Engine(?) noise on startup? Video inside...

[vt2tahoe]

Hello,

First time posting here. I own a 2005 S40 T5 AWD. Awesome car, but I'm concerned about the noise I hear on start up. I'll hear it during acceleration as well, but it's loudest at startup. If the car has been driven, I can stop it, run an errand, come back out and it stays quiet. So it's most apparent after the car has been sitting for a while.

I let it sit overnight and took a video this morning:

Hopefully someone here has experienced this before and can point me in the right direction. The car runs smooth, but the noise is driving me nuts and I'd rather be proactive about it than wait for something to become a problem.

Thanks so much!

[MadeInJapan]

Sounds like lifters...on start-up....would have like to have heard it going down the road? My first theory (without the on-road noise) is that the high RPM's on start-up is normal but not with all the clicking...so, as the engine rpm's slow down and oil circulates, things become calm. What comes to mind is how long has it been since an oil change, what oil do you use and also filter.... On older S70 models, I calmed lifter noise with Seafoam (sucking it through the intake) but I would be hesitant to try it on your S40 like that- though I might be tempted to put some in the gas tank... Your problem could also be the oil pick up lines (from the bottom of the engine to the top) that are starting to get clogged which open up some when things heat up... Really, I'm just guessing here. The Seafoam or other products that are known to be safe for our cars would break that down and help things flow again- but like I said, I would probably not suck it through the intake (to many stories of bad experiences although I've never experienced a bad thing with it). What kind of sound does the car make when you "punch it" on the highway- is it that same clacking sound you hear on start-up?

[vt2tahoe]

Thanks for the response!

Oil changes are always regular and done at a European specialist - they use the good stuff, including air filters. Oil pickup lines sound plausible. I also had a guy suggest an exhaust leak. (Once the exhaust heats up and expands, it closes the leak / noise goes away).

If I hit the gas relatively hard, I'll hear a similar, but less pronounced noise. As soon as I come off the accelerator it quiets down again.

I may try the Seafoam in the gas tank first and then up on a lift to find an exhaust leak if the noise persists.

I'll report back with results.

Thanks!

[MadeInJapan]

What did you find?

[10V50]

I know this post is pretty ancient but we are having the exact problem with our V50! This is the only place on the net I have found the same problem, does anyone know what this fix was? If anyone replies thank you.

[Joshuahunt]

I also realise this is an old post, but my 09 C70 is having the same issues, did anyone find out what it was?

[theWIFES_S70]

Is this a PCV whine? PCVs leak from the little diaphragm piece and from the rubber seals... Sounds like air to me.

[10V50]

I finally figured it out after more searching here’s a link https://forums.swedespeed.com/showthrea ... 747?page=1