NOS PF-25 6438261 White Oil Filter

[David L.]

Based on my research the 6438261 (PF-25) oil filter replaced the 6437946 (PF-29) oil filter in January 1970 as per Chevrolet Parts History. The 6438261 (PF-25) oil filter is still listed in my 1981 Chevrolet parts catalog. Does anyone know how long they sold the white PF-25 oil filters? My NOS white PF-25 filter came in a AC box dated March 1974 on one of the bottom flaps.

Dave

http://dcl70.imgur.com/nos_pf25_ac_oil_filter_6438261#WXeDX

[Lyndon S.]

Re: NOS PF-25 6438261 White Oil Filter

I would think that before to long, those filters will be shown to be a service or over the counter part. The true assembly line PF 25 will be white with a BLACK AC on it.
And also it would be the embossed filter not the flat bottom one

[Ronald L.]

Re: NOS PF-25 6438261 White Oil Filter

Dave, the earliest PF25 as service had the embossing. Seems like it was there 1970...72? I think we covered how long in a thread back in February.

[Dave S.]

Re: NOS PF-25 6438261 White Oil Filter

Based on my research the 6438261 (PF-25) oil filter replaced the 6437946 (PF-29) oil filter in January 1970 as per Chevrolet Parts History. The 6438261 (PF-25) oil filter is still listed in my 1981 Chevrolet parts catalog. Does anyone know how long they sold the white PF-25 oil filters? My NOS white PF-25 filter came in a AC box dated March 1974 on one of the bottom flaps.

Dave

http://dcl70.imgur.com/nos_pf25_ac_o..._6438261#WXeDX

Dave,
It's my opinion that the PF-25's changed from white to dark blue sometime around 1974 or possibly 1975. Along the way I've discovered a pale(er) blue PF-25 and cannot seem to find the application or vintage of the pale blue. It has proper decal like the early dark blue PF-25's but where was it used.???

[Joe L.]

Re: NOS PF-25 6438261 White Oil Filter

Dave,
It's my opinion that the PF-25's changed from white to dark blue sometime around 1974 or possibly 1975. Along the way I've discovered a pale(er) blue PF-25 and cannot seem to find the application or vintage of the pale blue. It has proper decal like the early dark blue PF-25's but where was it used.???

Dave------


I believe that Don Griffin, who once worked at AC, has posted quite a bit of information on this subject in the past. It should be in the archives. While, as I recall, there are still some "gaps" in the full understanding of the utilization/application of these various filter configurations, Don filled in a lot of those "gaps".

[Joe L.]

Re: NOS PF-25 6438261 White Oil Filter

Dave,
It's my opinion that the PF-25's changed from white to dark blue sometime around 1974 or possibly 1975. Along the way I've discovered a pale(er) blue PF-25 and cannot seem to find the application or vintage of the pale blue. It has proper decal like the early dark blue PF-25's but where was it used.???

Dave------


I agree. I think that the change from white to dark blue occurred sometime in the 74-75 period. I think that Don Griffin's previous posts covered that.

As far as the light blue PF-25's go, my recollection is that change took place after the change in labels from "1975 style" label to the smaller, "mostly white" labels.

[Dave S.]

Re: NOS PF-25 6438261 White Oil Filter

Dave------


I agree. I think that the change from white to dark blue occurred sometime in the 74-75 period. I think that Don Griffin's previous posts covered that.

As far as the light blue PF-25's go, my recollection is that change took place after the change in labels from "1975 style" label to the smaller, "mostly white" labels.

Joe,
Strange thing is these pale blue filters have the first design label that was used on the dark blue PF-25's in 1974/1975.

[Tory S.]

Re: NOS PF-25 6438261 White Oil Filter

I've gone through some confusion on my '75. The TIM originally stated that a '75 had a white filter with red AC and some were embossed. This later changed as it was discoverd on March 13, 1974 AC approved a color change from white to blue. It is then assumed that by the start of '75 production the filters were blue...and with the larger foil lable. blue with paper lables were the replacements.

One would have to guess, given the color change date of 3/13/74 that most '74s had white filters and most '75s had blue. Hope this helps.

I have the white PF-25 with red AC & embossed bottom NOS that I no longer need if someone else could use it.

Tory
'75 Conv
Original owner

[Joe L.]

Re: NOS PF-25 6438261 White Oil Filter

I've gone through some confusion on my '75. The TIM originally stated that a '75 had a white filter with red AC and some were embossed. This later changed as it was discoverd on March 13, 1974 AC approved a color change from white to blue. It is then assumed that by the start of '75 production the filters were blue...and with the larger foil lable. blue with paper lables were the replacements.

One would have to guess, given the color change date of 3/13/74 that most '74s had white filters and most '75s had blue. Hope this helps.

I have the white PF-25 with red AC & embossed bottom NOS that I no longer need if someone else could use it.

Tory
'75 Conv
Original owner

Tory-----


...and there's no way any 1975 ever had a filter with an embossed bottom. The embossed filters ended WAY BEFORE 1975.

[Tory S.]

Re: NOS PF-25 6438261 White Oil Filter

Joe,

I'm sure your right. But it's interesting to note that the revised 75-77 TIM states that the '75 blue PF-25 with foil lables may have had embossed AC on the bottom. The only embossed filters I've seen were the earlier white ones...never the later '75+ blue version. Have you seen an embossed blue filter?

[Joe L.]

Re: NOS PF-25 6438261 White Oil Filter

Joe,

I'm sure your right. But it's interesting to note that the revised 75-77 TIM states that the '75 blue PF-25 with foil lables may have had embossed AC on the bottom. The only embossed filters I've seen were the earlier white ones...never the later '75+ blue version. Have you seen an embossed blue filter?

Tory------


I have never seen an embossed blue filter. As a matter of fact, the bottom embossment disappeared even from the white filters prior to the change to the blue. This occurred about 1972, or so. As a result, the 72-74 white filters have no bottom embossment. I highly doubt that GM would have gone back to the embossment when the blue filters came into use about 1975 or at any time thereafter.