Temp climbs at speed

[Dmichels]

Car 440 mild build 410 rear 4 speed. Stock cooling system in good shape. cruise rpm is 3000. 180 thermostat It was hot today 90f I am using the stock gauge so I do not have a real number, but I can see the needle creep up. Not crazy fast but I saw it climb in a 20 min run on the highway. Car did not overheat. I got the feeling I was pushing the capacity of the cooling system. any thoughts?
Thanks Dave

[69wannabe]

Do you have a spring in the bottom radiator hose, if not it maybe sucking the hose together at highway speeds!! I just put a milidon 180 degree high flow thermostat in my big block. They are bout double the cost of a regular one but they do work better too. just a couple of things to consider!!

[Dmichels]

Yes I have a spring in the lower hose. I had a high flow thermostat that failed out after about 5 hours running left me stranded. I saw it was made in China and went back to stock, which should be ok.

[A383Wing]

partial plugged radiator? What size is radiator?

[Dmichels]

26 inch recently boiled out

[tan top]

what the other guys say 

what water pump housing you got ? 
what about water pump ?  correct pulleys ?
fan belt slipping  although prolly would know all about ,  any more than just momentarly , when nailing the gas .




  , also would not trust stock gauges even rebuilt ones  ,  fit a  mechanical one 

[Dmichels]

stock WP housing correct non AC pulley set
I realize the stock gauge is not accurate BUT it will show an increase and slow rise in temp A slow rise always scares me as it tells me something is not right. If a gauge is holding rock solid you know you are good.
Thanks for the help
Dave

[Mebsuta]

I was getting hot at speed until I bypassed the heater core. 

[69wannabe]

My buddy had some issues and put a high flow thermostat in his and it worked fine like you said in a short time it failed and I had to rescue him off the road. He went with the milidon brand high flow thermostat and hasn't had any problems since. I have also used the milidon brand in a jeep CJ 7 I swapped a 304 V8 in where a 6 cylinder was and used a factory 6 cylinder radiator and a milidon thermostat and that was two years ago and it is still working fine too!! I just put one of these in my car and took out a factory style and noticed a lower reading temp gauge between the two and they are both 180 degree thermostats so a good name brand high flow may be worth a try. Jeg's and summit racing have them ready to send i'm sure!! You running a strait fan or torque style, or clutch style fan?? Are you running a shroud too?? My old car has never had heating up issues unless its 100 degrees and I been stuck in slow traffic but my buddy has had some of these higher temp issuses he has had to deal with but has finally got it beat I am pretty sure!! Had a 440 one time that we gutted the stock thermostat so that there was just an open hole there and that was the only way we could keep it cool. Keep picking and you will get it figured out!!

[chargerbr549]

I remember working on an early 80's 5th avenue the car was all original when it came in the shop it had alot of miles and the engine was tired so we replaced the engine and had the radiator cleaned and checked out which flow tested what it was suppose to but the car temp would be ok at idle and light driving was ok but when you took it out on the road it would slowly start to overheat and the faster you pushed it the hotter it got, to make a long story short we ended up replacing the radiator which solved the problem even though it flow tested ok the radiator fins were loose enough and apparently not conducting heat away from the tubes so it couldn't cool effectively definately didn't make shop time on that one.

Possibly replace the radiator or have it recored.

[ws23rt]

Car 440 mild build 410 rear 4 speed. Stock cooling system in good shape. cruise rpm is 3000. 180 thermostat It was hot today 90f I am using the stock gauge so I do not have a real number, but I can see the needle creep up. Not crazy fast but I saw it climb in a 20 min run on the highway. Car did not overheat. I got the feeling I was pushing the capacity of the cooling system. any thoughts?
Thanks Dave

You see the needle creep up but not peg. You say the car did not overheat? How did you come by that assessment? All fine but the gauge?
I have had high temp readings that made me feel the car was overheating but aside from the gauge there was no other indication. (knocking, steaming,etc). Was it just a concern?
I have seen rise on the gauge that was followed by a quick fall that made me think of a sticking thermostat.
The other thing I would look for is good coolant flow. (Cap off-engine hot)

[Cooter]

3000 RPM's will move water too fast to cool it down even with a T-stat I've found. ALOT of heat is generated at those engine speeds for ext. periods of time.

