View Full Version : Synthetic oil and oil leaks

charley norton
11-08-2005, 01:21 PM
I made the comment in a recent topic about my avantis sudden start of oil leaks. i have a friend who I think confirmed my suspicion that it may have something to do with me changing to castrol syntec oil. He has worked as a mechanic with UPS for 25 years and recalled when synthec oil came out, UPS had all its vehicles converted to that oil. Soon after the swap, they had a big problem with leaks, especially with vehicles with a good bit of hours on them.Their still using synthetic oil and don't have any problems now. He didn't know if it was the nature of the oil to go through tighter spaces or if it had stronger detergents that removed build up that was keeping the older engines from leaking. Anyway, he told me I should switch back and the leak should get better but probably won't stop completely. Or just put new seals in it.
Charley with the left pulling avanti(known as "Lefty")

63 R2 Avanti

11-08-2005, 05:20 PM
I talked to Fel-Pro about this some years ago. My main concern was the rear main seal. The Fel-pro rep I spoke with advised against using synthetic oil in older cars as the stuff wasn't kind to the older style rubber seals. He did say that recent manufacture seals from them would be compatible with the stuff tho. :D

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

charley norton
11-08-2005, 05:28 PM
While we're on the subject, are the rear seals gold are what? I just checked my pricebook and it said the seal was $40.00!!
Has anyone got any advice on changing the front and rear seals? Can the pan be removed without jacking the engine? Does the front seal pop in or does the timing cover have to be removed?

Charley and Lefty

63 R2 Avanti

Mike Van Veghten
11-08-2005, 05:58 PM
I use Mobil I in "most" everything I have. Bikes (no leaks) and cars....no leaks that weren't there before. The oldest car was a 67 Chevy II. I've only got the gear oil in my 59 Lark (the engine leaks toooo much now!). I will be using the Mobil I in the new 299 Stude engine (after a short break in) in my Conestoga. The "quick change" in the back is already using it.

11-12-2005, 11:00 PM
A good cure for this problem is to use a 50/50 Semi-synthetic blend, It has less tendency to destroying older neoprene seals and gaskets. Some of the full synthetic oils may have very strong detergents, as whatever exists in these oils eats some of the older neoprene seals. There exists some very good non synthetic oils that have plenty of merrit, and are proven winners in todays high end race cars aswell. In our stock cars We used GM oil, exactly what you would buy over the counter in 20W/40W. Valvoline, Quaker state, Red Line, SWEPCO, and more produce exceptional street/race blends that are are easy on seals and your pocket book. Hydro-treated oils are superb oils. More money spent on oil does not always give better insurance against wear and tear. The timken bearing test has been our guide for many years. One thing that more people should do is read up on products in various Buyers guides, Sometimes cautions come up for certain products. Tom

11-13-2005, 12:40 AM
The timing cover has to be removed there 4 self taping sheet metal screws that hold the plate that holds the felt seal in place, if you use the same type felt seal drill a hole about .045 to .062 at the bottom of the retainer plate to let oil that builds up in there to drain. On the rear main, offset the seal so that it dosen't line up with the block and main surfaces.

Dan White
11-13-2005, 07:47 PM
I saw this company talked about in my Hudson discussion group. It sounds like interesting angle on lubricants, but have never tried their products.


Dan White
64 R1 GT
64 R2 GT

11-13-2005, 08:17 PM
Allan, You hit patdirt!!! I also figured that one out, I drilled a 3/16ths hole instead. no more problems. The seal method works great too. Best regards Tom.