'01 Chevy truck engine clatter at startup when cold

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  #1  
Old 07-26-09, 11:05 AM
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'01 Chevy truck engine clatter at startup when cold

Engine clatters at cold startup. I have 188k miles.
 
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Old 07-26-09, 11:31 AM
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Welcome to the forums! Sounds as if your valve seals may be worn, allowing oil that is normally held up in the valve area to seep back down, taking a few seconds for the oil to be pumped back up and lubricate the valve area.
 
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Old 07-26-09, 11:38 AM
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I'd say worn lifters are likely..

A step up in oil viscosity may help...from the name it looks like you may be in a warm area..so there wouldn't be any cold weather oiling problems by trying that.


chandler...worn seals? Doesn't that cause smoking? Any oil in the rocker arm area drains back anyway after the engine is shut off...

You haven't been sniffing the bear repellent have you? Have you checked yourself for ticks recently?
 
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Old 07-26-09, 12:15 PM
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Could this possiblly be a bad oil pump?
 
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Old 07-26-09, 12:27 PM
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No expert...but I doubt it...not if it goes away within a very short time. Do you have an oil press gauge, or just a light?

Actually..let me qualify...you could have a worn pump..which then takes a bit to pressurise all the passages..maybe. I think pumps have checkvalves to keep oil in the main areas from draining back through the pump....

Again..I think that is right...couple of the mechanics may be around later or tomorrow.

Might want to post what engine you have...some have known isses that the Pro's would be able to tell you.
 
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Old 07-26-09, 12:34 PM
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My '01 w/ 5.3 has 80k miles and does that too. Sounds to me like the lifters are bleeding off and it takes a few seconds for them to take up the valve lash.
Mike
 
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Old 07-26-09, 12:42 PM
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Thanks for the input. I have a 5.3L. The noise is so loud so have wondered if it was a diesel.
 
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Old 07-26-09, 06:03 PM
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GG, the only experience I had was a 73 Jeep CJ5 Renegade with the 304 in it. No smoking, but similar rattling at start up. Had it checked and the Chrysler short block needed new rocker blocks (weird set up) and valve seals to keep residual oil in the valve area. Now the bear repellent is stout, but I remember that even 35 years ago. They told me it was due to rubber being used and it just melted, while the replacements were neoprene.
But I agree the lifters are a good area to look into. If they are weak, the lift is compromised and they will slap.
 
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Old 07-27-09, 08:01 AM
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engine rattle

How long does it last? These engines have a history of piston slap when cold. GM says its normal. Of course if the crank brngs are loose they will make noise till the oil gets there.Lifters take a little longer and pistons take several minutes.
 
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Old 07-27-09, 09:16 AM
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I would try using a thicker oil as was mentioned earlier to see if it makes a difference, you may have to use a strait 30 or 40 weight oil. I know there are some additives out there that are suppose to help quite lifters, what they do is actually swell the rubber seals to help seal better.
 
  #11  
Old 07-27-09, 01:57 PM
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knocking

If the engine knocks only when cold on start up. I would guess that it is piston slap. Also check oil pressure could have hydraulic lifters bleeding down and causing valves to clatter.
The noise will be very loud and tinny ritght under the valve covers and Piston slap is lower pitched and deep withen the block.

Ususally a bad bearing will knock when the oil is hot. If it doesn't knock when it is hot and oil viscosity is at it's thinist point. It is probably not bearings.

Oil pump would also cause a knock when warmed up at idle and under load. ie foot on brake in drive sitting at a stop sign when hot. oil pressure gauge would drop.

What I was told (as a service advisor) was if the noise goes away in 30 secs it is ok when referring to piston slap.
 
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