Cooling Issue Decision Time

[Turtleman]

So I'll try a poll to see what You'd do in this case;
The Issue I really have is overheating,, it runs at 210 to 230 regularly and will boil over when I stop.
The Previous owner added a 16" electric fan.. but he also added a 25amp breaker in-line to the fuse box.. ( I don't know what it should be).
I've cleaned out the radiator,, water pump is good, theres just not enough air flow in my opinion.



He has the yellow wire added to the heater fuse but also runs it off a toggle switch on the dash


A. Would you try to find out what air flow that fan will move and try to wire it to carry the amps so it will cool things down?

B. Remove the whole thing and install a Fan with a clutch and shroud?

[padresag]

easiest way way to solve the problem is not to stop. has it always been this way or did it just start doing this. is the breaker tripping. if not then that is not a problem
what are you running for a coolant mixture. did you pressure test your system for a leak and is your rad cap up to par and what is it's pressure rating
ron

[LVPhotos]

Yet to run mine in '62, but I ran the same Flex-a-lite Black Magic #188 in my 98 Durango with 35s and 1500 watt stereo no issues in Las Vegas heat.. It is a 3300 cfm fan. I ran and run it as a stand alone wire "harness"

[Turtleman]

Originally Posted by padresag

easiest way way to solve the problem is not to stop. has it always been this way or did it just start doing this. is the breaker tripping. if not then that is not a problem
what are you running for a coolant mixture. did you pressure test your system for a leak and is your rad cap up to par and what is it's pressure rating
ron

I'm using PEAK 50/50 PreDiluted.. this has Always been a issue since I've had the truck I've never seen any leaks and have changed caps once,, I just looked at both caps and don't see ratings on them,, and I don't know what cap to use because the radiator's been swapped out to a Aluminium one.. I also thought at first to simply just not Stop but the local Police don't seem to have any kind of sense of humor around red lights..

[72shorbox]

Turtleman, is there a thermostat in the cooling system? Without one the coolant will circulate to quickly through the radiator.

[padresag]

the original system was 50/50 and a 7lb cap. newer rads are usually 13 or 15#. your temps stay steady between 215 and 235 consistently when driving. when you stop does the temp spike or stay the same
if your system is in good shape with a 7 lb cap and a 50/50 mix is should not boil unless it hits 251F and with a 13 lb cap and 50/50 it should not hit boil until 269 F. one of those little hand pump pressure testers will tell you if your system will hold those pressures as well as your cap. that is the basis to your system. that is esy to do and eliminate.
sometimes it can be the heater core has a small leak.
ron

[Turtleman]

Originally Posted by padresag

the original system was 50/50 and a 7lb cap. newer rads are usually 13 or 15#. your temps stay steady between 215 and 235 consistently when driving. when you stop does the temp spike or stay the same
if your system is in good shape with a 7 lb cap and a 50/50 mix is should not boil unless it hits 251F and with a 13 lb cap and 50/50 it should not hit boil until 269 F. one of those little hand pump pressure testers will tell you if your system will hold those pressures as well as your cap. that is the basis to your system. that is esy to do and eliminate.
sometimes it can be the heater core has a small leak.
ron

I did a test to 10 pounds and it holds fine.. Temps always seem to rise at a slow steady pace,, never a sharp/fast spike/rise, just a steady rise,, unless I get on a freeway then temps stay steady,, until I get off the freeway and I have less air flow

is there a thermostat in the cooling system? Without one the coolant will circulate to quickly through the radiator.

WOW... good question,, Thank You!... allot of owners around here remove them during our summers.. I have done that in the past myself so I couldnt remember if I put it back in.. LOL "Yes" I did ,, then I remembered I installed a new one

[padresag]

Originally Posted by Turtleman

I did a test to 10 pounds and it holds fine.. Temps always seem to rise at a slow steady pace,, never a sharp/fast spike/rise, just a steady rise,, unless I get on a freeway then temps stay steady,, until I get off the freeway and I have less air flow

if your running a 13 lb cap then you test at 13. did you test the cap.
what does the gauge do when you come off the hwy and you stop.
ron

[Turtleman]

if your running a 13 lb cap then you test at 13. did you test the cap.
what does the gauge do when you come off the hwy and you stop.
ron

Both the caps have no indication of what lbs they are so I'm only guessing here, the motor is a 350 and the radiator is changed out to.
When I slow down I have much less air flow so the Temps starts it's rise to higher numbers.. not a fast rise,, but its a steady move up

[padresag]

pressure can control heat. go by a rad shop and get them to test both your rad and cap, then you know where you are at, other wise you are just guessing. so everytime that it boils do you just add water or do you add the mix

[Turtleman]

I always add the Mix

[siggyfreud]

Really just sounds like you're not moving enough air at slow speeds. Do you know what temp your thermostat is rated for? Is the fan a single or dual speed?

