yoram611

hi ,

I have a 2003 E320 , it has on it only 22500 miles (36000 KM) on it .

sometimes when I start the car for the first 1 or 2 seconds I hear a strong valves ticking and then when the oil pressure builds up the noise is gone.

unfortunatly its not always there , I went to the dealer a few times to let them hear it but when I was there it didnt make the noise.

has anybody had the same problem ?

what could be done ?

thanks.

steveberde

As mentioned in someone else's post - let it warm up get it out as best you can on an open road and drive it as fast as you can for as long as you can - (don't let them think you're an Arab running from the IDF however) or put it in a lower gear like 2nd and let the rpm's stay up there for a long while - these engines must be driven hard - they need to be run at some speed to keep them running well - my dealer swears that it's the major problem for many owners - they just baby their engines way too much and never get them broken in.

Boker tov

Steve

ECLASS500SPORT

(don't let them think you're an Arab running from the IDF however)

What kind of Stupid comment is this???

4matic

i dont know why that was necessary to include??

Untertürkheim

Most importantly, are you using the correct oil, filter, and fuel? Also, is your service up to date?

Do not drive your engine in low gear, it will only wear your engine faster and burn more fuel.

High speeds are probably the best treatment.

yoram611

Hi Steve,

thanks for the reply , could you please explain a little more why driving at high speed will repair the oil pressure at start.

I can understand that it cleans up the injectors and the firing chamber but why will it improve the oil pressure at start.

I have been driving Mercedes for many years, in the past the oil filter use to have a valve that holds the oil pressure up even when the engine was turned off , so when you restart you will not hear the valves knocking.

sometimes then if the valves where knocking at start , you would replace the oil filter and the problem was gone.

but the 2003 E320 has an oil filter without a valve , so what is suppose to keep the oil pressure up to avoid the knocking at start ??

thanks Yoram

ss3964spd

The valve in an oil filter assembly is only designed to prevent oil from draining out of the filter. It cannot, and will not, maintain oil pressure in the engine. Here's why.

One needs to understand that there are a LOT of small, controlled (engineered) oil "leaks" throughout the engine. The crankshaft and connecting rod bearings, the self-adjusting hydralic lifters (which is the source of the noise you are hearing), the camshaft bearings. Take, for instance, the crankshaft and its bearings (the bearings are not ball or roller bearings, but what are called "plain" bearings. So, you have the two halves of the bearing - which encircle the crankshaft "main journal" (there are 5 main journals in most, if not all, modern V8's, 4 in a V6, usually 7 in an in-line 6), then you have an engineered space between the bearing face and the crankshaft journal. This engineered space, which is measured in hundreds of an inch, gets filled with pressurized oil from the oil pump when the engine is running. The crankshaft main journals do not actually touch the bearing surface, rather the two are separated by the thin film of oil provided under pressure by the oil pump. Each side of the crankshaft journal, and it's attendant bearing, cannot be sealed. Thus, the space between the crankshaft main journal and the bearing itself is a leak; when the engine is shut down the oil pressure provided by the pil pump is no longer present and, because of the gap between the journal and bearing, the oil between the two basically drains away. In fact, the clearance between the journals and the bearings leak oil while the engine is running (which is, incidently, how the cylinder walls get lubricated; from leaked oil being thrown from the spinning crankshaft).

Which is exactly what's happening to the self adjusting hydralic valve adjusters that these engines use. The adjusters (or followers, or lifters, depending on engine architecture) use engine oil pressure to remove the slight clearence between the tip of the valve stem and whatever device is employeed to depress the valve, and removing the clearence eliminates the ticking noise. After shut down, and typically after sitting, say, over night, enough of the oil has drained out of the adjuster (because they also have their own engineered leaks) that clearance at the valve tip is much larger, resulting in the ticking.

