DIY: Heater Core Bypass

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RubberFrog

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I had this done on my 04 and never got around to it on my 07.

What is this for? The heater core is not completely isolated from the air system and constantly radiates heat whether you have the heater on or not. This is why the fresh air vent always feels hot, even on a cool night. Shutting off flow to the heater core allows you to actually enjoy cool air from the vent. Also, this will improve the function of your AC as you will not be releasing heat into the air after it is cooled down.

I typically shut mine off around May and turn it back on around October.

Here are a few pics and tips for anyone looking to do it. Use the top hose so it's easier to reach the valve when you need to change it. The hoses are 5/8". Don't try to use 3/4" barbs as they're too big and they'll leak. Also, watch the tails of your clamps so they're not rubbing the bottom hose or the valve cover. Use a 5/8" or 3/4" valve, any smaller and you'll restrict flow thru your heater core when you want to use it (less heat in the winter!). After clamping the hose, cut out a section of hose slightly shorter than the body of the valve (not including barbs). If you don't, the hose will be too long and the valve will hang to the side all funky.

hoses.jpg

clamped.jpg

valveinstalled.jpg

valve.jpg
 

ramhunter9

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this one is on my list to do , great wright up george .
 

Mega-Hemi

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Ya know, I've worked on Semi's for years and most have these, never thought about putting one in a p/u. Good idea. Just don't forget to open it in the fall. I can't tell you ow many times guys have brought their rigs in the shop complaining of no heat, all they had to do was open the valve.
 

ramhunter9

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i really need to do this ....off to the parts store in the AM
 

rocket

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Believe me I'm no expert on diy"s , but vicegrips would be a tad handier too shut off them hoses. imo.
 
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RubberFrog

RubberFrog

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Yes they would. I just didn't have a pair handy at the time I was doing this.
 

OklaHemi

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i know its getting close to winter and this mod is not needed right now but i have all the parts so im going to knock it out soon. nice write up as usual george
 

jsmith180601

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I do this with my concrete truck every fall and spring....
Looks like I got another project coming up lol

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ZakkBaker

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Oh wow, very cool. Is it really that simple? No complications or anything?
 

jsmith180601

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eha3e5yj.jpg
I just did this diy and man works great..
Woulda worked better if I clamped off the hoses better and didn't lose about a half gallon of antifreeze

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RTom

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Boom! On the to-do list!! Very nice write up!!
 

moops

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Your write-up inspired me to do this mod. Just finished. This will take care of one of my biggest pet-peeves about vehicle air systems. Sometimes I just want air from outside, inside. Thanks for the help!
 

CorDog009

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I think I have enough odds and ends lying around to make one of those setups. Plumbing on jetboats has left me with tons of misc. fittings and valves. So only the upper hose needs a valve?
 

JPT

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I just had my heater core replaced. This would worry me, wouldn't want to cause any corrosion.
 

indy05daytona

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Working this in when I change my cam

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HemiDrew

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Thanks for the write up. Gonna do this in the spring. Already have the material laying around the shop.
 

Egress

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wow, why am I just seeing this thread for the first time? Great idea and write-up. Did this yesterday, cant tell yet what diff its made since its actually a cool day. Entire mod took me ~10 minutes, removed the air box for easy accessibility.
 
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Zacedward

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I heard o the 6.7 engines you can't do that it runs to the turbo
 

Izzyb47

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are u sure your allowed to do that wouldnt that stop the circulation of the cooling system.
 
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