engine chatter / clacking noise upon start up?
Thread Starter
Instructor
Joined: Jul 2004
Posts: 174
Likes: 0
From: Texas
engine chatter / clacking noise upon start up?
I noticed this about a week ago, but especially this morning (dunno if weather affects it but it was 50 this morning ... normally we were seeing about 80 in the mornings) - anyway, I start it up and hear a clacking or chattering. When it warms up and the idle drops down to about 900-1000, it goes away after a minute of idling. What is this?
3rd Gear
Joined: May 2005
Posts: 3
Likes: 0
I have the same situation. Cold weather startups produce a clacking sound. It sounds like one or more lifters are making the noise. I wouldnt expect lifters to go bad at 90k miles but that is what it sounds like. I dont know how hard they are to change. Maybe others have some input.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
It appears there is a lot of this happening to lots of people all of a sudden. I'll wager that the lifters are failing or bleeding down when cold. It happened to mine a couple of years ago, but I have a lot more miles on it than most everyone.
Thread Starter
Instructor
Joined: Jul 2004
Posts: 174
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From: Texas
yikes!! that sounds scary! How can I tell for sure?
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
I can only tell you what happened on my '99 therefore you can apply it to your car or not as needed. Mine started clattering or tapping whenever I started it up cold. At first it would only happen for seconds but progressively took longer and longer before the noise would go away. After a couple of months of this, it finally would not go away till the engine temp actually started to show on the analog gauge, then within about 3 weeks of that time, it suddenly got real bad and loud. I paid the dealer to confirm my suspicion that it was the lifters and the report was in fact exactly as I thought.
I replaced the lifters, along with the pushrods, rockers, had the valve seats checked and heads clean, replaced the springs and valve stem guides and seals all at the same time. Problem solved.
I replaced the lifters, along with the pushrods, rockers, had the valve seats checked and heads clean, replaced the springs and valve stem guides and seals all at the same time. Problem solved.
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Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
The miles on mine are freeway miles from many years of doing anywhere from 60 to 91 miles one-way to work everyday. Then started car-pooling therefore going to work and back was every other day. I do think that cars driven get better long term use than those who are garage queens....just a guess though. In fact, my turn to drive today and leaving again for work in about 15 minutes. I take good care of my car and try to make sure everything is perfect all the time or as near to perfect as I can make it.
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
What oil filter are you using?
I recently changed from DELCO's UPF-44 (premium filter) to WIX or NAPA Gold (same filter) and my cold start oil pressure went up 10-15 psi (the C5 oil pressure sensor is after the oil filter). This helps with initial noises. An oil analysis showed no problems with these filters, and Blackstone Labs said they usually see no difference with different oil filters. Add to this Evil Twin (an ex-GM C5 Engineer) once told me to save money, that stock DELCO Oil Filters were good enough for 200,000 mile engine life. Premium filters often filter "too good" at the expense of flow and pressure.
BTW I have 109,000 miles on my 1998 C5 Coupe.
I recently changed from DELCO's UPF-44 (premium filter) to WIX or NAPA Gold (same filter) and my cold start oil pressure went up 10-15 psi (the C5 oil pressure sensor is after the oil filter). This helps with initial noises. An oil analysis showed no problems with these filters, and Blackstone Labs said they usually see no difference with different oil filters. Add to this Evil Twin (an ex-GM C5 Engineer) once told me to save money, that stock DELCO Oil Filters were good enough for 200,000 mile engine life. Premium filters often filter "too good" at the expense of flow and pressure.
BTW I have 109,000 miles on my 1998 C5 Coupe.
Last edited by Oldvetter; Oct 26, 2007 at 03:50 PM.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Not using any special filter... have the oil changed at Walmart. I assume they are using either a Fram or Mobil 1 filter. What I do though I closely keep a watch on everything...wheel alignment, balance, use Techron every 3 months or so, on my 3rd set of wires and plugs, and I replace anything and everything that has failed on it. That last part means I've spent some serious money keeping it running with the best of them. Right now, I'm still having pinging issues which I can't seem to get rid of and yes, I tried Seafoam twice. It had little effect on the pinging. I heard that there is a PCM Flash for this, but would like to know what it is first.
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
small block chevy piston slap. common on cold weather.
Just let the car sit for 45-60 sec to warm up and you will be fine.
Or put an accu or dry sump in to prelub the block before start up
Just let the car sit for 45-60 sec to warm up and you will be fine.
Or put an accu or dry sump in to prelub the block before start up
Drifting
Joined: Aug 2001
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From: SANTA MARIA,CA. formerly Magnolia Texas
St. Jude Donor '08-'09
Team Owner
Joined: Jan 2004
Posts: 22,185
Likes: 65
From: NJ
Piston slap is not dependent on temperature. Its worse when its cold but can happen in all temperatures. It's also called cold start knock, meaning the first start of the day.
Burning Brakes
Joined: Mar 2003
Posts: 1,156
Likes: 2
From: Arlington VA
Piston Slap. Once contributing factor may be carbon buildup on the pistons. If you are not running a carbon depletion additiive on a regular maintenance schedule, you might be cotnributing to the problem. Try running some BG44K or Techron concentrate through the fuel system for a couple of tanks and see if this helps the issue. Good luck with it.
