Hey all,

I know that this is not the right forum for the question, but I figured some of you mechanically inclined geniuses can help out.

My wife's 97 Subaru Outback has had an engine knock for--well, forever I think.  Are there any additives I can throw into the fuel tank to eliminate / lessen this knock?  It only seems to make the noise at low speeds and when it hasn't been run in awhile.

Thanks,

Chilly

A clickity-clickity sound?  If that's what you hear it's likely the hydraulic valve lifters are in need of replacement.  What's the mileage on the engine?

They're not complicated to replace.  Pull the camshaft(s), suck them off the valve tips with a magnet and replace.  While you're in there you might as well do valve seals.   

Additives are a waste of time.  The usual failure modes are wear and sludge.  Whatever the case, the lifter can no longer "pump up" which results in valve lash.  This will reduce the valve lift and increase the valve noise, but won't adversely affect engine life.    The main reason for using hydraulic lifters on cars is to make it convenient - no more valve adjustments.  The second reason is it quiets the valve train significantly, as a hydraulically adjusted valve train runs with zero clearance.   

Thanks!  You're right, it is a clickity-clickity sound.  I've taken it to the stealership several times and have been told that it's "normal" for the Subaru outback.  Looks like I'll have to dig out my Haynes manual soon.

Chilly

I know older Subaru's had a problem with the fuel pump. It was located along the frame to the aft of the vehicle, and made an interesting "tapping" sound that seemed come from the engine. Subaru dealers reported this as being "typical" of all subarus, and did nothing to fix it. This usually occured around 100,000 miles, and simply replacing the pump helped greatly.

Good luck though!

nah it's normal lifter noise.  you can hear it on some of their NEW cars...

I had a 97 Legacy 2.5GT... exact same engine as yours and the exact same ticking the whole time I had it.  Only happened when the engine was cold.  I was also told its normal (I forget the exact reason now) so I just drove it and never had any problems.  Think of it as a reminder to take it easy on the engine while it's still warming up

Oftentimes a quart of Marvel mystery oil will help to clear out the lifters. Being winter, it will be good for it anyways as it will help the oil flow more quickly at startup.

How many miles are on the car? Dose the sound go away once the car warms up?

For best results, change the oil before adding the marvel, but it should work if you just add it too, just don't overfill it.

Thanks all,

I think we have 180-190K miles on the car.  It hasn't really given us too many problems, so we may just drive it until it expires.  Now that the weather's turning colder, I've noticed the sound more.

Chilly

Try the Marvel mystery oil, if it works it's a cheap fix. If it dosen't work, no harm done, just drive it till it blows.

I've got a WRX... it's completely normal for the boxer engine.

i hate to say it but mak is right i work on alot of them and it's normal. but with 180k the oil pump may be getting week                                                                                                                                                                                                                                             

Quote from: makenzie71 on October 17, 2006, 11:19:29 AM
nah it's normal lifter noise. you can hear it on some of their NEW cars...

sounds normal.  keep on driving!


Any other Subaru people around here?  If so, what ones?

soobies are terrible for sticky lifters, get some engine flush, run the car for about 20mins with it in (don't drive it) drain the oil, may as well do the filter as well while your there.
refill with some nice thin synthetic oil and hopefully you'll be away laughing, it happened on my legacy quite a bit as well.
good luck

Thanks all!  You've given me quite a bit to work with here.  I'll start with an oil change and then move on from there.

Chilly

My wife and I purchased an '06 OB 2.5i April of this year.  That's probably 'valve slap' or whatever it is commonly called.  Boxer engines are known for it.  Does it get better as your engine gets warmer?  Our car has 7500 miles and I can hear it when it's warming up.

Regards,
Randy

Yeah, once it's warmed up and up to speed, the sound goes away.  Now that I live on a fairly small island, though, it doesn't achieve highway speeds too often.

Chilly

go and speak to the guys on www.ausubaru.com a real good bunch of guys on the forums they helped me out heaps with both my leone and my legacys
good luck

Thank you for the link!  Oh no, not another board--I'll never leave my computer now!

Chilly