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Hey everyone, for those who read my post about being for or against Synthetic motor oils, I went with Motorcraft Synthetic Blend 10W-30 in my '89 BII 2.9(70K miles), and after my last change and noticed some small leaks starting to spring up. Looked to be a mix of rear main seal and a few others, although it was a little hard to tell. I found drips in a few different spots, including the bottom of the oil filter. The valve covers look like they may be starting to seep as well, but not enough to drain down onto the manifold and leave that all too familiar stink. All of these leaks seem to be par for the course for an engine this age, but it was the fact that they all seemed to spring up at once that made me a little suspicious. Talked to my uncle about it and he said it was the Synthetic stuff, saying it gets into smaller spaces than conventional oil, and that it wouldn't have gotten past seals if say, this engine used Snyth oil from the beginning. He suggested I go back to convetional oil and see if they dry up. Went to Napa and got store brand oil & filter(Valvoline & Wix, can't go wrong there). Cleaned things up with carb cleaner, gonna wait & see.

Anyone else have this experience?

Yep smaller molecules means leaks......Now before you go nuts hating synthetics those leaks were prone to show up sooner or later. It's not the oils fault your seals are on the way out. I use synthetic oil in my '70 vw camper van with only one leak! And that's saying something. The cost of synthetics don't make them cost effective for all our vechiles. Oh I use it in that rig because of the air cooled engine ( keeps it running cooler)

All too true. I knew it was time for those leaks to begin showing up one way or another. A vehicle that age with such low mileage means it did a lot of sitting, and thusly some seals dried a bit. Truthfully the only reason I went with the synth-blend is because of the price! The Motorcraft stuff is muy cheap @ Wal Mart. Cheaper than some conventionals, actually. Something like $2.60 a quart. I figured it couldn't hurt, and at the worst would prolong that little 2.9.

Cheers!

Thanks for the follow-up.. I'm still using it in the '84.. Haven't noticed anything different, but haven't been closely monitoring either.. As said, some of those leaks would have shown up eventually, and some of them have shown up because you are now looking for them..... That Motorcraft oil is a very nice price and it is called for on new Ford vehicles, so if anyone's been looking for a good quality oil at a really good price, here you go.

Sometimes I think I'd go insane if I owned a new vehicle. That is to say,...a vehicle with no problems to diagnose and tinker with. When I first got this truck it was absolutely flawless (aside from the float in the gas tank), and I remember driving it around, looking under the hood, crawling under it and almost having anxiety because there was nothing that needed working on or replacing. It's a disease!