For the second time I have an oil leak around the oil filter plate on my 340. I'm not sure what I am doing wrong. I have cleaned the outer ring gasket area well, but it still leaks.

Is there a trick to getting this to seal?

Try a new plate...

Did you remove the plate for any reason? There is a gasket (or an inner and outer gasket) behind it. I wouldn't think you could damage it, but you might have a big scratch across the filter gasket sealing area. I have a friend that could bend it by overtightening the filter, but he was able to break off the stud on a trailer hitch ball.

I'm on my second gasket, looks like three is going on next weekend. Weird thing is, it sealed fine for 3 or 4 hours of run time, then, bang, starts leaking pretty heavy.

I will check to see if I have another plate.

That's the route I'd go. Another adapter and gasket too.

FWIW 340's came with the 90 degree angled adapter.. But I went through two cracked adapters before I got one that didn't leak... It has been suggested if you get another plate some had more holes than others so either find one with six holes or if you fine one with only four drill four more...

You are using only on gasket and that is around the outer circumfrerence of the plate aren't you?? There is no center gasket used on the filter plat. It will limit how much the outer rim can be tightened down to seal too much. Make sure that when the outer sealing surface of the plate is flat on the block that ther is clearance between the block and the center surface where the double ended hollow bolt goes through. There has to be clearance in the center in order for it to draw cdown tight.
I make sure to have the block surface clean and dry, then put a nice coat of gun grease on the gasket to basically hold it in place and keep it somewhat flexible and it will also expande from this put it in the block and then put the plate in making sure that it is in square and tighten down. No problems so far doing it that way and have done many in the last 40 or so years.

1 gasket and have clearance where the tube/nipple goes in to pull the center down to the block to seal the outer edge

I drill 4 extra holes in all of mine,deburr them and chamfer the holes some

have smacked the center of the plate on the back side to help get an older one to seal before

check with straight edge for flatness and clearance in the middle hole

good luck..

I did drill 4 extra holes. I am only using the outside gasket, though I remember having a heck of a time finding one last time. I will check to be sure there is enough to draw it down and seal.

Does anyone know the part number or description of that plate gasket, the parts stores couldn't find one last time I had to replace it.

I had this problem with a 318 in my truck. Finaly got a new plate and gasket from the dealer and everything was fine.

The gasket is available at about any good parts store like NAPA or Carquest.
If all else fails use theis: http://www.proracestore.com/index.php?ma...roducts_id=2416

FYI The plates are differant from magnum to LA motors make sure you have the right one and if buy a new one buy a pre magnum one.....You can guess how I found out the hard way !!!

I also found out the hard way that the magnums are different. Tried one after the first blowout!
Napa was able to find the gasket, so I'll give it another try this weekend.

I had this problem make sure that the thing your screwing the filter is on all the way...listen it takes a 1/2 square drive like the end of a 1/2 extension.


with the filter off stick the extension in the middle of the hole.
let me know it that fixes it.

The plates changed around 1991 on LA engines. Sorting Out: Chrysler’s 238, 318, 360 Engines

Ding Ding Ding, MoparforLife got it right (at least for now). At one point I had the 90 degree adapter on, and when I took it off, the small steel covered gasket must have stuck to the block, cause sure enough, it was still there.

So I cleaned it up and put on a new outer gasket, no leak now! Let's hope it stays that way.

Thanks for all the help guys, I appreciate it. Now i have to enter a new post about my newest issue!

What I always do is take the adapter and turn it upside down. Then, holding it tightly and square, take a big socket and place it in the center and smack it a couple times with a hammer. It will deflect the center back outwards slightly. These adapters distort inward when the fitting is tightened and can be a nuisance for leaks when reused. I've done dozens of these in this manner, on just about every small block I build anymore, and it works great every time. If you're considering getting a new plate anyway, you're not losing anything by trying, right? It's worked well for me!

The felpro single one (for the outer perimeter) is much thicker than the one that comes in the 3 piece MP cellophane PKG. dont have the part # for it but it fixed my leak.