65 C10 heater core removal !!

[jmcap]

Hey Guys,

I know I'm overlooking something. Removed what appears to be all sheet metal screws and can't separate upper and lower components of the box to remove the core. Two parts will not separate but are opening like a clam not wide enough for the core to pass through. I know I'll do a 'Dah' when you give me the missing step.

Thanks,
John

[69 C10 LWB]

There are 4 screws that come in from the back side. You will need to pull the whole assembly to get to them. There are 2 nuts inside the cab under the dash and the whole assembly will come out. I just had mine out last week. There is no other way to get them as they are between the heater box and the firewall.

[69 C10 LWB]

You will also need to pull the bolts that go into firewall for the fresh air intake if you haven’t already.

[jmcap]

69 C10,

Thank You. On the interior I removed the two sheet metal screws that secure the air box to the firewall but looked no further. Removing the yet located nuts that secure the external core box will shortly be found and removed to hopefully remove the entire unit.

Thank You, Thank You, Thank You,

John

[Brentwe]

Studs and nuts are higher than you would expect them.
Inner box has screws around the pass thru and one above the trans hump.
Remember to check the size of coil, 66 had 7 and 9 inch heaters.

[jmcap]

Thanks Brent. Will do as soon as I get to my son's house as it's his truck I'm working on. I'm just the "aged wrencher" always looking for things to repair. RETIRED !!

[jmcap]

Removed easily after following your suggestions. Thank You.

Wondering why I shouldn't skip re-installing the 4 blind screws on the back of the box cover plate so as to be able to get to the heater core in the future without having to remove the entire external heater box. Rather than the sheet metal screws, I would use a silicone adhesive to seal as well as " glue" that back edge. Your Thoughts?

[Brentwe]

Trying to remember, but. Don't think the top half of the box ( core is attached to)will come off without the whole box removed. And core is under the top plate, how could you work that out of there?
Didn't give that one too much thought as I am not expecting to go in there again.

[Captainfab]

I haven't tried it but I have had that same thought of leaving those 4 screws out. I don't see why it wouldn't work.

[jmcap]

I'll be re- installing tmrw. Let you know if my theory will work. Also, located an alternative to paying high prices for a new one from Classic Industries and/or LMC. $119, $79 respectfully.

Spectra Premium #94531. Exact dimensions but for the in and out ports that are not bent 90 deg. but are shorties coming straight out. $34 @ Amazon Prime/ $38, shipping inc.for me, @ Rock Auto.

Can be seen on Rock Auto listed for 65 Bel Air

[Captainfab]

Why not just spend a few bucks more and get the correct heater core?

https://www.ebay.com/itm/HVAC-Heater...1/281997550517

[jmcap]

Tired of building trailer queens. www.oldsmobilesforever.com . The C10 is a performance updated rat rod. Chevy 350, 700r4, etc.,etc. A functional and safe driver not a looker. mismatched parts kind of add to the look.

[Brentwe]

Liking it.

[Rust-O-Matic]

Just one more note:

I replaced the heater core in my '66 last year with a new one from Classic Parts. They carry a nicer looking copper version, much like the original, and a cheaper aluminum version that is much lighter and doesn't feel near as well made.

I don't remember the brand of the copper one, but I believe the aluminum one was a Spectra or Spectre, which was much cheaper if purchased from Rockauto or ebay. It's probably safe to assume all of the other vendors for our trucks carry the same ones; LMC, Brothers, Classic Industries, etc.

I bought the copper one first, and the lines were not positioned quite right before they were soldered on, so they wouldn't fit through the notches on my housing. I took it back and tried a couple others, and they were all this way.

The cheaper aluminum one fit like a charm, so I put one of those in. I don't know if it will last as long as the original did, but it's been fine ever since.

[jmcap]

I put the heater box back up today after testing my theory about not installing the 4 blind screws on the back side of the top half to the base unit. Totally solves the problem to never again climb under the dash to remove the 2 major nuts that retain the unit to the firewall. By merely removing all the screws on the engine compartment side ( but for the 4 that retain the core to the top plate) the top plate lifts right off with the core attached. I used one sided sticky rubber insulation as a seal between the two surfaces before buttoning it all up. Still no heat yet, however. God knows what former owners did or did not do. Will check for thermostat and while I'm at it put in a new water pump.

[1998c1500]

I noticed in the picture that the hoses look like they are the same diameter. I found this post just to double check things.

http://67-72chevytrucks.com/vboard/s...d.php?t=716754

[jmcap]

1998,

Thanks for the thread referral. Found so many things that were wrongly done. As you noted the wrong size hoses were routed improperly: the intake manifold fitting is 3/4" and going to the "out" side of the core, and the fitting at the water pump is wrongly 5/8" and going to the "in".

Here's the kicker !!

I didn't mention, but pictured above, I found the rubber cap over the 'out' port of the heater core blocking the flow path. Going back after your post I was shocked to find the 'in' port rubber cap within the end of the hose.!!!! Can only assume that the core was replaced at some point and the caps were never removed before attaching the hoses.
I will test for heat tmrw. If successful will buy new hoses, swap out the 5/8" and 3/4" fittings , and route the hoses properly.