The oiling system has designed priorities. The most important parts, those that must receive oil pressure before anything else, are the crankshaft main journals and the connecting rod journals. The oil pump must fill those journal clearances with pressurized oil, indeed supply more oil than they can leak, before oil pressure will get to the top of the engine where the valve adjusters live. Soon as the adjusters get pressurized again - no more valve tapping.

Having said all that, in apparently long winded fashion, it's a pretty common thing in these engines. It's also pretty much a non-issue. The valve train components are not under the same type of stress as that of the rotating assembly. There is still oil on the components so a few seconds of clatter at start up generally isn't a problem.

If the clattering lasts longer than a few seconds it could be indicative of other issues, like highly worn crank and rod bearings.

Dan

ss3964spd

And oh, BTW, running the engine hard, (high RPM for extended periods) will do nothing to solve the (preceived) problem of clattering valves. If the engine has been properly maintained (changing oil, correct oil) the only thing you might address by sustained high RPM operation is clearing some carbon build up from the combustion chambers.

Dan

yoram611

hi Dan,

thank you very much for the long and detailed info about how the bearings get oiled.

before I bought this car 2003 E320 I used to have a 1999 E320 both of the engines were identical same model , yet I never had this noise at the start on the 1999 one .

someone on another thread described the noise as the same noise you get at the first start after an oil change till the pressure builds up.

so what you are saying Dan is that it is normal ?? why does it happen in one car and does not happens in another ?? can anything be done ??

I always change oil by the dealer only MB recommanded oil and I even do it before its time, and always put a new filter.

thanks again

Yoram

ss3964spd

Hi Yoram,

There are any number of explanations as to why it occurs in some engines and not others of the same design. It could be that the engine was poorly maintained prior to you getting the car. It could be that a different parts supplier for the adjusters was used - even though they are supposed have the same specifications. It could be that when the engine was assembled that some of the internal clearances - like where the adjusters are installed, were just a little looser than they should be due to production line tollerances and are therefore allowing the adjusters to bleed down quickly. Take your pick of any of these, it could even be all of these.

I'm betting that you hear the noise most often when you start the engine after it has been sitting unused over night. You get home from work in the evening, park it, and don't start it again until the morning. I'm also betting that you don't hear it much, if at all, if you are using the car off and on during the day.

My '05 E500 does exactly the same thing. First start in the morning after it's been sitting all night the valves will usually clatter for 1-2 seconds. Drive the car to work where it then sits for 9 hours. No clatter on re-start after work. No clatter on any other re-start if I am using the car off and on during the day (which is why you can get yours to do it for your dealer).

Two possible remedies come to mind. 1st, you might try using a thicker viscosity oil. The owners manual lists them. Thicker oil will take longer to bleed out of the clearances. If that doesn't do the trick - 2nd option is to have the hydraulic adjusters replaced. If MB is saying the clattering is normal replacing the adjusters will likely be at your cost.

Dan

berrill

Change the oil filter, this is easy and cheap. Just make sure its a MB part.

The no return valve in the oil filter is not there to maintain the pressure, it is there to ensure the oil does not drain out the oil filter. If the valve is faulty the oil can drain out of the filter and when you start the engine in the morning the oil pump must first re fill the oil filter and then gets to the valves. The noise you hear is the time it takes to fill the filter.

The other points raised above may be correct but this is the easiest and cheapest starting point.

Revving and engine to solve a problem is like being a bush mechanic - it solves noting

yoram611

Hi Dan and Berrill ,

Dan my problem is that it makes the noise somtimes even after a 10 - 15 minutes stop during the day , first thing in the morning it does it very seldom.

sometimes it does not do it for days and sometimes it does it a few times a day . ???

Berrill this car has only 36000 KM the oil and filter was always replaced on or before time.

I bought the car about a month ago and the first time I heard the noise I went and relpaced the oil and filter even before its time . it didnt help.
I always use only OEM parts.

thanks

Yoram

berrill

Yoram, sometimes the soln. is very simple and cheap I an sorry to tell u ------ u know the rest.