fenza89

i have a 2006 ford f150 80,000 miles on it with the 5.4 engine. my truck runs great nice and quite engine. recently i read a article about a tsb out from ford to replace the VCT solenoids for updated ones. so i ordered the new ones from the ford dealer and installed them a week ago. right after installing the new solenoids my engine developed a knocking noise, very steady and noticeable at idle. sounded like it was coming from under the truck,right by the left side cat converter, EXTREMELY annoying. it sounded like a rod knock. i decided to put the old vat solenoids back in my engine, and the noise is gone, back to being super quite again and running great. just thought i would share this story with you guys, see if anyone else had a similar experience with replacing vct solenoids for the new updated ones.

tcp2

Sounds like the new ones are flowing so much oil that other parts of the engine are not getting enough. The old ones must be more restrictive keeping the pressure up elsewhere. Obviously you are still getting enough flow to the phasers to keep things quiet with the older ones.

fenza89

yeah its weird man. I'm very confused how that is possible. the new vctsolenoids are actually smaller with smaller holes and screens.

lewissa81

The new ones have a smaller exit orifice, which will create more pressure before the vct's, and less after. The noise could be the timing chains slapping. If the tensioners are faulty, and aren't getting enough pressure, they can cause the chain to slack.
Just a thought. I'd personally leave the old ones in until you start hearing more noises again, then replace everything. But then again, less pressure behind the vct's means the cam shaft isn't getting as much oil.

fenza89

I've never had a problem with the 5.4 engine. I change my oil with full synthetic use a motor craft oil filter. The only noise I sometimes hear is a rattle under light acceleration. It has done that for over 30000 miles.

lewissa81

In my opinion, that noise sounds like the issue. A rattle under acceleration is normally a sign of timing chains going slack.

Especial86

iTrader: (1)

Did you have any crud on the old solenoids and screens when you pulled them out?

The new solenoids definitely maintain pressure to the phaser better.. They help aid with the tension of the phaser from inside the phaser veins via oil (hydraulic).. This is so the clock spring doesn't have to fight the valve spring tension "as much"...

I'm wondering if maybe your VCT valve body has a slight blockage. This would possibly explain why an old solenoid that dumps a lot more oil through it will help. If there's a blockage, plus new "check valved" VCT's, your basically just adding another slight hinderance to flow..

fenza89

Yeah I don't know. All I know is the truck runs great. Smooth power and no ticking besides that rattle sometimes honestly I think that rattle is a characteristic of these engine. It's just how they are

tcp2

My thinking was that the VCT system is fine, but when more oil flows through to the phasers, less is available elsewhere and the knocking is from the crank bearings not getting as much oil as before.

The slight rattle off-idle (800-1200 rpm) is inherent in this engine design.

fenza89

Yeah that's the rattle low rim just the nature of this engine