1968-2006 Oil Filters

[Joe L.]

Well, for a long time I've been concerned regarding the effect of DELPHI's departure from the oil filter manufacturing business relative to the AC oil filters we've used for so long. I've suspected that the new suppliers of these filters to GM were going to be making filters that are not like those of old. It looks like that has come to pass, at least for some of the filters.

The AC PF-25 of old, as well as the PF-35 and original PF-1218 were filters with a cellulose fiber medium, steel end caps, and a steel core. These filters were manufactured internally by the old AC Division of GM and, later, by DELPHI. These were filters that I had a lot of confidence in and recommended over any of the other brands on the market. Well, things have changed.

As you all know, the PF-25 was long-ago replaced by the PF-454, a shorter length filter. The PF-35 was replaced by the PF-1218, a slightly shorter length filter which also included an anti-drain back valve.

I have acquired samples of the current production PF-454 and PF-1218. I am quite sure that these filters are now manufactured by Champion Laboratories, a major supplier of filters for all sorts of things. I have now performed an "autopsy" on these filters, revealing their "guts" and I don't like what I see. Gone are the metal end caps and metal core. They're replaced with "thermo-sealed" ("glued") end "wafers" and nylon (plastic) cores. While I'm sure that this construction meets GM's specifications, I don't like it. Actually, it APPEARS even to be a downgrade from the construction of Fram filters of the recent past.

So far, the PF-52 (applicable to 92-96 Corvettes) and the PF-46 (applicable to 97-2006 Corvettes) appear to be manufactured in the original style as to construction. My feeling is that these filters are still being manufactured by DELPHI as the "phasing out" process continues. My guess would be that at some point their manufacture will be transferred to Champion (or, other manufacturers) and similar internal changes will be seen. Time will tell.

So, what an I going to do? Well, it's a non-issue for me. Some time ago I acquired a life-time+ supply of AC UPF-1218, UPF-25, PF-35L, UPF-52, and UPF-47. These cover most of my cars and I don't think that I'll ever really need to purchase another oil filter until I buy a new car that uses a filter model I don't have. Incidentally, the UPF-series filters are a Champion Laboratory-manufactured, Delco filter. They use a synthetic media, steel end caps, steel core and teflon-coated gasket. They're an outstanding filter, but virtually all are discontinued (except the UPF-44 which can be used for 1997-2006).

What do I recommend for others:

1968-91 owners

1) You can use a PF-35L. This filter is now a Champion labs-manufactured filter. It's a little shorter than the original PF-35L and the same as a current PF-1218. However, it's a synthetic media, steel end caps, steel core filter. Essentially, it's exactly the same as the discontinued UPF-1218, but without the teflon coated gasket and the anti-drain back valve (of no real importance in a Corvette application). Beware of possible future design changes for this filter, though, in case it "morphs" to the same design as current PF-1218 and PF-454;

2) Use a Mobil 1 filter of their #M1-302. This is also a Champion labs-manufactured filter, but it's not made the same way they make the new filters for Delco. It's more like the UPF-1218, but about the length of the original PF-35. It has synthetic media, steel core, and anti-drain back valve. I don't know (yet) if it has steel end caps, or not;

3) Use a WIX filter of their #51060 (without anti-drain back valve) or 51061 (with anti drain back valve). These are a premium filter with high quality filter media, steel end caps, steel core, and a coil spring to seal the filter element to the base plate. This is superior to the so-called leaf spring used for all the above-referenced filters.

For 92-96 owners:

1) Continue to use the AC Delco PF-52 until the design changes. Then, switch to a Mobil 1 synthetic media filter or a Wix 51036.

For 97-06 owners:

1) Continue to use the AC Delco PF-46 until the design changes, then switch to Mobil 1 or Wix 51042;

2) switch to AC Delco UPF-44 for as long as it's available.

A few more things I'd like to add:

1) The "thermo-sealed" end design and nylon (plastic) core (sometimes called an "E-core") is a feature of many new-design oil filters, especially for European makes, Mercedes-Benz and Porsche to name a few. Presumably, their engineers know what they're doing. For me, though, I still much prefer the old style, steel end cap, steel core filters. I say leave the new design filters for Mercedes and Porsches;

2) Regardless of my feelings toward the new design filters, I have no doubt, at all, that they meet GM specifications. They must or they wouldn't be selling them. Plus, they wouldn't be PRODUCTION-validated (although the PF-1218 has not been used in a PRODUCTION application since the 2002 model year and before the filter design changed, the PF-454 is used in current model year vehicles and, consequently, the new design filter must be PRODUCTION-validated).

[Joe L.]

Additional Filter Photo *NM*

[Joe L.]

Additional Filter Photo *NM*

[Chuck S.]

Re: Additional Filter Photo

Thanks for the filter info, Joe.

I'm thinking I should order a couple more cases of UPF44s while you can still find them. I didn't know the UPF was made by Champion Labs...I thought they were made by Delphi.

On another board, someone asked if there would ever be a UPF filter for the 2007 (PF48). I think the PF48 is already made by Champion...I suppose it's possible Champion could make a UPF48, but I doubt GM will let it happen. My local dealer's counter guy didn't know what I was talking about when I asked for a UPF44.

[Chuck S.]

Re: Additional Filter Photo

Thanks for the filter info, Joe.

I'm thinking I should order a couple more cases of UPF44s while you can still find them. I didn't know the UPF was made by Champion Labs...I thought they were made by Delphi.

On another board, someone asked if there would ever be a UPF filter for the 2007 (PF48). I think the PF48 is already made by Champion...I suppose it's possible Champion could make a UPF48, but I doubt GM will let it happen. My local dealer's counter guy didn't know what I was talking about when I asked for a UPF44.

[Joe L.]

