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1998 318iS - Knocking noise from engine - BeemerCoupe
I have a knocking noise coming from my engine, more noticeable when idling and sometimes louder than others and sometiomes not at all! The noise doesn't increase with the revs. Other than this (touch wood), the car runs fine. Any ideas what this is?

Cheers

Edited by Dynamic Dave on 27/11/2007 at 13:35

Knocking noise - Dynamic Dave
Vague questions get vague answers, so

Age of car.
Petrol or diesel.
Engine CC.
Manual or auto.
And anything else of relevance.

DD. BR Moderator.
Knocking noise - BeemerCoupe
Apologies...

Its a '98 BMW E36 318iS coupe, manual


{Thanks, some of which now added to header - DD}

Edited by Dynamic Dave on 27/11/2007 at 13:36

Knocking noise - Peter D
'The noise doesn't increase with the revs' are you sure ?? does not increase in frequency or not in loudness. Where does it sound as though it is coming from top, sump, side, front or an aux drive belt, steering or A/C pump. Regards Peter
Knocking noise - BeemerCoupe
it doesnt get louder or increase in frequency. ive tried to hear the noise from the engine bay, but can only hear it inside the car, sounds like its coming from the passenger side dash
Knocking noise - Collos25
Heater fan maybe.
Knocking noise - Screwloose
BC

Try pulling the fuses for the air-con and see if that stops it. This could be a heat distribution flap motor in the dash that's broken it's stop and is running continuously.

If you drop the glovebox out you'll probably see it.
Knocking noise - marty1979
The 318's suffer from noisy tappets. There's not much you can do unless you want to fork out for a new set of tappets, otherwise you just have to live with it. The spray bar at the top end could benefit from a clean, and probably an oil change might quieten it a bit but it will eventually come back.
Knocking noise - BeemerCoupe
sounds likely to be something to do with the heater as the fan is intermittent and comes on when it feels like it! i'll have a look and see what i can find. cheers
Knocking noise - shoulders
I have this problem on my 98 EU 318is. Has anyone found out what it is. sometimes i have this noise when the engine is not running (after running the car), but turned on. when i turn the car off the noise stops which points me towards it being some sort of electrical issue. maybe a relay.

thanks
Knocking noise - ggh1
I traced an irritating cabin knocking noise in my 320i to the cylindrical, two hose water valve which is mounted on the engine bay bulkhead just under the inlet manifold to no. 6 cylinder and close to the oil dipstick tube.
Knocking noise - ggh1
P.S. The water valve is electrically operated.
Knocking noise - Drewdaks
I've had this noise for brief moments probably 2-4 seconds, didn't really think much of it. Until my car started leaking radiator fluids, probably 500ml per drive.
I could see it was leaking from underneath the car but couldn't trace it back to anything. So for about 2 months Ive been filling up my radiator fluids (about 400ml per drive). Until I had time to fix it or take it in for a service.

However, last night, while driving, I was at a set of lights. The same knocking noise happen but this time it was for a longer period of time and sounded more aggressive. Then I heard a sizzling noise and saw steam pouring out the bonnet, so I pulled over. Saw where the water was leaking from which was.. the water pump forums.pelicanparts.com/uploads6/64118375792a21136...g

The bottom attachment hose has fully come off. It seems it not connected by a hose clamp its got a weird fitting where the hose fits inside and outside onto the water pump.
Doesnt seem like it could stand any pressure.

I drive a E36 1994 320i.

Anybody know what has caused this or how to fix?
Knocking noise - ggh1
Your photo is not showing a water pump, but I would guess it is a later type of heater water valve to mine. My heater water valve makes a noise like a loud relay inside the car and I will check how the 2 hoses are attached and report back.
Knocking noise - ggh1
The hoses to my heater electric water valve (J reg 320i) are fitted with jubilee clips.