petew

Car has just been confirmed with the dreaded piston slap. 1998 Terzo 37000 so its under warranty. Garage have cofirmed replacement piston etc but not whole engine. Should i accept this or push for a new short motor? Garage confirmed Subaru UK now acknowledge this fault as Dealer bulletin was issued about 4 months ago!
Advice or comments appreciated.

Pete

scoobyboy

the only fix you will be offered is the piston change because subaru have come up with this as the cheaper alternative to having a new engine.

Simon

You don't have a choice. I have just had the piston replaced on my Terzo... the noise is now gone.

Simon

petew

Thanks for the replies,
thought i would ask the question anyhow but was quite happy that they offered the replacement following a check carried out at 37500 service.
only problem no scoob for 5 to 7 days whilst work is carried out!!
pete

Gerg2

Dont mean to rain on the parade but I heard that just replacing #4 piston was only a temp fix and a short motor is the only cure?

Could be wrong but you might want to do a search on piston slap around here to come up with some more info.

Regards.

AlexM

I have discussed this with my dealer at some length as I had some reservations.

The replacement piston is a very slightly oversized to close up the clearance to the piston wall when cold. This should permanently resolve the problem - I think the short engine replacement would quite possibly re-occur unless the piston was also of a different design.

The only issue that I had is that the bore isn't measured before ordering a suitably sized piston, so clearances aren't as good as they could possibly be. Apparently no damage to the bore is expected so there shouldn't be an issue there.

I'm waiting to have my MY98 done, so I'll let you know.

Cheers,

Alex

Jason L

Just to add to what Alex said...

I had Piston Slap on a MY98 about a year ago and at that time the only solution was a new short engine...

This fixed the problem... for a while.. then it came back..

Now had the new oversized piston and this appears to have solved it... saying that i've only done about 4000 miles on the new piston so can't guarantee it...

I guess the morale to the story is.. a new short engine has solved some peoples piston slap problems and not others, it doesnt appear to be the definative fix... all a bit consequential anyway as i believe that only piston replacement is offered now so i guess this isn't an issue !

Jason

slimshady

alex,
i too have an my98, but as yet my car is ok on start-up, no piston slap . anyway what would happen if i started to get piston slap after my warranty had expired (its 2.5 yrs old and has done 27.5k ). does anybody have any experience of this ? are subaru willing to except responsibility after the 3 years ? .

AlexM

Slimshady,

Again from my earlier conversations with my dealer....

Subaru aparently are quite generous with their warranty with respect to claims outside the warranty period where a claim relates to a known problem.

Apparently a justy owner had a brand new auto box fitted after seven years because there was a recognised design problem and failure was only a matter of time.

A broken gearbox is one thing, but piston slap can vary from barely noticeable to very bad apparently, and it is this subjective element concerns me a bit. Goodwill out of warranty claims are unlikely to be met if your mileage is >60k anyway....

it should be pointed out that a bit of piston slap when cold isn't really that serious, and your engine will probably last as long as any other (more or less). If you don't notice it when warmed up I probably wouldn't worry too much. I have a very acute ear for mechanical noises so even the fairly slight piston slap on my car drives me crazy.

With regard to your own car it may never suffer from this problem (most MY98 don't) and I would have expected the problem to emerge by 27k if it was going to. Talk to your dealer if you suspect a problem though.

Cheers,

Alex

slimshady

thanks alex ,
the only noise i seem to get is a slight ticking (tappets i think ), but its barely audible , but since the boxer engine is so different to most others , its not as easy to identify as other engine types . anyway car runs great, so no worries.

Harka MY98

I have piston slap on a MY98.
Garage told me that the #4 cylinder is oval.
So they are going to bore all the cylinders and put larger pistons.
This was the best thing to do...they told me.
They have done this to a another scoob...and it is working great
Sorry for my poor englisch...but I´m learning more everyday.

Cheers

Harka

AlexM

Harka,

Provided the cylinder bore hasn't become ovalised or tapered (checked with a micrometer), then there should be no problem fitting a slightly overbored piston in one cylinder, as differences in weight and capcity of the new cylinder are minimal. I understand that this is almost always the case with this problem.

The 'proper' engineering solution is what you suggest, i.e. rebore all cylinders and fit correctly sized pistons so that the clearences are correct on all cylinders, cylinder capacities are equal, and everything is balanced properly. All four cylinders should be done if any reboring is needed to correct a problem with one.

Cheers,

Alex

scoobyboy

regarding the balancing of the engine i think the oversize piston is only 60 microns bigger so it woulden't cause that much trouble as regards unbalancing the engine.