300te rattles & stalls

[brucemillar]

Folks

My 124 300te cut out (stalled) today after a 1 hour motorway drive. I had pulled into the Services when it simply stalled.

On re-starting, it has a top end front rattle and cuts out when you shift into D, unless you have some revs.

It has clean coolant and oil with no smoke or steam. Temp is good and no warning lights.

At idle you can hear a faint ticking but the idle is fine. Any revs and it rattles. It seems to be from the top front. As if it is the rocker cover.

Take of the oil filler cap it is slightly louder but not much. No smoke.

So a rattle that increases with revs and stalls without revs.

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[merc85]

is the Timing chain tensioner ok?

 

[brucemillar]

^ no idea?

I'm looking for ideas ;^)

Tensioner would be possible. Could that cause the stalling?

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[merc85]

Just wonder if its jumped a tooth put the timing out enough so runs rough, good enough for tick over but not under load.

I'm not that mechanically minded, The fact the noise doesn't really increase when you take the oil cap off but sounds at the top just makes me think the problem is in the timing end of things.

 

[Robbo Cop]

Crankshaft position sensor?

Fuel Filter?

Best of luck ...

 

[carat 3.6]

Bruce, by the sounds of it you have a problem with the timing chain. Either the tensioner has given up, or the guides are starting to break up. This will put the ignition timing out a few degrees as the rotor arm is driven from the camshaft.

 

[brucemillar]

Simon Is this expensive? Worst case.

Car owes me too much to back out now after full re-spray.

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[carat 3.6]

Simon Is this expensive? Worst case.

Car owes me too much to back out now after full re-spray.

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No, timing chain, guide rails, and the tensioner are not that expensive from MB.

Need's confirming that the above is the problem first, but I wouldn't use the car until it has been looked over. Bad things happen if the guide rails let go!

 

[brucemillar]

quick update:

Just spoke to Andy at Wright Tech. The car started and moved absolutely fine this morning with NO symptoms.

He is going to get the rocker cover / top end off and have a good look.

It seems odd that whatever is happening? happens only when the engine is hot?

We did notice yesterday that after the car was trailered back to Wright Tech it started first time with only a small ticking noise present.

 

[Mike Walker]

Bruce Hi
Sorry to hear about your engine problems but it appears to be a lot better than the report I got at Charles's yesterday morning.

Do hope you get it all sorted satisfactorily.

Mike

 

[brucemillar]

The plot thickens.

The garage have taken the camshaft out all ok. The chain had no slack and tensioner was free. We have ordered in chain and tensioner anyway makes sense to replace them whilst we have it stripped, guides also fine.

So no obvious issue but it still sound like top end and only when hot. Ruled ancillaries out by removing belts etc. Will check oil filter tomorrow for any metal. Sent from my iPhone using MBClub UK

 

[notsofast]

Valve / valve guide maybe? Also compression check in case of broken piston ring?

 

[Tim203]

Valve / valve guide maybe? Also compression check in case of broken piston ring?

Could be a valve sticking.

 

[John Jones Jr]

A ticking noise from the rocker cover area is generally a stuck valve lifter which is not uncommon on M103's. Having said that it wouldn't explain the engine stalling.

Anyway Bruce, it's time to dump the KE-Jet system and get Simon to retrofit an aftermarket EFI system.

 

[carat 3.6]

Anyway Bruce, it's time to dump the KE-Jet system and get Simon to retrofit an aftermarket EFI system.

Along with the stroker crank, throttle bodies, and dbilas cam I've got hidden in the basement.

 

[brucemillar]

We are sure it is not a valve as the engine does not actually run rough or badly. It just makes a mechanical ticking/knocking when you rev it.

What drives the oil pump in these engines?

I ask, as I thought that when it initially went wrong, on re-starting I noticed that the oil pressure gauge needle was flicking up and down with the revs as opposed to smoothly rising and falling?

I may have made this up ;^) but I am sure I noticed this. At that point the noise was so pronounced that I was convinced the engine had dumped all it's oil (it had not).

The noise is what I would have expected to hear if the Viscous Fan was loose.

 

[carat 3.6]

What drives the oil pump in these engines?

Has a small single row chain driven from the crank, it has a sprung plastic guide rail to maintain tension.

Now is the time to inspect it, as you need to remove the main timing chain to get the oil pump chain off.

 

[carat 3.6]

Another possibility....

The flexplate between the crankshaft and torque converter can crack around the bolts, sounds like a light ticking with the engine at idle.

 

[brucemillar]

Simon

As always thank you for your great input.

I just spoke with Andy @ Wright Tech

He is convinced that the noise is "top end front". That is what I heard on the day. But we know that noise can play tricks.

The plan now, is to replace the chain, the guides and the tensioner, along with an inspection of the oil filter for any metal particles.

The oil is good and clean (it was recently changed). There is no sign(s) of oil starvation or metal damage on the top end.

The gearbox has just been re-built.

 

[John Jones Jr]

The plan now, is to replace the chain, the guides and the tensioner,

Money well spent imo and worth doing regardless even if it doesn't resolve the issue.