Been thinking on this and seems that the oil level should be higher with the larger filter. Done this on several cars and mowers, wanting a second opinion. Seems when the oil is pumping the filter should fill completely up. This would leave less oil in the pan with the larger filter. Or does the filter stay full even when not running? Or maybe half full. If it stays full then the full mark on the stick would be right but if it drains back it would have to be above the full mark to be the proper level when running. Your thoughts .

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85 GT 3.4
14.9 @ 90 1.9 60' Old TH125/3.06
Unknown New 4T60/3.42

depends on the filter design, generally most filters stay full while the engine is not running, this prevents dry starts. I have seen a couple upside down filters not hold oil while off, but 90% of oil filters hold oil while the engine is not running. This means, yes, a larger filter capacity will effect the amount of quarts the engine takes... however its not that much, probably only about 0.1qt, or 0.2qt. Unless you put like, a diesel truck filter on a Geo Metro :P

seems like when the sump is "full", it's "full"! With a larger filter, it might take a bit more oil to hit the full mark on the dipstick, but raising the level should not be necessary. I would just start with the standard amount, run the engine a bit to fill the filter and adjust the level if necessary.

Filter that Fiero uses has anti drain valve. If valve works then pan level should not change once filter is full even on L4 engine.

jazz4cash is correct.

Dif between PF47 and PF52 (old version) about 1-1.5 cup more oil. (PF52 current version uses less oil... use search)

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

Bigger oil filter will require to add a little more oil than normal capacity BUT DO NOT ADD OIL ABOVE YOUR MAXIMUM LEVEL.
The safest way would be do as follow:
When you change the oil with the new filter, you top up the level to the maximum.
Run engine 1 minute
Let the oil go down to the pan (several minutes)
Check your oil level (it will be lower since the oil filter will have been filled when you run your engine)
Top up to the maximum level (no more)

Adding more than the maximum level will increase oil pressure inside your engine and most probably let your car smoke blue because, with the pressure, the oil will go through the valve guides.

Hope this helps,

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Bernard
Fiero V6 GT 1987 (Manual)

quote Originally posted by BL3200: Adding more than the maximum level will increase oil pressure inside your engine and most probably let your car smoke blue because, with the pressure, the oil will go through the valve guides. Hope this helps,

The difference between the short and long filters, especially the small diameter filters that Fieros use is negligible, a few ounces at most. putting on a longer filter and adding half a quart more to the crankcase is NOT going to increase your oil pressure, I think the previous poster meant to say crankcase pressure, it won't do anything to that either. Even if you were to add a quart too much it wouldn't do anything to the engine except rob a little power when the crank has to slosh thru the extra oil.

I remember seeing a thread recently comparing several brands and models of oil filter. I think a couple of them had no check valve (can't remember which). Avoid those filters like the plague. Here's the link:

https://www.fiero.nl/forum/Forum2/HTML/101903.html

But aside from that, the extra size of the filter shouldn't be a concern. If anything, it's a benefit. It increases oil capacity by a small amount, and more importantly increases the filter media's surface area considerably.

I have to agree with theogre , putting too much oil in is almost as bad as too little oil, in addition to the valve guide issue, there is a chance of hydrolocking the engine and doing serious damage, just read your dipstick and fill to the full line whatever filter you use.

quote Originally posted by BL3200: Adding more than the maximum level will increase oil pressure inside your engine and most probably let your car smoke blue because, with the pressure, the oil will go through the valve guides.

No!

1) Overfilling the crankcase will not "increase oil pressure inside your engine." How can it? In extreme cases of overfill, the oil pressure can actually decrease due to oil foaming.

2) Overfilling will not cause oil to "go through the valve guides." The valve guides are splash lubricated, so there is always zero oil pressure at the guides, whether the crankcase is overfilled or not.

No comment )

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Bernard
Fiero V6 GT 1987 (Manual)

The oil level on the dipstick remains the same. The bigger oil filter simply just means you need a little more to keep that same level.

Thanks for all the replies. This wasn't as much for my Fiero 3.4 but my Saturn and riding mower. Both filters sit at a 90 degree. And both are twice the size of original. I look up the oil capacity on the mower and said 2 quarts, added 2 qts ran motor and rechecked, think it's 8 oz. low (on the add mark). Think I over think things too much, oh well, better to ask a dum question than not at all.

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85 GT 3.4
14.9 @ 90 1.9 60' Old TH125/3.06
Unknown New 4T60/3.42

I used the larger filter on both my cars and both Corvettes. It added about almost a pint to total in the crankcase.