I finished my HG replacement (96 2.5 175K) this weekend and I now have an issue I did not have before. I have a very loud tap coming from the driver side engine at idle. I hear it go away when I am driving but that might because of the noise of the road and the rest of the car. I had the heads milled and a valve job done. Its not eating coolant as it did before. This year did have the hydraulic bucket lifters and I did notice that during installation one was more spongy then the rest. But did not think anything of it as there was no tap before the swap. Could I have a bad lifter? Could I now have a cylinder banging against a wall, Maybe my timing is off. Anyone ever see this?

Did you change the oil?

 

nipper

i only have a second. subaru engines can be VERY loud after a rebuild or head job. that's extremely normal. a few dozen/hundred miles will often pump up and solidify HLA's if that's what the engine has. if the engine was fine prior to the job then there's a good chance it'll work itself out. (keeping in mind i can't hear what kind of sound it is). but HLA's can be very loud.

 

there's a chance it could be a rod bearing knock.

 

the timing was properly set and installed right, timing tensioner was good? a bad tensioner can cause slop/noises.

 

gotta go, hope that helps.

I'd run it for a while, change to oil to flush any junk out from the HG job, then give it the old "italian tuneup" to make sure all the lifters get a chance to be fully pressurized. It generally doesn't hurt anything to run with a bad lifter, so I'd give it a chance to sort itself out.

How careful were you when compressing the Hydraulic timing belt tensioner? If you go to hard on it you can damage it and it won't work properly. It will appear to be fine until you start the engine. Take the timing belt covers off and watch the timing belt and the adjuster to see if they are slapping around to verify.

 

Keith

How careful were you when compressing the Hydraulic timing belt tensioner? If you go to hard on it you can damage it and it won't work properly. It will appear to be fine until you start the engine. Take the timing belt covers off and watch the timing belt and the adjuster to see if they are slapping around to verify.

 

Keith

 

I second this.

 

Especially for the newer style *pivot* tensioners like is probably on you're 2.5

 

I make it a standard procedure to take out slack from the belt and then to leverage the tensioner so it's plunger can extend out, making sure it applies good force.

This engine has the old style tensioner. It seemed solid when I re-installed. I am going to pull the cover off and check it for play. I am also noticing an exhaust hole type of sound coming from that same side of the engine as the knock when I apply pressure to the gas pedal. I renstalled the exhaust and there were no holes I could see. May something under the heat shields!.