I am trying to figure out where my issue is with this noise from my 1mzfe with 215k miles. It has had plenty of power and only some oil leaks...not bad though.
I had a check engine light for a while (rear o2 sensor, I think). I ignored it
. Recheck after the issue did not show anything new....
Driving home (55mph) the car felt like it died for a half a second (bearing froze??)....I slowed down and started listening. It sounded like a valve tick, so I limped home for the last 10 miles.
-The noise changes a bit as the rpms change. Low rpm (pre-start) has no noise. Once started it taps. If I rev it up, the tap gets louder, or cuts out or changes like something is moving around causing the noise to stop or get louder (EDIT: The noise also sounds like a slapping...like a fast paced type...like a coin slapping against a metal piece when revved just right). Honestly, I thought the shims in the valve area where jumping out of their seats based on the noise....but that all looks fine!
-The sound is definitely in side the engine. I cannot pinpoint it because it is coming from all sides. I listened from the top and it sounds like the rear valve cover area. from the passenger side it sounds like the front of the engine, possibly on the lower end. From underneath the car it sounds more like rod knock. On the driver side, it sounds like it could be anywhere.
-Power seams to be fine, so the car is not in limp mode from what I can tell.
-No leaks other then what was already there (power steering and a little oil).
Suspected that a valve stem was bent, but the noise changes with RPM, so I discounted this suspicion.
-Sludge is at a minimum. A lot of build up on the underside of the valve covers and primary oil pan. Some sludge on the secondary oil pan but the bottom of the engine and the top of the heads were more of a copper color then a black and sludgy color....so I don't think sludge is the cause here.
-The car did overheat due to a bad water pump 20k miles previous, but after changing the pump all seems to be fine...no oil leaks, no anti-freeze leaks, no loss of power....don't think it did any real damage. (this is why I suspected valves or shims originally)
Back to the issue:
Got it home and listened but could not pinpoint the noise. I got some seafoam and marvel mystery oil and added those...no help (I did not do the high rev part of the seafoam though....didn't want to blow anything or make it worse).
So I tore apart the top end and adjusted the valve shims. Most were in spec and a few were out of spec, so I swapped some shims around to get them all within spec. Still had a ticking sound.
This happened about a year ago, so I can't remember everything that I have checked, but I think I already checked the timing belt and belt idler bearings......need to do this again.
After listening to it again a few months ago, I started to think it was something lower like a main or connecting rod bearing.... It had a tick/tap sound like a valve, but there was also a knock with it as well.... So I dropped the oil pan tonight (btw, chiltons manual does not say to remove the lower AC compressor mounting bolts! That took me a while to figure out why the oil pan would not move!) There is no obvious signs of damage in the lower end.... The oil did have a few metal bits in it (silver and a little copper colored stuff), but nothing on the top or bottom appeared to be missing anything or any damage to parts around them. I have not looked at the oil pump yet, but that is about the last thing that I can check.
So....from what I can tell, it is not the valves shims or camshafts. The lower end looks good. Crank/bearings/rods look fine. Cylinders look good from the bottom.
Still to check:
timing cover area/idler pullys. Water pump (replace ~20k miles ago). Oil pump.
Something that is not *in* the engine.....alt, ac, ps pump, trans. I doubt that it is any of these as the sound is *in* the engine, but I cannot pinpoint the sound.
I am getting confused as I cannot locate any damage so far and I don't want to start pulling the heads ($$ for head gaskets) and randomly troubleshooting.
I suspect the oil pump or water pump base on other things I read on the web...but I really don't want to tear all that down if I don't have to, so I turned to this forum for some insight and direction.
Sorry for the long post, but I wanted to include as much detail as I can remember. Hope someone has run across this before and can point me in the right direction. I don't have a ton of money to throw at a 215k mile car, but I should be able to get another 100k miles out of it....