Awhile back I read on BITOG how many people had a high opinion of Wix filters. Because of this I bought some NAPA Gold (i.e. Wix) oil and air filters for my 2003 Trailblazer. The oil filters seem fine but I had an issue with the air filter.
The air filter that I took out was a made in Canada Fram and the filter that I replaced it with was a made in Poland NAPA Gold. I had some difficulty reinstalling the top half of the filter housing with the NAPA Gold. Both the NAPA Gold and the Fram filters were the same size, however the NAPA Gold was significantly less compliant. Its expanded metal screening was a heavier gage and the elastomer used was more firm. Because of these issues it didn't seat properly in the filter housing. The filter housing in this vehicle contains a Helmholtz resonator in the upper half of the housing to damp out a resonance in the intake tube. There is a passage between the intake tube and the upper filter housing downstream of the air filter, which if not sealed properly could allow unfiltered air into the engine. I was concerned about the possibility of the NAPA Gold filter preventing the filter housing from sealing properly and decided to change to a different make of filter. In the pucture below the filter on the left is the Canadian Fram and the one on the right is the NAPA Gold.
I bought another Fram, but this one was made in Mexico. The new Fram fit better than the NAPA Gold but the Silicon measurement in a recent UOA is now 17 ppm whereas it used to be 13 ppm with the NAPA Gold and 9 ppm with the Canadian Fram. Oil change intervals were about 6,000 miles in all instances. 17 ppm isn't horrible but is higher than I would like.
I went shopping for another replacement filter and passed on the made in Mexico Fram. I looked at a STP filter, made by Champ I think, and initially thought that it looked good until I noticed that it only had an expanded metal screen on the outside and none on the inside. Except for the STP, every one of these filters that I have seen has a screen on both the outside and the inside. If the manufacturer wanted to delete one of the screens I would think that the one on the outside should be deleted and the one on the inside retained. I passed on the STP and looked at a Purolator. The Purolator looked good but was made in China. Short of going to the dealer to purchase an AC Delco branded filter I was running out of options, so I bought the Purolator.
The Purolater installed without any problems and I hope that it brings the Silicon measurement down a bit.
The air filter that I took out was a made in Canada Fram and the filter that I replaced it with was a made in Poland NAPA Gold. I had some difficulty reinstalling the top half of the filter housing with the NAPA Gold. Both the NAPA Gold and the Fram filters were the same size, however the NAPA Gold was significantly less compliant. Its expanded metal screening was a heavier gage and the elastomer used was more firm. Because of these issues it didn't seat properly in the filter housing. The filter housing in this vehicle contains a Helmholtz resonator in the upper half of the housing to damp out a resonance in the intake tube. There is a passage between the intake tube and the upper filter housing downstream of the air filter, which if not sealed properly could allow unfiltered air into the engine. I was concerned about the possibility of the NAPA Gold filter preventing the filter housing from sealing properly and decided to change to a different make of filter. In the pucture below the filter on the left is the Canadian Fram and the one on the right is the NAPA Gold.
I bought another Fram, but this one was made in Mexico. The new Fram fit better than the NAPA Gold but the Silicon measurement in a recent UOA is now 17 ppm whereas it used to be 13 ppm with the NAPA Gold and 9 ppm with the Canadian Fram. Oil change intervals were about 6,000 miles in all instances. 17 ppm isn't horrible but is higher than I would like.
I went shopping for another replacement filter and passed on the made in Mexico Fram. I looked at a STP filter, made by Champ I think, and initially thought that it looked good until I noticed that it only had an expanded metal screen on the outside and none on the inside. Except for the STP, every one of these filters that I have seen has a screen on both the outside and the inside. If the manufacturer wanted to delete one of the screens I would think that the one on the outside should be deleted and the one on the inside retained. I passed on the STP and looked at a Purolator. The Purolator looked good but was made in China. Short of going to the dealer to purchase an AC Delco branded filter I was running out of options, so I bought the Purolator.
The Purolater installed without any problems and I hope that it brings the Silicon measurement down a bit.
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