So the other day I turn on my g in the morning and after a few minuets I hear a slight knock I don't drive the car every day so when I do I allways let her run for a few till she warms up and i usually listen for things like that and it's the first time I hear it.. so I pop the hood and I can hear it sounds like a very soft knock but not a tick ticking sound like valves it sounds very much like a rod bearing going bad..I drove the car and the knock is not heard as the engine has load on it but at idle it's heard..I was wondering since I caught it early would me just changing the rod bearings fix the problem..before my crank and rods get beyond repair

 

Slight rod knock is like a flat tire, it needs to be fixed! The severity of the problem depends on what it will take to fix it, you won't know that until it's apart.
Gary

 

Your absolutely right..could I just drop the oil pan and gain access to the rods? Just do one rod bearing at a time and turn the engine over by hand and torquing them as I go

 

What's the story behind your car? Year, number of owners, milleage, and is it driven hard or raced?

 

I think I'm third owner I don't race or rag on it either I bought it about 10months ago I usto live in Florida and now I live in ny..it has about 90k I did an oil change before I left Florida with 5 quarts of mobile 1 5w 40 synthetic and since I use the train to work I barely drive so when I do I always warm her up and just the other day I herd the slight knock..I Haven't drove the car..I bought some Lucas oil stabilizer this morning and let the car run for a few min..when I first started the car it was silent the engine was purring like a kitten as it warmed up the knock became slowly more apparent so I turned it of..I came home from work today and cranked her up and again silent until it warmed up but this time took much longer to hear the knock then this morning so again I turned it off..I don't plan on turning it on anymore.. I'm going to order all new rod bearings and just change them all.. I know it's not the right thing to do but I'm hoping that I've caught it very early and its not until the engine warms up that you slightly hear it I'm hopping this will work..if not I gotta decide new engine, rebuild , or new car

 

I've never done it before personally, but from everything I've ever heard, replacing just the bearings alone from beneath is not likely to be a very long lasting fix. They say that if you can hear a rod knock, you probably already have slight damage down there to the crank. Normally you'd rebuild the whole bottom end that way any wear or anomalies in the crank are also repaired with a hone or a full crank replacement.

How much are new rod bearings?

How's your oil pressure?

I really hope it's not something in the bottom end, especially since it sounds like you haven't done much with this car since buying it due to your regular use of public transportation.

Are you certain it's not something with the timing chain or in the top end with the lifters?

 

Well after doing some research I found that this engine is notorious for bad timing chain guides causing a bit of what sounds like knock at initial start of engine..which my engine does have it sounds for a split second on start up then goes away (that will be my next project if it doesn't blow up)..but that's not what I was hearing I was hearing a soft steady knock definitely from the bottom end..well to my disbelief I ran the engine again for a few minutes and ever since I put that Lucas stabilizer it has stopped making the knocking sound...it kinda sorta starts knocking again once the engine is fully warmed up but it actually got allot better with the Lucas oil thing...the way It seems to me if just adding thicker oil helped quiet the knock it might not be THAT bad..so I am definitely ordering a set of rod bearings and Im just gonna spend the day replacing them all.. I'm also going to buy a magnetic oil drain plug and replace my oil filter and I will just do a repeat oil change after I put a couple miles on the new bearings and just do a finale oil change hopefully I'll be able to flush out any metal shavings..I think the fact I caught this early is going to be my saving grace..

 

Is there something else I need to remove to gain access to the rods..I seems the oil pan is kinda small..will removing the oil pan expose all the rods?

 

hahahah god no. you will need to remove the upper pan before you can gain access to everything.
pick up tube, windage tray ect. you will need to replace the crank as well since its damaged. or on the one thats out of spec and causing the knock you can try for an oversized bearing.

you must pull the motor, or remove the subframe and use a cherry picker to hold the motor in place. there is NO easy fix here. thats why most people sell their cars when this happens and people that can fix it find good deals.

 

Yup I think that's what might end up happening...anybody want to buy a 04 g35x with 90k and bad rod bearings?