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Old 04-20-2012, 09:47 AM
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Engine Knock High Oil Pressure

Hello everyone. New member from SE PA. Read everything I could about engine knock but still befuddled by a knock coming from the oil pan in my 1994 2.5l 5 speed w/ 114k miles. Two mechanics said it's the engine (surprising no one) and don't worry about it till it blows. Another suggested it might be the main bearings and, then, don't worry about it till it blows. Me. I worry. Want to address the problem and am looking for others who have diagnosed a knock like mine.

Here are the facts:

1. Knock starts about one minute after a cold start in the morning or sitting for a while.
2. Sounds like a tackatickatackatickatacka.... It's louder than valve ping but not quite hammer/anvil.
3. Knock really seems to disappear over 1500 rpms (or around 1200 rpms when warm). Also gets a little quieter when engine warms up. Knock is present at idles and in gear moving.
4. Stock oil pressure gauge hovers around 50 (hot, cold, fast, or slow). It doesn't drop at idle or raise at high rpms more than a little bit either way. Hooked up a cheap mechanical gauge and it hovered just under 60.
5. Loudest with the hood up or under the car. Wooden dowel stethoscope emits the loudest knock around and under the low part of the oil pan and bell housing. Don't hear much around the front or top with a stethoscope, but without the stethoscope you'd swear it was coming from the under the valve cover.
6. Pulled each plug wire -- no change in sound.
7. Changed oil and filter (10w30) and no change in sound. Drained and put in 10w40 with a qt. of Lucas oil. No change in sound. Haven't put any MMO or Seafoam type cleaners in the crankcase.
8. Doesn't smoke, use oil, or drip. Both CCVs are clear. No engine codes.
9. Looked in oil cap. Oil splashing around in there.
10. Cannot locate an exhaust leak anywhere between the engine and cat.
11. Last, I swear I can just barely feel the knock in the clutch pedal.

I am not a mechanic. Here's some of my noobish ideas:
1. Clogged oil passage causing high oil pressure while starving bearings?
2. Flywheel loose or cracked?
3. Too late. Engine at DDKL.

I would be grateful for anyone's thoughts on this problem. I am already grateful for all of the knowledge and enjoyment I have received from this forum already.
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Old 04-20-2012, 10:05 AM   #2
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i'm thinking #2 after reading all your diagnostics...

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Old 04-20-2012, 10:54 AM   #3
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Drive it till she blows! results will be the same. You may be able to save the crank if you rebuild it now. Take the pan off and rotate the assembly and wiggle rod ends to see if it has slop. Do a compression test first just to see.
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Old 04-21-2012, 06:36 AM
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Thanks for the replies so far. Will do compression test and drop pan.
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high oil pressure , knock

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