I agree it sure has, I wasnt thinking it would turn out this way but now im glad I made it LOL. Now lets talk tranny temps.....hehehe here we go again.

Hey guy and gals, I just finished a fun little experiment.
I fabricated a polyethylene washer just the right size to completely block off all the inlet holes on the oil filter. (using a new clean, dry filter, of course,,).
Then, here is the cool part. I started the engine ('99 Bonneville 3800 vin K) and make careful reading of the oil pressure: exactly 60 psi, as close as possible to read on the factory gage, at idle. (-the wife had just returned from shopping, and the engine was at normal operating temp.) Shut it off, removed the filter, installed the block-off washer, reinstalled the filter, and restarted the engine.

-care to guess what the outcome was :?:

Well, how about this: With the flow through the filter totally blocked off, the oil pressure once again read exactly 60 psi.

So, once and for all, no one needs to worry about their oil pressure being affected by any one oil filter, versus any other.

(Darn, once again the engine manufacturer'* engineering data proves that the basic laws of science are still working)

Oh, by the way, a sort of "what it'* worth: For years now, I have used ONE filter to fit MANY different engines. That is the WIX # 51036, or NAPA gold 1036, or even the NAPA Silver 21036. I use it on 1990 Chevy 350 4X4, 1987 Chevy Astro Van 4.3L, 1987 Olds 88 3.8L, 1984 Olds Cierra (sp?) 2.5L, 1994 Olds 88 3.8L, 1990 GMC 4x4 350, 1993 Buick LaSabre 3800, and now this 1999 Bonneville.

One of the reasons it works on all these, is that it is the larger 1 quart filter with about twice the square inches of filter media compared to the little one, has a very well designed "anti-drain back" valve (important on some engines designs, and a good idea for all applications), has the correct thread size, the correct gasket size, and has excellent clearances on all applications.

So, what do you think of that ??

I use a Purolator L10111.......I used to use WIX but they are a little pricy and dont have much more protection. Plus the Purolator is only 3 bucks!! Besides I use Mobil 1 10W30 Synthetic at every 3000 miles, and since I manage the shop (therefore spend more time there than at home!!!) that does my oil changes I can get it changed right at 3000 miles everytime.

Riddle me this: Why is one of the first steps in diagnosing low oil pressure to check the oil filter for blockage? This would seem to indicate that if there is a restriction (or a heavy duty filter) the pressure would drop...seems common sense to me. A clean and thin filter element won't cause much restriction so you may not notice a drop in oil pressure at idle. But if you throw in one of these newer heavy duty double guard filters the restriction (as long as they aren't lying) should go up and hence your oil pressure will go down. Especially at idle when the pump isn't turning fast enough to force oil through it. Skipping the oil filter and testing the pressure proved nothing. Try filling it with grit then test it.

I know I had variations in my oil pressure depending on what filter I used, I thought it was odd so I kept track of it a little as I changed filters. I probably should have noted which filters did what, but the fact that there was change was noticed. The maximum pressure didn't change any. It would stay at around 40psi no matter what, I changed the filter and it would drop to 35 at idle, change again stays at 40...this repeated over the year I had the car before pulling the engine. BTW: I always used Mobil 1 synthetic.

Just going through the filters here that I have dissected several years ago, and here are the numbers that I believe are all the same. AC PF-52, STP *-051A, Motorvator 52012, Fram PH3980, Napa 21036 (silver line), Napa 1036 (gold line), Motocraft FL-402, Purolator L20173, AutoPro 2036, Baldwin B35-*, Luber-finer PH-51A.

However that was several years ago, and although all of these meet or exceed the industry standards, including the certain percentage of certain particle size trapped on first pass, I do personally have to suspect that some of them have slightly different quality of construction, some differences in square inches of media, and possible differences in the size particles trapped.

Does anyone know what the minimum standards are? -it seems to me that it is something like 25 microns ? I suspect that all of the commonly availble filters are trapping particles down to 20, or even 18 microns.

Funny thing when you think of those filters that use the cardboard ends glued to the pleated media: (-and there are more than just the one popular brand mentioned). Psychology is an interesting thing: We seem to worry about the cardboard ends, but have no concern about the paper fiber filter media itself. I will have to admit that I have used a bunch of them through the years (although I don't now, mostly due to the psychological factor) and have cut apart and inspected dozens and dozens of them. (cut the can off with a filter can cutter, remove the media, remove then ends, (the cardboard ones seem to be the hardest to remove), stretch out the pleated media, allow to drip-dry for a few days, and then inspected for amount and types of visible debris. I have yet to see even the slightest indication of any type of filter failure. Of course, with a "lab analysis," we are limited to only that we can see.

More than you ever cared to know about different filters:

http://people.msoe.edu/~yoderw/oilfi...lterstudy.html