What was used by the detailers back in the 70`s when a dealer sent out a car to get cleaned up for the used car lots? The stuff they used lasted quite a while not like the cleaners/coatings they use today. The interiors and the engine compartments would stay shiny. Any ideas?

Probably something the EPA banned.

I have to disagree. Having been involved with this since at least '72. The old single stage paint would oxidize and would typically do it in a few months. They needed to be waxed at least twice a year. Most waxes then and now have compound or polish in them which is why they are often called 'cleaning waxes'. They actually remove some surface material in the waxing process rather than compounding and then waxing. 'Pure waxes' do not remove surface material. They only 'coat' the surface. 'Cleaning waxes', because they remove surface material by 'scuffing' it, can actually dull down a really slick paint surface and should not be used except to help correct neglected or less that stellar paint. Fifty years ago the wax helped to 'seal' the single stage paint from the environment thereby slowing down the oxidation process keeping the shine there longer. It often took a half dozen clean towels to do a car back then because they loaded up with the oxidized paint and heavy wax/compound.

Much of today's base/clear paint is much, much harder than the old single stage. But certainly not all. There are all levels of quality of clear coats on production cars today as well as in the after market. And despite the EPA's efforts, there are many automotive painting products available today that are far and away superior to anything available 'back then'.

And it's the same with the products that we use to maintain the coatings on our cars today. There are far more and far better products now than we had available 50 years ago.

Fifty years ago, the primary reason for waxing our cars was to barrier the paint from the atmosphere due to the oxidation process. Today, wax is primarily for stain protection. Personally, I do not wax my Cuda. Of course, it is not a daily driver. If I think it might be getting a little dull, I just do a quick machine polish and it is good for a few more years. You don't have to remove much surface at all anymore to get to a good gloss. Unlike 50 years ago.

This is a deep subject. And there are LOTS of variables; how hard is the clear? What kind of shape is the paint in now? Is the car a daily driver or more of a show poodle? How much time will it spend in the sun and rain/etc? And on and on....................

^^^ Quite true - enamels like Chrysler used - especially the light metallic colors, like Dad's '66 Sport Fury - oxidized ("faded") in gloss a a few years if left outside.
Some pigments were of course better than others - reds would oxidize quickly but seemed easiest to bring back.

I remember the revelation when ArmorAll was introduced - prior to that, Lemon Pledge was popular, and I can recall someone wiping brake fluid on tire sidewalls.
There was a somewhat greasy/oily product out there back in that time period, but I don't know what it was - I thought it was creepy...

Speaking only to the engine compartments, what we would do (early 80's) is clean the as good as we could, apply a liberal coat of Armor All, and leave it alone (meaning not wipe it off).

Banana oil, believe it or not.

Pledge on the interior and banana oil on the tires. Aaaahhhhhhh, the good old days.

^^^this^^^ The night before a car show.. liberal amounts of Armor All would be used.

The ceramic coating on my new truck is far better than anything used in the 70s. Light years better.

Absolutely agreed!!
The latest automotive paints and finshes are far superior to earlier products.
Plus the various detailer options including chemicals and tools available today to the car pro are far better..

Just my $0.02...

Sorry I must have indicated that I was talking about the painted surfaces of the vehicle. I was not. I was referring to the shine that was applied to the engine compartment and the vinyl interior when a used car was send out for cleanup. The engine was usually power washed and then sprayed with some type of shiny coating. Maybe is was a clear of some type, I don`t really know but I don`t think so. It was not a store bought coating that was sold at the time that I knew of. This was back in the 70`s when I was a lot boy at a car dealer and loved how nice they looked after coming back from cleanup. The vinyl door panels looked so nice and shiny for a long time and weren`t greasy or oily.

This company has been selling detail supplies since 1971, and still sells many of the same vinyl protectants and stuff people have been using forever. https://mark-v.com/

Locally the detail shops will spray diluted vinyl treatment under the hood and let it soak into the plastic after the engine compartment has been pressure washed. When you go to a a car lot and buy a trade-in that has been detailed and all the stuff under the hood looks new that is what has been done to it to make it look that way. Drive some miles on a dusty road and it will collect dust and look like a chocolate powdered donut.

ATF on wood grain exterior panels

Water based silicone is what is normally used under the hood as well as in other places. It dries, has a moderate shine that lasts very well, makes next time's cleaning much easier, and does not collect dust.

In years gone by, there wasn't much plastic under the hood unlike today. So, the chosen products and processes have changed accordingly.

And competent detailers don't use a pressure washer. Well, I guess I should say; they shouldn't use them. They can cause far more harm and problems than you can imagine. Besides, most vehicles today that are in for detailing aren't nearly bad enough to warrant that anyway. But then, as with everything automotive, nothing should surprise us. Even blasting the engine with excessive water pressure.

Years ago there were a lot of farms around here, and they would track dirt from their property out into the streets making the rural roads dusty. A lot of farmland has been replaced with subdivisions so it's not as bad as it used to be.

Detailers and mechanics still use Hotsy pressure washers and engine degreaser on trade-ins and customer cars being serviced. Low mile new stuff with better made gaskets and tighter machining tolerances don't really leak oil like the older vehicles did. It all depends on who owned it, and where they drove it at. If you camp, hike, or fish around here like many do chances are you'll find yourself driving on miles of dirt roads to get to the good spots, which will make your engine compartment filthy if you follow behind anyone for long enough. Most vehicles get the engine compartment washed to get rid of dust buildup more than degreased these days.

RE: the clarification about the engine compartment stuff -

Yeah, I remember some shiny stuff, looked like a clear coat, but I never knew what exactly it was.
I thought it looked goofy.

Clear plastic ignition spray, most likely.

As a child of the 70's I remember that stuff very well. I always wondered what it was. It was before Armor All and STP Son of a gun, if you remember that one. It was very shiny and completely dry to the touch. I always thought it was a clear laquer, but an sure it wasn't. I even asked some of the lot guys what it was but didn't get any conclusive reply. It did make the engine compartments look very nice.

Yes it did look like clear coat. Not sure what it was that they used. I`m sure the shiny gloss was not for everyone`s taste.

Now I know I `m not crazy LOL I never could find out what it was. They used something similar on the vinyl interior door panels and seats.to make it shiny too and it would come off if cleaned with a strong cleaner. That looked like it was sprayed also...

When I was detailing cars in the 80s I used a product called Trim Shine to make engine compartments look new and shiny. It was a silicone based product. It was made by Stoner Products if I recall.