Knock/vibration sound on start

[faral]

when i do a cold start, there's a string of knock/vibration sounds. it always goes away after 1 second or so of this. i don't hear knocking when driving at any range, hot or cold.

anyone know what this might be? it's a 2002 protege5

 

[flash75]

The oil filter can cause startup knocks if the anti-drain-back valve in the filter fails. I would
try another oil filter.

If very little or not oil drains out when the filter is removed the anti-drain-back valve is probably
defective.

Clifton

 

[beej336]

i believe its the VTCS. mine makes the same noise. almost like the valve rockers are completely dry, right?

 

[flash75]

He said the noise goes away in a second or so. VTCS doesn't go away that quickly.
The dry oil filter sound is a sharp metallic rattle as in rod knocking. VTCS sounds a
little like a piston slap.

I have experienced the oil filter problem several times on my P5 with 2 OEM filters, one NAPA
and one O'reilly filter made by Purolator. In each case changing the oil filter stopped the rattle.
I do have the VTCS noise for a few minutes until the engine warms up.

Clifton

 

[faral]

hmm, i *just* changed my oil last night (and filter). the noise was there on the first startup after the oil change, but so far hasn't happened again (2 or 3 startups since that noisy one). but the problem isn't entirely repeatable...i can't tell when it'll happen and when it won't. i plunked a recorder on the engine today to record it before bringing it in to shop for another problem (brake fluid leak)...it sounds okay (actually, sounds like there is knock that i couldn't hear until i put the mic right on the engine)

 

[faral]

does vtcs happen on 2002's? I thought that was only 2003

 

[CheeseHelmet]

hmm, i *just* changed my oil last night (and filter). the noise was there on the first startup after the oil change, but so far hasn't happened again (2 or 3 startups since that noisy one). but the problem isn't entirely repeatable...i can't tell when it'll happen and when it won't. i plunked a recorder on the engine today to record it before bringing it in to shop for another problem (brake fluid leak)...it sounds okay (actually, sounds like there is knock that i couldn't hear until i put the mic right on the engine)

Please record the sound, I *think* I'm experiencing this too.

 

[flash75]

hmm, i *just* changed my oil last night (and filter). the noise was there on the first startup after the oil change, but so far hasn't happened again (2 or 3 startups since that noisy one). but the problem isn't entirely repeatable...i can't tell when it'll happen and when it won't. i plunked a recorder on the engine today to record it before bringing it in to shop for another problem (brake fluid leak)...it sounds okay (actually, sounds like there is knock that i couldn't hear until i put the mic right on the engine)

If you didn't precharge the filter with oil that noise is probably normal because the filter was dry. I always pour enough oil into the filter to saturate the filter media allowing
oil pressure to build quickly and usually prevents startup rattle.

"does vtcs happen on 2002's?"

Yes, ithe 2002 has VTCS.

Clifton

 

[faral]

okay so i brought it into the shop. he couldn't reproduce it (and i wasn't surprised...it is pretty random), but from my soundbite and description, he thinks it is rod knock. he thinks it stops so fast because 1. it isn't so bad (yet) and 2. once the oil pressure fills in, it stops knocking.

options: replace engine or do a rebuild. for now, since it isn't so bad yet, i'm going with "lets wait and see"

 

[flash75]

It probably is a rod knock, caused by lack of oil on start up with a new dry oil filter.
Pre-charge new filters with oil and it probably will not happen. I believe your mechanic
is wrong. Some very poor quality oil filters are out there.

Clifton

 

[beej336]

clifton why are you pushing the dry oil filter so hard? i highly doubt that it is that. nearly every oil filter is put in dry and after starting and running the engine for a little will fill it and it will be fine after that.

 

[flash75]

Most good mechanics recommend filling the oil filter before it's installed. I learned that when
I went to auto mechanics school 30 years ago. Lots of articles on oil changing recommend filling
the filter before instaling.

This article mentions it.

http://www.wikihow.com/Change-the-Oil-in-Your-Car

Clifton

 

[faral]

yeah...i've never had this until now. two different oil filters. it doesn't seem to be progressing so far...so i may sit and wait for a little bit...see what happens. i might also need a new cat...my car is intermitently throwing a P0421 code...so i can't just up and ditch this car =(

 

[fragile]

Zombie revival, i know, but i'm wondering what has happened in 3 years with this noise? my gf's new to her p5 has the same thing...

 

[thuzil]

Could be valve rattle. After the car sits for awhile, the pistons and valves cool down and the metal shrinks ever so slightly, coupled with the fact that all the oil has drained out of the head, when you start a bit of rattle is to be expected. You can try and up the oil viscosity to see if it helps. As long as it goes away after a minute or so no worries.