1922 Cadillac Type 61 Gas Tank

[Sunnyjay]

Hello all, Is anyone aware of any sheet or screen above the drain plug in a 1922 Cadillac Gas tank? Today I removed the drain plug on my 1922 Type 61 gas tank and to my shock nothing came out. Not a drop! I gently pushed a screw driver up the hole and it felt like there was some kind of screen or solid surface in the settling chamber. A gentle push seemed to lift it and gas started dribbling out slowly.

Is there a screen or anything above the drain plug? I don't see anything on the illustration (attached).

Also, any cautions to removing the gas gauge? It appears to just unscrew from the top of the tank.

[Matt Harwood]

Likely clogged with rust. Not uncommon and always the first thing to address when sorting out an old car. Sooner or later it'll work its way into the rest of the fuel system and cause all kinds of mischief. Can you pull the tank and have a look inside?

[Sunnyjay]

2 minutes ago, Matt Harwood said:

Likely clogged with rust. Not uncommon and always the first thing to address when sorting out an old car. Sooner or later it'll work its way into the rest of the fuel system and cause all kinds of mischief. Can you pull the tank and have a look inside?

Hey Matt, yeah, that's what I was worried about. I was just surprised at how solid and plate-like the gunk above the drain was, so I wanted to ask before I prod it any more. I think I will drain the tank and clean it out.

 

Thanks!

[bobcanuck]

or perhaps the tank has been "coated" inside at some point in the past ...?

[Sunnyjay]

15 minutes ago, bobcanuck said:

or perhaps the tank has been "coated" inside at some point in the past ...?

Perhaps.. but I don't see any other signs of that at the filler neck or inside the drain plug it self. I'm thinking I should remove the gas gauge and peer inside.

[JV Puleo]

If it's anything like the 1920 Cadillac I've worked on, the gage is one of those "float attached to a gear" types. It's very simple but be careful of two things. Chances are the gear is pot metal and about to fall apart and the screws that hold the bezel on are likely to be stuck and difficult to take out without breaking them. I would definitely take it out and fix it  you may have to find a replacement gear and a new float but it would be worth it. Does it work now? Most I've seen don't so if it is working that is a good sign.

[Sunnyjay]

2 hours ago, JV Puleo said:

If it's anything like the 1920 Cadillac I've worked on, the gage is...

Hello JV - Yes! I think that's exactly the kind of set up I have. It works currently, and I wouldn't remove it, except that I really need to see how much crud is on the bottom of the tank and if that is blocking the fuel line and causing my fuel supply problems.

 

The attached picture is my gauge. It looks like it unscrews, is that how that 1920 one was?

[edinmass]

There is no free lunch. Take the tank out, and have it cleaned…….if you live near the ocean, take it to a boatyard that cleans heat exchangers on yachts. Radiator shops are a thing of the past, so they are your best bet. It’s made of turneplate, so it most likely will be fine.

[JV Puleo]

I seem to remember the 1920 gage attached a little differently but yours looks to be simpler and more likely to come out intact. I wouldn't be too worried about taking it out, it's just that one has to be very careful. First, I'd see if the bezel unscrews. If it appears stuck, I'd apply heat with a heat gun, not a flame. There might well be some varnish buildup on the threads. Like Ed says... bite the bullet and take it out and have it cleaned. In the long run, you'll be glad you did.

[Sunnyjay]

Thanks! I think that is a good Idea. I'll drain and drop the tank.

[JV Puleo]

Another thought...try to unscrew the bezel before you drop the tank. I say that because it will be very difficult to get a firm purchase on it after it is out.

[sagefinds]

When the tank in the '15 we had plugged up with crap,I took it out,filled it almost full of water,and dumped a can of draincleaning lye in it. After 45 minutes or an hour I dumped it in the floor drain,flushed it out real good with the garden hose and it was clean. After it dried out  I sealed it with Bill Hirsh sealer and never had any more problems. I did that with the gauge and outlet both out of it of course. 

[JMac1]

We work on many antique gas tanks (we have a dozen in the shop right now). If they've been setting for a long time, the fuel that is in the tank will turn solid. This is most likely what you're feeling in there. Your best bet is to send it to a radiator shop (yes, we do still exist), get it boiled, cleaned out and (if necessary) coated with Red-Kote® (40+ years in the business, we've tried most of them and this is by far the best product). If the shop knows what they are doing, you will not only have a tank that will function properly for decades longer, but you will also be able to use your drain plug.

[Sunnyjay]

2 hours ago, JMac1 said:

coated with Red-Kote® (40+ years in the business, we've tried most of them and this is by far the best product). If the shop knows what they are doing, you will not only have a tank that will function properly for decades longer, but you will also be able to use your drain plug.

Great information JMac1! This car has done a lot of sitting over the last 15 years, and what you describe does perfectly match what I'm seeing.

 

I did talk to a radiator shop near me, and they also recommended Red-Kote. I was going to ask the forum if that was recommended vs. the Bill Hirsch brand that seems to pop up everywhere. I'm glad Red-Kote is recommended. Is there anything I should specifically ask about or confirm before dropping off the tank?

[JMac1]

21 hours ago, Sunnyjay said:

Is there anything I should specifically ask about or confirm before dropping off the tank?

The fact that they use Red-Kote®, as opposed to a cheaper brand that won't work anywhere near as well, is a good indicator that they know what they're doing. Also, coating is a process and even if the shop has no other work, it will take several days; plan for them to have it for at least a week at this time of year. Also tell them that you want your drain plug to function when it's done, or they might seal it. However, any good radiator shop knows to keep it open, but just remind them anyway.

Edited May 6, 2022 by JMac1
just remembered something (see edit history)

[Sunnyjay]

2 hours ago, JMac1 said:

tell them that you want your drain plug to function

Thank you! I appreciate it.