Heater Core Bypass help
Thread Starter
Melting Slicks
Joined: Apr 2007
Posts: 2,678
Likes: 0
From: Atlanta Georgia
Heater Core Bypass help
Hey everyone,
My heater core is beginning to fail, so until I can fix it later this summer I was going to bypass it since I would not need heat til the winter. So i read that you can disconnect two lines when they go through the firewall you can connect them together with a brass tube, to bypass the heater core. Can anyone point out in a picture or describe where it is? What are the pros and cons to doing this, besides not having a defroster? Thanks in advance, I appreciate all the help.
Jason
My heater core is beginning to fail, so until I can fix it later this summer I was going to bypass it since I would not need heat til the winter. So i read that you can disconnect two lines when they go through the firewall you can connect them together with a brass tube, to bypass the heater core. Can anyone point out in a picture or describe where it is? What are the pros and cons to doing this, besides not having a defroster? Thanks in advance, I appreciate all the help.
Jason
Instructor
Joined: Apr 2008
Posts: 105
Likes: 1
From: New Ulm MN
Disconnect the two hoses running into the heater core at the fire wall. Buy a new hose long enough to loop 180 degrees to the brass hose fittings so it feeds from one fitting right back into the other. Essentially you are just making a U shaped hose fitting and skipping the heater core. I ran mine like that all last summer with no ill effects including no increased water temps etc. Just make sure the hose is long enough that it does not pinch and reduce flow. Initially, I though I had a heater core leak as well but later discovered it was only my hot water valve that was leaking, which is located right outside the firewall where you are going to reroute your hoses. In the end, I just cut out the valve with my Saws-All and ran two new(slightly longer) hoses into my firewall restoring flow and heat to the interior, problem solved. Contrary to some beliefs, your air does not always blow hot without a hotwater valve. When my temp selector is on "cold" I still only get cool air.
Instructor
Joined: Apr 2008
Posts: 105
Likes: 1
From: New Ulm MN
Disconnect the two hoses running into the heater core at the fire wall. Buy a new hose long enough to loop 180 degrees to the brass hose fittings so it feeds from one fitting right back into the other. Essentially you are just making a U shaped hose fitting and skipping the heater core. I ran mine like that all last summer with no ill effects including no increased water temps etc. Just make sure the hose is long enough that it does not pinch and reduce flow. Initially, I though I had a heater core leak as well but later discovered it was only my hot water valve (L98) that was leaking, which is located right outside the firewall where you are going to reroute your hoses. In the end, I just cut out the valve with my Saws-All and ran two new(slightly longer) hoses into my firewall restoring flow and heat to the interior, problem solved. Contrary to some beliefs, your air does not always blow hot without a hotwater valve. When my temp selector is on "cold" I still only get cool air.
Racer
Joined: Jun 2006
Posts: 408
Likes: 0
From: Elkton MD
'95 heater bypass
5point7,
Since you have a '95, you don't have a hot water valve.
The two hoses running into the firewall on the passenger side under the black plastic 'pressure fill' tank need to be connected. The two hoses are different size so a single pipe doesn't work well. I used a 3/4" to 1/2" copper adapter pipe but had to really squeeze the 1/2" side as that hose is actually 5/8" inner diameter. Many choices at the hardware store to connect a 3/4" hose to a 5/8" hose.
Since the hoses are next to each other, the connector does not have to be more than 1" or 3" long; whatever you can find.
Really a simple job.
So long as you don't need heat, no down side at all. You can continue to get defrost air; just not heated.
Good luck.
Since you have a '95, you don't have a hot water valve.
The two hoses running into the firewall on the passenger side under the black plastic 'pressure fill' tank need to be connected. The two hoses are different size so a single pipe doesn't work well. I used a 3/4" to 1/2" copper adapter pipe but had to really squeeze the 1/2" side as that hose is actually 5/8" inner diameter. Many choices at the hardware store to connect a 3/4" hose to a 5/8" hose.
Since the hoses are next to each other, the connector does not have to be more than 1" or 3" long; whatever you can find.
Really a simple job.
So long as you don't need heat, no down side at all. You can continue to get defrost air; just not heated.
Good luck.
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
Another option is: One hose will be already connected to the reservoir (leave it connected). The other hose (a 180* hose) from the reservoir goes to the heater core, and the other side of the heater core goes back to the motor. Take the "loop (180* bend hose)" hose off from that goes from the reservoir to heater core, and take the other side from the heater core off and go direct to the reservoir....hope this makes sense.
Le Mans Master
Joined: Aug 2005
Posts: 5,002
Likes: 5
From: No Opti Here Tn
St. Jude Donor '06
Just loop an existing heater hose around
He is in Atl and I am sure there is a Atl Brutha out there who can help bc if you are unsure how to loop a heater hose you probably should get some help
At least 5 points has the fastest color ever on a Vette
He is in Atl and I am sure there is a Atl Brutha out there who can help bc if you are unsure how to loop a heater hose you probably should get some help
At least 5 points has the fastest color ever on a Vette
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Thread Starter
Melting Slicks
Joined: Apr 2007
Posts: 2,678
Likes: 0
From: Atlanta Georgia
i took a couple pics of where i thought it was from of the descriptions and directions I have gotten, but just to make sure if someone can circle them or point them out, i just want to be sure i have the right ones, thanks
Last edited by 5POINT7; May 4, 2009 at 01:47 PM.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
You'll want to disconnect them way back under the overflow tank at the blower motor housing....they will mostlikly be tough to get off the heater core tubes....the hoses connect to the core so it should be pretty odvious once you find them these should be the 2 connections you'd need to bypass.
Last edited by engle1147; May 5, 2009 at 01:27 PM.