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Author Topic:   Cooling question
Fastymz
Moderator

Posts: 12015
From: Reno Nv USA MEM#1240
Registered: Apr 2001

posted 08-19-2002 08:53 PM     Click Here to See the Profile for Fastymz   Click Here to Email Fastymz     Edit/Delete Message   Reply w/Quote
What makes a car heat up more at freeway speeds.I always thought with more wind flowing thur the Rad,more cooling you'd get.This is not just my car but I know 3 other guys that have the same thing.One guy told me it's because my small 65 3row rad is just not big enough.The other cars that do the same thing also have 3row rad's and they are all differnt cars.

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

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SteveLaRiviere
Administrator

Posts: 33988
From: Saco, Maine
Registered: May 99

posted 08-19-2002 09:02 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
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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All Fords since 1977!

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RADRIDE
Gearhead

Posts: 243
From: Va.Beach, Va.
Registered: Aug 2002

posted 08-19-2002 09:10 PM     Click Here to See the Profile for RADRIDE   Click Here to Email RADRIDE     Edit/Delete Message   Reply w/Quote
Good call I was having problems blowing water out and spent a lot of money and time before finding out about the spring.Tony Branda has a good hose with spring installed could not find one locally.

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Fastymz
Moderator

Posts: 12015
From: Reno Nv USA MEM#1240
Registered: Apr 2001

posted 08-19-2002 09:20 PM     Click Here to See the Profile for Fastymz   Click Here to Email Fastymz     Edit/Delete Message   Reply w/Quote
quote:
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.


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.

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lyle29464
Gearhead

Posts: 827
From: Mt. Pleasant S.C.
Registered: Mar 2000

posted 08-19-2002 10:15 PM     Click Here to See the Profile for lyle29464   Click Here to Email lyle29464     Edit/Delete Message   Reply w/Quote
I have had a head gasket that would leak above 2500 rpm and not below.
drove me nuts till I found it.

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mustangs68
Moderator

Posts: 18183
From: Hampton,Virginia,USA MCA#39406 M&M #12
Registered: May 99

posted 08-19-2002 10:20 PM     Click Here to See the Profile for mustangs68   Click Here to Email mustangs68     Edit/Delete Message   Reply w/Quote
SCOOP,
ya got a fan shrod (dang I can't spell that tonight)on her?
sam

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Fastymz
Moderator

Posts: 12015
From: Reno Nv USA MEM#1240
Registered: Apr 2001

posted 08-20-2002 02:55 AM     Click Here to See the Profile for Fastymz   Click Here to Email Fastymz     Edit/Delete Message   Reply w/Quote
Lyle i'm getting more suspicious about a head gasket.

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.

https://mustangsandmore.com/ubb/Fastymz.html

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Fastback68
Gearhead

Posts: 1746
From: Sucat, Paranaque, Philippines
Registered: Jul 99

posted 08-20-2002 03:09 AM     Click Here to See the Profile for Fastback68   Click Here to Email Fastback68     Edit/Delete Message   Reply w/Quote
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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Fastymz
Moderator

Posts: 12015
From: Reno Nv USA MEM#1240
Registered: Apr 2001

posted 08-20-2002 03:14 AM     Click Here to See the Profile for Fastymz   Click Here to Email Fastymz     Edit/Delete Message   Reply w/Quote
quote:
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.

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.

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indyphil
Gearhead

Posts: 877
From: Lafayette, IN, USA
Registered: Jul 2002

posted 08-20-2002 08:14 AM     Click Here to See the Profile for indyphil   Click Here to Email indyphil     Edit/Delete Message   Reply w/Quote
I realise that this is not seemingly normal, but here is my take...

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.

Phil

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indyphil
Gearhead

Posts: 877
From: Lafayette, IN, USA
Registered: Jul 2002

posted 08-20-2002 08:20 AM     Click Here to See the Profile for indyphil   Click Here to Email indyphil     Edit/Delete Message   Reply w/Quote
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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Fastymz
Moderator

Posts: 12015
From: Reno Nv USA MEM#1240
Registered: Apr 2001

posted 08-20-2002 11:40 AM     Click Here to See the Profile for Fastymz   Click Here to Email Fastymz     Edit/Delete Message   Reply w/Quote
quote:
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


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.

https://mustangsandmore.com/ubb/Fastymz.html

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indyphil
Gearhead

Posts: 877
From: Lafayette, IN, USA
Registered: Jul 2002

posted 08-20-2002 12:01 PM     Click Here to See the Profile for indyphil   Click Here to Email indyphil     Edit/Delete Message   Reply w/Quote
I think maybe that the key is that your radiator/coolant flow just is not big enough for the power your car is producing for 90 degree days. You have a 351 with only a 20" 3 row rad is that correct?

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)

Phil

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Fastymz
Moderator

Posts: 12015
From: Reno Nv USA MEM#1240
Registered: Apr 2001

posted 08-20-2002 12:20 PM     Click Here to See the Profile for Fastymz   Click Here to Email Fastymz     Edit/Delete Message   Reply w/Quote
Phil it's a 17" wide down flow rad,like any stock 65-66 rad.But it's a 3row.

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.

https://mustangsandmore.com/ubb/Fastymz.html

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indyphil
Gearhead

Posts: 877
From: Lafayette, IN, USA
Registered: Jul 2002

posted 08-20-2002 12:29 PM     Click Here to See the Profile for indyphil   Click Here to Email indyphil     Edit/Delete Message   Reply w/Quote
OK, Im not an xpert in rad sizing, but it does sound small. Perhaps the 68 optional 3 row rad (180 bucks at NAPA) would be one option.

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

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'68 coupe 289 2V
CAT engine performance engineer

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