from the FSM for '68 models, Cooling section 7-9.
As a matter of fact, I don't recall even being able to get a higher degree thermostat for these back in those days; those came later, like mid 70's?
Click to expand...

The OP's car is a 70, which states 190, like I said. That said, IMHO, 180 is high enough for proper coolant and oil operation. 190 puts you too close to the red zone. Interestingly, rock auto shows a 195 as OEM for a 69 HEMI roadrunner

moparedtn said:
Correct, sort of. Once the engine gets to the temperature rating of the thermostat, it opens. It doesn't know if you're sitting still or hauling down the freeway, it's temperature sensitive, as explained in the FSM above.
Click to expand...

I know how a stat works. My point was clear - please reread before correcting me. Based on the symptoms and the fact that the car stays cool at idle, the stat isn't the problem.
 
HT413 said:
The OP's car is a 70, which states 190, like I said. That said, IMHO, 180 is high enough for proper coolant and oil operation. 190 puts you too close to the red zone. Interestingly, rock auto shows a 195 as OEM for a 69 HEMI roadrunner
Click to expand...
Agree with all that and although Rock is a good source of parts and info sometimes,
this is an example of where they're wrong.
Might be a 190 isn't even made anymore?

I know how a stat works. My point was clear - please reread before correcting me. Based on the symptoms and the fact that the car stays cool at idle, the stat isn't the problem.
Click to expand...
Not correcting as much as clarifying your statement for others. You said:
at idle it opens and keeps the engine regulated.
Click to expand...
that could be misconstrued, obviously - the stat doesn't open as a result of the engine idling, of course.

We're in agreement with what is happening with the OP's situation, of that I'm sure. :thumbsup:
 
I have and have run 6packs all my life,I'm 59, the factory recommends a195 for a 440/6, I've run my Bee with no thermostat ,also taken out the middle of the stat and leave the housing in,on any hot day that 440 will be hot, just feel the heat through the fire wall!! 200 for that car is ok,if it bothers you go for a BE COOL Or a CHAMPION RADIATOR and away YOUR TROUBLES DOWN THE DRAIN!!!
 
Thank you all, looks like we have a consensus that not enough radiator is the cause of the problem?
 
MoparHonda said:
Thank you all, looks like we have a consensus that not enough radiator is the cause of the problem?
Click to expand...

Rad swap is last. Lots of good advice up above. First, give the lower hose a squeeze and feel if there is a spring in it. If not, that's your problem.

Have you drained it and checked for scale / rust? Take a look.

Maybe I missed it, but what are you running for fan? As was stated up above, perhaps your fan clutch is slipping? To check, get the car up to temp and shut her down and try to spin the fan (use gloves, its hot!) The clutch should give you serious resistance.

Just before buying the rad, try some water wetter / coolant additive. It might work for ya.
 
HT413 said:
Rad swap is last. Lots of good advice up above. First, give the lower hose a squeeze and feel if there is a spring in it. If not, that's your problem.
Click to expand...
Not so fast, not entirely accurate. I've never ran a spring, never had a lower hose collapse. Zero new cars run springs in hoses, haven't seen those since the late 90's/ early 2000's. Honestly never even heard hard facts as to why they're there in the first place, too much opinions on that. If the lower hose is collapsing you have something wrong causing that to happen. The fact that he's "only" reaching 200 at Hwy speeds, I think his car is working just fine, we're just chasing to shave off a few degrees .....
 
65-440 said:
Not so fast, not entirely accurate. I've never ran a spring, never had a lower hose collapse. Zero new cars run springs in hoses, haven't seen those since the late 90's/ early 2000's. Honestly never even heard hard facts as to why they're there in the first place, too much opinions on that. If the lower hose is collapsing you have something wrong causing that to happen. The fact that he's "only" reaching 200 at Hwy speeds, I think his car is working just fine, we're just chasing to shave off a few degrees .....
Click to expand...
There are actually videos on YT right now of 440s on dynos sucking the lower hose collapsed; been there seen that, even on my own car.
I made a spring for it just for peace of mind, after having zero luck finding one online (other than from that wonky Mustang parts supplier).
 
A stainless tig rod is perfect for making a spring in the lower hose.
 
moparedtn said:
There are actually videos on YT right now of 440s on dynos sucking the lower hose collapsed; been there seen that, even on my own car.
I made a spring for it just for peace of mind, after having zero luck finding one online (other than from that wonky Mustang parts supplier).
Click to expand...
I understand that, I've heard this many times. All I'm saying is if your hose is collapsing it's due to another issue. A spring is just a band - aid to cover the real culprit. I proper working coolant system will not allow a hose to collapse ....
 
65-440 said:
Not so fast, not entirely accurate. I've never ran a spring, never had a lower hose collapse. Zero new cars run springs in hoses, haven't seen those since the late 90's/ early 2000's. Honestly never even heard hard facts as to why they're there in the first place, too much opinions on that. If the lower hose is collapsing you have something wrong causing that to happen. The fact that he's "only" reaching 200 at Hwy speeds, I think his car is working just fine, we're just chasing to shave off a few degrees .....
Click to expand...

That's fair, I think we can agree though that replacing the radiator is certainly not the first step.
 
65-440 said:
I understand that, I've heard this many times. All I'm saying is if your hose is collapsing it's due to another issue. A spring is just a band - aid to cover the real culprit. I proper working coolant system will not allow a hose to collapse ....
Click to expand...
I'm not sure what could cause such (other than an old/soft hose itself, of course).
Restriction in the radiator?
My bottom hose is a new Gates and it's plenty soft, easily collapsed by hand.

We do know hoses pretty much had springs in them routinely "back when" and they don't now. Must be a reason.
 
Last edited:
HT413 said:
That's fair, I think we can agree though that replacing the radiator is certainly not the first step.
Click to expand...
All I'm saying is that if the car isn't getting "too hot" at idle, yet IS getting too hot cruising down the highway then that's a radiator issue, short of there being some huge air restriction getting through the radiator.
 
moparedtn said:
I'm not sure what could cause such (other than an old/soft hose itself, of course).
Restriction in the radiator?
My bottom hose is a new Gates and it's plenty soft, easily collapsed by hand.

We do know hoses pretty much had springs in them routinely "back when" and they don't now. Must be a reason.
Click to expand...
restriction, too much air in the system, or the most over looked item .... radiator cap ! If there was a restriction you'd definitely be running hot at idle though.
 
You must log in or register to reply here.

Similar threads

shrekomo
Power loss
2 3
Replies
44
Views
3K
shrekomo
shrekomo
Daytrepper
A/C Compressor "locking up" intermittently
Replies
3
Views
231
vance.dykes
vance.dykes
M
I love chrysler
Replies
12
Views
1K
Demonic
Demonic
DanJ
Overheating problem
2
Replies
25
Views
4K
Ron H
R
Dave383
Maybe there is high-flow thermostat for $10 for big blocks
Replies
1
Views
1K
multimopes
multimopes
Back
Top