Enigine Knock / Tick???? Help

[DR.WA///M]

My car is a 1994 BMW 325i.(Manual) with 105,000 miles on it

Does anyone know why Engines have a knock. Just recently I flushed my radiator, put a new thermostat, thermostat housing, waterpump (metal impeller), belts (accesory and a/c), and sparkplugs in my car. After driving my car home a night after the fix, I have noticed that the car has a little knock to it when it idles! (oil is fine) I don't know what it is or where it is from anyone have any ideas? Does anyone have a little knock in there engine?

The only other thing I could think of is the fuel injector cleaner which I used on a full tank is it a possibility??

Please Help

[Steeve]

what octane gas did you put in your car? Try a tank of supreme and see if that helps.

[DR.WA///M]

I never use anything but 93 octane. Mobil or BP

[DR.WA///M]

ANYONE????????? By the Way of narrowed it down to a tick it does not increase when accelerating. my deductions = sparkplugs and or timing if so how do i change it and or fuel injector cleaner???

[BMWCowboy]

There is an air valve that ticks-->this is normal....It is on the right side as ur lookn under the hood-->should be held in by a rubber hanger->4get what it does

[Jeron]

Is the knock rapid like a valve or slow and rythmic?

My 97 E36 M3 has a noise like a flap opening and closing every few seconds. Maybe this is what BMWCowboy is refering to. The description he gave sounds like the ICV-Idle Control Valve maybe. I haven't diagnosed mine yet since it only seems to do it when I'm away from home :-)

[sjkemp]

Try using a piece of tubing or hose to listen through and place it at various places on and around the engine. Tell us what you find. Check around the power steering pump, water pump, generator, and especially the valve cover.

Scott

[DR.WA///M]

The Tick is rythmic with the cars rpm's as rpm's go up you don't hear it but i know its there. It is on the left side around the valve cover, but defenetly left side

My friends dad said it might be a pushrod what do you guys think???

Thanks guys I'll take a look around with the hose idea and try do narrow down the location.

[DR.WA///M]

Hey guys also wanted to say Im going to change my oil. I live around the Chicago area so its starting to get cold and right now my cars is running with 15W50 Mobil 1 fully synthetic. Im not sure what the manual calls for lower temps but I'll check it out and according to the manual I'll use the proper viscosity in synthetic Mobil 1.

[DR.WA///M]

Hey guys check out this sound clip I found of some guys car similar probs. Keep in mind this is not my car and does not sound as bad as what you hear in the clip it is a little softer...

http://www-scf.usc.edu/~ricardoa/99_m3_ENGINE_NOISE.MP3

[DR.WA///M]

I found this on a forum first thing tommorow I'm chekin it out.

"My 95 ///M3 had developed a ticking problem over the past few weeks..I asked arround in the forum and many of you said M3 have this ticking problem.. mine has a 140K HWY miles.. very clean and strong, anyway, I wasn't sure where this ticking sound was coming from, so I wanted to change the spark plugs and when I was doing that I noticed that the plugs are VERY loose!!! I seen carbon deposit also on the area arround the plug.. ALL of the 6 plugs were loose!! I am not sure how they got loose but the last to change my plugs was the dealer.. anyhow, I changed the plugs and made sure they are tight.. I started the car and the ticking sound is GONE!!!!!!! yes.. GONE"

[sjkemp]

This sounds like a problem with the valve train. If it appeared with the cold weather it could be no oil getting to the valves, go with 5-30W. The other possiblity is a broken spring or stucking valve. I do believe your engine is an overhead cam so no pushrods are present.

Scott

[Jeron]

I'm glad it was as simple as the plugs.

I am running 5w-30 in the winter in TX and I think it is too thin for TX. (I have a oil temp and oil press gauge that I watch closely.) My choice would be 5w-40 for winter but it is more difficult to find. I run 15w-50 summer but only because I race, otherwise I would run 10w-40 summer.

(The way our TX summer is going this year I could still run 15w-50.)

[blkongry]

First off, if anyone ever wonders about octane and the 'clammer' you get from predetonation, it only really happens under throttle and load. I have a steep hill I come up to in getting to my place, and I can tell when I get a 'bad' batch of gas, because under a certain load I'll get that uncomfortable predetonation clammer... back off on the throttle and it goes away. It shouldn't show up at all at idle or no load revs.

A 'tick' coming from under the hood could be from a slight high pressure leak (namely from the combustion chamber) or from valvetrain. If it's a high pressure leak, then it's either from around the spark plugs or from a crack/misalignment/warp in the exhaust manifold (especially if some is running headers, but those are rare on these cars). The other 'tick' is from a worn/sticky valve or a crushed/broken valve spring (like sjkemp said). The cams are hardened, and less likely to wear a lobe down. There are other valves and parts of the engine that can 'tick' a little, not so distinctive and clear as the afore mentioned. Lastly, the worst 'knock' you'll hear in your engine is a rod knock, and that almost never happens on these cars without abuse, chronic low/dirty oil, or a plugged oil journal. It's also a sick sound if you've ever heard it.

It sounds like the tick you are experiencing is very minor. One thing you can to do track it down is use and insulated tube and listen for the tick as you move the end of the tube around the engine. A thick solid wooden dowel works to... just press the end of the dowel up against and spot and listen to the other end for the tick.

[Jeron]

I get a 'clammer' that sounds like a diesel under a light load when the engine is cold. I'm running 93 octane. I don't particularly like the noise but I've never considered it a problem.

[blkongry]

Are you sure that's not the VANOS kicking in? VANOS gives off a weird gurgle sound. But then again, if the engine is cold, the combustion cycle isn't up to speed, and with cold cylinder walls I can foresee you getting more pre-detonation. Also, I've found 'reported' 93 octane doesn't seem to be the same 'grade' throughout the gas vendors. My 2.5L is chipped with a CAI and a performance Catback, so I run 92-93 premium solely, and on some the tanks of gas I get the clammer, on others I don't. You never really know what's coming out of the pump.

[DR.WA///M]

So check this out guys...

I opened the up the hood and retighned the spark plugs ...They were a bit loose I made sure the car was warm this time. So I can safley say the Spark Plugs are in GOOD.

Next I used a stethascope with a metal rod attached to it and the (clicking, ticking, or knocking) is coming from the VANOS unit???

Does this mean I nead a new one? How can I check if it is working and am I heading in the right direction? (Anything else I can check???)

[Jeron]

Make sure you didn't overtighten your sparkplugs. You dont want that causing some other problem later.

VANOS noise is common, can you compare it to another similar car. Pay $40 for a set of dyno runs to see if everything is normal and then just drive it until the VANOS goes out.

Actually, I take that back partially. Make sure a failed VANOS wont cause any major problems

[DR.WA///M]

I'll Compare it to my buddies car thanks for the advice... Anyone else got ideas????

[blkongry]

If it helps reassure you any, my 94 325ic does the same thing (128K on the odo), and it pulls smooth and strong all across the rpm band.