Drip, drip, goes the oil.

[Robert Smith]

Yes, you've guest it... Rear main is the factor in the spots of oil on the garage floor.

So, I've heard conflicting answers regarding the replacement of this difficult part. Some say it is possible to replace without removing the motor... Others say it's not. That the motor MUST come out to replace the seal. And as long as the motor is out, may as well rebuild. If I had a dollar every time I've heard that song and dance...

Gentlemen of the board, I'm in search of an answer to find out whether it is possible to replace the rear main seal without removing it out of the car or is it possible to perform the job while still in the car?

Thanks!

[Plymouthy Adams]

Robert..the vehicle is just taking charge as the alpha car and marking it's territory...the problem lies with you cleaning it up and it's need to lay down some more...(that's my theory and i'm sticking with it)

[Robert Smith]

Ha, Ha... Alpha car huh? That's funny. Well, it's seeming to spray oil under it's self while driving 45+. Thus, requiring me to ad more oil on longer trips.

[1941Rick]

How much do you add per 100 miles? I just drove 2200 miles on 1 quart....

These cars are like old Harley's......When you get one that does not leak that means it is out of oil.

[Plymouthy Adams]

that sounds a bit more than norm..usually they do not leak while crank is spinning unless...bring my next question to rise..what amount of crankcase pressure do you think you may have at speed?..positive pressure will tend to blow a lot of oil from areas not normally as prone to leaking..do you now have a PCV system or have you considered building one...even on a modern car if the valve is not working right..will blow out a quart in 500 miles with no real visible signs..

[Joe Flanagan]

I frequent another forum for vintage Chevrolet trucks. Those things have a reputation for leaking, too. An old-timer on the forum says he worked at a dealership in the 50s and he said it wasn't uncommon to see drip pans under the cars on the showroom floor.

[Plymouthy Adams]

Joe, chebbies still come with drip pans....my friend owned a chebbie, he got rather upset when I told him could pick his car out in the parking lot just by feeling for oil under the car...he later swore it off as the worse car he had..that is till he bought his wife a new Pontiac...we will not discuss the BMW..another sore spot with the guy..he has for many years now owned Mopars..took forever to convert the guy..

[Young Ed]

Joe, chebbies still come with drip pans....my friend owned a chebbie, he got rather upset when I told him could pick his car out in the parking lot just by feeling for oil under the car...he later swore it off as the worse car he had..that is till he bought his wife a new Pontiac...we will not discuss the BMW..another sore spot with the guy..he has for many years now owned Mopars..took forever to convert the guy..

Does he have any mopars made in the last 5-10 years? He might go running back to chevy or beamer. Buddy had a 05 dakota that had more repairs than my 94 when he got rid of it.

[Plymouthy Adams]

for every car maker, every line of car there is always a few that are problematic..never seems to fail..he has been with Mopar since 1993 and has been very happy..who is to say how the car was treated when bought, did he buy it new? and if so and it was that prone to failure I would think he got hoo-doo'ed by the dealership, any problem car they like to go back and reopen the original ticket..this does not provide a history of problem..any problem on a differenct day gets a new ticket or else you have no history..anyway that was the tactic at the dealership where I used to trun wrenches..I am glad I grew tired of that life fast..

[Robert Smith]

How much do you add per 100 miles? I just drove 2200 miles on 1 quart....

These cars are like old Harley's......When you get one that does not leak that means it is out of oil.

Ok, this may help:

I drove the car from Monrovia CA to Long Beach a week ago for the Long Beach swap. I drove surface streets and at most points I drove 45-50mph. I had topped off the oil before I left. I got to the swap meet, spent a few hours there and drove home. I got home and checked the oil. It read: Replace! So, I topped off the oil again. The distance between Monrovia and Long Beach is roughly 25-26 miles one way. So, I drove about 50 miles give or take round trip and needed to replenish the oil.

When I park it in the garage, I noticed spots of oil from different points of the car, from the motor area to the muffler. It seems it's spraying oil all over the underside of the car while driving at speeds over 35. So, I'm loosing a lot of oil on even a 25-50 mile trip.

[Young Ed]

for every car maker, every line of car there is always a few that are problematic..never seems to fail..he has been with Mopar since 1993 and has been very happy..who is to say how the car was treated when bought, did he buy it new? and if so and it was that prone to failure I would think he got hoo-doo'ed by the dealership, any problem car they like to go back and reopen the original ticket..this does not provide a history of problem..any problem on a differenct day gets a new ticket or else you have no history..anyway that was the tactic at the dealership where I used to trun wrenches..I am glad I grew tired of that life fast..

Yup bought it new and he drives nicely. Never towed anything-never even had a hitch put on. Hardly even hauled anything in the bed. By 50K miles it had multiple ball joints replaced, tie rod ends, and the rear end had to be rebuilt. I don't recall any issues with the engine or the electronics. Mostly just the suspension and then the rear end as he was getting rid of it.

[Tom Skinner]

Robert Smith,

If its spraying oil its probably coming out of the timing Chain Gasket up front.

Back by the rear seal it would just drip back off into the road.

Check for the origin of the leak. I have changed rear seals on 251 cu. in. Flat Heads with the Engine in, however, having said that, there is much nashing of the teeth that goes along with removing and installing the top half of the rear seal. It will take the better part of a Day (8 hrs) what with cleaning the oil pan up Etc, etc, etc.

Tom

[Robert Smith]

Interesting, I notice that the leak comes from behind the oil pan... Above the drain plug. Maybe I'll have to take it in and put it on the lift and race the motor some and see what the mechanic notices under the car?

[BobT-47P15]

Well.....would it be possible for the pan gasket to be leaking in that

area?? Just tossing out a guess as I'm certainly no expert. I have

found on my car that sometimes pan bolts work a bit loose.....

