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| | | Forums66 Topics128,134 Posts1,056,401 Members48,441 | | Most Online14,466 Apr 26th, 2026 | | AD Chevy Trucks Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
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on the Internet for over 30 years! and not clogged down with Ads! Again, thanks! | | | | Joined: Dec 2016 Posts: 80 'Bolter | | 'Bolter Joined: Dec 2016 Posts: 80 | Looking for some assistance with a 59 Apache with a "recirculating" heater set up, NOT a deluxe heater! Here is my issue, I have had the original heater core recored by a local shop. Both inlet and outlet tubes are 3/4" hose. Did the original setup have a shut off valve for summer use or is it live all the time? Everyone seems to sell heater hose kits but one hose is 5/8" and the other 3/4". The Factory Assembly Manual and the Shop Manual have no information and I can't find a picture to save my life, thanks for any help!
1959 3204 Basic Cab
| | | | | Joined: Feb 2004 Posts: 29,814 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,814 | A pretty common installation was to put a T-type shutoff valve at the cylinder head port with a pipe thread going into the head and a hose nipple to attach the heater hose. The valve had a threaded shank to shut off the flow when heat was not needed. The return line attached to the water pump housing with a pipe/hose adapter fitting. Those parts should be included in any automotive heat/air conditioning universal parts catalog. Try NAPA or one of the other "professional" auto shop parts suppliers, not Auto Zone, etc.
Just checked- - - -there are bunches of them on Ebay. Search "Heater hose shutoff valve". Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
| | | | | Joined: Dec 2016 Posts: 80 'Bolter | | 'Bolter Joined: Dec 2016 Posts: 80 | I stay as far away from Auto Zone as possible!!!!!
1959 3204 Basic Cab
| | | | | Joined: Feb 2002 Posts: 12,029 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Feb 2002 Posts: 12,029 | as Jerry says, just get hose the size you need from a local parts store, skip the "kit" here's the 57 info, different heater box but the same installation .... there was no shutoff included originally Bill | | | | | Joined: Dec 2016 Posts: 80 'Bolter | | 'Bolter Joined: Dec 2016 Posts: 80 | Sounds like a plan! Thanks everyone!
1959 3204 Basic Cab
| | | | | Joined: Aug 2015 Posts: 48 'Bolter | | 'Bolter Joined: Aug 2015 Posts: 48 | Hello Wrencher88
I believe that some models used 3/4 on one heater hose fitting and 5/8 on the other. I can't remember whether it was the earlier or the later years that had split sizes.
respectfully, 59shortfleet | | | | | Joined: Apr 2015 Posts: 336 Shop Shark | | Shop Shark Joined: Apr 2015 Posts: 336 | The 59's with the recirculating heater didn't have a shut off valve from the factory. If your core has 3/4 on both rigid lines from the core, somebody did that, it came from the factory with one 5/8's and one 3/4's. I believe the 5/8 was the return flow line into the heater core.
Last edited by Cablesmill; 04/08/2017 7:24 AM.
1959 3100 Apache Fleetside
| | | | | Joined: Dec 2016 Posts: 80 'Bolter | | 'Bolter Joined: Dec 2016 Posts: 80 | Very interesting, the heater core tank ends both have "Harrison" stamped on them. The radiator guy came up with a core that had the same dimensions from an available core and used the tank ends from the original. Either way I will get it functioning!
1959 3204 Basic Cab
| | | | | Joined: Feb 2004 Posts: 29,814 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,814 | I seem to recall that on the cores with different size hoses, the 5/8" line was on the "pressure" side, from the cylinder head. They seemed to think a bigger return hose was needed because of pressure drop across the core, sort of like an air conditioner "suction" line. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
| | | | | Joined: Feb 2002 Posts: 12,029 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Feb 2002 Posts: 12,029 | I've found the 2 sizes on some standard truck heater cores, the car heater core always had both 3/4
Bill | | | | | Joined: Feb 2012 Posts: 506 'Bolter | | 'Bolter Joined: Feb 2012 Posts: 506 | Is there any concern with having coolant sitting/rotting in the heater core all summer if you install the shut off valve? Seems like it would be better to have constant flow versus coolant just sitting there. Am I off base??
Thanks
Larry
| | | | | Joined: Jun 2006 Posts: 693 'Bolter | | 'Bolter Joined: Jun 2006 Posts: 693 | i think you're off base. i cant see any way that coolant sitting there would do anything. frankly i would think that repeated heating/cooling cycles of the core as you use the truck and circulate hot water would put stress on the tank/core/pipe connections and be more likely to cause a leak. people who store their classics for the off season leave coolant in the core and radiator for months. | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Just so you have anti-freeze and distilled water in there.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires. '47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle. '54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed. '55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Dec 2016 Posts: 80 'Bolter | | 'Bolter Joined: Dec 2016 Posts: 80 | The main reason for the shut off valve was to stop the flow during the hot months to kill extra heat in the cab even if the fan was not on.
1959 3204 Basic Cab
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