Hi All! I've heard that running synthetic oil in an older engine can loosen lots of crud to get in the filters.... Here's my little story... I own a '94 Chevy K3500 with a 5.7 in it with just over 200K miles on it. Last year I had the engine out to fix a cracked frame, and while the engine was out, on the stand I opened it up and washed it as well as I could by filling it with diesel, sloshing it around and draining it out, twice. I installed a new melling high volume oil pump and then did a filter relocation to the upper left corner of the engine compartment, and upped the filtration from the small stock spin on to a pair of Wix 51515 filters, connected to the block by three foot braided 1/2" lines..... After a lot of reading, here, I decided to switch to a full synthetic oil, last fall, to avoid pushing thickened oil through those filters during a cold Montana winter.
Everything was working just fine. I had no leaks and good oil pressure, and the system wintered well. Then, just a couple of weeks ago, after less than three thousand miles, I started the truck one morning and watch the oil pressure dump! Nothing on the dip stick (out of 7 total quarts in the system) and probably less than a quart in the engine when I drained the sump. It seems that the filters had plugged up and caused a pressure spike that was puking oil out from around the "O" ring in the adapter on the block. (this is after several months of driving daily with no sign of leaks or oil loss). Thankfully, I caught the problem in time and suffered no damage. I changed the filters (but didn't think to cut the old ones open before I tossed them) and the oil and the problem has not recurred in a month of daily use. I installed two sending units on the filter inlet and outlets, and ran them to a switch and a (Dakota) digital oil gauge. The gauge off the back of the block, and the filter inlet show the same pressure, within one pound. The apparent difference at this time, between the engine pressure and the OUTLET of the filters is about two pounds on the new filters. So, I'm looking for two things: Weather or not it is a true fact that putting synthetic oil in an older engine can and does loosen enough gunk to clog filters, and secondly, does anyone have any info on what might be a "normal" spread between filter inlet and outlet pressures as a filter loads up? I would like to go back to synthetic before winter, this fall, and would surely like to avoid a repeat of my problem.... Great site, and thanks, in advance, for any input!
Everything was working just fine. I had no leaks and good oil pressure, and the system wintered well. Then, just a couple of weeks ago, after less than three thousand miles, I started the truck one morning and watch the oil pressure dump! Nothing on the dip stick (out of 7 total quarts in the system) and probably less than a quart in the engine when I drained the sump. It seems that the filters had plugged up and caused a pressure spike that was puking oil out from around the "O" ring in the adapter on the block. (this is after several months of driving daily with no sign of leaks or oil loss). Thankfully, I caught the problem in time and suffered no damage. I changed the filters (but didn't think to cut the old ones open before I tossed them) and the oil and the problem has not recurred in a month of daily use. I installed two sending units on the filter inlet and outlets, and ran them to a switch and a (Dakota) digital oil gauge. The gauge off the back of the block, and the filter inlet show the same pressure, within one pound. The apparent difference at this time, between the engine pressure and the OUTLET of the filters is about two pounds on the new filters. So, I'm looking for two things: Weather or not it is a true fact that putting synthetic oil in an older engine can and does loosen enough gunk to clog filters, and secondly, does anyone have any info on what might be a "normal" spread between filter inlet and outlet pressures as a filter loads up? I would like to go back to synthetic before winter, this fall, and would surely like to avoid a repeat of my problem.... Great site, and thanks, in advance, for any input!