I have a 1967 Delmont 88 425 Holiday Coupe. Need to drop the tank and replace the sending unit, so fuel gauge will work. My thoughts are with the tank out, have it cleaned on general principles since it is 50 years old. As far as the sending unit in tank, what I have seen online is plastic, and doesn't look like any units I have replaced over the years. Anybody care to throw in their 2 cents? or if like me and windy, just e-mail me bnvle64@windstream.net

Since heater is not warm, figured to pull radiator and heater core and have them rodded out, too

 

Hello Golden Rocket. Welcome to the site! You posted this message to another thread, I think you might get more help with your own thread so I moved it to here.

I took a fuel tank that had rust & sludge in it to a radiator shop. They ran it through the chemical bath they use to clean radiators and it came back looking nice inside. I did call around and this service varied widely on price, so don't call just one shop unless their price sounds good to you.

John

 

Thanks for the help, still learning to navigate the site. Seems to me like Oklahoma is trying to be like some states that bust the chops of hobbyist. There is a radiator shop in town and several others in the Tulsa Area. So will be checking prices. I did talk with several other guys and they said don't coat the inside of the tank. Just leave it bare metal. Any thoughts on that. Am going to pull the radiator and heater core and have them vatted also.

I have been surfing for a fuel tank sending unit for it, since gauge doesn't work. Any ideas where to get one?

Thanks for any help, I'm not looking to race thru this one, but take my time, so I'm out from under foot in the house.

mike II

 

There is coating sold for the inside of gas tanks. But the guy who boiled mine out for me recommended not using it. He said it might come loose and plug the screen on the outlet. He said since there were no holes to plug that it would be better to leave it bare metal.

Sorry, I can't help with a source for the sending unit. Hopefully someone here will be able to help.

John

 

I would not coat the tank as some of the coatings do not like ethanol gas.

 

I believe that the ethanol problem has been dealt with and the bad results people had years ago were all in the past. Modern coatings are completely different from the ones that everyone used (once) 20 years ago.

There is no reason not to use a modern tank coating, so long as you prepare the surface properly first.

- Eric

 

Either use an inspection camera or look inside when you have the tank out. You might be surprised how clean it may be. I know for some models new tanks are not that expensive, not sure for your application. Good luck.

 

Why? There are a lot of possible causes of no heat that don't involve the heater core or radiator. You MIGHT want to try some troubleshooting before spending time an money to "fix" something that isn't broken.

Does the car overheat? If not, chances are the radiator isn't plugged.

Does the car have A/C? If so, is the heater control valve connected and working properly? This car uses a heater control valve that is normally closed and only opens when the controls are set to HEAT or DEFROST. The valve can stick closed, thus no heat.

Are the heater controls themselves working properly? Is the vacuum-operated heater blend door working?

 

So the car was delivered today. Just a rough walk around, and a look see. The right exhaust manifold is cracked, JB Weld a good repair or replace it? Have several places where it appears to be a bondo repair bubbling up on quarter panels, and other than needing to re-install all the A/C parts under the hood, and the needle for the fuel gage pointing over to the hot light, not much needs done to it. Any thoughts or info to impart to me? Thanks in advance. Mike II

 

Seriously? Replace it. These are the same on all 1965-1970 full size big block cars with either single or dual exhaust. Not that hard to find.

The bubbling is guaranteed to be worse than it looks.

Condition of the brakes? Suspension? Steering?

 

Mike, I used this kit to restore the fuel tank on my 71 98:

https://www.summitracing.com/parts/s...56-3/overview/

It works great. It didn't say anything in the documentation about susceptibility to ethanol gas; however, in OK we can still buy 100% gas. That's what I always run in my Olds.

If the exhaust manifold is cracked or damaged, remove it and have it welded professionally (or do it yourself if you know how to weld cast iron). JB Weld doesn't make an epoxy strong enough to withstand the heat of an exhaust manifold. If it was a timing chain cover or thermostat neck it might be different.

 

Casting number 398708, used on every single 1965-1970 full size Olds with either 425 or 455.

 

Bit of advice I was given for my Delta: If your sender turns out to be stuck and unserviceable, it might be a good idea to use the FG106A sending unit for a '71 Delta instead of the old canister type. It's $47 + shipping on RockAuto, I think I found mine cheaper on ebay. The originals are available NOS (unused) now and then, but I've been warned away from them as they're usually expensive and may be prone to sticking just as much as a used one.

In my experience, with this same sender in this same fuel tank design, the FG106A fits well, though the metal fuel outlets are a bit shorter than original, making it a little tricky to secure or loosen the fuel line's hose clamps with the tank up in the car. Only other issue is that the needle swings around while accelerating/braking/turning since the rheostat and gauge aren't dampened and the '67 tanks don't have the anti-slosh baffles the later tanks had (didn't need them with the canister type sender). Might bend the float arm down a little bit next time I pull the tank to make it more accurate, since mine reads "E" while I have a full nine gallons left in the tank, but other than that it works well enough.

Since you mentioned AC parts, your engine should have the AC-specific fuel pump with the third return line fitting on it, which this sender has a mate for.



