The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Engine & Drivetrain > LSx Swaps

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-15-2018, 11:47 PM   #1
1968aj
Registered User
 
Join Date: Apr 2009
Location: houston texas
Posts: 1,438
heater hose question

I have a 71 c10. it has a 2005 5.3 out of a Silverado.right now I have no a/c or heater.the installer blocked off the heater hose outlets. should they be blocked off or looped together?if looped together is the answer what size hose do I need?THANKS
Attached Images
 
1968aj is offline   Reply With Quote
Old 07-16-2018, 12:01 AM   #2
Ghost's68
Registered User
 
Ghost's68's Avatar
 
Join Date: Jun 2016
Location: American Canyon, CA
Posts: 253
Re: heater hose question

Better to run a bypass hose. I’m running one on my LS swap.
https://www.amazon.com/Heater-Bypass.../dp/B013QNJ9SQ
Ghost's68 is offline   Reply With Quote
Old 07-16-2018, 12:36 AM   #3
1968aj
Registered User
 
Join Date: Apr 2009
Location: houston texas
Posts: 1,438
Re: heater hose question

THANKS I was not comfortable with capping them off.
1968aj is offline   Reply With Quote
Old 07-16-2018, 01:06 AM   #4
mongocanfly
Post Whore

 
mongocanfly's Avatar
 
Join Date: May 2015
Location: Alabama
Posts: 14,557
Re: heater hose question

X2....I was told not to block them off if not running a heater...and to use a loop....
__________________
Mongo...aka Greg

RIP Dad
RIP Jesse

1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598
Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334
Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563
2023 Chevy Z71..daily driver
mongocanfly is offline   Reply With Quote
Old 07-16-2018, 11:20 AM   #5
davepl
Registered User
 
davepl's Avatar
 
Join Date: Aug 2006
Location: Redmond, WA
Posts: 6,332
Re: heater hose question

Yes, they must be looped because the LS water pump, unlike the old small block chevy, does not have an internal bypass.
__________________
1970 GMC Sierra Grande Custom Camper - Built, not Bought
1969 Pontiac 2+2 427/390 4-speed Coupe
1969 Pontiac 2+2 427/390 4-speed Convertible
davepl is offline   Reply With Quote
Old 07-16-2018, 09:56 PM   #6
1968aj
Registered User
 
Join Date: Apr 2009
Location: houston texas
Posts: 1,438
Re: heater hose question

THANKS everyone bypass hose is ordered. I ordered a extra for the guy who did the swap for me to show him the best way. this is only temporary till I can get the vintage air ordered.
1968aj is offline   Reply With Quote
Old 07-17-2018, 12:01 AM   #7
ls1nova71
Registered User
 
ls1nova71's Avatar
 
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,117
Re: heater hose question

Quote:
Originally Posted by 1968aj View Post
THANKS everyone bypass hose is ordered. I ordered a extra for the guy who did the swap for me to show him the best way. this is only temporary till I can get the vintage air ordered.
At which time you will go right back to blocking them off...... The way I understand it, which may or may not be right, is the system was designed the way it is for faster warm ups to help with emissions. Once the cooling system is full, it shouldn't matter. When you put a Vintage Air set up on it, whenever the A/C is on, the heater hoses will be blocked off by the heater control valve, essentially blocking the same ports off. I've personally put well over 200k miles on LS swapped vehicles with this same set up and never had an issue, most of which miles were put on in the heat of the summer with the aircon on.
__________________
My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html

5.3 swap into my RUSTY '71 C10
http://ls1tech.com/forums/conversion...71-c-10-a.html
ls1nova71 is offline   Reply With Quote
Old 07-17-2018, 05:11 AM   #8
NC_John
Registered User
 
NC_John's Avatar
 
Join Date: Jul 2013
Location: Rockwell, NC
Posts: 1,639
Re: heater hose question

Quote:
Originally Posted by ls1nova71 View Post
At which time you will go right back to blocking them off...... The way I understand it, which may or may not be right, is the system was designed the way it is for faster warm ups to help with emissions. Once the cooling system is full, it shouldn't matter. When you put a Vintage Air set up on it, whenever the A/C is on, the heater hoses will be blocked off by the heater control valve, essentially blocking the same ports off. I've personally put well over 200k miles on LS swapped vehicles with this same set up and never had an issue, most of which miles were put on in the heat of the summer with the aircon on.
There is a big discussion regarding that on ls1tech, isn't there. Some guys put that pre-heater bypass loop in, others say its not necessary. I went your route. Leave it (without) until I see a need for it.
__________________
1970 C-10 LWB "Blu"

Instagram (current build pictures) 70_nc_c10
NC_John is offline   Reply With Quote
Old 07-17-2018, 06:22 AM   #9
ls1nova71
Registered User
 
ls1nova71's Avatar
 
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,117
Re: heater hose question

Quote:
Originally Posted by NC_John View Post
There is a big discussion regarding that on ls1tech, isn't there. Some guys put that pre-heater bypass loop in, others say its not necessary. I went your route. Leave it (without) until I see a need for it.
Yes there is, those discussions get pretty heated at times. LOL! I've done it both ways and haven't seen a difference in either one.
__________________
My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html

5.3 swap into my RUSTY '71 C10
http://ls1tech.com/forums/conversion...71-c-10-a.html
ls1nova71 is offline   Reply With Quote
Old 07-17-2018, 10:27 AM   #10
Macdaddy1
Registered User
 
