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#1 |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Cooling system issue....
I have a 72 GMC, with a 350 put in by the P.O.
I was told it out of a 94 GMC Truck 1500. When I lived up in Nor Cal, it would run at 190 Degrees, all day in 90 degree weather. Today was the 1st time I've taken it out in the Heat, (since moving down here to So Cal, Palm Springs Area). Left the House at 11 am, and it was 100 Degrees out. Drove to the Gas Station (about 9 miles away), on City Streets doing 45-55 MPH, with the A/C Running. Didn't even bother to look down at the Temp Gauge until after I got Gas. It seemed a little hard to start after I filled up. Looked at the Temp Gauge and it read about 210. I started driving, and got about 1/4 of a mile and the Temp stayed around 205. I took it straight home, as I knew if I got caught, in any "Stop-n-Go" Traffic, it would overheat on me. That got me to start looking under the Hood. What I have is a Serpentine Belt System, with No Shroud and what looks to be a Cheap Brand "Flex Fan", mounted on a 2" Hub. Now the Blades are about 2" from the radiator. My 1st thought was to get a Shroud, Clutch Fan and Flush the Cooling System, and re-fill the Anti Freeze. Money IS an issue, so if it WEREN'T, I'd be installing Dual Cooling Fans, and wouldn't need to post here. I'm at the Tip of the Iceberg, looking through the Internet and researching this issue and what's available. I was wondering if someone has made a shroud to fit our 67-72 Chevy/GMC's that has an electric Fan built into it already? I was wondering if I'm headed in the right direction with the Shroud/Clutch Fan idea above, or if I should go straight to a electric cooling Fan? I've seen some single Fans that clip onto your existing radiator ect. This is a real Generalized question/Post. I was just wondering what others did with the same problem as I have, and how you corrected it.
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Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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#2 |
laying low
![]() Join Date: Mar 2001
Location: Searcy, Ark. USA
Posts: 13,222
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Re: Cooling system issue....
Roger is that a 4 row radiator? If so it should be plenty.
That "cheap" flex fan may be suspect. 2" from the rad isn't bad but could be better with a shroud. Or you might consider an electric pusher fan in front of the condensor. Does it have a 160 or 195* thermostat?
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Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross |
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#3 | |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Re: Cooling system issue....
Quote:
that sucker would be HARD PRESSED to reach 190. I'd say 75 % of the time it was running 165-180 tops. Rarely would it ever get to 190. ![]() So would this "Pusher Fan" be in addition to a shroud? (Pusher Fan on the outside and shroud on the inside)?
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Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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#4 |
Registered User
Join Date: Jun 2010
Location: Upland Ca
Posts: 4,143
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Re: Cooling system issue....
Please check the accuracy of the gauge before throwing any money at it. Then start with shroud followed by clutch fan. In stop and go with AC, 21x in 100 degree plus is not that bad.
Posted via Mobile Device
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1972 C10 SWB, Air, PS, PB, 350/350THM. Second owner. 1965 Corvette roadster, 44K miles, 327/365 SHP, 4 speed, side exhaust, knockoffs, teak, second owner (bought in 1970), Have ALL numbers matching components. My frame off restoration thread: http://67-72chevytrucks.com/vboard/s...d.php?t=556703 |
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#5 | |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Re: Cooling system issue....
Quote:
Gauges are fine and have all been re-wired/Tested when the Truck was in the Shop earlier this year. This has been the longest drive I've taken it on, (in the Summer),since moving here 10 Months ago. Before thisd I only took it out between November thru April, because its so mild here, but I goit tired of watching it sit in the Garage, so since it wasn't 119 out, I thought I'd take it for a "Test Summer Drive", before REALLY heading out for a longer Cruise.
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Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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#6 |
Senior Member
Join Date: Nov 2003
Location: Brookings, SD
Posts: 10,497
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Re: Cooling system issue....
Have you seen the pictures of the flex fan blades through the hood? Scary deal.
I am certain that with a stock fan and shroud you won't have any problems. It may not be so simple though. That is a reverse rotation water pump right? So you would need to get a newer fan, but the older shroud. It may take a little work but I am sure you can get it to work.
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Some people are like slinkies, they aren't good for anything, but you can't help but smile when you see one tumble down the stairs. |
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#7 |
Old member
Join Date: Jan 2002
Location: Liberty, & Garden City S.C. , U.S.
Posts: 19,936
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My 1st question here. Is that flex fan blades for a reversable rotation water pump?
It looks to me like it's for a normal rotation pump which would mean it's not doing anything for you. Can you crank the truck up and see if you feel air being pulled through the grille with it sitting still. If not get the correct clutch fan since you have AC and forget about it. Well you need a shroud also. ![]() ![]()
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1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 ![]() Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs. |
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#8 | |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Re: Cooling system issue....
Quote:
__________________
Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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#9 |
Old Skool Club
![]() Join Date: Jun 2001
Location: Benton, AR "The Heart of Arkansas"
Posts: 10,880
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Re: Cooling system issue....
