After 12 years of DIY oil changes, I noticed an oil puddle on my driveway after start up. The oil filter has loosened on its own. This has happened on the last two oil changes, with the most recent oil change two weeks ago. I've always hand tightened the filter with both hands as hard as I can. I always put a little oil on the seal prior to installing the Mann filter. I purchased four Mann oil filters earlier this year. Could it be bad oil filters?
This is a 1998 C70 HPT Coupe with 190k on it. I'm going to Auto Zone this morning to purchase an oil filter wrench.

There are other complaints on the RWD side of the same problem. It might be the fault of the supplier of the seal? A few microns off and the seal becomes worthless. Also, the age of the seal becomes suspect, not knowing the manufacture date of the filter.

Now I need to check my oil filter! Thanks!

Also a god tip: using a sharpie, write the date and mileage on the filter bottom before you install it.
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Keeping it running is better than buying new

"hand tightened the filter with both hands as hard as I can" is too tight.
There is no reason to have that much torque on the filter.

I've never experienced it, but have read of the old filter gasket sometimes staying stuck to the block. Then a poor soul installing a new filter not realizing that there are now 2 gaskets in place. And 2 doesn't mean it will seal twice as much!

Don't ever use an oil filter wrench to tighten a filter.

I think you may be squishing the gasket too much by over-tightening it.

I too am not questioning your mechanical skills. Maybe you've just been lucky so far.

Hmmm. A while back on the RWD side there was some discussion about leaky oil filters. I forget the details, but they were from a well regarded name brand. Tighter was not the solution.
https://www.brickboard.com/RWD/volvo/1581936/mann_oil_filters.html

Or of course, you may have forgetten how to install an oil filter...

Greg

I don't doubt your mechanical skills and I also don't think that the filter is a problem. When tightening the filter, I always turn it until there is tension and then turn the filter another 1/2 turn. Some would say that a full turn is needed, but then trying to get it off becomes much to hard.

Be careful with a filter wrench. First, it is difficult to get a wrench on it because of the limited space. Second, if it is too tight, you will never get it off.

The amount of oil on the new seal should be just a coating. Wet your gloved finger and rub the oil onto the seal. It should appear damp without any oil dripping into the groove.
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Keeping it running is better than buying new

I've never had one come loose on a car after hand tightening them. I am getting weaker and arthritis is setting in so it is becoming more difficult to get them down hand tight.

Don't tighten it with a wrench. Removal will be very difficult without destroying the filter.

Just an aside, I've had Moto Guzzi motorcycles for 30 years. They us an automotive type filter but it's inside the sump. Some guys have had them come loose and as security they put a large hoseclamp around them that will interfere with the pressure relief valve if the filter starts to loosen. You may try the same trick if there's something near the filter such as the pan, which will stop the filter from turning. See below for a peek at the Guzzi sump.