E34 M50 Tick Tick Tick Tick Tick... Help!

[wishihad50k]

I know that this problem is nearly impossible to diagnose by reading a post but I thought I'd give it a shot anyway. My engine has a nasty Tick Tick Tick at idle. It only happens once and a while and its not very consistent (it happens when its cold, hot, right after start up, etc.). If I give it a little gas and rev the engine it goes away for a bit and comes back. I tryed to clean the fuel injection with a can of BG44 K and that stopped it for about a month, but then it came back. I have also noticed lately that is smells like gas in the cab??? I need some help! I thought maybe exhaust leak? Any suggestions would be great! Thanks guys!

[shogun]

Which M50 engine do you have?
The BMW M50 is an I6 piston engine. It was introduced in 1989 to replace the BMW M20 and was replaced by the BMW M52 in 1994. Displacement ranges from 2.0 L to 3.0 L. It is a DOHC 24-valve engine. A Technical Update or M50TU version from 1992 introduced VANOS variable valve timing.

The M50 was related to the M20 with the same 91 mm cylinder spacing, bore, and stroke at 2.0 and 2.5 liters.

M50B20
The 2.0 L (1991 cc) M50B20 was introduced with the 1989 520i. It has an 80 mm bore and 66 mm stroke and produces 150 hp.

Applications:

1989 520i
M50B25
The 2.5 L (2494 cc) M50B25 was introduced with the 1992 525i. It has an 84 mm bore and 75 mm stroke and produces 192 hp.

Applications:

1992-1994 525i
Note: This is the engine from which the M50TU evolved. The VaNoS update was added late 1992 and sold for 1993 model year E34s.

M50B30
The M50B30 was a 3.0 L version, which powered the US-spec E36 M3.

VANOS (Variable Nockenwellen Steuerung) is an automobile variable valve timing technology developed by BMW. VANOS varies the duration and lift of the intake valves by moving the fulcrum of the camshaft. BMW recently began offering "double" VANOS, which operates on the exhaust camshaft as well, on the BMW 3-series cars.

(copied from a BMW info page)

[Rory]

I know that this problem is nearly impossible to diagnose by reading a post but I thought I'd give it a shot anyway. My engine has a nasty Tick Tick Tick at idle. It only happens once and a while and its not very consistent (it happens when its cold, hot, right after start up, etc.). If I give it a little gas and rev the engine it goes away for a bit and comes back. I tryed to clean the fuel injection with a can of BG44 K and that stopped it for about a month, but then it came back. I have also noticed lately that is smells like gas in the cab??? I need some help! I thought maybe exhaust leak? Any suggestions would be great! Thanks guys!

Sticky lifters.....let me guess that it goes away above 2500 RPM's or so? It is perfectly acceptable but annoying. Many (including myself) have suffered from this on the M50 and it is the price yout wy for not having to do valve adjustments. What weight oil are you running? Synthetic or dino? I was running 20W-50 and the tick was really bad. Switching to 10W30 (Mobil 1 on both) takes care of most of my problem. Also, a long jaunt down the highway in 2nd and 3rd gear (5-nearly 7K RPM's) helped my noise out a lot. I think I had/have a lot of carbon buildup on the valves due to lots of short trips so the valves tend to stick a bit causing the noise. I would play with oil weights and drive it like you stole it for a few days and see if it helps.

Good Luck,
Rory

[Burell]

I know that this problem is nearly impossible to diagnose by reading a post but I thought I'd give it a shot anyway. My engine has a nasty Tick Tick Tick at idle. It only happens once and a while and its not very consistent (it happens when its cold, hot, right after start up, etc.). If I give it a little gas and rev the engine it goes away for a bit and comes back. I tryed to clean the fuel injection with a can of BG44 K and that stopped it for about a month, but then it came back. I have also noticed lately that is smells like gas in the cab??? I need some help! I thought maybe exhaust leak? Any suggestions would be great! Thanks guys!

The funny thing is ... I had what I thought was a ticking valve/sticky lifter too. After I replaced most parts of the cooling system (the famous exploding plastic impeller) the tick has totally gone since. These would still be unrelated events in my book hadn't had my father _exactly_ the same thing (familiar tick->failing waterpump) with a totally different car (GM).

Explanations anyone?

Burell

[wishihad50k]

I will try to use different oil weights, and "drive is like I stole it" (dont need an excuse to do that). If it was sticky lifters, would it come and go though? It doesnt do it all the time (thank you God) its very random, but its always during idel and yes it goes away after 2500 rpms. Thanks for the suggestions!

[Interceptor]

I will try to use different oil weights, and "drive is like I stole it" (dont need an excuse to do that). If it was sticky lifters, would it come and go though? It doesnt do it all the time (thank you God) its very random, but its always during idel and yes it goes away after 2500 rpms. Thanks for the suggestions!

Probably the hydraulic valve lifters. I had the same noise during cold starts when using 10W40 Shell Helix Plus. After switching to Mobil1 0W40 and adding LiquiMoly Hydraulic Valve Lifter Cleaner the ticking noise is almost gone (except for the first second after a cold start - this is normal behaviour, since oil needs to circulate thru the valve lifters).

[liquidtiger720]

hmm, i have the same problem! I just never thought anything of it. At the moment I am running 20w50 castrol gtx. I need to switch to synthetic, but I am afraid of a leaks. How does that hydraulic valve lifter cleaner work? pour it in, drive it awhile, then change oil?

[632 Regal]

if the lifter has a worn area on it you will hear a tick as it rotates from the worn spot to a good spot?

just guessin here.

[Brett619310]

I heard the same thing for about 5 or 10 seconds on a cold start the other day. I love this board... my question is answered before I ask it. I will switch to 0w40 on the next oil change and see what happens.

[Rory]

I heard the same thing for about 5 or 10 seconds on a cold start the other day. I love this board... my question is answered before I ask it. I will switch to 0w40 on the next oil change and see what happens.

Just to clarify a few points from this discussion as it sounds like a few folks might be confused. When your car sits, the oil will bleed down out of the lifters (and the rest of the engine) making its way to the oil pan. When you start the engine, pressure builds and circulates through the engine. The initial "tick" on startup is a delay in the hydraulic valve lifters building pressure to get to their normal operating range. It is much more prevalent in cold temperatures because of the chemical properties of the oil in cold weather as oil is much thicker at colder temps. Light weight oil is much more fluid in cold temperatures and flows more smoothly, so the oil gets into the lifters and the pressure builds. A thicker oil will not flow as well in the cold and takes more time to build the pressure. Thus the reason you run a lighter oil in Yankee Country or other cold climates.

The intermittent tick that wishihad50k had posted about is most likely a different problem. It is probably a mechanical "defect" in 1 or more lifters where pressure temporarily drops and the valves crash closed. As you press the go pedal, oil pressure builds in the engine and the lifters overcome the "defect" pumping up and the noise goes away. Playing with oil weights may or may not help depending on the problem. Some common areas are either a stuck/failed lifter, debris/crud caught in the lifter blocking path (like artherosclerosis), air pocket in the lifter displacing oil, etc. But this tick is not from the oil being too heavy initially.

Interceptor, can you give a little info on the Lubro Molly Hydraulic Valve Cleaner you used? I tried searching for it but couldn't find any info and it sounds like an interesting product.

Thanks,
Rory