Gas Engine sounds like Diesel at Startup?

[Ulu]

My neighbor has a lovely 2017 F150, with a 3.5L gas engine. It has about 60,000 miles on it. When he starts that thing cold it makes a racket just like a diesel engine. I swear to God it sounds like an old Detroit diesel 6 starting up.

The sound goes away after a minute or two, And it sounds like any normal gas engine. Very smooth.

The dealer told him this was caused by some solenoid, and related to the fact that the truck was a four-wheel-drive. They also told him that he would have to bring the truck in and leave it for a few days to get it fixed.

This noise doesn’t sound like it’s coming from inside the transmission or someplace inaccessible. It sounds like it’s coming right from the top of the engine, but it is very loud. It sounds louder than any 3.5 L engine which is dieseling during shut off.

I told him I would ask around and see if any of you folks have heard this before.

[Plymouthy Adams]

likely the timing chain tensioner....old, leaking and has to be pumped up to quieting down....

[Dave72dt]

cam phasers for the variable cam timing

[Dan Hiebert]

Similar deal for the lifters.  Rattling after startup until they get oil.  60K miles shouldn't be old or worn out yet, unless rode hard and put up wet pretty often.  Our 2017 Jeep Cherokee does that, dealer said it's normal to some degree.  They said our 2019 Ram truck with a hemi should be doing that, but it doesn't.  Off hand, I want to say 4-wheel drive shouldn't have anything to do with it, but with the way they engineer modern vehicles, it could be a solenoid that's set up to direct oil pressure from something in the drive train to wherever the oil starvation is that's making the noise.   

[Sniper]

An oil filter with a bad anti drain back valve will cause similar symptoms. I'm not sure what type of filter that particular engine uses though but it has to have an anti drain back valve somewhere

 

 

Edited April 17, 2023 by Sniper

[Merle Coggins]

Yup… cam phasers and/or cam chain adjuster. My 2013 F150 / 3.5 Eco Boost started doing that around 150,000 miles and had to have them done. Now my 2020 / 3.5 Eco Boost has just started the same thing at 85,000. I’ll probably have to take it in soon. Rattles and sounds nasty at startup but quiets down within a few seconds. 

[Ulu]

Sorry guys…. It’s the cam phasers.

Based on what information the dealer gave my neighbor, I expected this to be a far more exotic problem.

 

It turns out that it is VERY well-known and all over Google if I had taken a minute to look.

 

It appears that the parts to fix his truck are going to cost about $800 plus the gaskets if we do it.  I think that he may be under some kind of warranty. Otherwise I expect the dealer to want $3000.

 

It would be interesting if you could put a pre-luber on this engine, that would bump the oil pressure up electricity before you started.

 

it looks like those phasers are supposed to have a lockout pin that engages when no pressure exists, but it appears to be a flimsy arrangement compared to the mass of the rotating cam assembly, chains and phaser assembly etc. All that stuff has lots of inertia and it looks like it slams that little spring pin around until it wallows out.

 

At that point it gets stuck and the cam phasers can slam back-and-forth under start up, until enough oil pressure builds to cushion them.

[kencombs]

Ford has had issues with variable valve timing for years, on more than one engine design. Yet other brands seem to have it figured out.  My 5.7 Tundra is nearing 90K with no issues.  Nor have I ever heard on any on the 'net.

[Ulu]

On 4/17/2023 at 9:12 AM, Sniper said:

An oil filter with a bad anti drain back valve will cause similar symptoms. I'm not sure what type of filter that particular engine uses though but it has to have an anti drain back valve somewhere

 

 

I considered this. I think modern engines all have bypass oil filtration so the filter doesn’t fill until the rest of the engine has pressure. But yeah the weak spring in the bypass valve could possibly do this.

 

I would imagine it has an Autolite filter because he has it serviced at the Ford dealer. I didn’t look to see. I’ll probably get the chance, because it sounds like his starter solenoid is going out.