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Caddyinfo's Cadillac How-To Section

Cadillac Oil Filters

 Oil Filters FAQ    11:30 am thursday february 7, 2002
Below is the compilation of several e-mails regarding oil filters, specifically the PF58 used on the Northstar.  Info contained may be useful.....

Question: what is the difference in the PF58 oil filters on the market and what is the UPF58 filter


The slight design changes in the PF58 don't surprise me.  From past development with AC and now Delphi there are periodic, ongoing process and product improvements and design changes.  
Sometimes changes are incorporated simply to improve the productivity at the plant making the filters and some are product driven, i.e., increased oil flow requirements, the desire to use
a common filter design or components on two different applications, etc.   All of these changes are tested and validated on the products affected.  I can assure you from past experience
that nothing is changed that deteriorates the filter's capability.  In general the changes will either be "transparent" or actually improve the filters performance, i.e., more flow capability, less pressure drop, finer filtration, etc.

One difference noted, the color of the seal is likely due to the fact that our OEM filters have a teflon coating on the gasket to eliminate the need for lubing the gasket.  Also the teflon coated
gaskets have less tendency to "vulcanize" themselves to the oil filter adapter over time.  The teflon gaskets are usually red or blue.  The after market gaskets are either plain or teflon coated, depending on where they went to and when they were made.  As the aftermarket filter pricing is very competitive any small item that costs that may be eliminated as a non value added item
(teflon coating) is often "optional".  The teflon is really just an assembly aid in the engine plant as the replacement filters generally get oiled or at least the surface of the oil filter adapter is oily not squeeky clean like at brand new assembly.  I would not consider this to be of any consequence when purchasing a filter.

I don't know if the PF58 production is out-  or inside  of Delphi at the time.  Over the past 20 or 30 years different filters have been outsourced depending on the volume and demand for the
filter.  Delphi will generally only manufacture the highest volume parts themselves.  It really doesn't matter who makes it in a way because the filter will be made to our specifications and our
quality standards.  We buy the tooling for those filters no matter where they might be manufactured so the manufacturing source is not really an issue.  It is NOT a situation where we would go to a "Fram" and just buy their filter and paint it blue......

The PF58 has always been used for our in house testing and validation so I am sure that the latest changes are always being tested on our dynos and in our test fleets.  If a substantial change takes place we change the GM part number  ( the actual relesed part number not the PF58 designator) and only the new part number will be used as the OEM and for testing to validate the
new changes.   Say, for instance, Delphi wants to change the method of "hemming" the filter  parts together.  This would be of no interest to the end consumer but we would run a complete
series of cold pressure burst tests, etc to  validate the change.  The filters could be made either way from that point on and it wouldn't matter.

The worst case for a filter is a brand new engine at breakin.  The breakin material from the cylinder walls, any miniscule maching particles , dust sediment, etc. in the engine must be trapped in the filter.   Probably 90 percent of all the material to be trapped by the oil filter over the life of the engine is trapped by the first filter....which was a Delphi filter.

Please don't be offended but I think everyone is being way too anal about the oil filter controversy.  It is true that some filters are better than others but the filter is of so little use and importance after the first one (breakin is 90 percent over in 500 miles) that I think it is needless worry.  There are much more important things to worry about.  In fact, the only real reason I always change the filter is to get that 1/2 quart of dirty oil out of the engine.  Once I have unscrewed the filter to
do this it is just easier to put a new one one rather than the old one !!!  

Also, be aware that many of the claims of aftermarket filters are pretty hollow.  If the filter media is "finer"...i.e...lower micron filtration....then you would think it is better.....UNLESS...the finer filtration causes a greater pressure drop across the filter which causes more unfiltered oil
to bypass the filter .  so you could go to a higher filtration but send more "dirty" oil back to the engine.  It is all a game of pressure drop and filtration level.

Use the Delphi filter and let us do the worrying for you.   There are MUCH more important things to worry about.

I will check on the latest story for the Delphi PF58 and let you know.....

One last thought......many times the factory filter is not even the "correct" one listed for the engine of the aftermarket version is different from the OEM filter of the same part number.
 Some engines like an anti-siphon or anti-drainback valve in the filter to keep the filter from draining dry each time at shutdown.  But the anti-backflow valves can impede the factory
oil fill.  We pressure fill through the oil gallery typically to fill/prime/prelube the green engine.  Also , on the assembly line, we only have 20 or 25 seconds to put 7 or 8 quarts of oil
in!!   So, the factory filter may not have an anti-siphon valve but the service filter will have one to minimize drainback.  The difference in color you mentioned is not critical, either.  
At one time or another I have seen black , blue, black with no label, etc. filters in the Livonia plant for OEM assembly.  I think the color depends on when the filter was produced and is not necessarily a differentiator in change level or supplier.

News flash:  I did talk directly to our oil filter Design/Release Engineer and found that indeed somethings had changed since I was intimately involved with the Northstar oil filter.   The OEM
PF-58 filters are produced at Delphi in Flint.   All the aftermarket PF-58 filters distributed through Service Parts Organization ( SPO ) are manufactured by......Champion Labs...!!!!     There are slight differences in construction between the two and the DRE actually considers the Champion Labs filter construction to be slightly  more robust and desireable.  This was a new one on me??   The DRE did confirm that we have tested and validated the champion Labs PF-58 and that it is our design adapted to their manufacturing process not their filter painted blue/black.

Additionally, the UPF-58 filter was a "premium" filter produced only by Champion Labs.  It had 100 percent synthetic media.  This filter has been discontinued as there was too great a
pressure drop across the filter due to the tight weave of the synthetic material.   There are probably still some filters on dealers shelves but once used up there will be no more.

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