Dan64456

On my 1998 Lincoln Towncar, I switched to synthetic Mobile 1, and I swear the engine ran much quieter (less lifter like noises, even tho it was OHC) and the gas milage improved by like 3 - 4 mpg. That was 5w30. It used a bit of oil when I used regular oil, (the car had like 75K on it) And contrary to the rumors, the car stopped using any oil at all when I made the switch.. It ran alot better.

Since our mustangs take 5w20, would it be ok to switch to the Mobile 1 5w20 after the first oil change? (5000 miles)

06GT4RAD

Yes it will be fine to do that. In fact that is exactly what i plan on doing. Picked up two case of it a few days ago just to be ready when the day arrives.

Richard

W1ldcat

I put it in at 700 miles. What comes from Ford is part syn. to begin with..

classj

I wouldent pull the factory fill till at least 3K miles. Most car companies have some type of break in additive they use. No real need to pull the oil before 3K miles IMO.

Bob D.

FWIW, the service schedule in my Saleen warranty booklet requires an oil switch to synthetic at 500 miles. I don't think there is any problem switching to synthetic pretty early on.

W1ldcat

I believe in an early first change to remove any impuritys from assembly. Parts have assembly lube on them, like the crank and cam, valves ets. I have done this with every new car I have bought so far with good results.

ncspack

I talked to a Ford master technician about this exact topic and he told me that if you switch to full synthetic with these new 3 valve engines then you are taking an unecessary chance on SERIOUSLY messing up your engine. He told me that it would be o.k. to switch to full synthetic at 15,000 miles, but the seals and other internal areas of the engine would be damaged if you changed any earlier. He also said he's has seen people bring their vehicles back with 50,000 miles or so and already be seriously messed up. I trust this guy and he's just trying to save me a big hassle later down the road.

BoidMorphs

So if a master technician is saying that then it certainly sounds like a valid reason for Ford to void the engine warranty. In reality, I can't see that happening because if you read the specification codes on the synthetic oil containers they all say "meets or exceeds" blah blah blah so who do you believe? I've already bought 5 quarts of Castrol synthetic and was going to do a change this week with 4,000 miles (my second change) but now you've got me thinking.

Sonic Boom NH

Bear with me a bit as my technical description may be off a bit. I do not buy into having to wait until 15,000 miles to change over to full synthetic. I also do not buy into “seriously messing up your engine” because of full synthetic oil before 15,000 miles.

Today’s motors break in much sooner then older motors did. In any case your cylinders have crosshatch marks in them which are to wear in and seat the piston rings. One reason many “experts” suggest to wait until around 5,000 miles is to give the motor time to wear in the piston rings.

Full synthetic is much better at lubricating then regular oil and regular/synthetic mix, like Ford recommends for these motors. That being said if you were to use full synthetic at say 50 miles you won’t wear in the piston rings, against the crosshatch marks in the cylinder walls, as well as you would with the break in oil from the factory which I am willing to bet is NOT the regular/synthetic mix Ford recommends.

Regardless what you may hear these motors are NOT broken in at the factory. Yes there are some vehicles that come straight from the factory with full synthetic like Corvettes I believe but I do not know if Chevy does anything different with those motors or if they have more aggressive crosshatch marks in the cylinder walls to aid in seating the rings. It may not be a full synthetic oil to begin with but I don’t know.

Full synthetic oil will NOT damage any internal parts of the motor or any seals. The worst thing synthetic oil will do to a motor is not allow it to properly seat the piston rings and that is why many people highly recommend waiting to at least 5,000 miles before going with a full synthetic oil…

06GT4RAD

Sorry but that is absolute nonsense. It is clear that he does not know what he is talking about, and that is down right scary considering these are the guys working on our cars. The Motorcraft oil Ford puts in at the factory is a Synthetic Blend so why does that not damage the engine but a full synthetic will. That is one of the most ridiculous things i have heard. And people wonder how mis-information gets passed around. Well there is a perfect example.

Richard