Oil pan inside finish

[Steve L.]

The inside of my oil plan looks like it had a green chromate finish.
Towards the front, some surface rust has destroyed this finish.
I've cleaned it up but this section no longer has the chromate.

Is this a problem leaving it this way since the pan has oil in it anyways?

[Joe L.]

Re: Oil pan inside finish

The inside of my oil plan looks like it had a green chromate finish.
Towards the front, some surface rust has destroyed this finish.
I've cleaned it up but this section no longer has the chromate.

Is this a problem leaving it this way since the pan has oil in it anyways?

Steve------


So far, I've never seen an original oil pan that had anything but a natural steel inner finish. If by "chromate" you are referring to the "gold" dichromate overplate, then I would say that your pan is not an original GM pan. I have never seen that finish on any GM pan, either inner or outer. However, it is used on a lot of aftermarket pans.

Some later GM SERVICE pans were powder-coated BLACK, inner and outer, but I don't think this was ever used on PRODUCTION pans during the C1, C2, and C3 period.

In any event, I don't think the partial lack of whatever coating your pad had on the inner surface will affect functionality in any way, at all.

By the way, could you post photos of the pan and, especially, the worn area?

[Steve L.]

Re: Oil pan inside finish

Thanks Joe,
It's not the gold dichromate. It looks more like the green cadmium used on military connectors but not as green.

It's definitely the original oil pan.

Even the drain bolt(with a copper gasket) has the same greenish finish.

This is on a '73 base L48. It has the baffles(windage trays?) inside.

I've used a scotch bright pad on the inside to clean it up, so a picture won't show anything at this stage.

The outside seemed to have the same finish.

In any case, if others are plain steel, then this shouldn't be a problem.

I've already repainted with self etching epoxy primer and quanta engine orange. The bolt has the orange paint only. If your really interested, I could remove the paint from the bolt and take a picture.

[Joe L.]

Re: Oil pan inside finish

Thanks Joe,
It's not the gold dichromate. It looks more like the green cadmium used on military connectors but not as green.

It's definitely the original oil pan.

Even the drain bolt(with a copper gasket) has the same greenish finish.

This is on a '73 base L48. It has the baffles(windage trays?) inside.

I've used a scotch bright pad on the inside to clean it up, so a picture won't show anything at this stage.

The outside seemed to have the same finish.

In any case, if others are plain steel, then this shouldn't be a problem.

I've already repainted with self etching epoxy primer and quanta engine orange. The bolt has the orange paint only. If your really interested, I could remove the paint from the bolt and take a picture.

Steve-----


Thanks but it's not worth removing anything.

What you describe sounds like zinc chromate primer. I've never seen a GM oil pan so-coated but it sounds like at least one of them was originally treated that way.