Clacking from head/block

Added rec.autos.tech...

That's what I was thinking. Trying 1/2 QT of Marvel Mystery Oil for this change and the next one. But it's still not on the road yet, the E-Brake is frozen and the rotors and pads are no longer separate items...

20 minutes running with MMO will LIKELY solve the problem if it is a gummed up lash adjuster.

I was hoping for some back-up approval! ;)

This is what I was thinking, too. We only ran the car for about 15 minutes with fresh 10W30, so next time I go there I'll put in some MMO and let it run for a while.

Perhaps after I change the valve cover gaskets...I *HOPE* that's what's leaking! :0

(It's not dripping, but there is burning oil coming from that area when the engine is running. Had the same thing happen on a Supra...)

Piston slap is pretty easy to diagnose in its early stages. You will hear piston slap most prominently when the engine is dead cold and under a load, and it will diminish as the engine warms up. Is this what the OP was experiencing?

Hard to say. This engine, if I am interpreting it correctly, should be a 2.2 litre SOHC H4 boxer arrangement.

I have been curious about these for a long time, but have no experience with Subaru. They are supposed to be good strong engines.

I'd like to hear any comments about this setup.

On the boxer engine, I found this:

They claim the slap IS typical of this boxer engine.

i experienced this for years with honda engines, and was particularly disappointed when my new 2000 civic started doing it after only 30k miles.

but recently, i tried an oversize oil filter on a high mileage civic because the motor was particularly noisy, because i figured there was nothing to lose from better oil flow. i was stunned at the result - "piston slap" almost entirely gone when cold. looking back on the 2000 civic, the noise started round about the same time i transitioned to the new smaller honda filter pattern - it would have been interesting to see what would have happened if i'd gone back to the old size honda filter. since the old noisy civic discovery, i've tried this on my accord too

- same noisy "cold slap" went away using a larger filter.

bottom line, these new smaller "more efficient" filters may be fine in terms of performance when the oil is at full working temperature, but i believe their cold flow characteristics are inferior and restrict flow. it follows that the noise we're therefore hearing is actually bearings, not pistons.

i don't know if a larger filter [with larger medium area and thus less cold flow restriction] is available for subaru, but if it is, for

i'd like to hear your comments on logical thinking with regard to engine coolant color.

Nope. Idle was the loudest, and it got smoother and a little less pronounced when run at higher RPMs. Car is not on the road right now.

Definite clicking noise, like a sticky lifter makes.

Piston slap is generally a light "double knock" that generally changes with load - just tap the accellerator and let off and it should change pitch and "quality" or intensity - while a lifter is a heavier "single knock".

Also, piston slap will be engine speed or double engine speed (double or singlee knock), while valve will be half engine speed. Piston noise will generally pretty well dissapear when the engine is warm - and will not be there on a warm restart. Valve noise may go away when warm, but usually gets intermittent first - and it often will do a little "tap dance" at idle even if it has quieted down at fast idle - and it will often be there on initial hat restart as well.

Not sure about the Sube, but some engines with an oil leak from the oil gallery will drain the oil from the lifter gallery when shut off, allowing the lifters to start dry and will take time to pump up and quiet down. Same problem with some cheap oil filters - the orange ones I don't need to bother naming are NOTORIOUS for having bad anti-drainback valves, and OFTEN cause engines to be noisy on a cold start. VERY often, just replacing the Orange crap with a quality filter like a WIX /Dana / Etc stops the cold-start noise.

Another test is to remove one plug wire at a time until you find the one that eliminates or greatly changes the sound. If you find one, it is a piston (or rod) noise - not a valve....

Head gasket is very unlikely to fail with the engine not being used.

This motor has hydraulic lash adjusters. When the engine is stopped for a long while, the adjusters that where under pressure all the time will leak oil causing the clacking on starting the engine. The reason why the noise is more noticeable at idle is because the oil pressure is lower. If you are lucky, the lash adjusters will evacuate the air inside with repeated use. If unlucky, as with some Nissan Maxima engines, the only way to get rid of air inside the lash adjusters is by bleeding the adjusters inside a container full of clean oil.

Sticky valve would be noticeable as a miss on the pressure coming out from the exhaust pipe.

Other than the nuisance and the "reduced" engine output (if noticeable at all) the noise wont be too harmful.

Good luck.

AS

hachiroku wrote:

If the lifter is collapsed, driving it will beat the heck out of the valve stem and lifter, as well as possibly damage the camshaft. I agree it's not likely a "sticking valve" - but the "sticking lifter" is very likely - and the MMO solution is the first step.

Forgot to mention, that the 2.2 has an o-ring between the engine block, and the oil pickup tube. That oring gets flat and then the oil pump sucks air causing all the lifter noise. I now remember that after I replaced that o-ring, not a fun job to do because of the removal of the oil pan, all the lifters quieted down, probably an indication that they self bleed.

Good luck,

AS

AS wrote:

Thanks! I have a 1989 Mazda with HLAs and after I bought a box of 4 I changed the oil to a different brand and the clacking stopped. Luckily, i got my $55 back! Hopefully, this is what the issue is, but it sounds like it's in the block side of the head... :( But it's not a rapping, it's a distintive clack, like on the old hyrdaulic lifters on Chevys.

Shoot. On my '89 GL, the oil pump was right up front, and changing the O ring was a piece of cake! Took me 25 minutes.

He did say pump - but I think he means pick-up tube in the pan.

The o-ring I mentioned is in between the oil pick up tube and engine block. This is different front he o-ring sealing the oil pump which is located in the front part of the engine.

When the pick up tube o-ring flattens, the pump sucks air. The 95 legacy L I had, with the 2.2, was noisy till i replaced that o-ring.

The o-ring is # 3 in the illustration found here:

Regular Buna o-rings will not last here, you need higher temperature resistance, e.g. Viton.

Good luck,

AS

1 Lucky Texan wrote: