Here's the truth about the difference between the AC PF 58 and PF 59

[Alex D]

I e-mailed AC Delco and here is their response:
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Thank you for writing ACDelco.

The PF59 is the same as the PF58 except that it has an antidrainback valve.
The antidrainback valve keeps a slight amount of oil in the engine for
start up. We recommend asking for the PF59. No other manufacturer has a
PF59. They have a version of the PF58, and may cross reference that as
'close enough.' The PF59 is relatively new and because the Silverado and
Sierra were the only vehicles that originally called for this filter, you
may have a bit of difficulty finding one. If you are unable to find a PF59
at your local ACDelco facility, a GM Dealer can always order one for you.

Thank you for your interest in ACDelco.
ACDelco Customer Assistance


Subject: ACD - ACDelco - Other Suggestions
11/30/2002 06:07
PM

 

[Alex D]

If I had a lathe, I'd be cutting oneof each of these babies open.............I don't have one though........is there someone here who can do this for us ???

I also wrote back to them asking if we can replace the PF 44 with the PF 59 instead the PF58 like I have done in the past......let's see what they say...

 

[RobZ71LM7]

FYI: Silverado's/Sierra's originally came from the factory with PF58's but a TSB came out that stated to switch them to PF59's because of excessive valvetrain noise at startup.

 

[Alex D]

In all of this I still wonder why GM doesn't just discontinue the PF58......

quote:

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Originally posted by RobZ71LM7:
FYI: Silverado's/Sierra's originally came from the factory with PF58's but a TSB came out that stated to switch them to PF59's because of excessive valvetrain noise at startup.

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[dickwells]

Somewhere I recently read that the PF58 is required for some kind of Cadillac.

 

[RobZ71LM7]

quote:

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Originally posted by dickwells:
Somewhere I recently read that the PF58 is required for some kind of Cadillac.

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My aunt's '86 Eldorado has a 4.1L V8 which takes PF58's.

 

[Mike_dup1]

I don't think they came with the PF58 but the Owners manual etc listed it as the filter to use. I had a 1999 and mine came with a PF59. There was a loose page in my owners manaul that told of the misprint. Mine was an early build 1999, it was built in August of 1998 in Oshawa. At the time the new 1999 models came out only 2 plants were building them, Oshawas and Pontiac East.

Sorry if these take long to load, I am on Cable so its only a second or two for me.
PF58.........PF59........Fram Equal to PF59..

..

Notice the Fram is smaller? The center hole goes all the way thru compared to AC which is only open on the inlet end. It uses that metal plate to block the hole.

[ December 04, 2002, 06:08 PM: Message edited by: Mike ]

 

[Alex D]

Yeah...the PF 58 basically is a filter for early 80s to early 90s Cadillac/Chevrolet/Pontiac with the Cad V8 and some of the other small V8 such as the 307. it's an old filter design if it hasn't changed since then. maybe they are not even making them anymore, just selling off the stock.

quote:

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Originally posted by dickwells:
Somewhere I recently read that the PF58 is required for some kind of Cadillac.

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[GROUCHO MARX]

That's a fine look at a cardboard endcap, no? There also appears to be more pleats in the Fram. Are my eyes playing tricks on me?

 

[Alex D]

Thank you Mike for opening these filters !! We owe you one! Looks like the PF59 has a bigger anti drain back valve than the PF58. Guess we should all move onto the PF59.....

 

[eldawg4100]

the local book at my autozone has said use the PF58 for all my ex-cadillacs... i had an 85 eldo with 4.1, 89 fleetwood with 4.5 and now my 92 seville with 4.9...

funny, since yesterday was the first day I saw pf-59 at my autzone... still have plenty of PF-58's....

guess its time to move on to the 59? if the drainback valve helps, thats great! maybe a little better protection at start up?

 

[Alex D]

I went back to AC Delco after the first message on top of this thread and asked what the longer style replacement for the AC Delco PF44 would be. I told them that in the past I had always used the PF58 and wondered if I should use the PF59 now.
Here is their response:
--------------------------------------------------
Thank you for writing ACDelco.

Unfortunately sir, we can not tell you to use any thing other than stock
applications, but we can tell you that the PF58 and the PF59 is the exact
same filter other than the antidrain back valve. If your vehicle uses the
PF58 then you can interchange and use the PF59.

Thank you for your interest in ACDelco.
ACDelco Customer Assistance

 

[DoctorZ]

quote:

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Originally posted by Mike:
Just to clarify the photo above, the rubber for the PF58 is not a valve, just a spacer. It a hard rubber.