AC trucks had 4-row radiators, with shrouds and thermostatic fan clutches. I'm thinking that if you don't have all of those, you're probably going to overheat....as it has.
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Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was. |
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#10 | |
Account Suspended
Join Date: Jun 2010
Location: Placerville Ca.
Posts: 982
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Re: Cooling system issue....
Quote:
So take notes on when its overheating both sitting still and cruising. If it ONLY overheats when setting still its most likely a airflow problem, inadequate or not properly working fan setup, or possibly dirty or crushed fins. If it ONLY overheats cruising over 50 mph it's most likely a fluid flow problem. If it's overheating all the time ...this is usually some sort of restriction in fluid flow not air flow. Flush the system chemically and inspect the best you can with a flashlight inside the radiator for heavy deposits (you may have to have a shop clean it if its really bad.) Now take the radiator cap, and the thermostat off and throw them in the trash ...why? because there cheap and the easiest things to eliminate, these two items alone can cause all sorts of problems and together they only cost between $15 and $20 tops. Make sure to use the correct temp thermostat for your engine...removing the thermostat WILL NOT fix overheating problems, and will make your engine run worse because of the constant temp fluctuations. Now refill the system like this: drive the front wheels up on ramps so the cap is the absolute highest place in the system and turn the heater on high, fill the radiator to the top and start the engine ...leave the cap off!!!...now when the thermostat opens the level should drop considerably, keep adding coolant and wait till it cycles for a while. If you have a closed system that has a reservoir and recirculates, fill it completely full. If you don't have a recirculating system leave a couple inches at the top for expansion, otherwise it will just blow the excess out through the cap and on the ground. Now put the cap on and fill the reservoir (if you have one) to the mark only. Use the least amount of antifreeze you can get away within your climate conditions (straight water cools better than any antifreeze mixture)....but you need some in there for anti corrosion purposes and it does raise the boil over point a little ....along with the pressure in the system. If all this doesn't solve the problem the water pump may be inadequate for your motor .... though this is very unlikely until you get into the high rpm modified engines. If it still overheats, write back and describe the details and we'll get it figured out. All right I'm spent ....hope this helps ...later.......Rushnbobo |
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#11 |
Moderator
![]() Join Date: May 2007
Location: Southern Cal
Posts: 20,004
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Re: Cooling system issue....
lots of good advice here.
i am running a big block with a/c full blast all the time under the same conditions you are. i have the factory setup and have never had an overheating issue. if you never had problems before moving to palm springs, i would suspect your cooling system is functioning and adequate. the first problem i see is the lack of a shroud. air takes the least path of resistance, and without a shroud to channel it through the radiator, it largely goes around it. many other things listed above could also be the issue.....but i would definitely start with a shroud. if that does not solve the issue, it is not money wasted because you need it regardless. Posted via Mobile Device
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1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man |
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#12 |
~Rest In Peace~
Join Date: May 2005
Location: CALIFORNIA NOR CAL
Posts: 9,707
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Re: Cooling system issue....
wet wetter to coolant
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is it fast ? it has a lighting bolt donut? B___H please, I can remove 90% of your so called "beauty" with a kleenex |
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#13 |
Eat, Sleep, Drive a Chevy
Join Date: Apr 2010
Location: the town of the cow, Texas
Posts: 1,152
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Re: Cooling system issue....
I think he meant to say "Water Wetter" a cooling system additive by Redline
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Trey Silence may be Golden, but Duct Tape is Silver! 72 Short Step 57 "big window" short step |
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#14 |
~Rest In Peace~
Join Date: May 2005
Location: CALIFORNIA NOR CAL
Posts: 9,707
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Re: Cooling system issue....
yeah water wet same thing or even 40 below is good to add
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is it fast ? it has a lighting bolt donut? B___H please, I can remove 90% of your so called "beauty" with a kleenex |
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#15 |
67-72 parts collector,…
![]() Join Date: Nov 2002
Location: Mid-MO
Posts: 22,698
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Re: Cooling system issue....
The serpentine set-up require a fan for the reverse rotation of the water pump.
That appears to be the correct fan for that application. I would install a correct fan shroud and clutch fan (reverse rotation), and you should be good!
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Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823 |
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#16 |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Re: Cooling system issue....
Thanks Guys.
An update...... I went looking for a Fan Shroud, and every aftermarket parts dealer seemed to be in the $99.00-$140.00 Range! ![]() I found a new shroud, Clips, Screws at LMC, shipped to my Door for $78.00. ![]() Gonna have my Mechanic get the Clutch Fan. So I'm gonna have the Shroud put on, New Clutch Fan, New 160 Degree Thermostat and Flush the Cooling System and add new Coolant. One question though.... When I looked at Clutch Fans online in the application, they wanted to know the "Rear end Gear Ratio"!!?? I thought maybe I was outta my mind until my Mechanic got asked the SAME THING, by HIS Parts Guy. I'm pretty sure its got to do with the RPM's the Engine will turn, with the Clutch Fan that would Determine WHAT the Correct Fan is? I thought the more knowledgable could simplify/spell it out for me? ![]()
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Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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#17 |
Eat, Sleep, Drive a Chevy
Join Date: Apr 2010
Location: the town of the cow, Texas
Posts: 1,152
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Re: Cooling system issue....
