Oil Sump Oil Leak Repair

The cork gasket between the engine block and the oil sump (oil pan) has deteriorated and needs to be replaced. It appears that the gasoline flow from the intake manifold overflow pipes contributed to the problem. The oil sump is an aftermarket cast aluminum piece, not the original pressed steel pan. The sump was painted silver just before installing ten-eleven years ago. While it is off the car, I am going to have it blasted and ceramic coated to make it easier to keep clean. The coating is being done by a local firm, C2 Powder Coating in Bradenton, FL.

The first step was to drain the oil from the sump. While I will replace the oil with fresh, I decided to leave the K&N filter in place as it has only been on the car ten months and has only about 350 miles on it.

To remove the oil sump, I lowered the car on my lift to the lowest brake stop setting. This allowed me to access the sump while on the floor below the car with my floor jack and a few 2x4s. I removed all of the mounting bolts except four to support the sump on the block.

Twenty-two of the twenty-four mounting hex head bolts are 1/4″-28 x 1,” the two additional bolts are 1/4″-28 x 1 1/2″ and these are used to secure the clips used to route the intake manifold copper drain pipes. These two bolts require a nut to hold the clips. Each of the twenty four bolts use a flat washer and a split washer. Tom, at Tom’s Import Toy, recommends using internal star lock washers rather than split washers as the split washers require  greater torque to tighten them down than is required for the bolts. Others have suggested to me that 6-8 lbs. of torque is sufficient for the cork gasket.

Cast Aluminum Oil Sump Before Clean Up

Oil Sump Supported for Removal with Floor Jack

All but four Bolts Removed

I found that I needed to remove the ground strap connected to one of the bell housing/engine backplate bolts so that the sump would clear to fall free.

 

Ground Strap Interference

It will take about a week to have the sump coated so I sealed the bottom of the block to keep things clean.

Sealing the Block

C2 Powder Coating did a great job with the oil sump. It looks new and bright now rather than stained and tired.

Ceramic Coated Oil Sump

Steve Gerow posted that Tom’s Import Toys https://tomsimport.com/category/new-parts/gaskets/ sells nitrile oil sump gaskets as a modern replacement for the original cork gaskets. Since I was waiting for the ceramic coating anyway I decided to order the nitrile gasket and I was very pleased with the product. I am sure that it will hold up much better than the cork. I used Permatex Aviation Form-A-Gasket Sealant Liquid to seal the nitrile gasket to the oil sump.

Permatex Form A Gasket

After waiting a little while for the sealant to set and get tacky, I placed the gasket on the sump and used the bolts that mount the sump to the engine block to line up the holes for mounting later.

Nitrile Gasket

Nitrile Gasket Up Close

There are some fairly narrow cavities at the front and rear of the block. I had new cork gaskets to go into the slots, but they required some trimming before installation.

Cork Gaskets trimmed

Cork Gasket Installed

I made some guide screws from longer bolts by cutting the heads off and then slotting the new screws with a Dremel.

Fabricated Mounting Screws

Once lifted into approximate position using the floor jack, I then screwed the guides through three gasket/sump holes to line up the sump for mounting to the block. This worked quite well.

Oil Sump In Place For Mounting Bolts

I then secured the oil sump to the block with approximately twenty-five 1/4″-28 x 1″ machine bolts. A small clip with a rubber grommet is used to steady the front intake manifold copper overflow pipe. At this location a 1 1/12″ bolt is used with the accompanying washer and nut. I tightened the bolts securely but not so tight as to deform the nitrile gasket. After some use, I will inspect the seal and retighten if required.

To conclude the project, I installed the oil sump drain plug with a new copper crush washer and refilled the engine with seven quarts of oil. 

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