The worse that can happen with an older motor switched to synthetic oil is that it will start leaking at the gaskets as the synthetic cleans out crud that have accumulated in the gasket areas.

A transmission is a much different story considering that there are clutch packs involved. In a motor, it is all metal-on-metal.

1. Royal Purple is an excellent oil
2. Motorcraft Synthetic Blend 5W-20 is an excellent oil, too.
3. If you're going to change your oil at 3-5k, RP is a huge waste of money.

What is the oil change interval on Royal Purple? I was thinking that if I was to Run Royal Purple, and it can run twice as long as the motorcraft, technically one oil change with royal purple that lasts twice as long, would be the same price as two changes with Motorcraft?

^Their is no "change interval" on any oil...you could just ask the stealership though they usually have an anwser for everything lol. just the sooner the better to keep your engine clean and lubercated. I change mine monthly, to each is own. it just preference and oil dosen't last forever

You change your oil monthly? Dude your the king of penny pinchers....for some reason I can't see that.

^lmao man u know me, but really I change it ever month, I try to give the vic the best...but being a gas a$$ don't help either

Yes, your right, and from my research, that Supertech stuff at Wally Whurld doesn't seem to be too bad. I just prefer Motorcraft stuff, seems to work good....just don't use FRAM filters.

Just stick with Motorcraft synthetic, royal purple's nothing special.

supertech is walmart oil. depending on where you live, it's usually penzoil. but if the bottle is shaped like moble 1 then it's that. I rather spend $12 for supertech thats mobil 1 rather than $21 for mobil 1 conventional paying for the name. I do it myself monthly like said. oil is oil, some brands have additives that you really don't want in your engine. ever hear of that waterless antifreeze stay away from it unless you want you dorman intake cracking twice as fast. it has additives in it that can't expand and contract like regular antifreeze does and the chemical composition actually eats plastics over a period of time.

you know I use fram filters. and want to get me going... but I know some guys think fram filters are the devil on this forum so I'm gonna keep to myself and not start up anything. they do a good job, yeah they don't have the "drain back valve" like motorcraft. "drainback Valves" were made for people who don't change their oil/filter.

The anti drainback valve has absolutely nothing even remotely to do with oil change interval. It holds oil in the system to allow for quicker oil flow on startup, reducing the milliseconds your engine runs without oil (the time much of engine wear occurs). But its more than that. It is also a difference of a filter with cardboard holding it together vs metal, for honestly the same amount of money.

Not starting an argument though. If you're changing your oil regularly, FRAM or not, you are still better than a whole lot of people on the road today.

Fram Ultra oil filters are awesome. The rest of them, not so much.

Those drainback valves are very important on Modular motors. I forgot what it was that it helps prevent a dry start on - think it was cam or something...I don't remember.

But I personally have seen why Fram filters suck. When I had my 99 PI, I went from a Motorcraft to a Fram Orange Can of Death for an oil change. First and every time I started the car, timing chain squeal. Went back to the FL-820S, problem went away. Just to make sure it wasn't a fluke, I put it back in. Problem came back.

Plus, with what I've seen with pleats that aren't even sealed together (literally a giant hole that unfiltered oil goes thru), and paper endcaps, for more money than a FL-820S, I won't touch them. The other Fram filters are apparently OK, but the OCD is a no-no in Modualr motors.

Anyone use Penzoil Platinum? Supposed to be very good oil. Priced the same as M1 around here, tempted to give it a go. maybe. I just dumped some into my mom's oil chugging Honduh that usually runs M1 (because it burns full synthetic less than conventional as I've found, plus that little high revving 4-banger likes thin oil).

I've used Pennzoil Platinum 5W-30 in my Marauder for years. Would Castrol Edge, M1, RP, QS Ultimate Durability, or AMSOIL be just as good? Probably, I've just always been a Pennzoil fanboy.