heater hose question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Fatback · 08-25-2005, 10:47 PM

Does it make any difference where the hoses go from intake/water pump to heater core?? Thanks

Longhorn Man · 08-25-2005, 10:55 PM

not really. Hot water in....cool water out.

Fatback · 08-25-2005, 11:08 PM

Quote:

Originally Posted by Longhorn Man

not really. Hot water in....cool water out.

Thanks...just wanted to be sure.

da-burb · 08-27-2005, 10:51 PM

Huh? There is a right way to do them. 5/8" hose from the intake manifold to the bottom of the heater core. 3/4" hose from the top fitting to either the radiator or the water pump depending on what you have.

70GMCer · 08-28-2005, 07:36 AM

Fatback · 08-28-2005, 08:45 AM

I know its a dumb question....But the reason I asked was, I hooked everything up as follows:
Top core 3/4 to the intake....Bottom 5/8 to the nipple on the water pump.
I did it thinking that was the way it went. I started looking at pictures on here and see they are the way you describe. I'll have to go buy more 3/4 heater hose to change it. Thanks!

Longhorn Man · 08-28-2005, 11:32 AM

Quote:

Top core 3/4 to the intake....Bottom 5/8 to the nipple on the water pump.

That will work perfectly fine. It makes no differance which is on top, nor what size hose you use, as long as you have hot water flowing in, and not as hot water flowing out.

chipflyer · 08-28-2005, 05:23 PM

Hey Fastback,
To be correct it needs to be the way da-burb posted. While it will work hooked up backwards, its not the way GM intended it to be setup. The hotest water in the engine goes out the 5/8 hose on the intake and goes into the lower nipple on the heater core also 5/8. Cooler water returns from the top 3/4 inch nipple to either the radiator or waterpump which will also be 3/4. When dealing with hyrdaulics or any kind of fluid pressure system, the return line will always be the larger line. Thats why one nipple is 5/8 and the other is 3/4, they didn't accidently do that!

Jeff

**hilljob26** · 08-28-2005, 08:18 PM

will it hurt it if it is backwards,is there something that can happen,or will the heater just not be as hot,just curious

Longhorn Man · 08-28-2005, 10:44 PM

not as hot? Nothing you'll ever be able to feel...no damage either.

Fatback · 08-28-2005, 11:12 PM

It's correct now. Thanks for the info!!

08-25-2005, 10:47 PM	#1
Fatback Registered User Join Date: Dec 2003 Location: North Central FL Posts: 126	heater hose question Does it make any difference where the hoses go from intake/water pump to heater core?? Thanks __________________ 70 C/10 LWB 69 Cougar 68 Mustang 68 GMC 4X4 SWB

08-27-2005, 10:51 PM	#4
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	Huh? There is a right way to do them. 5/8" hose from the intake manifold to the bottom of the heater core. 3/4" hose from the top fitting to either the radiator or the water pump depending on what you have. __________________ Bowtie Truck Stop Inc. Mid-West GM Truck Restoration Parts Supplier Your Key Parts, Auto Metal Direct, Dynacorn, and Goodmark dealer. like us @ www.facebook.com/BowtieTruckStop 1971 C-10 Suburban (Ochre) 1971 K-10 Suburban (Ochre) 1972 C-10 Suburban (Ochre) 1972 K-20 Suburban (Yellow- that just aint right!) Springfield, Minnesota 56087

08-28-2005, 07:36 AM	#5
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	__________________ 1997 GMC Sierra Ext 1965 Mustang

08-28-2005, 08:45 AM	#6
Fatback Registered User Join Date: Dec 2003 Location: North Central FL Posts: 126	I know its a dumb question....But the reason I asked was, I hooked everything up as follows: Top core 3/4 to the intake....Bottom 5/8 to the nipple on the water pump. I did it thinking that was the way it went. I started looking at pictures on here and see they are the way you describe. I'll have to go buy more 3/4 heater hose to change it. Thanks! __________________ 70 C/10 LWB 69 Cougar 68 Mustang 68 GMC 4X4 SWB Last edited by Fatback; 08-28-2005 at 08:48 AM.

08-28-2005, 05:23 PM	#8
chipflyer Registered User Join Date: May 2004 Location: Topeka, Ks Posts: 2,293	Hey Fastback, To be correct it needs to be the way da-burb posted. While it will work hooked up backwards, its not the way GM intended it to be setup. The hotest water in the engine goes out the 5/8 hose on the intake and goes into the lower nipple on the heater core also 5/8. Cooler water returns from the top 3/4 inch nipple to either the radiator or waterpump which will also be 3/4. When dealing with hyrdaulics or any kind of fluid pressure system, the return line will always be the larger line. Thats why one nipple is 5/8 and the other is 3/4, they didn't accidently do that! Jeff __________________ I'm not a pessimist, I'm just optimistic that bad things are going to happen. 1971 Cheyenne Super K10 - tilt, cruise, air, am/fm, tow hooks, factory buckets! 1986 Jeep J10 pickup, - 5.3L Vortec with 4L60e and NP241.

08-25-2005, 10:55 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	not really. Hot water in....cool water out.

08-28-2005, 08:18 PM	#9
hilljob26 Registered User Join Date: Dec 2004 Location: Gypsum Kansas 67448 Posts: 1,681	will it hurt it if it is backwards,is there something that can happen,or will the heater just not be as hot,just curious __________________ 21 2500hd duramax 58 apache HILLJOB GRAPHIX--for all your graphic needs My build thread http://67-72chevytrucks.com/vboard/s...d.php?t=542497 LS ENGINE SWAP INFORMATION THREAD http://67-72chevytrucks.com/vboard/s...d.php?t=377348 4l60 to an NP205 http://67-72chevytrucks.com/vboard/s...43#post3697343

08-28-2005, 10:44 PM	#10
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	not as hot? Nothing you'll ever be able to feel...no damage either.

08-28-2005, 11:12 PM	#11
Fatback Registered User Join Date: Dec 2003 Location: North Central FL Posts: 126	It's correct now. Thanks for the info!! __________________ 70 C/10 LWB 69 Cougar 68 Mustang 68 GMC 4X4 SWB

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