I'd be looking into slowing the water pump down by another ratio of crank/WP pulleys.

[MSRacing89]

Where is your timing at?.....and how is the tune on carb at that RPM?

[HPP]

3000 RPM's will move water too fast to cool it down even with a T-stat I've found. ALOT of heat is generated at those engine speeds for ext. periods of time.

I'd be looking into slowing the water pump down by another ratio of crank/WP pulleys.

x2.

Low speed overheat is air flow related. High speed overheat is water flow related.

[Dmichels]

Cooter, I like your thinking, makes sense. The car will get up to temp and sit and idle forever and the temp will stay solid even on a very hot day. Traffic is not my problem. The problem I have at speed is the water does not have enough time in the radiator to cool. I did put in someones fancy "hi flow pump" maybe I should plug the stock one back in and see what happens
Dave

[A383Wing]

I think there was a thread on here about those "hi-flow" pumps and they said they were-are crap.

I say put a stock pump on and go from there

[firefighter3931]

I've run a high flow Milodon pump and high flow Milodon stat with no issues in a 4.10 geared Charger at 108* ambiant temps....no problem. 

Where is your timing at?.....and how is the tune on carb at that RPM?

Marty is on the right path here ; what is your timing and how are the A/F ratios at 3000 rpm. Retarded timing or too lean will make it run hot 


Ron

[Dmichels]

Thanks for all the help on the things to check. I will get on it this weekend and report back on what I found
Dave

[Dmichels]

I am an ASS
When I threw things back together I guessed on the timing After all I am a bull headed "expert" who has been working on cars for 25 plus years and can set timing thew mental telepathy. Well it was WAY off 25  initial and about 50 total I am surprised it ran as well as it did. Running great now.
I should have known better
Never ASSUME
DaVE

[MSRacing89]

We are here to help.......never assume you have to tear the whole thing down before you check the basic stuff first!

[firefighter3931]

I am an ASS

I had a  at that one.....we've all been there Dave ! 

Glad that it turned out to be something simple....it usually is with these old cars. 



Ron

[GPULLER]

I've run a high flow Milodon pump and high flow Milodon stat with no issues in a 4.10 geared Charger at 108* ambiant temps....no problem. 

It gets that warm in Canada? 

[firefighter3931]

I've run a high flow Milodon pump and high flow Milodon stat with no issues in a 4.10 geared Charger at 108* ambiant temps....no problem. 

It gets that warm in Canada? 

You bet !     Last summer we had a couple of days at 120*F with the heat index 

The freakin pool temp was 94* 

So far this year it's been cooler and wet....but still hitting triple digits with the humidity    Pool water is a nice 82* last night 


Ron

[GPULLER]

I've run a high flow Milodon pump and high flow Milodon stat with no issues in a 4.10 geared Charger at 108* ambiant temps....no problem. 

It gets that warm in Canada? 

You bet !     Last summer we had a couple of days at 120*F with the heat index 

The freakin pool temp was 94* 

So far this year it's been cooler and wet....but still hitting triple digits with the humidity    Pool water is a nice 82* last night 


Ron

No thanks! ha ha ha
We get a few 100deg days, but its pretty rare.  Just 90's and humid.   

[maxwellwedge]

I've run a high flow Milodon pump and high flow Milodon stat with no issues in a 4.10 geared Charger at 108* ambiant temps....no problem. 

It gets that warm in Canada? 

You bet !     Last summer we had a couple of days at 120*F with the heat index 

The freakin pool temp was 94* 

So far this year it's been cooler and wet....but still hitting triple digits with the humidity    Pool water is a nice 82* last night 


Ron

I must be older than you Ron. I think 88 is a good pool temp....especially when in my floaty chair with the built-in drink holders. 

Plus - The air is a lot hotter in Ottawa.....wonder why?