[Andydodge]

Robert........in answer to your question......maybe........it depends on which type of oil seal is living there now.......the rope seals apparently can be replaced top & bottom in situ with a "sneaky pete" tool......but it the seal has been replaced by either of the 2 types of neoprene seal them you cannot get the top part replaced without dropping the flywheel........my 1941 Plymouth should have had a rope seal........it didn't........had a neoprene seal BUT the fools that did the "restoration" didn't bother to use the small "ears" that the neoprene seals come with..............I installed these and the oil leak was greatly reduced............so I'd check what is exactly there before making a decision........lol..........and either way that means dropping the sump..........lol.............andyd

[Andydodge]

And this was done with everything still in the car, just jacked the SOB up.........lol..............andyd

[1flipdog]

B/4 you do anything else wipe everything down real good and let the car idle for 5 min. Shut it down and see if you can see were the oil is comming from. I would ck the oil pan bolts (don't over tighten) and oil pump for leaks first.

[Robert Smith]

Well.....would it be possible for the pan gasket to be leaking in that

area?? Just tossing out a guess as I'm certainly no expert. I have

found on my car that sometimes pan bolts work a bit loose.....

Good idea to check that... I appreciate that input! I'll have to have the seal on the pan checked and see how tight the bolts are.

I also had another idea, maybe it's blow by coming out of the lower tube on the passenger side that's causing the build up of oil under the car? I do notice a white oil smoke wafting out of the filler tube when the motor warms up some. At higher speeds and after driving for 30+ minutes, one can smell hot oil burning. Maybe blow by vapors are depositing under neath the car and then dropping in random spots that I'm noticing on the garage floor.

[Desotodav]

I watch your post with great interest Robert as I still have a couple of oil leaks in my 52 truck motor that I am trying to resolve, but I don't appear to be losing oil at the rate that you are.

So far, I have installed a new 'o' ring in my oil pump, tightened my engine side valve covers, replaced my sump gasket, cleaned out the filter traps at both ends of the engine ventilation system, and tightened my oil pump (into the block). My next move is to install a new timing cover gasket, and then consider changing the engine rear seal.

I feel that the majority of oil leaked from my motor that blows back onto the exhaust whilst travelling is coming from the timing chain cover gasket. In your case though, it would appear more that you have problems back further on your motor. I am no Mechanic by any certain terms. I have listed avenues that I have taken so far in the event that you might look toward those areas to find a possible solution to your issue.

My eventual goal is to have a oil-leak free engine, but I now wonder is it possible to have a flathead that is 'dry as an Arabian's armpit'?

Desotodav

[Robert Smith]

Well, those are mighty good points you make there, I'd consider looking at the seals all over and making sure they are good in fact. I'm not too positive at this point, seeing the car sat outside for over a year under a carport in Arizona. The many seals could have dried out and may not be doing their job.

I was going to call some shops today and get some ideas and maybe some quotes but, my phone has been in and out of service (along with my internet) so, that wasn't happening. I was to order some things from Robert's today but, that didn't happen either. :/

Hopefully this week I'll have the car looked over and have the seals checked at a local garage.

[bamfordsgarage]

I've replaced the real seal in my 25" long-block 1947 D25 with the engine in place. I suppose it could have been done in one long day, but this job stretched over several days in order to do a few other things.

Here are the steps in order: Remove driveshaft. Remove transmission. Remove flywheel and clutch parts. Remove two-part (upper and lower) rear seal. Clean everything spic & span. Grease crankshaft. Install upper seal first, using "Right Stuff" between seal flange and block. Repeat for lower half. Realize seal is in backwards, repeat the right way 'round. Centre clutch disc between pressure plate and flywheel. Reinstall flywheel, transmission and driveshaft.

It would have been more difficult had I not had the engine out 5K miles earlier, as there was very little crud buildup and I already knew how everything came apart and went back together — you're working half blind up in the bellhousing with that upper half seal.

Here is the seal I installed. The brown goo is waxy protectant (Cosmoline?) for preservation. Even though the seal had been in that package since 1952 it was in fine, ready to use condition.

[BobT-47P15]

And, regarding the smoke from your breather pipe......do you also get

any smoke from where you fill the oil??

My car suddenly started smoking from the oil fill.........after I replaced

the carb with one I bought from the area old parts dealer. I simply put

it on and it seemed to work OK. But, apparently it was putting gas

into the oil pan, as determined by my son in law. So, my point is - is

your carb in truly good condition? It might be a contributor to the

blow-by situation.

[Robert Smith]

Yes Bob, I am getting oil vapors coming out of the filler tube! I'm not sure how well the carb is, it works ok it seems but, I am also noticing some oil covering the carb that may be leaking from the oil bath air filter.

I may investigate to see if the carb may be allowing gas into the oil... Thanks for the tip, I hope it's that... It could save a lot of money!

[plymouthcranbrook]

In a somewhat related area, is there any way to tell for sure if the rear main in a 52 is a rope type or a rubber one? I have read that 52 was the year of change and also that it was rope seals till 53. I have a slight leaker too and have read about a sealing solution that will help rubber one but not rope ones.

[Andydodge]

Plymouthcranbrook........this might help.....NOT.......lol, my 1941 Plymouth(original 201 1941 P11 engine still intact) SHOULD have had a rope seal, I bought a rope seal & sneaky pete to replace it.......dropped the sump....and there staring at me was a neoprene seal..........albeit without the "neoprene ears" which didn't help at all........it now has the "ears", still leaks but nowhere near what it did........as far as I know there is no guarrantee as to what you'll find till you have at it.........lol.........best wishes, andyd