laserman1955
New Member
Consider this an FYI or Warning for owners of 2005 and later, 5.4L motors which have VCT.
The VCT system (solenoid, valve, cams, etc.) are very sensitive to contamination of the engine lubrication system. Debris, varnish, sludge and plain old dirt WILL foul the operation of the VCT system and cause poor performance, erratic idle and at times, under sever conditions, no start.
Sources indicate that the recommended 5W-20 oil is a key item in the continued reliability of the VCT system. Heavier oil may cause problems. However, for those who live in places like Florida you may find 5W-20 is too thin for summer operation in extreme heat. I, myself, have experienced "clatter" in my motor with 5W-20 in the summer. So, I switched to 10W-30 and relieved the clatter. But now I worry about the VCT. To reduce the chances that 10W-30 will cause problems I use 1/2 quart of Marvel Mystery Oil to help lower viscosity of the 10W-30 and to keep the engine internals squeaky clean. For those of you who don't know what Marvel Mystery Oil is, you should do some research. I've been getting 200K+ miles out of my engines for over 30 years using Marvel without ever having a major, internal engine failure. Want to know more? Let me know.
The VCT system (solenoid, valve, cams, etc.) are very sensitive to contamination of the engine lubrication system. Debris, varnish, sludge and plain old dirt WILL foul the operation of the VCT system and cause poor performance, erratic idle and at times, under sever conditions, no start.
Sources indicate that the recommended 5W-20 oil is a key item in the continued reliability of the VCT system. Heavier oil may cause problems. However, for those who live in places like Florida you may find 5W-20 is too thin for summer operation in extreme heat. I, myself, have experienced "clatter" in my motor with 5W-20 in the summer. So, I switched to 10W-30 and relieved the clatter. But now I worry about the VCT. To reduce the chances that 10W-30 will cause problems I use 1/2 quart of Marvel Mystery Oil to help lower viscosity of the 10W-30 and to keep the engine internals squeaky clean. For those of you who don't know what Marvel Mystery Oil is, you should do some research. I've been getting 200K+ miles out of my engines for over 30 years using Marvel without ever having a major, internal engine failure. Want to know more? Let me know.
