5.7 knock

[jemezcrusher]

Now that the weather has cooled, I am noticing a knock in the 5.7 until the engine completely warms up. If you didn't know better, you would think you were driving a diesel.

Goes away (mostly) after after20-30 minutes, and I don't hear it again until it sits all night. Dropped it off at the dealer this morning to see what they say, but it is very noticeable (concerning) and was wondering if anyone else has experienced this

 

[cruiser88]

Maybe one of those bad cranks we heard about

 

[SteveH]

Piston slap?

 

[jemezcrusher]

Got it back from the dealer. They said they did not hear anything out of the ordinary. Guess I need to drive another new one under the same situation

 

[Duane]

ya sort of thinking what SteveH said. Piston slap?
GM had a knocking symptom going in the late 90's with their 350 and 454 models which would rattle a while when cold.

Far as I know Toyota assembles engines with very tight tolerances thus I would be concerned if I heard any knocking. I never hear a tick or knock out of my 4.7

Perhaps post up your oil pressure when cold and after it warms up to compare to what other Toyota 5.7 owners are seeing.

Keep an eye on your oil for filings when you pull your dipstick and get them to catch the oil when it is changed to see if anything is noticeable.

 

[cruiser88]

ya sort of thinking what SteveH said. Piston slap?
GM had a knocking symptom going in the late 90's with their 350 and 454 models which would rattle a while when cold.

Far as I know Toyota assembles engines with very tight tolerances thus I would be concerned if I heard any knocking. I never hear a tick or knock out of my 4.7

Perhaps post up your oil pressure when cold and after it warms up to compare to what other Toyota 5.7 owners are seeing.

Keep an eye on your oil for filings when you pull your dipstick and get them to catch the oil when it is changed to see if anything is noticeable.

How thick is the oil that toyota puts in?

 

[Duane]

my local Toyota dealership has 5W30 written on my oil change invoices/workorders for my 4.7 litre engine.

 

[jemezcrusher]

The 5.7 calls for 0W20 or 5W20 Went with the 5W20

The tech that rode with me said the 5.7 has really loud injectors. We'll see

 

[JJS]

ya sort of thinking what SteveH said. Piston slap?
GM had a knocking symptom going in the late 90's with their 350 and 454 models which would rattle a while when cold.

Had? The newer 4.8/5.3/6.0 motors tend to develop this as well.

It sounds like the dealer is giving you the runaround.

 

[Gumby]

Mine knocks like a mofo on startup. Louder when cold. 5W-20.

They can put a new motor in as long as they give me the old one. I bet I can find a use for it.

 

[Duane]

The tech that rode with me said the 5.7 has really loud injectors. We'll see

What????? Really loud injectors for 20 minutes or so..
as in the injectors make a knock until it warms up or some idea!... hmmmm

You know JJS and Gumby...my friend still has a 98 chev 454 with 140,000 miles on it I would think... that thing knocked liked a bugger since new and it is still in one piece.... maybe the engineers have taken this into consideration.... it doesn't make me real optimistic that a Toyota 5.7 is going to last 300,000 miles though if this is a normal thing.... or maybe in Wisconsin good luck but maybe Arizona won't be a problem

 

[Gumby]

It's not injectors. It's a one cylinder speed low end knock. Injector tick is a whole different sound.

Wrist pin/ piston skirt/ rod knock is what is sounds like.

I could see a PAIR valve, or an exhaust tick, but it's really deep in tone for those ticks in my experience.

 

[jemezcrusher]

I'm right with you Gumby. Seems like the sound is coming from the bottem end, not valve train or injectors.

Being a life long motorhead, it is the kind of noise that makes you reluctant to step on the gas with other than feather pressure for fear of tearing something up

 

[jemezcrusher]

JSS

My buddy in Colorado says his 2001 4.7 does the same thing. Haven't had much feed back from other "little motor" guys

 

[Gumby]

I listened closely this morning on the way to work. It's a little high in pitch for a rod knock. I wonder about a timing chain noise. The 80 did the same thing, but only for a few seconds. The 5.7 does it for 5-10 minutes.

 

[SteveH]

Recall that newer engines have shorter piston skirts to reduce friction and improve gas mileage. The shorter they are, the more they allow the piston to rock in the bore during its travel. This has been known to cause some wear and noise issues in some newer engines.