Hey yall,

A few weeks ago, I finally got my 2005 F150 truck back. It took a long while, but I thank God I have gotten it back. The engine needed to be rebuilt.

The engine runs really quiet, even quieter than when I first bought it.

They gave me a 3-year 100,000 mile warranty to go with it. Which is almost like a new truck.

I was talking to their shop foreman. He gave me specific instructions so that I would not void the warranty:

1. Change oil after only 500 miles.
2. After oil change, change the oil after 1500 miles.
3. After oil change, change the oil after 3000 miles.
4. Continue changing oil after 3000 miles.


He also informed me that '5W-20' is not a good oil to use on V8s (especially high mileage ones).

5W-20 is too light for most V8s and they burn much quicker, and don't lubricate well.

He told Castrol 50-60 is what he recommends.

I told him 5W-20 is what Ford's manual recommended, but he stood firmly on his 50-60 recommendation.



Any one got any comments and input?

I forgot to add:

I drive a 2005 F150 XLT Supercrew (V8 5.4L)

Never heard of that. I would demand him to put that in writing and have it notorized. That way your lawyer will know who to sue this winter.

No way would I use 5w-20. Especially in the summer. 10w30 or even 20w-40 is fine.

50/60 is getting close to differential fluid. You might get by with it if the year around temperature was 120 degrees, but I'd venture to say the engine wouldn't even turn over in freezing weather.

as a master tech I would advise u to use the oil in which ford recommended, if the cap says 5/20 use motor craft it is a syn blend!!!!!! with the eng now days they are built w such tight tolerances no way would I run anything over a 10/30 I use 5/30 in both my vehicles!!!! my 03 z71 w 180k pulls the boat at 70 mph and never has leaked or given any oil related issues!!!
didn,t u say rebuilt? then it should be a low mileage eng. rt????

My 02 Ranger says 5W20, have 136K miles. In the summer after driving on the highway for a few hours when I stop and idle at a stop light, the oil pressure gage indicator jumps back and forth. After it cools off and normal around town driving it doesn't do it. I always use Motorcraft oil and change at 5K-7K. Should I look at 5W30?

Is he saying for now on or just during the break in period?

He said from now on.

Little hard to decipher.....

Cap says 5w-20, manual says 5w-20.
But like I said, the foreman was pretty firm on his suggestion.

These guys are a really highly reputable place (Thunderbolt Motors, been in business since the 1940s). Due to bad timing chain design on 2004-2008 F150 V8s, they've already rebuilt well over 200 of them.

I've never heard of a 50/60. Did you mean 20-50?
If it were me the thickest id go is 10-30.

The reason why you use 5w20 syn blend is in a simple term is that it is thin when you crank up your motor thats why it sounds like the lifters rattles but that is diseighned to do that,plus the phasers are desighned to have that thin of oil ran threw them and the timing chain componets also. Those 5.4 dont even use gas for cobustion for the first 700 rpm as it is cranked up do to the oil wieght and phasers along with the timing of the motor. its hard to explian so I could set here and write a book about how that wieght oil effcts your phasers and timing chain componets and guides but it would be a while. As the oil heats up the oil becomes thicker not thinner because of the syn blend and a few other aditves that is put in the oil. Plus the engine is desighned to run on that wieght of oil and blend. I have used motorcraft 5w20 syn blend for years in ford gas motors and have never had a problem or known of any one having any problems with it. I have seen ford motors with 240,000 miles on them before the blow that have used that oil only.

Plus 1 jimmye123

Right on Jimmy and Titanium.

Not sure how long you have lived in the Houston area but yes Thunderbolt has bee around forever, But so has their reputation. I would be concerned about any advice given by anyone there.