Would a bigger rad help this and if so what should I get.I cant do a $300+ rad,so are there any out there for under $300 that would help.I've read that a 67-68 rad is about 20" wide and a 3row of that would cure it from ever getting hot.

SCOOP
SCOOP

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2.634 60's
[email protected] 1/8 mile

65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede.

quote:

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Originally posted by SteveLaRiviere:
A lot of time it is a lower hose missing it's support spring and being sucked flat. Also, a weak water pump can do it, in addition to timing too advanced or retarded, or air/fuel ratio too lean.

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Steve I've had my timing all over the place to no change.I have a lower hose with a sping in it.i could change all the hoses just to see what happens.And the air/fuel ratio I've changed to no help.

SCOOP

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2.634 60's
[email protected] 1/8 mile

65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede.

Sam yes I have a shroud around the electric fan it comes all together.

My car will be at 180 driving slow around town.I'll get on the freeway and do 60-65 and it will get up too 195-200 in time.And if I go up a hill too it'll go to 205.I know those temps aren't to bad it's just why would it get more hot at a higher speed,and not at a lower speed?

SCOOP

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2.634 60's
[email protected] 1/8 mile

65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede.

quote:

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Originally posted by Fastback68:
You're right, of course, to think that everything should run cooler at highway speeds if working correctly. But I can't help making one observation: it's August and you live in Nevada! The apparent air temperature must be hot enough, let alone the actual air temperature.

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Good point it's been hot here,around 90+.But the same hold ture at night or even in the cool morning hours.It might get as hot as it dose mid day in August but it still heats up.I just wonder why,it gets more hot when moving faster the slower.
Thanks for the help.

SCOOP

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2.634 60's
[email protected] 1/8 mile

65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede.

When you are moving faster, especially accelerating or going uphill, the engine is burning a lot of fuel (producing a lot of power) the by-product of power is heat rejection to the coolant.

Ordinarily the speed helps because you get more airflow through the rad. In your case airflow isnt the problem and you stay cool in traffic because you have a good fan that keeps the airflow high. When the car idles it isnt rejecting much heat to the coolant, normally cars overheat in traffic because of lack of airflow.

I am wondering if you are getting hot simply because at highway speeds you are making more power. especially since the air through the rad is so hot (90 or above) the extra air flow by moving fast isnt helping to keep the engine cool.

So how do you keep it cool? just check everything you would normally check on an engine thats running hot. Since you have a good fan the usual defficiency isnt showing up in traffic, but you can still improve things by cleaning the rad, checking the t-stat, pump etc...

Someone said in a post not that long ago to check behind the drain plugs in the block, sometimes it gets blocked up in there.

quote:

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Originally posted by indyphil:
In short If you have an electric fan... the Usual thoughts on when the engine should be hot and when it shouldnt is changed becuase now the fan runs fast independant of engine speed.

So the critical factor here is your electric fan. Put a plain engine fan back on and youll probably get REALLY hot in 90 degree stop-go traffic just like the rest of us

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Yes with my stock fan the car would get hot in traffic and at highway speeds too.
Put it used to cool off alittle at freeway speeds from what it was at in traffic.The rad is a 3row about 4years old.I've tried a whole stack of T-stat's.I've tried all kinds of mixtures too right now I run a 70%water with two bottles of watter wetter.That helped alittle.The water pump is a stock one from NAPA it's about 3years old.Would a hi flow pump help any?like the flow cooler ones.

SCOOP

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2.634 60's
[email protected] 1/8 mile

65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede.

More flow or a bigger rad would do it, the increased flow seems like the best deal, keeps the size weight and cost of a bigger rad away. BUT i dont know how much more flow the system can take before other problems arise. Maybe someone out there can tell you about their experiences with high flow pumps.

The fact that you have a new pump, good t-stat, and a new rad, tells me that you have a good system, so long as something isnt blocking engine passages you are confirming that the engine is making too much heat for the current rad/pump package (on 90+deg days)

SCOOP

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2.634 60's
[email protected] 1/8 mile

65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede.

I did some thinking and some asking around. We (here at CAT engines) have limits on coolant flow for our engines. This is based on velocity of coolant. If you flow too much coolant YES you get the increased heat transfer but you can cause local low pressure points which cause localised boiling, and cavitation (which can eat away at the block looks like you have a rat that nibbles away at the cylinder walls from inside the water jacket)

The fix is to run the whole system at higher pressures (that means a stiffer spring in the rad cap) but that causes leaks. So maybe you have SOME headroom to increase flow, but beware of the dreaded cavitation. Maybe you can get a high flow pump and a new high pressure rad cap, i wonder if thats cheaper than a bigger rad? The bigger rad will add weight too dont forget that!

Hope you get it fixed!

Phil