I would run a 180 deg thermostat if it were me. If you think about this when the water is circulating through the engine it is stopped inlarge part by the t-stat until the t-stat reaches its setpoint in your case 160 then it opens and then water moves through the radiator. When the t-stat is closed and water is stopped in the engine it is also stopped in the radiator allowing the air moving through the radiator to cool the water back down. If you run a cooler t-stat the water wont stay in the radiator long enough to cool back down. just my .02
good luck with it
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Trey Silence may be Golden, but Duct Tape is Silver! 72 Short Step 57 "big window" short step |
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#18 | |
Registered User
Join Date: Oct 2010
Location: Largo Florida
Posts: 632
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Re: Cooling system issue....
Quote:
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Lifes journey is not to arrive at the gate well preserved, it is to slide in sideways all used up and wore out yelling.....God what'a ride! Where patience fails, force prevails Stapp's Ironical Paradox "The universal aptitude for ineptitude makes any human accomplishment an incredible miracle." |
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#19 | |
Registered User
Join Date: Jan 2009
Location: Arizona
Posts: 404
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Re: Cooling system issue....
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#20 | |
Account Suspended
Join Date: Jun 2010
Location: Placerville Ca.
Posts: 982
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Re: Cooling system issue....
Quote:
"A common misconception is that if coolant flows too quickly through the system, that it will not have time to cool properly. However the cooling system is a closed loop, so if you are keeping the coolant in the radiator longer to allow it to cool, you are also allowing it to stay in the engine longer, which increases coolant temperatures. Coolant in the engine will actually boil away from critical heat areas within the cooling system if not forced through the cooling system at a sufficiently high velocity. This situation is a common cause of so-called "hot spots", which can lead to failures." Basically moving coolant is better than idle coolant....and a higher velocity is better than slow moving...thats why we have high flow water pumps if slow or idle were better we should all use stock flow pumps ...even race cars |
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#21 | |
Account Suspended
Join Date: Jun 2010
Location: Placerville Ca.
Posts: 982
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Re: Cooling system issue....
Quote:
Can you go a little over? sure ...but a system with the right combo of water pump, radiator, thermostat, fan, and shroud. Should not go over the thermostat temp, if it does something is either not adequate enough for the application or is not functioning correctly. I run a 4 row copper brass radiator, Stewart Warner high velocity pump and a 160 degree thermostat, with a stock clutch fan setup. With a 400 hp 355 sbc I can drive up a 10 mile grade with a C/30 dually weighing 4400 lbs........ at 20-30 mph on a 100 degree day and the needle never moves off 160. It will also sit at idle in traffic at the same temps ....still never overheat. This is because the components are very efficient at heat exchanging. |
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#22 | |
Registered User
Join Date: Jan 2009
Location: Arizona
Posts: 404
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Re: Cooling system issue....
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#23 | |
Account Suspended
Join Date: Jun 2010
Location: Placerville Ca.
Posts: 982
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Re: Cooling system issue....
Quote:
A 160 degree temp can sometimes make a little more power, and curb detonation issues in some high compression engines. But the downside can be too cold of a cumbustion chamber temp which will eventually lead to excessive carbon buildup and possibly an incomplete burn. So on the street a 180 in gen 1 sbc is usually considered the best compromise for both power and clean efficient combustion. I swapped out the 180 to the 160, because of the detonation, but have since installed an in cab MSD ignition dialback which I can on the fly, adjust the initial and overall timing when I change elevation. Where I live at 2000 ft. the setting is perfect, if I drive to 1000 ft. it will begin to ping, "more dense air". Since max power is made right on the edge of ping or no ping I can now just dial it back to the sweet spot a couple degrees at a time. I will eventually go back to the 180 so I don't worry about carbon buildup problems and possibly "loading up" the plugs at idle. |
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#24 | |
Registered User
Join Date: Jan 2005
Location: Clearlake Oaks CA
Posts: 1,716
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Re: Cooling system issue....
Quote:
Is that driving around town in stop-n-Go traffic? That's my issue, as I rarely do any Freeway Driving.
__________________
Hello members... I'd like you to know that I sold, my 72 GMC (Ratikle), back in November of 2011. I don't visit the site much anymore, but please feel free, to drop me a private message. RIP...."RATIKLE" |
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#25 | |||
"I ain't nobody, dork."
Join Date: Sep 2007
Location: Whidbey Island, Washington
Posts: 8,938
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Re: Cooling system issue....
Quote:
Sticking a 160 degree t-stat won't help. The earlyier 350's had 180 t-stats in them. Thats' all I have ran in all my 1st gen, non-fuel injected engines. No probs. Gary
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'cuz chicks dig scars... My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread. The Rebuild of Creeping Death after the wreck Quote:
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