5Alive

Hendrickson360... Your user name may or may not be different, but I think I recognize your writing... and believe you are from somewhere in Scandanavia, Norway, or Belgium (forgot which) and have posted similar type of frame questions on a Ford truck enthusiast website about a year or two ago concerning the strength of Ford chassis cabs frames. I'm curious what you are ultimately looking for?

If the trans is overheating, why would there be a strategy to unlock the torque converter when cruising down the highway? Wouldn't unlocking the converter put more drive pressure on the fluid, creating more heat? If so, I don't understand the reports where people said the dealership replaced the TC due to overheating, and when they experience overheating, the trans strategy was to create more heat. I do believe the posters when they say that whatever the dealer replaced remedied the problem. I just have a hard time understanding the reason given for why?

This question concerns the supersession of part numbers for replacement OEM factory pleated paper air filters for use in stock GM air boxes in LQ4 and LQ9 6.0L 8 cylinder engines with RPO K47 High Capacity air cleaners fitted. Model Years 2000-2006 GM Original Equipment Part Number: 25313349 AC/Delco OEM equivalent/replacement: A1518C Model Years 2007-2010 GM Original Equipment Part Number: 15908915 AC/Delco OEM equivalent/replacement: A3085C Some GM dealership parts counters report that the later listed filter (A3085C) SUPERCEDES the former listed filter (A1518C). These dealerships no longer offer the original A1518C for sale, and automatically issue the newer A3085C as a replacement even for older vehicle (2000-2006) applications. However, other GM dealership parts counters continue to sell and suggest the original A1518C, and claim no knowledge of any supersession in their computers for older applications. This is what is troubling... the disparity in the reports from equally credible sources, presumably with equal access to the GM "mothership" of information resources. I have both filters in my possession, and have observed that while both filters are indeed interchangeable from a fitment standpoint, they are constructed SLIGHTLY differently. The differences are subtle, barely significant enough to notice. Another difference is cost... in every instance where price comparisons were available from the same vendor, either online or on the ground, the later A3085C is cheaper than the earlier A1518C. This makes one wonder if the newer A3085C filter was merely redesigned to reduce manufacturing costs, thrifting out some engineering benefits formerly found in the A1518C filter? On the other hand, upon physical inspection, it appears the newer A3085C filter has some SLIGHT differences that have some possible benefits over the A1518C filter, such as: 1. Pillowed Pleating - corrugated air pillow bumps integrated in the construction of the pleat and arranged to match, high point to high point, adjacent pleats. These rows of linear pillows formed into the pleats themselves maintain space separation between pleats to prevent pleat collapse and sandwiching together under suction. When pleats become sandwiched together, originally designed surface area is reduced, so to the extent that an even amount of space can be maintained between each individual pleat, both the dirt trapping capacity as well as the flow rate of the filter can be better maintained. I first became aware of this technology from an air filter engineer working at Wix, at a time when new pleat formulation technologies (superior to plain flat surfaces) were being invented and implemented for turbodiesel engine panel filter applications in light trucks. There is corrugation in the A1518C filter media as well, but it doesn't seem as pronounced as it is in the A3085C. 2. Pleat Count: 110 pleats in the A3085C, 102 pleats in the A1518C. 3. Expanded metal wire mesh: Thicker wire, but larger spaces in the A3085C. Smaller wire, but tighter spaced in the A1518C. 4. Gasket: The newer A3085C has a subtly wider bulb seal on the perimeter bead, a much wider formed land at the inside of the perimeter bulb seal, and less gasket spillover on the wire mesh at the inside of the formed land, than the A1518C. I am not an air filter engineer or expert, so I don't know if these observations are relevant or worthy for consideration in comparing these air filters. I posted what I have observed and learned in order to inspire your curiosity and inquisitiveness if you are interested, and perhaps you will find out more, and post it here, and we can all eventually learn which filter is best to use. IF there was not a discrepancy between different GM dealerships consulted, I wouldn't bother asking this questions. It would be a no-brainer, I'd just go with GM's recommendations. But since I don't know which GM source to believe, and they differ, I put the question to you. The owners manual suggests the A1518C. What have you heard about the original high capacity air filter (25313349 - A1518C) for GMT800 6.0 liter engines being superseded by the newer air filter (15908915 - A3085C) used in the GMT900? Thanks! (PS... CAI's are not an option or interest. There are plenty of other topics on this forum about cold air intakes from GMPP, K&N, Volant, and other aftermarket companies. I searched for air filters here, and that is all that comes up... various CAIs. So please let this topic remain exclusively dedicated to GM and AC/Delco factory replacement air filters for use in the stock air box)