Aside from my introductory post in the new member section, this is my first real post.
I asked this same question on another Subaru forum and basically was laughed at for asking for help.
I have a 95 Impreza wagon with the 2.2 and 119k miles. I've owned it for about 3 years. Love the car!!
About 2 months ago, we had our first cold night this season with temps dropping to the upper 20's. The day prior, the engine was very quiet with no noises, as it's been for the 3 years I've owned it. The following morning after the cold temps at night, I drove about 2 miles and the engine started making a ticking sound, which I have found out is the HLA's. I researched the issue and pulled the passenger side rocker assembly off, reprimed the (1) intake HLA which was collapsed and reinstalled everything. The noise disappeared, but returned about 2 days later. I pulled the valve cover and found all (4) intake HLA's were now compressed. The exhausts were nice and solid. I went to my Subaru dealer and got (4) new HLA's, replaced all (4) intakes and put her back together. The tick was gone, but reappeared soon thereafter.
Yesterday morning, after dealing with the tick for a few weeks, I pulled the passenger side apart again and found all (4) intakes collapsed, while the exhausts were still nice and solid. I reprimed the intakes, blew out the oil feed holes with air and went to put it back together. I thought about this, seeing I'm having a problem with the intake side - I put the known good exhaust HLAs in the intake rockers and put the reprimed intake HLAs into the exhaust rockers. I put it all back together, turned the key, and she fired right up, purring like a kitten. I let the engine idle for about 10 minutes, revving to 2000rpm a few times and the noise was still non-existent.
Now, here is where I'm pulling my hair out. About 3 hours after the repair, I left to go run some errands. The engine started fine, no ticking, nice quiet ride to my destination. An hour later when I came back to my car, the tick was back. It was not loud, but you could tell it was there. I drove home, the tick became more noticable and is now roughly as loud as it was yesterday morning before the teardown.
I haven't pulled the valve cover off yet to see which HLAs are compressed. The engine runs great, has all sorts of power...just has the annoying tick. Am I overlooking something or is it possible the new HLAs I got from the dealer were defective out of the bag? While cleaning things out, I did notice the oil ports for the exhaust side were draining when I blew air through them. I didn't seem to be getting anything from the intakes. There also doesn't seem to be any ports where the intake HLAs sit for oil to access the top of the rocker, only a small hole in the side of the part of the arm where the HLA sits in. I've read that there may be crud or deposits blocking the ports that feed the intake rockers on the rocker shaft. If this is a possibility, can these be accessed without taking the entire rocker assembly completely apart?
I change my oil & filter every 5k and use Pennzoil 5W-30 with a Purolator classic filter. Any thoughts on how to fix this? I'm pulling my hair out. What am I missing? Sorry for being long-winded, I like to be thorough. Thanks in advance for all help!