I've got ticking HLA's on my 90 Legacy, 194k miles. I've got heads from a 93 w/100k which had blown a rod through the crankcase. I've had them for several years now. Thinking of swapping rocker arms & all hla's depending on condition. Would welcome suggestions about things to consider in the process. Thanks in advance.

a good starting point would be to determine whether the HLA's are not receiving enough oil pressure or just sticky/frozen. if it's oil pressure related it'll vary a lot and could be any/multiple HLA's. if it's a sticky or frozen HLA it should be just one HLA making the noise. a mechanics stethoscope helps but often you can just tell by listening too. if it's on one side and one cylinder then you know it's one or two HLA's and probably not oil supply related.

 

have you resealed the oil pump yet and tightened as well as tighten the backing plate screws on the back of it? this as well as fixing any bad oil leaks would be a good first step.

 

after that - try some oil treatment if you want to avoid the work. for such a high mileage easy to find car i personally wouldn't want to put a ton of work into it. i'd probably try a can or two of sea foam or marvel mystery oil in the crankcase oil and see if that helps.

Thanks. The engine has been resealed along with the oil pump being replaced. It sounds like one side and one HLA, not more than two. It's had plenty of oil treatments which take care of the problem briefly. It's also had considerable maintenance and worth putting a bit more effort into. Emissions still as clean as ever. Thanks for your input.

+1 for seafoam....i had a HLA tick and i ran like 1/2 can of seafoam through it and it hasnt come back in a good while....knock on wood....

I'm guessing you have those big honking HLA's then. If they're the same style they should be swappable. I think there is a special tool that is supposed to make getting them out easier?

 

Some people have said marvel mystery oil MMO has helped free up stuck hla's.

 

I think there is a note on endwrench about some oil passage that can get blocked and cause ticking hla's.....i can have a look see if i can find it.

I think this was it:

 

Loyale And Legacy HLA Noise http://endwrench.com/images/pdfs/LoyalInfo.pdf

Should you encounter a Legacy or an Impreza with noisy hydraulic lash adjusters (HLA) which do not pressurize

during normal running, the cause may be a partially blocked oil passage in the rocker shaft. Also, Loyale vehicles, especially those with higher mileage, may have an

oil flow problem due to the oil pump. When checking oil pressure, it may be within specifications but the volume of

oil may not be sufficient. In this case, it is recommended the oil pump be replaced.

Swapped out drivers side. Purrs like a kitten. Except now I can hear a slight tick on the passenger side. Another day and likely a third of the time to do it.