About the heat, I agree with Joe, do some diagnostics on the climate control system before you go tearing out the rad or the heater core. Anything is possible, but I doubt the heater core is to blame here, as the usual mode of failure is a leak that results in "steam"/mist coming out of the vents and/or traces of a leak from the heater core case under the dash. If you do have to take the heater core out for some reason, you'll find that it's really simple in this car. The process is identical for a '67. I don't think I've owned a single other car with a heater core easier to access, except maybe a '52 Plymouth with the heater core mounted on the inner fender in the engine bay.

Joe's right that it could well be an inoperative heater control valve, or maybe the blend door cable is disconnected, frozen in its sheath, or the red securing clip that holds the sheath to the duct case is broken? Make sure the vacuum check ball is hooked up, it's mounted to the firewall below and to the passenger's side of the heater/AC blower motor in the engine bay.



Quick test to try out:

1. Warm the engine up, slide the heat lever to "Hot" and fully push in the Heat button on the dash controls until it clicks. The air should be coming out of the floor vent, if it's coming out of the AC vents then already the vacuum system would seem suspect.

2a. Locate the blend door cable, it comes down and attaches to the bottom of the duct case under the dash, close to the passenger's side end of the case. Carefully feel the fiberglass case that the cable attackes to, particularly the side of it facing you and the interior of the car. It should feel hot. If it doesn't, you have no coolant flow through the heater core, see step 2b. If it's good and hot, move on to step 3.

2b. In the engine bay, engine running and temperature lever at the "Hot" position, locate the hot water control valve on the engine (you can see it in the above video thumbnail, it's at the passenger's side rear corner of the engine, comes straight up and bends 90 degrees to connect with the heater hose, has a large vacuum diaphragm on it. Hard to miss it). The big coolant hose going from the valve to the firewall will be your clue here. Don't grab onto it since it will be hotter than hell if your valve is working, but generally feel around it, it should be radiating a ton of heat.

If this supply hose is only lukewarm at most, then you can probably rule out a clogged heater core. Disconnect the little vacuum hose connected to the valve's diaphragm and feel the end of it for vacuum. If there's no vacuum, you'll have to trace where the vacuum is getting lost. If there is vacuum, the valve itself is suspect. Fortunately they're not that expensive or hard to access for replacement. In my case the valve worked, but when I went to replace the coolant hose I found that the end of the valve where the hose connects had mostly rotted away so it had to be replaced anyway, YMMV.

3. Move the temperature slider on the controls from hot to cold and back again, while watching the exposed end of that blend door cable for movement. The black sheath should remain totally stationary, and the thin inner cable should be moving in and out at the end of the sheath, and its looped end should be hooked to the blend door stud on the bottom of the duct case with a tiny e-clip.



If the blend door and heater valve check out fine, then I'd consider rodding/replacing the heater core, but if it's something else causing the problem it'd be a shame for you to expend money and effort and still not have the problem fixed.

Let us know what you find. I've had the whole climate control system apart in my same-year Delta fairly recently so it's all pretty fresh in my mind, so I'll lend whatever help I can.

 

This is the same part I bought for my 71 98 when I coated the tank with the kit from Summit. In fact, I bought it from RockAuto.

Here is a thread about my install. Apparently, I need to update it:

https://classicoldsmobile.com/forums...1971-98-a.html

Ultimately, I found that the threaded stud on top of the fuel sending unit was grounding to the body of the car whenever I installed the tank. This gave me an erroneous reading even when I installed the wires correctly. I had to remove the threaded stud on top of the sending unit and attach the wire with a machine screw.

I used a nylon lock nut and Loc-tite on the underside of the fuel sending unit to secure the machine screw. I figured the gasoline might damage the nylon in the lock nut, but if I start getting a bad reading again I will know what the problem is.

 

Great tip, thanks. It seemed to install cleanly enough for me, but I'll have to have a look. That could possibly be the cause of the low-ball fuel level estimates it gives me.

 

I checked out the tank according to the shop manual and the problem is in the gage, on the fuel. Pulling an instrument panel is a royal pain but according to the shop manual only way to get to the gage.

steering and brakes are tight, as is the suspension. Odometer reads 69K, and from all indications could possibly be correct.

did put new tires on it, replacing the dry rotted tires it came with. my personal opinion is that whitewalls look good on a somewhat slab sided car, so that is what I went with, sort of "period" with the S/S chrome keystones it came with.

decoded the build sheet and will post it along with the pictures, hopefully within a few days. health issues keep slowing me down and pi**ing me off, since weather is better and it is easier to work on car for me, but that is life.

mike

 

Never happened unless you provide pics.

Really though, if you've followed your TM troubleshooting guide and the next step says to disassemble the dash then that's probably a good plan of action. Let us know what you find, good luck.

 

Fuel gage is on hold for now, need to get it to run right. Replaced the Packard ignition wires (green corrosion on the cap terminal ends) real heavy carbon tracking inside the distributor cap. So new plugs, points, condenser, wires, cap and rotor. to many cracks in the base and air horn on the carb, so replaced with a remanufactured unit. Need to check dwell and set timing tomorrow.

The right exhaust manifold was warped, had it off and planed, so had a set of duals installed when put back together. I farmed out the exhaust manifold, since the machine shop broke most all the bolts trying to get them out. their headache, not mine. Besides I have a bad habit of breaking E Z Outs.

How do you post pictures to this site. I'm no techy, so I use the KISS method (Keep It Simple Stupid!) Still having trouble trying to lean my "dumb" phone. an android system, but it confuses the fire out of me.

thanks for any ideas/ info. mike