540i engine knock!

ace

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Dubai - UAE
#1
guys,

just bot a 2000 model 540i m sport. offlate i have noticed a very slight knockn sound when idling. seems to go away when i increase throttle.

it speeds up as i step on the gas. doesnt get louder though. cant hear it well outside...have to pop the hood and listen real carefully....

any idea what it could be???

help me out guys...

thnx

cheers
 
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Location
Florida
#2
Probably just the valve lifters. Mine does that too. I think it's pretty normal.

One other thing to check is open the hood while running and look at the water pump pulley. When my bearing started to fail, the pulley would wobble in and out slightly and make a rythmic knocking sound. the pulley should not move at all in or out.
 

ace

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Dubai - UAE
#3
hey!,

well the pulleys seem intact. no movement wat so ever. is dat a common prob with the 5 series (the water pump)?

well if its the valve lifters, can i get rid off it? and how much wud it cost approx?

thnx...btw, wats the output on ur ride after the dinan s/w upgrade?

cheers!
 
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Location
Florida
#4
Yeah the water pupmp will go sometime and that's how you'll notice the bearing waering out...and hearing the wobble.

The lifter thing, I'm not an expert, but I think you just have to live with it. I'm not sure if it's fixable or what it would cost.

I see you are in Dubai...hot as hell? I would make sure you run 10w40 or 20w50 oil (always synthetic!) That may help with the noise too.

The engine puts out 295 HP on the dyno....about 13hp over stock. The intake nor anything else is modified.
 

ace

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Dubai - UAE
#5
yea, me in dubai! well im makin sure bout the oil and yea! it is hot as hell!

how much does it cost to get the water pump replaced? when do u suggest i do it? the car has about 80k kms on the odo.

got any pics of ur ride?

i will taking my car in for a check this sat. hope they can pin point the root cause of the knock!

cheers mate
 
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Location
Florida
#6
the water pump is about $100 or a little more or so but the labor will be like $200 or more (in the US). Make sure they replace with coolant 50/50 ratio with DISTILLED water. Buy it and bring it if they do not have it. Do not go below 40% coolant ratio or you will risk corrosion. Do not go over 70% or you will severely reduce heat transfer ability. Stick to 50%.

I would just keep an eye on it and wait until you see a leak, or detect a wobble in the bearing (pulley) while running. OR if you have the timing cover and everything off for another reason and you have a lot of miles on it, go ahead and throw a new one on there.

Good luck...couple pics attached
 

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