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#1 |
Registered User
Join Date: Dec 2018
Location: Punta Gorda FL
Posts: 83
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I'm getting HOT!!
Well, I tried searching for answers. Couldn't find what I wanted/needed. I have an all original 71 C10 and 350. Temps are fine when driving, but get me stopped at a long light or worse, stop and go traffic here in southwest Florida and in a matter of a few short minutes, and I mean SHORT, the water temp goes all the way to the right. It doesn't knock, but if I shut down it of course gets hotter and will "buck" a little on start up. As soon as I start moving even 15-20 MPH, all is well. Original radiator. New cap. New 160 thermostat. What am I missing? Got 100K on the engine. Remove and clean the radiator? Change fan blades? I would like to stay "old school" and not go electric. Help please!
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#2 |
Senior Member
![]() Join Date: Apr 2016
Location: Cypress, TX
Posts: 3,691
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Re: I'm getting HOT!!
Hmm. I would suspect the fan clutch based on what you're saying. Did the problem start at some point? What changed?
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#3 |
Registered User
Join Date: Jan 2003
Location: Safford,AZ
Posts: 3,612
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Re: I'm getting HOT!!
Fan shroud? 7 blade fan?
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#4 |
Senior Member
![]() Join Date: Dec 2006
Location: Studio City, Calif.
Posts: 2,869
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Re: I'm getting HOT!!
No expert, but is the radiator clear of debris in front, no mass of insects or other objects? Is there and old A/C condenser with the fins all folded over in front? Is the fan shroud intact and firmly attached? Lower Hose not collapsing from the internal wire corroded away? Water pump old and ineffective (is it weeping at all from the shaft area)?
I had this problem like you describe and if memory serves (rare) it was internal blockage inside the engine and I think I tried running a cleaner through it. Another time it was just a water pump with the vanes all corroded.
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'69 GMC C2500 Custom Camper, 8 1/2' bed, New GM 350, NP 435 Close Ratio 4spd. Trans., 3.73 Dana-60 open.Camper and Trailer wiring, PS, PB, AC, tach , three gas tanks, stereo speakers, 2nd owner, Work-Truck supreme. |
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#5 |
20' Daredevil (Ret)
![]() Join Date: May 2003
Location: Jefferson State
Posts: 13,623
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Re: I'm getting HOT!!
Need a bit more info on your setup..... is there a fan shroud, what type of fan is it (clutch, fixed-blade)? Pics might help too. Is it a new problem?
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- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
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#6 |
Senior Member
![]() ![]() Join Date: Sep 2008
Location: Harrison, Arkansas
Posts: 9,815
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Re: I'm getting HOT!!
Shroud and fan clutch would be my first suspects.
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other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless. |
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#7 |
Registered User
Join Date: Jul 2013
Location: Mount Albert.Ontario
Posts: 119
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Re: I'm getting HOT!!
Sounds like clutch fan if you are running one.
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#8 |
Registered User
Join Date: Apr 2009
Location: PNW
Posts: 553
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Re: I'm getting HOT!!
That shroud needs to be sealed up against the rad, and the fan should be the right size for the shroud and the blade half in and half out of the shroud. I run about 20% coolant and 80% water. Got a good Hayden HD clutch too. No need for a 160 thermostat. I've got a 180 and mine runs 180 all summer long, including in temps of 100ish.
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#9 |
Registered User
Join Date: Dec 2018
Location: Punta Gorda FL
Posts: 83
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Re: I'm getting HOT!!
Hey Folks,
No bugs in the radiator and the fins are in very good shape. Fan shroud intact and set up properly with blades half into the shroud. Water pump is making zero noise and there is no weeping, etc.. I have not checked the bottom hose for collapsing. This overheat problem seems to have always been there since I bought it 18 months ago. It didn't seem as severe as it does now,... so I'm thinking as a lot of you that the fan clutch needs to be replaced. I'm fairly confident it's OE. So it's probably due. Then if the overheat continues,...I'll look for blockages or have the radiator boiled out. Thank y'all for your inputs. Have a great Memorial Day. Jack |
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#10 |
Registered User
Join Date: Apr 2011
Location: Fairview Park, Ohio
Posts: 1,031
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Re: I'm getting HOT!!
May also want to add cleaner kit and backflish to cooling system to clean it out. Sounds like that’s overdue anyway.
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My build page http://67-72chevytrucks.com/vboard/s...d.php?t=764662 My cabinet building site http://www.cbcabinets.com |
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#11 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,387
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Re: I'm getting HOT!!
If it doesn't overheat running on the road at speed, your radiator is not clogged. I've seen the fan clutch mentioned. Does your truck have one? It's easy to diagnose. Just put your hand where you can feel the air flow. Weak flow will be obvious. Also, when the engine is hot, and turned off, see if you can spin the fan. If so, the clutch is shot.
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#12 |
Special Order
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Location: Mt Airy, MD
Posts: 85,859
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Re: I'm getting HOT!!
The fan is for moving air when the truck isn't moving.
When you have poor flow due to clogged radiator the truck will run hotter the harder you run it. Going up hills or hiway cruising above a certain RPM. I don't think you'd be cooling down at 15-20 mph if it was bad flow. Plus it doesn't actually overheat, right?
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ Last edited by special-K; 05-25-2020 at 11:25 AM. |
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#13 |
Registered User
Join Date: Dec 2018
Location: Punta Gorda FL
Posts: 83
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Re: I'm getting HOT!!
It does not actually overheat,...the OEM gauge goes right up tp the max limit on the hot side of the temp gauge. So far the needle has not moved into the white band. ( I do not have a laser temp, so I'm relegated to trusting the gauge which I do not like to do). New fan clutch ordered and will go in tomorrow. I will also run cleaner through with a backflush as well.
