I just purchased a 1999 with a 5.4L motor. It calls for 5W-30 Super Premium Motor Oil. Does anyone know if the Motorcraft brand is a synthetic blend or basic crude? I know the Motorcraft 5W-20 is a synthetic blend. Is it safe to run 5W-20 in a 1999 motor? I know the newer 5.4L's are running 5W-20 but I'm not sure if there was a change made to the newer motors. Thanks.

 

Engines are identical. Use either one.

 

Ford has released a tsb concerning this isssue. They are authorizing dealers to use the 5W-20 in 90% of the vehicles that use 5W-30. So according to Ford use the 5W-20. The 5W-30 is a regular crude oil. I started using the 5W-20 in my '98 when it had 90,000 miles on it. Drove it for another 35,000 miles with no problems at all.

 

Motorcraft 5w-30 is regular dino. Ford made no changed to the engine, they speced out the 5w-20 and recommened it for current and previous years including your engine. The 5w-20 is slightly thinner and meets higher specs. The 5w-20 is not only safe to run in your engine, but likely a better choice.

 

I'm not sure why 5w-20 would be better. Ford went to 5w-20 for fuel economy. So, use either one.

I run 5w-30 Amsoil but I'm a sucker for running what Ford says. Runs great, and have had no problems....

 

Ijust talked to ford about this very thing
we have 100 crown vics police cars that i
work on . well my boss(old school)
is useing 15w40 in the 4.6 inerceptor motor.
WRONG ford says no more than10 30 in them
well now to covince the boss... ya right!

 

Yeah don't you run something they didn't have on the sticker to run but then it is ok for them to change to something else.

I took issue with Ford for using 5w20 in my 2000 after they replaced a head gasket.

I had 5w30 Castrol full synthtic in when I took it in and they used the 5w20 crap Motorcraft in it.

I don't understand Ford saying anything about oil as noisy as these modular engines are no matter what oil you run.

Seems they should just run what they put on the oil filler cap. Would prove they atleast could read and wasn't in any possible violation of any warranty

IMHO

tom

 

I started running Mobil1 5w-30 synth in my 99 5.4 at 35k miles and it developed a small leak. I switched back to Motorcraft 5w-30 after a few changes and have had no problems since. The guy behind the counter at NAPA told me that the synth will find leaks and break down gaskets if it is not used from the start. He had experience with synth in a Mitsubishi and this is what the mechanic told him as it was being repaired. I only changed originally because I thought I was doing a good thing.

 

Yeah the synthetic found the leaky head gasket on mine. I just don't believe the head gasket started leaking over the synthetic oil. That has to be a bad gasket seeing as how both dino and syn trucks have that problem pretty regular.

tom

 

tkarter,
Actually the Motorcraft 5-20 oil is actually made by Mobil oil for Ford. So I guess that the Mobil 1 oil is crap also.

 

As long as it meets Ford's specs the 5w-20 oil is speced higher than 5w30. The 5w-30 dino oil would not pas the 5w-20 specs. Even though 5w-20 is a 20 weight it is at the higher end of the scale for a 20 weight. Not quite a 30, but almost.

It would be interesting to compare a bunch of UOAs of 5w-20 and compare them to a bunch of UOAs of 5w-30 to see which group procuded the beter results. I'll give the advantage to the 5w-20.

 

Motorcraft oil is not made by Mobil/Exxon. It is the same as Conoco Hydroclear which is a fine basestock oil. In the viscosity of 5w-20, the Motorcraft now has an HT/HS rating of 2.85 whereas the M1 has a rating of 2.6. The established minimum limits are 2.6 but most engineers agree that for normal beraing wear an absolute minimum is 2.8. The VI's are almost identical so the advantage goes to the Motorcraft in a comparison between these two oils. For what it's worth, the new Redline 5w-20 has a published HT/HS of 3.3. The cost of the oil makes it an expensive alternative.
I think before you decide on the oil that you want for your engine, you need to understand the factors that are applied to the 5w-20 weight oils. They will run cleaner longer and have less viscosity change than a Xw-30. They also allow far fewer deposits. But the choice is yours, either run a heavier oil that will allow more deposits and has more room for thermal breakdown or run the lighter weight oils that run cleaner, more stable, and cooler under load. Frankly though, if you are the type of person that performs the required maintenance on you engine at or before the factory recommends, your engine should give you 200,000 miles of service with either weight.

 

ok oil is a science. Now why would ford oil recommendations be any better than the head gaskets they use or some of the other quick failing parts?

Not sure what I was trying to say here other than Ford got my money now how far do I trust them seeing how much the truck has cost to maintain so far?

tom