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captvista
09-24-2010, 03:12 PM
If the manual to my 94 Maristar recommends 15W40 oil and at 4-5 quarts, whats the consequences if a mechanic put 10W40 and says six quarts was needed to fill it? Looking at the oil stick it looks above full and almost covering the word 'full'. The reason for him working on it was to replace rear main seals, plus other assorted gaskets on the bottom and front. Now after all this it is leaking a little bit. Is it overfull and too thin a oil so its blowing by somewhere? Or has he caused the new seal to leak again?

Cloaked
09-24-2010, 10:30 PM
If the manual to my 94 Maristar recommends 15W40 oil and at 4-5 quarts, whats the consequences if a mechanic put 10W40 and says six quarts was needed to fill it? Looking at the oil stick it looks above full and almost covering the word 'full'. The reason for him working on it was to replace rear main seals, plus other assorted gaskets on the bottom and front. Now after all this it is leaking a little bit. Is it overfull and too thin a oil so its blowing by somewhere? Or has he caused the new seal to leak again?Overfull is not necessarily a good thing. I'd drain a little out and level it off at the proper fill mark. As for the weight of the oil... it's no big deal. I mean it will not kill the engine or anything. The leak is likely from an insufficient repair, but it may also be (as you stated) from being too full and the oil pressure is pushing oil through (but I still contend that the weight isn't the issue, but the overfill. There is not that much difference in those two weights of oil). But........... if the seals and gaskets were relaced, it should hold. Drain it down to the proper level and see how it works. That should tell you if it's the repair or the overfill. I know this doesn't give you a definitive answer or opinion but it's about the only way to truely determine if the overfill is the issue. Let's hope so in this case.

JimN
09-24-2010, 10:37 PM
If the manual to my 94 Maristar recommends 15W40 oil and at 4-5 quarts, whats the consequences if a mechanic put 10W40 and says six quarts was needed to fill it? Looking at the oil stick it looks above full and almost covering the word 'full'. The reason for him working on it was to replace rear main seals, plus other assorted gaskets on the bottom and front. Now after all this it is leaking a little bit. Is it overfull and too thin a oil so its blowing by somewhere? Or has he caused the new seal to leak again?

If it leaks after gaskets were replaced, he has a re-work on his hands because they shouldn't leak at all. This motor can use 5W30, if needed. The only reason 15W40 is recommended is that it's run harder than on streets and highways. The difference between 10W and 15W isn't that great that it will automatically leak. I have a '90 Silverado with a 5.7l TBI and the only place it leaks is at the fitting for the remote oil cooler and it has about 300K miles on it with no major dis-assembly. I would get it on a level surface and re-check the dip stick. If it still shows too much oil, remove enough to get it to the FULL mark.

mayo93prostar
09-25-2010, 11:35 AM
I would take it back to the mechanic and make him fix it. if he replaced all of the gaskets, it should not leak. Make it his problem assuming you paid him to do the work. By the way, where is it leaking?

oldairboater
09-26-2010, 08:30 AM
How bad is the leak? May not be a seal problem--could be a shaft problem.

captvista
09-26-2010, 04:51 PM
Thanks for the reply, especially comment regarding oil viscosity as that clears up one issue in my mind. I drained down the oil to 5 1/4 quarts based on what i measured coming out. This put it at the top of the full mark. I cleaned out the bilge and cleaned off the motor with water and cleaner. After a test run it did not seem to leak as much. The drops of fresh oil can be found at the bell housing bottom, from center to starboard side of housing. The moisture of oil seems to be only hitting the starboard side as to the bell housing, bilge wall, air vent duct and even up under the starter motor case. I am going to drain down to a more mid-level fill and check it out.

Gamble
09-26-2010, 10:35 PM
sounds like your rear main is still leaking. I'd be taking it back with the oil in the bilge and on the motor so your mechanic can see what you're talking about.

Jesus_Freak
10-03-2010, 09:38 AM
...The difference between 10W and 15W isn't that great that it will automatically leak...

Yes. For a given shear rate, oil age, and temperature, it appears as though the 15W oil has 1.5x the viscosity of the 10W (as the names suggest). Leakage rate is linear with the reciprocal of viscosity. The leakage rate with the 15W oil should be about 1/1.5 times that with the 10W.

ted shred
10-10-2010, 06:52 PM
I would also check that the PCV valve is working . If it's not it can cause excess pressure in the crankcase.

Slinkyredfoot
10-10-2010, 07:27 PM
If the manual to my 94 Maristar recommends 15W40 oil and at 4-5 quarts, whats the consequences if a mechanic put 10W40 and says six quarts was needed to fill it? Looking at the oil stick it looks above full and almost covering the word 'full'. The reason for him working on it was to replace rear main seals, plus other assorted gaskets on the bottom and front. Now after all this it is leaking a little bit. Is it overfull and too thin a oil so its blowing by somewhere? Or has he caused the new seal to leak again?

5 quarts of new at the end of the season. Re check in the spring after starting and bring to full temp see where the oil level is. In my personal stupid opinion, 10w40, 20w50, 20w20, are all good, one just has better vision.

Just a casual observation, why are you not the mechanic?