340 overheating problem

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340Duster247

340Duster247

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Hey guys, I'm not saying that 210-220 is overheating but hotter then is like to be.
My 340 is .40 with aluminum heads.
"Northern" aluminum rad ( stock size). One electric fan.
The fan is over to the side because it would hit pulley if centered.
Have 50/50 mix with a bottle of redline water wet.
180 thermostat.
Spring in bottom hose.
Stays hot no matter what. Highway. Cruising. Idle.
If I left anything out please ask.

Just looking for good pointers to cool this Down
 

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If that thing, with that huge radiator, overheats "at speed" I'd look for things like

Are you SURE your temperature "is what it is" IE suspect the gauge.

sticking stat.........try a different hopefully QUALITY brand, not the average O'Really

water pump impeller rusted off shaft. You have a heater? Does it "smoke you out?" Heater hoses should both be too hot to touch with engine warmed up

Does it "puke" coolant? If so, find someone (who still) does chemical "blok checks". This is a chemical that changes color if there's combustion gases in the coolant
 
Has this current setup run cool before and this is something new, or has it been like this from the git go? The fact that at idle, low speeds, and highway are all the same, tells me it's not the fan position causing it.

Any chance your running ignition timing that's on the low/retarded side? That can in some instances cause issues, but still, at highway speeds, there should be plenty of advance to not run somewhat hot.

Your setup looks nice.....i'll think on it some more for now.
 
The pump is fine. We went over all that last week when then engine was torn down. To make a long story short. This is a fresh rebuild of a rebuild motor that had only 100 miles on it. ( we heard a noise. Engine builder took everything apart, couldn't find a problem. Checked everything Thanks for helping out. Text me when ur out of including water pump. Added better cam suited for this setup. Changed flexplate same time. Noise gone now) hmm. anyways. Even with my last setup she got up to 210-220. Today was a hot day tho.30 degrees Celsius. But you guys down south get even hotter. So there's no excuse.
I've tried to bleed air out of the system as well.
I've always been concerned with this gauge cause its my only gauge that isn't autometer. :s.
thermostat is definitely working.
My rad cap is 16psi. It is not over flowing when it's hot.
 
As far as timing right now, my engine builders tech came over last night to help with the break in. Brought over his badass digital timing gun and we put it a 18 initial and 32 total for now. He is coming back this weekend to do some more dialing in
 

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It seems like there's been a rash of threads that I've been reading lately about temperature gauges that aren't accurate. I know that I've got a problem with my own. My factory gauge reads hot but I'm running a Mr. Gasket radiator cap that has a built in thermometer and it reads 180'. I used a portable infrared thermometer to check the engine temp and it agrees with the radiator cap so my interior gauge is off.
 
Get an infrared gun. Only way to be sure.
 
looks like auto trans lines going to radiator. also with the high rise intake i'm assuming you have a powerband up in the 6-7k area. so i'm assuming a high stall converter?

tell us about the converter. trans cooler?

is the radiator 26" or 22" ?
 
340Duster247 said:
The pump is fine.
I've always been concerned with this gauge cause its my only gauge that isn't autometer. :s.
thermostat is definitely working.
My rad cap is 16psi. It is not over flowing when it's hot.
Click to expand...

You are leaving one hell of a lot on the table here

You can't assume the "water pump is fine." Unless you know this pump DID work "fine" and is still that way as such. That is, a new pump could be assembled wrong..........with the incorrect impeller and too much clearance behind the rotor

Gauge...........brand does not matter. The gauge can still be wrong / inaccurate. You MUST check it with a second opinion, IE a thermometer

Thermostat.........just because it opens does not mean "its working." Many stat problems are cause by stats that still appear to work, but don't open quite soon enough OR FAR ENOUGH. Buy yourself a high quality stat, take both stats before you install the new one and heat them in a pan with a thermometer.
 
the fact that it dosent spit when its hot maybe indicating your gauge is inaccurate.
 
I have the same problem with my 360 motor. It runs hot no matter what I do, new stat, radiator, hoses etc. Let me know if you fix yours.
 
Put a drop of water on the thermostat housing. If you're anywhere near sea level it will boil if the temp is over 212F.Kind of give you a starting point without dragging out a bunch of gauges, or tearing the dash apart...From what I see in the pics I will side with the temp gauge is off, or maybe there is some air still in the system.
 
Some water pumps have 6 impellers some have 8 impellers you want a water pump for a AC car 318-340-360 don't matter
 
I had nearly the same specs on my 340 running at the same temps (210-220). My temp was verified by my gauge and EFI coolant temp sensor. I changed to a high flow pump, high flow 180 stat, and increased the size of the stat housing and rad housing. All of this made no change in temps.

Went back to engine driven fan with shroud and now it doesn't budge from 180 degrees.
 
1967 'cuda said:
It seems like there's been a rash of threads that I've been reading lately about temperature gauges that aren't accurate. I know that I've got a problem with my own. My factory gauge reads hot but I'm running a Mr. Gasket radiator cap that has a built in thermometer and it reads 180'. I used a portable infrared thermometer to check the engine temp and it agrees with the radiator cap so my interior gauge is off.
Click to expand...

New parts store temp sending units for OEM guages have the wrong ohm resistance.

You need to add some resistors to adjust the unit correctly.
 
Bad cam timing causes a hot running engine.
Ignition timing might be good enough, but if the cam leads or follows the crankshaft, it will run hot because of insufficient cylinder filling.

Has the cam been installed properly?
 
autoxcuda said:
New parts store temp sending units for OEM guages have the wrong ohm resistance.

You need to add some resistors to adjust the unit correctly.
Click to expand...

I used my existing sending unit originally but after the gauge read inaccurately I did replace it with a new one. Either way my gauge maxed out. It (the original one) seemed to have read fine before I installed the new motor though.
 
Sorry guys been busy for a bit. About the converter it's a 3800 stall. With a trans cooler. The water pump is fine. The cooling is getting better. Went to a couple shows over the week and every morning I woke up I checked the rad and its been down a couple inches. So I'm getting the air out. But today still got to around 215-220. It does stay cooler longer but once it gets hot, it stays hot. Now that I got all the air out it's over flowing. As far as the timing of the engine, since I got the new cam and the engine only has a couple hours on it, one of my engine builders techs came over to the house to help break it in and he set the timing. He supposedly good at what he does when it comes to dialing in a motor. We're not a 100% yet but I'm confident he knows what he's doing
 
I remember years ago when I replaced the factory clutch fan on my '70 Roadrunner with a fiberglass flex fan and was surprised that it didn't run as cool.
 
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