Thanks all for everything! |
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#14 |
Registered User
Join Date: Jul 2015
Location: North East PA
Posts: 682
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Re: I'm getting HOT!!
this is my way of looking at it , if I was doing a fan clutch, a few more bucks a few more bolts and I would do the water pump , and if I decided to do a engine and rad flush, again a few more bucks and few more bolts new hoses and I would also do the T/stat , but hey that is just me if I do not know how old all the cooling system parts are they all get changed ,Why risk a expensive engine fail ,when a hundred fifty bucks gets me all but the radiator
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#15 |
Registered User
![]() Join Date: Mar 2005
Location: Jurupa Valley, Ca
Posts: 1,210
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Re: I'm getting HOT!!
I also think its the fan clutch. Let us know when you swap it out the results.
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Terry 1970 Custom Camper/C20 , GM Crate 350/7004R, Dana 60, factory AC |
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#16 |
Registered User
Join Date: Jan 2007
Location: Puyallup, WA
Posts: 1,662
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Re: I'm getting HOT!!
You should switch your vac advance to a manifold vac source to help the engine run cooler. Helps with mileage too. You have to set it up correctly first tho, you can't just switch ports or it won't work right. Also, advancing your timing helps with engine cooling. What's your timing set at?
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72 C10 lwb fleetside -stock 350/350 combo |
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#17 | |
Senior Member
![]() Join Date: Nov 2018
Location: Waterford California
Posts: 2,517
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Re: I'm getting HOT!!
Quote:
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#18 |
Registered User
Join Date: Apr 2011
Location: Fairview Park, Ohio
Posts: 1,031
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Re: I'm getting HOT!!
Get a $20. IR temp gun and get temp at stat housing where it meets the intake.
Guessing at the temp isn’t helpful. Check clutch if have one on fan. I added a pusher electric fan with 185 stat switch works great and quiet Shuts off at 165. Spal brand.
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#19 |
Special Order
![]() ![]() Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,859
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Re: I'm getting HOT!!
A properly operating fan clutch, water pump, and rest of OEM system works well to keep these trucks plenty cool, same as electric fans. Just have to fix what's wrong. There is nothing wrong with the how the OEM system was designed
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ Last edited by special-K; 05-27-2020 at 07:03 AM. |
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#20 |
Registered User
Join Date: Jul 2014
Location: South East Ohio
Posts: 644
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Re: I'm getting HOT!!
It's true there's nothing wrong with the OEM systems My fan is a 5 blade direct drive and moves plenty of air. In the cab it sounds like a hurricane under the hood but I know it's working.
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#21 | |
Registered User
Join Date: Dec 2018
Location: Punta Gorda FL
Posts: 83
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Quote:
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#22 | |
Registered User
Join Date: Jan 2007
Location: Puyallup, WA
Posts: 1,662
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Re: I'm getting HOT!!
Quote:
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72 C10 lwb fleetside -stock 350/350 combo |
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#23 |
One of the First
![]() Join Date: Jan 2000
Location: St. Augustine,FL.
Posts: 4,054
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Re: I'm getting HOT!!
I run a 180 deg thermostat in my engines. Seems to balance out the temperature when cruising or stopping at lights. Another thing is try to keep a good 50/50 mix coolant - distilled water. To much anti-freeze seems to make an old Chevy motor run warmer than needed.
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#24 | |
Special Order
![]() ![]() Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,859
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Re: I'm getting HOT!!
I always run 180s, too
Quote:
![]() Plus, that big thing all around the fan blocks air from the engine and makes it all go to the fan. I'm not worried about the fan getting hot... DUH? ![]()
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#25 |
Registered User
Join Date: Jul 2009
Location: Space Coast, Fl.
Posts: 1,050
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Re: I'm getting HOT!!
I also have GORILLA HANDS... W/ 5 thumbs on each. It's way easier to start washers & nuts on studs than trying to hit a bolt hole you can't see. Diddlin' & pokin' a hole you can't see can be fun but not bending over the front of your truck. A good hardware store should stock 5/16" SAE/USS studs in a variety of lengths. SAE(fine thread) end screws into the pump flange, washers & nuts on the front. There have been a few threads about replacing bolts w/studs. Seems like one of the auto parts chain stores sell a set of studs/nuts & washers in a little pkg. A guy with GORILLA HANDS & 10 thumbs could nick his old fragile radiator with the fan & clutch assy. Don't ask how I know.
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Dad always said, "Son, WISH IN ONE HAND, and ......." -------------------------------------- -------------------------------------- Current toy trucks: '71 GMC 1500 SUPER CUSTOM short/step, orig. dk. blue, 350/700r, ps,pb, A/C '72 Blazer 2wd, ochre & white, 454, tremecTKO 500 5spd. ps, pb, A/C, tilt Last 10yrs of hobby vehicles, had a FEW more in the 50yrs. before these: '66 Plymouth Belvedere City of Miami cop car clone. '70 Nova 406"sb, 13.5-1, solid roller, Brodix, p.glide/t.brake, back halved, 9" Ford, spool 4.88, cage,ladder bar/coilover, 10.5 tire....... SOLD!! '67 C10 short/step side mount spare -- SOLD!! '72 Jimmy 2wd, 350/350, ps, pb, fun driver, lots of bondo & a shiny red paint job..... SOLD!! '69 Nova 350, 4spd, A/C, ps, p.b, ...SOLD!! Last edited by RustyBucket; 05-27-2020 at 11:33 AM. Reason: typoo |
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