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#1 |
Registered User
Join Date: Dec 2015
Location: Lehi,Utah
Posts: 213
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Engine Overheating
I have a freshly rebuilt 350 in my truck. I run it for about 2-3 minutes and it starts to overheat. I have checked to see if the radiator is flowing and it is. I have replaced the thermostat and it still overheats. Where should I go/check next?
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1964 Chevy Factory K10 Short Bed Mitchell Sampson |
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#2 |
Registered User
Join Date: Aug 2013
Location: sumterville, florida
Posts: 914
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Re: Engine Overheating
first question: what is it that makes you think it is overheating?
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#3 |
Registered User
Join Date: Apr 2011
Location: Denver, CO
Posts: 98
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Re: Engine Overheating
What is your current fan setup? Stock clutch fan, flex fan, electric fan? Do you have a good shroud? Have you checked your water pump?
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1964 Chevrolet C10 SWB Stepside (350cid/TH400) 1978 Chevrolet C10 SWB Silverado Big 10 (454cid/TH400) -"Ah, the pressure's fierce!" |
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#4 |
Registered User
Join Date: Dec 2015
Location: Lehi,Utah
Posts: 213
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Re: Engine Overheating
I am running a electric fan. No shroud but fan is about three inches from water pump pulley and I have checked that the water pump is running the right way and I made sure it was seated correctly. It's is brand new.
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1964 Chevy Factory K10 Short Bed Mitchell Sampson |
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#5 |
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Join Date: Dec 2015
Location: Lehi,Utah
Posts: 213
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Re: Engine Overheating
The gauge says it is and everything inside the engine bay is very hot, like you cant even touch it.
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1964 Chevy Factory K10 Short Bed Mitchell Sampson |
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#6 |
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Location: China Spring, TX
Posts: 7,280
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Re: Engine Overheating
Where did you acquire the temperature sending unit?
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Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats? |
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#7 |
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Join Date: Dec 2015
Location: Lehi,Utah
Posts: 213
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Re: Engine Overheating
I am not sure. The place that wired my truck installed it.
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1964 Chevy Factory K10 Short Bed Mitchell Sampson |
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#8 |
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Join Date: Oct 2012
Location: Philly, PA
Posts: 540
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Re: Engine Overheating
Just spit balling here, but some possibilities depending on the motor's set up ...
- Radiator hose is collapsing, needs an internal spring - Timing is too advanced - Fan is incorrect size, installation, or needs to blow in opposite direction If you think it's any of the above, do a forum search for more info, they're all common culprits that come up from time to time. Good luck and let us know the outcome.
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My truck ain't dead, it just smells funny. |
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#9 | |
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Join Date: Apr 2011
Location: Denver, CO
Posts: 98
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Re: Engine Overheating
Quote:
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1964 Chevrolet C10 SWB Stepside (350cid/TH400) 1978 Chevrolet C10 SWB Silverado Big 10 (454cid/TH400) -"Ah, the pressure's fierce!" |
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#10 |
Registered User
Join Date: Dec 2015
Location: Lehi,Utah
Posts: 213
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Re: Engine Overheating
I just bought a infrared gun. After idling for about 5-10 mins it was at 220 and then I drove it around the block and it was 250. I checked and the fan is blowing the correct way.
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1964 Chevy Factory K10 Short Bed Mitchell Sampson |
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#11 |
Registered User
Join Date: Apr 2011
Location: Denver, CO
Posts: 98
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Re: Engine Overheating
I would pull the thermostat and run it without one to see if it makes a difference. You can test the thermostat in a pot of boiling water to see if it's opening properly.
If it's not the thermostat, it could be your water pump is not operating properly. It may have a bad impeller that could be circulating the coolant, but not enough to cool the engine. You said the coolant is flowing, but you might have enough of a blockage somewhere in the system to keep it from circulating enough coolant. Could need a radiator flush.
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1964 Chevrolet C10 SWB Stepside (350cid/TH400) 1978 Chevrolet C10 SWB Silverado Big 10 (454cid/TH400) -"Ah, the pressure's fierce!" |
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#12 |
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Join Date: Oct 2016
Location: San Diego, CA
Posts: 557
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Re: Engine Overheating
Where did you shoot it with the infrared? What's the radiator temp in the area where the top hose goes in?
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Everybody has to believe in something. I believe I'll have another beer. |
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#13 |
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Join Date: Dec 2015
Location: Lehi,Utah
Posts: 213
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Re: Engine Overheating
I shot the intake manifold and the block. The top hose was 200
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1964 Chevy Factory K10 Short Bed Mitchell Sampson |
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#14 | |
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Join Date: Sep 2012
Location: oceanside CA
Posts: 706
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Re: Engine Overheating
Quote:
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#15 |
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Join Date: Oct 2016
Location: San Diego, CA
Posts: 557
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Re: Engine Overheating
To see if the radiator is clogged, what's the temperature on the metal part behind where the bottom hose comes out.
My truck has a 195 tstat, top hose temp at metal about 198-200, bottom hose area at about 110-125. On my truck, the 195 tstat helped cooling, plus my sender was inaccurate. But it's a six. Shouldn't make any difference.
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Everybody has to believe in something. I believe I'll have another beer. |
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#16 |
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Join Date: May 2014
Location: SAN FRANCISCO
Posts: 447
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Re: Engine Overheating
2-3 minutes from cold? Shouldn't even be warmed up by then... No overheating problems before the rebuild? Radiator shouldn't have gone "bad" sitting around. Hate to say it but if you didn't have the problem before then I'd look first at the rebuild . timing, head gasket waterpump. btw have you had the radiator cap of while starting from cold and watched what happens? Should see when the thermostat opens and coolant starts to flow. Shouldn't pump water out either when cold. Hope it's something easy.
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'66 C10 SWB '64 C2 roadster '38 Indian Scout Flattracker '70 Triumph T120R '81 Laverda Jota Last edited by scuderia; 06-24-2017 at 08:09 PM. |
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#17 |
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Join Date: Feb 2009
Location: southeasternfoothillsofusa
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One more thought: did you install a serpentine belt system during the rebuild/install? If so, did you get proper water pump that should now have a reverse flow (it turns backwards to original pump)?
Sam |
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#18 |
Registered User
Join Date: Dec 2015
Location: Lehi,Utah
Posts: 213
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Re: Engine Overheating
Thanks for all of the replies. Took it in. The radiator was blocked. Replaced it with an aluminum radiator. Now doesn't get any hotter than 205 even after driving for 45 mins in 100 degree weather!
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1964 Chevy Factory K10 Short Bed Mitchell Sampson |
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