Got a problem... at night windows steam up on the inside. Coolant smell in cabin ( all the time). Pulled the carpet back (passenger side RHS) under the dash and it’s wet. Fluid trickling down from the cavity behind dash. Obviously a hole / leak somewhere. Where do I start?

 

It is time to put in a new heater core.

 

AC will make it interesting.

 

^^^x2

 

The only coolant under the dash is in the heater core, so that should tell you where to start.

 

x4

 

You can by pass the heater w the hoses under the hood. You wont have heat, but you wont have coolant or smell in your car.

then you can replace your heater core, or 10 years later say ill do that next like i do

 

Before I put the AC in my 54 I pulled the heater core and had a small leak in it repaired and also replace the Ranco valve. About a year ago it started leaking and there was no way I was pulling it again. So I got two shutoff valves that screw into the intake manifold and the water pump and installed them and closed them. It looks a lot better than running a hose from the water pump to the intake manifold. I used several applications of oil dry on my carpet to get the coolant out of the carpet.

 

Future upgrade, i plugged the intake like glenn did

 

I didn't plug it. I put cutoff valves in and hooked the heater hoses to the valves so it looks like the heater is hooked up which it actually is. The valves are just closed so no water goes to the heater.

 

Eh, I've replaced the heater core in my car so many times since the early 1980s that I can probably do it with my eyes closed.

The hardest part is accessing the one nut behind the fender well. I opted to not put that one back after the first heater core replacement, and I have been very glad I did that during every heater core replacement since then.

 

in what way please... thanks

 

You have AC so nothing you can do about it. You will need to pull that lower valence with ac vent for starters. Get a chassis manual, that will help a lot. It is not technically very hard, just more of PITA in that (as others have mentioned) you will need to at least partially remove the plastic wheel well to access one of the nuts. If you take out the seat (or passenger bucket) it will be much easier to move around it, especially for us older guys. I did one quite a while ago...……….

It is a project...…………...

 

many thanks

 

jackpot. Thanks a million.

 

FSM, 1966 anyway, says to drill a 3/4" hole in a dimple on the fender well, to provide forever access to that nut, then install a rubber plug. Not that I've ever gone that route, since taking off the hood/fender/inner-fender is not a big deal.
On a related note, any recommendations on where to source a '66 replacement core? Rock Auto doesn't sell them.

 

I think the challenge if finding a heater core replacement which accommodates AC, but I did find one place. Good luck!

Says they have x2 available w/AC
https://www.ebay.com/itm/12376666405...evt=1&mkcid=28

 

Mine isn't an A/C car, but I now see them on Rock Auto; $28 with A/C, $77 without A/C.

 

Sorry, for some reason I thought you had AC. Good luck!

 

thanks vintage chief... it’s 350RKT mine is an A/C car. That was someone else making that comment.

 

I've done the Redneck Version on Chevies where you pull one hose off the water pump, and the second hose off the firewall, then plug that second end to the water pump hole so it's just a loop.

Olds version would be rerouting the return hose from the firewall to the valve on the back of the block and stashing the block to firewall hose.