longhood oil tank removal - lessons learned

Sunroof · 07-09-2008, 08:17 AM

It was a struggle, but the oil tank finally came out without having to remove the lower panel. It required two people and bending back a little metal without mishap, but it came out..................the key is the detachment of all oil lines (oil cooler) and lowering (not removal) of the lower body panel about an inch or so.

I took the tank to a local (Simms Radiator) facility that cleaned it out and pressure tested it for leaks. One important note...............in the upper portion of the tank is a meshed filter that had to be carefully cleaned for fear that prolonging it to the caustic solution would deteriote it.

The oil tank is "Steel" with copper fittings brazed on the tank. The 1973 tank is not copper.

If you decide to refurbish your tank and have it pressure tested they will need an oil filter to seal that part of the tank. The shop tried over a dozen filters and could not match the thread with anyone of them. Odd, I thought! But, I had to bring them a new filter which became wasted with the exposure to a quick water submergence for the leak test. SAVE AN OLD FILTER>>>>>>>>>>>

The shop reiterated what was mentioned here on the board and that was DO NOT COAT THE INSIDE. I thought that since these rust from the inside out, why not at least coat the lower portion to protect the bottom of the tank in the event condensation or water gets in and rests on the bottom. Oil does float on water!
I never realized that oil may have far more solvent properties to degrade a coating then gasoline would. Even their mighty gas tank coating, "RedKote" was
dismissed to be effective against the affects of oil.............

It will get a POR 15 outer coating this weekend............no leaks by the way!! Hope any of this helps.......

Bob
1973.5T

911pcars · 07-09-2008, 09:10 AM

Use the cheapo Fram filters. For this purpose, they work fine.

Sherwood

Sunroof · 07-09-2008, 09:29 AM

Thanks Sherwood...

A bit late for me, but good info. for anyone else doing the same. I asked the guy who worked on the cleaning and testing why copper fittings (oil filler neck, hose connections, etc) brazed onto steel?

He thought it was a cost savings measure back then to save money, metal and welds! Thinking of Porsche back then, you'd think platinum over 14K gold! Interesting.

Bob

DSouth · DSouth's Garage

"The oil tank is "Steel" with copper fittings brazed on the tank. The 1973 tank is not copper. "

Perhaps the 1973.5 oil tank is not copper, but my 1973 oil tank is copper. Note, that my car is a 1973 that came with the 2.4 MFI engine.

Can anyone confirm that there was a change in the oil tank from 1973 to 1973.5?

DSouth · DSouth's Garage

double post

Sunroof · 07-09-2008, 10:09 AM

I cannot confirm that the 73.5T went to a steel tank; however, I can say that this tank is the original for the car as I have all receipts since this 73.5T left the Birmingham, Alabama Porsche showroom and their is no record of a replaced oil tank. Even the oil level sending unit I took off is original (part no. 901164154100). I ordered a new unit, but this part number confirmed it was good through 1973.

The 73.5T was a big change for Porsche so its possible they may have gone to a steel tank.
I did ask the guy who cleaned the tank about copper and they insisted the copper parts were welded on and that the tank was steel.

Bob

DSouth · DSouth's Garage

I wonder if there was a line change from copper to steel in 1973.5 or if perhaps it was a gradual cut in as the copper tank stock was used up, they moved to steel. Are there benefits to one or the other? I'd assume the obvious advantage of copper over steel is rust, but what else? Do the steel tanks have the larger return fitting?

silverc4s · silverc4s's Garage

I am pretty certain that all the early tanks were steel, with a "thick" ? CU plating. I know that I have seen tanks from 1969-1970 that were rusted through at the top, not likely to be CU...

DSouth · DSouth's Garage

I see. So even though the tank may appear to be CU from the outside doesn't mean it is solid CU through and through. I could see CU where paint flaked off on the body of my tank, so I assumed it was solid. Interesting....

911pcars · 07-09-2008, 11:48 AM

Use a magnet to confirm all.

Sherwood

Sunroof · 07-09-2008, 12:02 PM

I do not know if this will provide any more information, but the Porsche part number for oil tank's running from 1965 to 1977 is as follows according to the PET and Stoddard part numbers. You'll have to dig deep to get the specific materials of which these tanks were made
of.

. 1965 - 1971 - (91110700115)
. 1972 - (91120701000)
. 1973 - 1977 (91110700622)

I was impressed that after thirty five years the tank has held up great.

Bob

Sunroof · 07-09-2008, 12:03 PM

I do not know if this will provide any more information, but the Porsche part number for oil tank's running from 1965 to 1977 is as follows according to the PET and Stoddard part numbers. You'll have to dig deep to get the specific materials of which these tanks were made
of.

. 1965 - 1971 - (91110700115)
. 1972 - (91120701000)
. 1973 - 1977 (91110700622)

I was impressed that after thirty five years the tank has held up great.

Bob