[Turtleman]

Originally Posted by siggyfreud

Really just sounds like you're not moving enough air at slow speeds. Do you know what temp your thermostat is rated for? Is the fan a single or dual speed?

Thats what I'm thinking Siggy I have No Idea what the thermostat is rated or anything about the fan.. its a previous owner install so I cant find any info in some of this stuff.. thats why I did the Poll..

[AcampoDave]

What about air flow control. Are you missing factory pieces under your hood? I see a lot of trucks running around with the factory baffling missing, and many are missing the two bolt on pieces that go from grille surroumd to core support. Those things matter.

[blown240]

Another thing to think about is your alternator. Are you getting a nice charge at idle, and when the fans are on? Voltage drop will slow down an electric fan......

On my 61, I had issues with a 16" fan. I replaced it with a taurus fan, and a bigger alternator, and all my cooling issues are gone.

[par4tom]

I had the same problem with my 61 running a 16" fan. While all the other guys have some good ideas, the problem with the 16" fan is that on our radiators, the fan is only moving air through a fraction of the radiator when you are standing still. (Calculated out, a 16" fan covers about 200 inches of surface area). I don't remember what the radiator surface area was but you can calculate that out...the difference between the two is the area that is NOT getting air when the truck is standing still. Even if you put a higher CFM fan, you are not going to cool the rest of the radiator.

Think about it this way...when you drive, the truck is cooling fine which means that air flow through the entire radiator cools the engine. But when you stop, it overheats.

Bottom line, I went the Black Magic route with the full shroud and even in our 110 degree Central California summers, I rarely get over 210-220 degrees. About 180-200 degrees while driving down the road.

In cooler weather, the temperature runs about 170 to 180.

It does pull about 18 amps of current on start up but that should be a non-issue. Any high-volume fan is going to pull a lot of amperage...

I would go ahead and wire this as a standalone circuit through a 30 amp relay with a good, high quality 10 - 12 gauge wire from the battery to the #30 terminal (30 amp fused) so that you are pulling amperage directly from the battery and not through the circuit panel under the dash. You can wire to the fan from the #87 terminal. Connect the #86 terminal to your switch with its own 12v source and then ground through the 85 terminal to a good chassis ground.

[_Ogre]

wire it temporarily direct to the battery and take it for a spin, you may have voltage drop running thru the oem fuse panel
i see a gap between the fan and radiator, eliminate it
check your timing, maybe retard it a degree or 2

i had a 327 that ran fine at high speed but would overheat at low speeds turned out to be the timing chain
gm timing chains have a plastic coating on the v8 gears that deteriorates after a while
have you ever noticed any plastic when changing oil?

if you do go back to a mechanical fan make sure you have a shroud

[AcampoDave]

Here's what worked for me... when I added A/C my cooling suffered so I went with a new aluminum radiator. Then I trashed my flex fan for a Hayden 18 inch 6 blade mechanical fan, which uses a Hayden heavy duty thermostatically controlled clutch. I also took the time to ensure that all my baffling was up to par and added new rubber where needed. While doing this, I also fabricated a seal between my stock shroud and the new radiator. (I used a rear window gasket since glass channel groove fit perfectly around the plastic on the shroud.) My goal was to prevent my airflow from slipping around my radiator and A/C condenser and the extra effort in sealing up the open spaces paid dividends because I can cruise up to the mountains in triple digit temps. The motor stays cool and so do I.

[Turtleman]

I think allot agree about whats great about this forum.. The help and input from hands on experience from others who have "Been There,, Done That"
There's a number of reasons why I own a 66,, one of them is because there simple and I can work on it. Its kind of like my Tub Grinder and other farm machinery.. LOL
I've seen allot of issues that "Previous Owners" have done,, fortunately for me this hasn't been so bad.. I still have all the parts (baffling still on it).
I talked to a few of local friends here and I found out the fan only pulls 1600 Up To 2100 CFM... The Air Flow issue!
So that being the case and being someone who likes the simple things I'll pull the fan off instead of buying a new one and install the older style crank fan then install a shroud.
I "Will" post back with what I bought and where I got them along with the install... Oh Yeah,, Pictures!

I really do appreciate all the input from everyone on the forums