Hi all,

Over the years my car had developed a awful knock upon cold start up... it's bad, to the point of sounding like a old diesel motor.

It goes away as the car warms up completely, but in the beginning it's bad.

My moms 03' Forester does this to, but hers doesn't seem to go away as much as mine does.

I think i remember reading something about this at a dealer once, regarding tolerances of the motor being bigger when cold....

It sounds like I'm really low on oil, but i know this is not the case.

Any thoughts on this would be great people.

Thanks,
Aaron

Well, since noone else took a gander...

One thing to look at, is that because the motor as a whole is completely cold, all of your minute clearances are shrunken, possibly causing some of the noise, probably from valve clearances.. This, I assume, is the reason why we are told to let the engine warm up for a few minutes, especially when it is cold.

Then, depending on your oil (should be 5w30 in the cold regions), it may not be as 'liquid' as it is when it is warm, so the valves aren't being as oiled as they probably wish they are being, which may add to noise at the valve clearnaces. I run full synthetic Amsoil, and I noticed an improvement, even over the full synthetic Mobile 1 I used previously.

~Levi

probably piston slap - it's very common in subaru engines, particularly when cold - iirc, a note from Subaru said it has to do with the short piston skirts which they use. Not generally anything to worry about, unless it doesn't go away when the engine warms up.

Have you checked the timing?

Also, if you are low on oil at all (even by a quart) that can contribute to the clacking.

Well, thanks everyone for the ideas.... To answer you all

1. i will definitly consider the 5w30 as a soulition, i use straight 10w30 and it's been 20 and below for the past week or so..... so the oil is like honey..
I doubt i could run synthetic at this point, i've got bad valve seals and would prolly blow most of it out...

2. Piston slap, sounds about right and it does go away when warm....

3. Have i checked the timeing, NO, but i will in short order... well, at least i'll get my mechanic friend to help me do that.... I just did a timeing belt and all the TB drivetrain.... but this is something that's been around for quite some time... I also check the oil all the time.... i mean it sounds like low oil, but it's not low oil....

Thanks everyone... feel free to keep the ideas comming.
Aaron

1. i will definitly consider the 5w30 as a soulition, i use straight 10w30 and it's been 20 and below for the past week or so..... so the oil is like honey..
I doubt i could run synthetic at this point, i've got bad valve seals and would prolly blow most of it out...

If it's anywhere nearly as bad as my wife's '99 OB, the 5W30 will probably make it worse. It's thinner when you start the car so the noise will be louder. I've added 1 quart of 10W40 to the current fill of Havoline conventional 5W30 and it has helped the most out of anything that I've ever used.

IMO, my ideal mix for this car running conventional oil is 2 quarts of 10W40 and the rest 5W30. I've done a couple of used oil analyses and the engine is in great shape at 106k miles.

-Dennis

Also remember that we don't have alot of noise stuffing to quite things in the cabin.

Sounds like you have a loose spark plug... Makes a knocking sound? My car had the same exact problem... #3 spark plug came loose and was banging around.. I would of never thought it was that from the sound - but...

Well, thank you people,

I will look into all of this..!!