W124 petrol turned into a diesel overnight?

[neilz]

I have two engine faults I have no idea about

1) Often makes tapping sounds when starts for first 5 seconds (not tappets) and when the car starts and the engine revs a tiny bit up for a second or two (as usual on a car?) it is accompanied by a fast soft tapping
2) Makes tapping sound like diesel when idling after over 30 mins of driving (urban and extraurban)

My car has the M111.960 engine and is an E220 coupe from '95 (W124). It's not the tappets and carbon buildup has been suggested, I can tell you that the wiring harness has chosen to return to nature, eagerly degrading, which could explain why it sometimes revs up to 1600-1800 when idling for no apparent reason (otherwise it has a very slightly juddery idle)

I've noticed also that my car picks up quite slowly in first then either changes to second with a small lurch forwards or changes smoothly but makes a plastic scraping (or coarse rattling, ever heard one of those newish Land Rover Defenders which sounds like that as standard? You'll know what I mean if you have) sound in second which slowly fades away as the engine noise takes over. The engine is raspy but that's how I expect it to be I guess. Ideas?

Thanks for any help!

 

[grober]

Why have you ruled out the tappets???- they're hydraulic=self adjusting but sometimes if they get starved of oil they " clatter" till the oil gets through as it heats up. What grade+make of oil are you using ? Sounds very like timing gear to me. Engine wiring loom best simply to bite the bullet and get a replacement.

 

[neilz]

I went to a local garage to get my car serviced (much quicker than me doing it) and asked him about the noises so he checked the tappets and they are apparently fine.

I'm using 10W40 Mobil 1 synthetic oil as that's what Mercedes recommended in a leaflet which came with the car when new (but according to another forum I should be using 15W40 mineral oil (diesel-grade, even though I have a petrol))

It's a high-miler and has severe rust and I paid £1800 for it with dents, holes in the rear bumper, holes in the wings and a very very raspy engine (damn you, Gumtree!). I've already spent twice what it's actually worth on eBay getting things like the propshaft coupling replaced so now it's becoming my labour of love as I plan to get a rust-free (this is possible, right) W123 300D next

 

[grober]

I went to a local garage to get my car serviced (much quicker than me doing it) and asked him about the noises so he checked the tappets and they are apparently fine.

I'm using 10W40 Mobil 1 synthetic oil as that's what Mercedes recommended in a leaflet which came with the car when new (but according to another forum I should be using 15W40 mineral oil (diesel-grade, even though I have a petrol))

It's a high-miler and has severe rust and I paid £1800 for it with dents, holes in the rear bumper, holes in the wings and a very very raspy engine (damn you, Gumtree!). I've already spent twice what it's actually worth on eBay getting things like the propshaft coupling replaced so now it's becoming my labour of love as I plan to get a rust-free (this is possible, right) W123 300D next

The best way to test the hydraulic tappets is to remove them from the car. You can do a rough test by applying pressure to the top in situ [not enough to compress the valve springs obviously]and looking for movement any downwards movement means there's a problem - but the other cause of noise is a blockage in the oil supply channels----this is more likely to happen in a car where the previous owner didn't change the oil enough. A 10w40 semi-synthetic should normally be fine for your car.
I guess the other possibility is worn gudgeon pins/small ends at piston level- again infrequent oil changes are the chief cause of this.

 

[Dieselman]

Have a listen around the engine with an engine stethoscope.

 

[Satch]

It's a high-miler and has severe rust ...

A good start then.......

How many miles?

 

[neilz]

Well, when I parked it yesterday it was at 166666 miles, maybe it's trying to tell me something?

I know it's got a high mileage but it doesn't mean it should make sounds like that, I think when I bought it I was actually rescuing it judging by the level of care the previous owner had shown (there was evidence on the rear bumper that he couldn't drive!)

I will do the pressure test, are there any oil additives that could help clear the blockages?

 

[219]

I'd also wonder about the oil pump ? Could have been damaged due to running low / lack of oil changes being carried out .

111 engines should not sound 'raspy' - they are very smooth units normally ; even the earlier M102 which preceeded it was smooth and refined ( for a 4 cylinder ) . I'd wonder if something is amiss with the exhaust system , damaged or loose parts , or in light of other reported symptoms , whether something is seriously wrong with the engine .

It is probably not worth spending a huge amount on this engine since there are loads of donor cars out there and a good engine ( complete with loom ) could be picked up fairly cheaply .

You could probably pick up a MOT failure saloon or estate car for minimal cost and , as long as you check that the engine is good before buying , you would have everything you need to fix yours . Swapping out a complete engine is probably an easier and cheaper option than stripping and rebuilding a faulty one ..........

