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Discussion Starter · #1 ·
I was driving on the hwy for about 5hrs when a flash rain hit, as soon as the water hit...I could feel loss of compression and the sound of a exhaust leake near the manifold. The car starts and runs, but I hear an inconsitant sporadic knock along whith the exhaust leak. Doesn't sound like a lfter OR a rod, what should be my next steps?
 

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I know it's a pita, but you might want to remove opti cap and see if rotor has come loose. It's screws are known for coming out. While in there, take inner shield off and examine optical section for corrosion, oil, and coolant in there. Before you take opti cap off, since you have to remove water pump to get to opti, crank engine and let run for a couple of seconds to see if water pump was causing the noise.

Next find where exhaust is leaking. Fix that asap as exhaust leaks mess with your air/fuel ratio, big time, if leak is before o2 sensor.

If opti rotor good and exhaust leak fixed, you still get knock, investigate the valve train.

If noise not there try removing serpentine drive belt and see if noise goes away when accessories are not turning.

If all else fails to find the noise see if transmission is source. If no, it's time to remove oil pan and examine bearings. Do rod bearings first as they are the most likely to fail.
 

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Discussion Starter · #3 ·
Thanks for the suggestions, I did have the opti replaced about 6mo ago, water pump within the last 2yrs, and the noise that's "more like a sporadic knock" is coming from the far rear drivers side of the engine, well away from the opti or the water pump.

It's also where I get exhaust leaking when I rev the engine...I'm hoping I can get a specific opinion before tearing down the exhaust manifold or run across soem one who has had this same experience.
 

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Here's the thing. You can't dismiss a part as a suspect just because you had it replaced 6 months ago. Especially if someone else did the work.

Did they put locktite on the rotor screws when new opti went in. If not, or you don't know if locktite was used, you should inspect your opti.

You wanting to find someone with the exact same problem, and a solution to it, is about as probable as winning fantasy 5. In other words the odds are stacked way against you.

To give an example about noise, a friend of mine bought a car once thinking the noise the engine was making was coming from a lifter, on a ohc engine with bucket type lifters acting directly on the valves. I could have sworn the noise was coming from the top of engine also.

It ended up being a rod bearing.

Your only hope to resolve this problem will be a systematic approach to troubleshooting that leaves no stone unturned.

Noises can be funny also. What you thought came from one place ends up coming from another as metal transfers sound just like it conducts heat and electricity.

You should take care of the exhaust leak first, to help pinpoint where the knock is coming from. And who knows, maybe fate is smiling upon you and the knock will disappear when the exhaust leak is fixed.
 
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