Re: Additional Filter Photo

Chuck-----

All of the UPF-series filters were manufactured by Champion labs for AC-Delco. Foolishly, GM used Pep Boys as the "launch retailer" for the UPF series filters. Pep Boys primary customer base was not the customer who purchase expensive filters like these and, in any event, Pep Boys didn't market them properly. With poor sales, GM discontinued the line, except for the UPF-44. The only reason they kept that one was because of many complaints from C5 Corvette owners---otherwise that one would be "dead", too.

I don't think that you'll see a UPF-48, since I don't think that GM has any interest in expanding the UPF line at this point (although they might have an interest in "contracting" it to "0"). No problem, though. Champion will definitely manufacture the equivalent of the "UPF-48" under other brand names. Likely, Mobil 1 will be among them.

The UPF-48 is a different filter in that it contains an integral pressure relief valve. That's a first for Corvettes. All other Corvettes had the pressure relief valve as a "permanent" fixture of the engine. Actually, I don't like the filter-based pressure relief valve system. However, you do get a new pressure relief valve with each filter change.

As far as your local dealer counterman is concerned, just ask him to get you GM #25329389. Then, he'll "understand". With a GM part number, all dependence on parts man savvy is eliminated. I learned that over 40 years ago and that's why I got into this "part number thing" in the first place.

By the way, the trend in oil filters is to go back to the canister style filter. I predicted years ago that this was going to happen. It's taken longer than I expected (due to the convenience of the spin-on type filters), but the direction of the automotive industry is going in this direction now. Only a few GM products have this type of filter now, but I think you'll see it being "phased in". Many European cars have it now, including Mercedes and Porsche. By-and-large, Japanse manufacturers have not adopted it yet, though.

In any event, as far as oil filters go, it's "back-to-the-future".

[Clem Z.]

one of the problems with the UPF filters was

people at the self service auto parts were switching the expensive UPF filters into the std oil filter boxes and checking out. i know this for a fact as i found std filters in the UPF boxes i purchased after i got home. i opened the boxes after that before checking out.

[Clem Z.]

i am sure the std GM oil filter is good enought

because GM now has the 5 year 100,000 mile engine warranty and they would not want to have a filter that would cause them warranty probems down the road.

[Dale S.]

Re: i am sure the std GM oil filter is good enough

In the 60,s, Champ Labs was the bottom feeder of filters(they made the cheapest filters for all off brands). I think I will stick with "Wix",s. or I wonder if "Hastings" is still made in Hastings Mich. D/

[Joe L.]

Re: one of the problems with the UPF filters was

clem-------

Yes, that was a BIG problem. In fact, I was going to mention that, but I didn't. This problem was RAMPANT at Pep Boys and I suspect, but I don't know, that it was one of the major reasons that they "backed off" on aggressively marketing OR STOCKING these filters. I went into a Pep Boys once to purchase some of these filters and EVERY ONE on the shelf (for UPF-1218) had been switched! The solution to this would have been simple---just put a tamper-proof seal on the boxes. But, they never got that far in their thinking.

[Joe L.]

Re: i am sure the std GM oil filter is good enough

clem-----

Like I mentioned, I have no doubt that the filters meet GM specifications and are "adequate". However, for me, for something like an oil filter, "adequate" is not what I'm looking for. In the scheme of things, a SUPERIOR oil filter doesn't cost that much and, if nothing more, gives me a little peace-of-mind. That's easily worth the extra 5 bucks the filter costs.

Beyond that, there's no doubt that the synthetic media filters will "intercept" particle sizes considerably smaller than conventional media filters. Is that necessary or beneficial? I don't know, but I do know that it can't be harmful. Once again, it's worth the extra 5 bucks.

[Joe L.]

Re: i am sure the std GM oil filter is good enough

dale-----

Yes, and Champion Laboratories still manufactures and markets their "Champ" brand filters. You won't find them in Pep Boys, Auto Zone, Kragen, or Chief stores, though; those stores have their own "budget" line of store-brand oil filters (probably manufactured by Champion or Purolator).

I feel very sure that the current AC-Delco filters are exactly the same as the "Champ" brand filters, just labeled and packaged differently.

Also, I should mention that Champion Laboratories is in no way connected to Champion Spark Plugs. I would not rule out that their might be some historical connection (e.g. Albert Champion or some family member was once in the filter business), but there is no connection, whatsoever, in modern times.

In addition, Champion Laboratories does manufacture some premium filters. The old UPF-series AC filters and the Mobil 1 filters are examples. They just don't manufacture ALL of their filters in the same way.

[Clem Z.]

if you do not block the filter bypas valve

every time you start the engine the oil goes thru the by pass valve till the pressure on both sides of the valve equals. when you block the bypass valve and have a good oil pressure gauge you can see the pressure come up slowly as the oil makes it way thru the filter. with the by pass valve in there the oil pressure gauge jump to full pressue right away because the oil has no restiction like the filter to go thru.

[Clem Z.]

a story about oil filter bypass valves

i had one customer that his engine showed rear main bearing problems with dirt. i found out he was using a remote oil filter adapter that used a ford filter and ford filter have a bypass valve built into the filter. after he changed to a adapter that used a chevy filter no more dirt in rear main problems.

[Chuck S.]

Re: i am sure the std GM oil filter is good enough

The only thing I have found in using the UPF44 is you have to be careful to let oil temperature level off before you get on the throttle...jump on it too quickly, and oil will bypass the UPF44.

According to a test I saw on the internet comparing standard and UPF filters, the UPF filter flows about half what the standard filters flow at the same pressure and temperature. You shouldn't get on the throttle until oil temperature comes up, but the UPF filter gives you even more reason. At about 140 deg temp, you can still get pressures up to 70 psi...I've done it without thinking. I think the bypass in the LS2 filter adapter opens about 70 psi.