Johnredcornxl
Member
I have a 2014 Ford Raptor. 6.2 V8 engine. It has 165k on it. The other day I was pulling it into the garage and heard a new sound. I got out of the truck and stuck my head into the driver side wheel well... And I heard "rod knock." I was 100% sure it was rod knock, because I've heard it before with other vehicle right before they spun a bearing. It had that typical, low end knocking sound. Like I said, it is a new sound the truck has never done before.
I decided to just jack the truck up, dropped the front diff and pulled the rack and pinion out, dropped the oil pan, and pulled all the rod caps off. Every. Single. Bearing looked brand new. Not even the slightest sign of wear. But since I was already down there, I decided to buy new standard King bearings and tossed them in just to make sure. Every used bearing mic'd the exact same as the brand new bearings. What's even more impressive is the cross hatching in the cylinder walls looked brand new as well. The engine looked healthy as can be.
New bearings, oil pick-up tube o-ring, oil pan gasket, and fresh oil I cranked the truck back up and let it get up to temp and guess what? The sound is back. Nothing changed.
I took a mechanics stethoscope and was listening all around the bottom of the block. Listened at the block, freeze plugs, and bellhousing. The sound is nowhere to be found at the bottom. Which disappoints me because all of the work I did was in vain. The sound is coming from the back of the engine towards the firewall, it sounds top end, but it sounds identical to a bottom end, low rod knock to a tee. And the knock speed increases with revs. It's odd.
Today, I noticed when the electric fans kicked on the sound completely disappears. No more knock with the fans on?
My question is, has anyone had a similar experience with a rod knock sound that ended up being something minor? And what could the electric fans being on do with the sound disappearing?
And the sound only happens when the truck gets up to temp. The knock doesn't happen with a cold start. When it's up to temp it starts and it disappears with the fan kicking on. When the truck cools off I'll take a video of the sound and try to get it on camera and post it in the comments.
And BTW, it runs great. No issues. No CELs. Just the knock sound.
I decided to just jack the truck up, dropped the front diff and pulled the rack and pinion out, dropped the oil pan, and pulled all the rod caps off. Every. Single. Bearing looked brand new. Not even the slightest sign of wear. But since I was already down there, I decided to buy new standard King bearings and tossed them in just to make sure. Every used bearing mic'd the exact same as the brand new bearings. What's even more impressive is the cross hatching in the cylinder walls looked brand new as well. The engine looked healthy as can be.
New bearings, oil pick-up tube o-ring, oil pan gasket, and fresh oil I cranked the truck back up and let it get up to temp and guess what? The sound is back. Nothing changed.
I took a mechanics stethoscope and was listening all around the bottom of the block. Listened at the block, freeze plugs, and bellhousing. The sound is nowhere to be found at the bottom. Which disappoints me because all of the work I did was in vain. The sound is coming from the back of the engine towards the firewall, it sounds top end, but it sounds identical to a bottom end, low rod knock to a tee. And the knock speed increases with revs. It's odd.
Today, I noticed when the electric fans kicked on the sound completely disappears. No more knock with the fans on?
My question is, has anyone had a similar experience with a rod knock sound that ended up being something minor? And what could the electric fans being on do with the sound disappearing?
And the sound only happens when the truck gets up to temp. The knock doesn't happen with a cold start. When it's up to temp it starts and it disappears with the fan kicking on. When the truck cools off I'll take a video of the sound and try to get it on camera and post it in the comments.
And BTW, it runs great. No issues. No CELs. Just the knock sound.
