# Rod knock? wrist pin knock? bearing knock?



## srgtlord (Jun 4, 2010)

*Rod knock? wrist pin knock? bearing knock?How long do I have?*

So my 1992 cabriolet with its 8v engine decided to give me a nice knocking noise regaurdless of engine speed, I know for a fact it is not a lifter. The sound is coming from the bottom end of the engine. It is not a low knock it is kind of like someone lightly tapping on a Styrofoam cup and gets louder as engine speed increases. Im pretty sure it is one of the above issues. The engine only has 150,000 miles on it but it looks like it had some shoddy maintenance. Has anyone else had experience with this? Will it just blow up on me one day?


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## WaterWheels (Aug 14, 2005)

Rough guess right now would be a rod bearing. Hows your oil pressure? Main and rod bearings most times show in the oil pressure as being OK when cold and dropping as the engine heats up to become too low. You don't say, but does it also increase with engine speed (sure it does but you didn't say so)? When did it show up? All of a sudden, while the engine was under power (higher engine speeds or load)? In any case if it is a rod bearing it is not going to "blow up" unless you race the engine. I have know people with bearings knocking who drove their cars for long long times until they had the cash for a fix. If driven moderate it shold be OK, maybe get loader over time, but OK. Unless it turns out to be something else, I would start planning for a fix of some kind, swap, repair or whatever.


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## srgtlord (Jun 4, 2010)

To answer your questions the oil pressure stays around 1 bar when warmed up, the noise increases with engine speed and it showed up after a high load on the engine. I just can not believe my luck. Now for another question. If I pull the oil pan and find the bearing that needs replacing and replace it will I be all set?


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## WaterWheels (Aug 14, 2005)

That the oil pressure stays about the same as normal once warmed up would lead me towards the rod bearings rather than a main bearing. A rod bearing is a ton easier to fix with the motor in the car as a main would be so that is good luck, to boost you stats a little. Yes, fixing a bad bearing, of course changing the oil and fixing any other things you might discover while in there, should get you going again. I would however do all four bearings, one because they are a better deal to buy in sets and also for cheap insurance. The big problem you may run into is crankshaft wear/damage and what size bearings you need. If the crank is damaged you might as well just remove the engine and think rebuild or swap. As the bearings come in standard and oversized, you will not know which you need until you take measurements, you have the tools to do that right?


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