Heater Core how to

[SirRobyn0]

@Memaloose & @squaredeal91 I've done a few different write ups on different repairs and one problem I have is that I have no idea if folks find them useful unless someone says something, so I appreciate you saying something!

I would have to check my parts bin to get a parts number, but I once tried using a vacuum operated valve to bypass the heater core. I connected it into the vacuum line for the recirculate vacuum pod, so if I put the A/C into max/recirculate it shut off the water flow to the heater core. I eventually took it out because I still seemed to get residual heat in the plenum, even with the water flow shut off.

I think unless a person used a valve with an actual rubber seat in it like a hose bib has some coolant will make it's way past. In the case of my valve and probably the one you had it's just a ball in the flow of coolant with a hole drilled in it. Most are like that. So no it's not 100% cut off.

 

[Memaloose]

You seem to do a jobs thoroughly and with quality parts, I can appreciate that. Working as a fleet mechanic for many years, I've had to go back and repair jobs that were completed sloppily and with used parts that should not have been reused. Good work deserves praise in my opinion.

 

[Soundmound]

I just picked up a heater core last week. You couldn't have picked a better time to do this write up. Not that I'm looking forward to the job, but at least now I know what I'm in for.

 

[SirRobyn0]

I just picked up a heater core last week. You couldn't have picked a better time to do this write up. Not that I'm looking forward to the job, but at least now I know what I'm in for.

It's really not that bad. If you get stuck and want help of course you can post here, but you are more than welcome to call me at shop if it's during the week.

 

[ali_c20]

You *might* run into some cooling issues running a shut-off that doesn't incorporate a bypass. It shouldn't be a problem since the small block (pre '96) water pump has the bypass hole into the block, but the older Chevrolets with a heater valve incorporated a bypass in the valve. Engineers must have deemed it necessary.

I run this in my K5 and will put one in my C20.
https://www.oldairproducts.com/product/25-1018-bypass-heater-valve
It's available in push or pull cable to open. Cable is not included, but they are cheap . Engine warms up faster with valve closed. If you're running in a hot coolant situation you can add a shot off low temp coolant with opening the valve.
Works perfect since 3 years.

 

[scrap--metal]

Thanks, Rob! I'm sure I will be referencing this when my time comes. Quality stuff as always!

 

[SirRobyn0]

Thanks, Rob! I'm sure I will be referencing this when my time comes. Quality stuff as always!

Thank you!

 

[TotalyHucked]

Man, I wish you'd posted this a week earlier and I'd found it lol. I pulled mine out and managed to break the bottom tab off the blend door cuz my dumb ass just pulled on it's rod without trying to see if it was indexed a certain way Now I've gotta epoxy it back together

 

[SirRobyn0]

Man, I wish you'd posted this a week earlier and I'd found it lol. I pulled mine out and managed to break the bottom tab off the blend door cuz my dumb ass just pulled on it's rod without trying to see if it was indexed a certain way Now I've gotta epoxy it back together

That's too bad, but we have all been there. I'm sure a quality epoxy and it'll be good to go.

 

[Bextreme04]

I run this in my K5 and will put one in my C20.
https://www.oldairproducts.com/product/25-1018-bypass-heater-valve
It's available in push or pull cable to open. Cable is not included, but they are cheap . Engine warms up faster with valve closed. If you're running in a hot coolant situation you can add a shot off low temp coolant with opening the valve.
Works perfect since 3 years.

It should be noted that the way the heater lines are run on the squarebodies, it allows the coolant to completely bypass the thermostat and then circulate back into the suction side of the radiator. This means that the coolant is constantly circulating through the cold side of the radiator and it can keep the engine from warming up as fast. Adding a shutoff valve should allow the engine to warm up faster, but should have no effect on how well it cools when it warms up and the thermostat opens up. If anything, I would think it might actually force more coolant to flow through the radiator rather than bypassing through the heater core, which might actually cool the engine better.

 

[89Suburban]

Thanks for taking the time to do this @SirRobyn0

 

[SirRobyn0]

Thanks for taking the time to do this @SirRobyn0

My pleasure, and I appreciate all the positive feedback.

 

[SirRobyn0]

So I just wanted to give an update. The reason for the heater core replacement was that it was seeping. I wasn't having an issue with heater output, but tested it this afternoon just to see.

You must be registered for see images attach

That's 140F I think that will work!

 

[gmbellew]

Yeah, the heat will blow you out, even in my suburban! I rarely have to turn it up very much once the engine is warm or you will be sweating

 

[SirRobyn0]

Yeah, the heat will blow you out, even in my suburban! I rarely have to turn it up very much once the engine is warm or you will be sweating

I kind of wish I'd of taken a before temp, because I always felt the truck had a plenty strong heater in it. Guess we'll see this winter when it gets good and cold.