Safe To Drive.....?

C

CatMan1

Senior Member
My '28 has a.....decent rear main leak. I would like to attend the Model A Days in the Amanas next month, but I doubt I'll have enough time to address this. It's going to be anywhere from 80 - 100 miles one way. Would it be foolish to attempt this? When I bought the car I drove it 65 miles with the leak and no issues. Not that that was a smart move.
 
How much is it leaking? Stop and check the oil level every 10 or 15 miles until you know how often to add some and drive your car. You bought it to enjoy, so enjoy it.



You might put some oil absorbent pads in a pan to shove under the car when you stop so you don't make a mess. Maybe slide them inside a garbage bag so you don't get it in your car.



Go have fun.
 
Are you going by yourself or with a group? No one likes to tour with someone who has to stop all the time. If you are going by yourself I would bring plenty of oil and have a backup plan to get home.
 
A decent oil leak? How much oil did it use in your 65 mi run? Some engines leak oil at the full level, I run mine at halfway. Some people use a rear main janitor that catches the oil. With the oil level at halfway I would try running 30 mi out and then back and check the level, 50 mi out and then back and check the oil level. Again with the oil level at F it may leak and somewhere less than F it may not be so bad. One last thing are you put the oil level ( dip stick) in with both parts of the stick? If your put it all the way in you may be over filling the oil?
 
How much.....? Well I can follow myself out of the driveway at times! The puddle under the car is about a foot across.
 
anyone who was driving a model A in the 40s probably was leaving a bit behind. mine leaks a bunch if it has 5 quarts in it. leaks a lot less at 4.5 quarts




i keep a gallon of oil and water in the back.
 
That's a big puddle...What type of oil are you using? Sometimes as the rear main bearing wares...and the engine loosens up...you should/can move from 10-30 or some such to just 30wt and the dribble will slow down...long term, you need to drop the pan and measure the clearance at the rear main as well as the other two...you might need a general tightening up...also many A's will toss out the first one half quart and then settle down and not toss out much more at all...Ours has this habit. Ernie in Arizona
 
CatMan1 said:
How much.....? Well I can follow myself out of the driveway at times! The puddle under the car is about a foot across.
Click to expand...

Well, let's explore this from this perspective. If you have a tire on you vehicle with a leak, you can choose to keep airing it up however as it quickly deflates it does damage to the inside cords from the extra heat generated as the low pressure compromises the tire casing ...and this oversight ultimately ruins the tire. The same applies with your engine. Presently the bearing clearance is excessive which is allowing the oil to escape. That clearance is also allowing the crankshaft (-and potentially one or more connecting rods) to hammer. The more clearance you have, the harder the hammering blows will be. the harder the hammer blows, the more clearance it will make. At some point, the hammering forces will fracture the cast bearing where it will disintegrate. At this point, your engine rebuilder gets a portion of your wallet. So as the old Fram oil filter commercial said, 'You can pay me now, -or you can pay me later!'. I think what most are saying is it would be prudent to make the repair without creating undue stress by continuing to operate the engine.
 
Big hammer said:
A decent oil leak? How much oil did it use in your 65 mi run? Some engines leak oil at the full level, I run mine at halfway. Some people use a rear main janitor that catches the oil. With the oil level at halfway I would try running 30 mi out and then back and check the level, 50 mi out and then back and check the oil level. Again with the oil level at F it may leak and somewhere less than F it may not be so bad. One last thing are you put the oil level ( dip stick) in with both parts of the stick? If your put it all the way in you may be over filling the oil?
Click to expand...


I haven't gotten around to estimating yet. The last guy said he just ran it 2 quarts low all the time and it was fine. Where would that mark be on the dipstick? Yes, I do put the dipstick completely in.
 
Ernie Vitucci said:
That's a big puddle...What type of oil are you using? Sometimes as the rear main bearing wares...and the engine loosens up...you should/can move from 10-30 or some such to just 30wt and the dribble will slow down...long term, you need to drop the pan and measure the clearance at the rear main as well as the other two...you might need a general tightening up...also many A's will toss out the first one half quart and then settle down and not toss out much more at all...Ours has this habit. Ernie in Arizona
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I can't remember what I'm using now. I'd have to check.
 
BRENT in 10-uh-C said:
Well, let's explore this from this perspective. If you have a tire on you vehicle with a leak, you can choose to keep airing it up however as it quickly deflates it does damage to the inside cords from the extra heat generated as the low pressure compromises the tire casing ...and this oversight ultimately ruins the tire. The same applies with your engine. Presently the bearing clearance is excessive which is allowing the oil to escape. That clearance is also allowing the crankshaft (-and potentially one or more connecting rods) to hammer. The more clearance you have, the harder the hammering blows will be. the harder the hammer blows, the more clearance it will make. At some point, the hammering forces will fracture the cast bearing where it will disintegrate. At this point, your engine rebuilder gets a portion of your wallet. So as the old Fram oil filter commercial said, 'You can pay me now, -or you can pay me later!'. I think what most are saying is it would be prudent to make the repair without creating undue stress by continuing to operate the engine.
Click to expand...


That is a good way to look at it.
 
If you are intent on going to that event, trailer it, save your engine. If you don't have
a trailer, borrow or rent one.
 
It may be a combination of the rear main and the oil pan gasket. If it's all from the rear main then it's not like you can change out a seal since there is nothing but a slinger there. It may need the bottom end babbitt redone and the crank turned if it is still in decent condition. It sounds like the former owner wasn't too worried about it but that is usually the case when folks don't want to rebuild the bottom end. Folks tend to run the old model A engines till they're knocking but sometimes that's too late to repair things. It gets more expensive when more things are worn out.
 
mike657894 said:
anyone who was driving a model A in the 40s probably was leaving a bit behind. mine leaks a bunch if it has 5 quarts in it. leaks a lot less at 4.5 quarts




i keep a gallon of oil and water in the back.
Click to expand...

Five quarts is too much. Four at a change is adequate.
 
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