Join Date: Dec 2017
Location: Niceville Florida
Posts: 347
Re: heater hose question

So if you are blocking them off what is the correct method? Is there a part that fits over the tube and then tightens like a hose clamp?
Macdaddy1 is offline   Reply With Quote
Old 07-17-2018, 06:48 PM   #11
1968aj
Registered User
 
Join Date: Apr 2009
Location: houston texas
Posts: 1,438
Re: heater hose question

mine has some rubber caps held on with hose clamps
1968aj is offline   Reply With Quote
Old 07-18-2018, 12:42 AM   #12
87chevy.com
BMW & ASE Master Certified
 
87chevy.com's Avatar
 
Join Date: Feb 2004
Location: Houston, Texas
Posts: 1,255
Re: heater hose question

In can say with experience, you may overheat if you have a smaller radiator and the heater core lines are blocked. In my bmw 5 series LS swap, the heater core lines go to the factory heater valve. Maybe the same as vintage air system, ac on, no need for hot water to flow inside the ac box, and its closed. Ive seen the coolant temp rise above 220-230 before I realized what's going on (automerer gauge) That's at the water drilled and tapped next outlet by the tensioner. The temp sender in the head goes higher. As soon as the heater valve is opened, coolant temp goes down and back to normal. Before I thought the radiator was too small, stock. It wasn't the road, it was the design of the heater core flow. Also have the 160* stat
Clint
__________________
1987 Silverado - L83 5.3 w/ 6L80e ,A/C,P/W,P/L,TILT, HID projectors, Wilwood C-10 Pro Spindles w/ 2018 silverado front brakes & C-5 Corvette Rear Disc Brakes
1999 BMW 528i - 5.7 LS1 w/ 4l60e, Ford 8.8 IRS w31 spline posi & FX-r projector retrofit

New project: 2006 BMW x5 6cyl AWD to L83 6l80e 4wd to 2WD / RWD

A poor man buy's it twice

finally got my domain name back, 87chevy.com.... site rework in progress
87chevy.com is offline   Reply With Quote
Old 07-18-2018, 01:50 AM   #13
ls1nova71
Registered User
 
ls1nova71's Avatar
 
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,117
Re: heater hose question

Quote:
Originally Posted by 87chevy.com View Post
In can say with experience, you may overheat if you have a smaller radiator and the heater core lines are blocked. In my bmw 5 series LS swap, the heater core lines go to the factory heater valve. Maybe the same as vintage air system, ac on, no need for hot water to flow inside the ac box, and its closed. Ive seen the coolant temp rise above 220-230 before I realized what's going on (automerer gauge) That's at the water drilled and tapped next outlet by the tensioner. The temp sender in the head goes higher. As soon as the heater valve is opened, coolant temp goes down and back to normal. Before I thought the radiator was too small, stock. It wasn't the road, it was the design of the heater core flow. Also have the 160* stat
Clint
Sounds to me like your main problem is the too small of radiator matched with a 160* thermostat. It's been my experience that putting too cool of a thermostat in actually does the opposite of what you would think by not letting the coolant to spend a sufficient amount of time in the radiator therefore causing it to actually run hotter.
__________________
My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html

5.3 swap into my RUSTY '71 C10
http://ls1tech.com/forums/conversion...71-c-10-a.html
ls1nova71 is offline   Reply With Quote
Old 07-18-2018, 09:09 PM   #14
87chevy.com
BMW & ASE Master Certified
 
87chevy.com's Avatar
 
Join Date: Feb 2004
Location: Houston, Texas
Posts: 1,255
Re: heater hose question

Quote:
Originally Posted by ls1nova71 View Post
Sounds to me like your main problem is the too small of radiator matched with a 160* thermostat. It's been my experience that putting too cool of a thermostat in actually does the opposite of what you would think by not letting the coolant to spend a sufficient amount of time in the radiator therefore causing it to actually run hotter.
Never thought about it like that.. once I get the ac lines made up, I'll see how the temps are with the 160 stat and maybe change it to the 180 just to see.
Thanks for the help
__________________
1987 Silverado - L83 5.3 w/ 6L80e ,A/C,P/W,P/L,TILT, HID projectors, Wilwood C-10 Pro Spindles w/ 2018 silverado front brakes & C-5 Corvette Rear Disc Brakes
1999 BMW 528i - 5.7 LS1 w/ 4l60e, Ford 8.8 IRS w31 spline posi & FX-r projector retrofit

New project: 2006 BMW x5 6cyl AWD to L83 6l80e 4wd to 2WD / RWD

A poor man buy's it twice

finally got my domain name back, 87chevy.com.... site rework in progress
87chevy.com is offline   Reply With Quote
Old 07-19-2018, 05:12 PM   #15
Clyde65
1965 Chevy C10, 2005 4.8L/4l60
 
Clyde65's Avatar
 
Join Date: Aug 2004
Location: DFW Texas
Posts: 8,539
Re: heater hose question

The LS runs better when it’s at or around 195, this allows the intake to better atomized the fuel so it’s runs more efficiently and economically.
__________________
Clyde65

Rebuild of Clyde
http://67-72chevytrucks.com/vboard/s...84#post8338184

69 Aristocrat Lo Liner build
http://67-72chevytrucks.com/vboard/s...84#post7561684



support our troops!
Clyde65 is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:35 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com