Clickity clickity clack

[dhirocz]

So I got this nifty load that pays really well headed to OK from Boston. Barely enough time to run it, but I'm running through Thanksgiving so what the hell, right?

Most direct route was I-68W. Normally I prefer avoiding that when loaded because it's hilly as all hell, but today I decided to take it.

When I stop to fill up, I noticed my pyro gauge starting to bounce around. It had apparently come loose from the manifold...so what I thought was 500 degrees was more like 7-800. Ouch. This is the hottest I've seen it since @m*m^2.

What got my attention the most was this nice clicking sound from the driver's front of the engine, that I can't hear when driving. Without a stethoscope, I'm assuming it is the air compressor, seeing that it's coming from that area and it doesn't appear to sound like valvetrain noise. Overhead was just run 30k ago.

Still makes air, not diggin the noise. Typical of a failing compressor? I'm assuming being force fed very hot air for awhile might have pissed it off a little bit considering it's original with 720k on it. Very noticeable from the driver's front of the engine. Engine runs fine otherwise.

Also makes me wonder if there is a reason it doesn't pull from the intake pipe going to the turbo? I would think air that was much closer to ambient would be better for it long term...and it's directly mounted to the engine as well so I doubt it would get so cold that it would freeze up. Thoughts?

[smorgan87]

So does this "clickity clack" stop when the compressor cuts out?

[dhirocz]

It looks that way. It was doing it again when I fired it up this morning, low on air. Now it's idling quiet with both tanks full.

[JMBT]

I wouldn’t think the 7-800 degree air would hurt it man. On my truck (Volvo) with very poor under hood cooling, the pyro hits 900 regularly on hills, even on light loads and that is with @m*m^2 tuning as well. Maybe it is just it’s time to go. I have 630K with the original compressor and figure it is probably right around the corner as well.

[dhirocz]

Yeah, that's what I'm thinking. And yeah, now that it warmed up...it's constant.

[Rawze]

I replaced my air compressor few years ago at 680k miles. It started sounding like it was hammering and I did not want it to leave me on the side of the road. I think most guys get 600-800k out of one.

Some people re-build them, some replace the head, and some replace the whole thing. when i replaced mine, they said I had to paint the new compressor and replace the dryer or it would not be covered under warranty.

Lastly, the air compressor is fed off the intake PAST the charge air cooler. It should never see high temperatures going into it, and if egr is active, the egr cooler is supposed to ensure hot exhaust gases are cooled before getting to the intake too.

- The newest model prostars, I have seen, they re-routed the air compressor intake directly to the air filter instead of the intake. Just throwing that out there as an fyi.

[dhirocz]

Good point. I didn't even think about the CAC.

I'll probably get a new one and rebuild the old as a spare, unless it becomes cost prohibitive.

I'm considering adding a bung to my inlet pipe to feed the compressor and block off the inlet at the intake. I imagine there would still be a 50-100 degree difference, depending on conditions.

[redtick]

Could it be a cracked splined coupling? I've had one split on a 855.

[smorgan87]

Id rpl that compressor.