The other 2 filters, 59 and the Fram, the rubber is a valve, teh 59 is very soft and the Fram is much harder. It blocks the holes in the filter base preventing flow when engine is not running on the 59 and Fram.

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Looking at the rubber valve for the PF59, wouldn't this also cause restriction in the oiling system during normal operation (vs. the PF58)? It would seem that the rubber valve that the oil has to "push out of the way" during normal operation is convoluting the the oil path and would cause a significant restriction to oil flow.

Anyone have any insight into this?

DoctorZ

 

[Alex D]

Well I wouldn't be worried about that. The filter receives full pressure from the pump since the oil has to pass the filter before it re-enters the engine. So look at you oil pressure gage.......after passing thru the filter, your engine mostly still has anywhere from 20 to 60 psi available.

quote:

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Originally posted by DoctorZ:

quote:

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Originally posted by Mike:
Just to clarify the photo above, the rubber for the PF58 is not a valve, just a spacer. It a hard rubber.

The other 2 filters, 59 and the Fram, the rubber is a valve, teh 59 is very soft and the Fram is much harder. It blocks the holes in the filter base preventing flow when engine is not running on the 59 and Fram.

---

Looking at the rubber valve for the PF59, wouldn't this also cause restriction in the oiling system during normal operation (vs. the PF58)? It would seem that the rubber valve that the oil has to "push out of the way" during normal operation is convoluting the the oil path and would cause a significant restriction to oil flow.

Anyone have any insight into this?

DoctorZ

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[Propflux01]

You also have to take in the consideration of the way the filter is mounted. If its vertical, then it doesn't need an antidrain valve, becasue nothing can drain out anyhow. However, If it is side-mounted, then yes, an antidrain is needed to keep the oil inside.

 

[Alex D]

Actually that is not quie correct. First, GM says they especially designed this filter as a longer version of the PF44, for trucks (which the PF 58 is NOT) and secondly the oil in filter does not only drain back because the filter may be mounted horizontal or even upside down as in the LT5 engine, but drain back does also occur when the oil in the oil galleys starts running back after engine shut off. Remember all of the oil galleys in the block are above the filter (except the crankshaft oil pathways) and therefore the oil in them can brain back thru the filter and the oilpump into the oil pan if nothing prevents this and the oil galleys could be dry on start up. That's why an anti drainback valve can be important no matter what way the filter is mounted.

quote:

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Originally posted by Tim H.:
You also have to take in the consideration of the way the filter is mounted. If its vertical, then it doesn't need an antidrain valve, becasue nothing can drain out anyhow. However, If it is side-mounted, then yes, an antidrain is needed to keep the oil inside.

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[ December 03, 2002, 09:01 PM: Message edited by: Alex D ]

 

[Ken2]

quote:

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Originally posted by Alex D:

....
Remember all of the oil galleys in the block are above the filter (except the crankshaft oil pathways) and therefore the oil in them can brain back thru the filter and the oilpump into the oil pan if nothing prevents this and the oil galleys could be dry on start up. That's why an anti drainback valve can be important no matter what way the filter is mounted.

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But what keeps the oil in the upper parts of the engine from draining back down the oil passages and out the crankshaft oil ports?

Ken

 

[Alex D]

Ken, It's called cohesion and adhesion of liquids in small capillary spaces

quote:

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Originally posted by Ken2:

quote:

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Originally posted by Alex D:

....
Remember all of the oil galleys in the block are above the filter (except the crankshaft oil pathways) and therefore the oil in them can brain back thru the filter and the oilpump into the oil pan if nothing prevents this and the oil galleys could be dry on start up. That's why an anti drainback valve can be important no matter what way the filter is mounted.

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But what keeps the oil in the upper parts of the engine from draining back down the oil passages and out the crankshaft oil ports?

Ken

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[Ken2]

Cohesion & adhesion...OK.

But if the oil is going to drain down and through a shoddy antidrainback valve on a filter, won't it also drain down and through the crankshaft oil ports? The oil passages are big enough for hot oil to drain freely, aren't they?

Ken

 

[Alex D]

The drilled passages in the crank are but the clearanes in the mains and rod bearings are not. So the cohesion and adhesion of the oil will not allow the galleys to drain just based on gravity.

quote:

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Originally posted by Ken2:
Cohesion & adhesion...OK.

But if the oil is going to drain down and through a shoddy antidrainback valve on a filter, won't it also drain down and through the crankshaft oil ports? The oil passages are big enough for hot oil to drain freely, aren't they?

Ken

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[ December 03, 2002, 11:48 PM: Message edited by: Alex D ]