 

[neilz]

Unfortunately though I have the (limited) use of a garage/workshop I can only store my car there for very short periods and there is no room for a donor car. If it is anything serious, though, I will have to consider a donor car. I've already spent way more than it's worth on unexpected repairs (e.g. burned out ignition coils, HT leads, propshaft coupling, window regulator) so why stop there?!

What I will try to do is to record the sounds as that will be way more helpful than my ramblings. It will have to wait 'til next weekend

The oil pressure gauge on the whole is at 3 when driving, the oil is just under the max line on the dipstick though one thing did happen:

I was driving on the M3 back from Southampton when I noticed the engine got a bit louder, sounded like a 90s Transit a bit, and the oil low light was flashing every few seconds (running low but not out, phew), I went to the next service station (10 miles along...) and it was a Shell. I bought the oil they recommended for "older" cars (even 75k is a high mileage apparently, wonder how they'd have reacted if I told them my mileage). They didn't have the one I usually use but it was a must, so I bought the 25W60. I ended up using up the whole small container.

It had never leaked before, and hasn't leaked since and this was 2 months ago.

The funny thing is it drives very nicely, were I deaf I'd have no complaints (about the car)!

 

[bolide]

You're not giving us much to go on. How much oil did you put in? Does it leak oil and if so from where? Or is it burning oil? How did the guy at the local garage "check the tappets"? Have you replaced the engine bay wiring loom, all the coil packs and the ECU?

In my experience those engines vary a lot. Most are noisy & coarse. If it rattles badly check for a failed damper or damper top mount on the serpentine belt, broken exhaust mount on the gearbox and loose heat shields. Also see if the timing chain has stretched or the tensioner is loose

Nick Froome

 

[neilz]

I put in 1 litre of oil then another 1/4 litre when I got home. I don't know where the oil went, when I undid the cap on the engine to fill it it was smoking so I had to leave it a bit. There was nothing that I could see that would suggest a leak and my exhaust doesn't smoke at all. To be honest I have no idea how he checked the tappets but I know many people who use the garage and he is very reliable.

The wiring harness does need replacing and I'm trying to track one down for less than the £600 or so I've been quoted, if I have no luck I'll have to bite the bullet. The engine does tend to overrev in idle (up to 1600/1800) which I've put down to the harness. The ignition coils have been replaced as they were burned out. What makes you think the ECU might be at fault?

I will check everything you've said though it may take a while as I use the car a lot.

Like I said, I'll try to record the sound and see if it helps at all

Thanks for your input, much appreciated!

 

[219]

In my experience those engines vary a lot. Most are noisy & coarse.

It is probably fair to say that those which are noisy & coarse are ones which have been neglected/abused .

I have driven cars with these engines which , in good condition , are very smooth and refined . The M111 is , effectively , a 4 cylinder version of the M104 ; just as the M102 is a 4 cylinder version of the M103 - all of these engines were designed to be smooth and refined because that is what a Mercedes customer would expect and , indeed , demand .

I can fully accept that the ravages of time , high mileage and ignoring service intervals will eventually destroy even the finest machinery - just that noisy & coarse is not how they should be .

I agree with Nick that rattles could well be something external to the engine - exhaust heat shields are always an old favourite .

If you can record the noise(s) and post the files on here ( Photobucket will host video clips ) then we can try and help .

The further info about loss of oil without obvious external leaks , accompanied by 'tappety' 'rattling' noises has me wondering about the possibility of broken piston rings ??

 

[neilz]

This car was so neglected, do you think I was overcharged at £1800 for this (with 160000 or so miles on it)?

It was originally at £3000, I haggled!

I will record the noise, put it on photobucket and post it here, probably next weekend though as I don't have time during the week and today I'm having to rebuild something a little smaller - my '92 Laserjet 4 printer needs a lot of work which I've been putting off for a while

 

[neilz]

Well, my "beloved" mobile seemed to record a very exaggerated version of the standard raspy engine noise at idle and hardly any of the tapping. The very poorly recorded video (I'm not too great with videoing, even holding the phone still was obviously not my forté) is linked to below:

IMG_0024.mp4 video by neilz2 - Photobucket

It's very short as I had just got home and remembered I promised to record the sound. Tomorrow I'll be toying with my phone until I can actually get a decent recording of the sound. In the meantime, anything you can hear in that rushed, terrible video that isn't normal? The tapping is very faint in the video but is very pronounced in reality so I need to record that better.

 

[neilz]

A better video (sorry for wind sound)

IMG_0031.mp4 video by neilz2 - Photobucket

 

[neilz]

Bump... anyone?

 

[HF2]

Does it sound like this one:

[YOUTUBE]http://www.youtube.com/watch?v=udQmPrP6AXs[/YOUTUBE]


Here's the thread

http://www.mbclub.co.uk/forums/engine/40464-c200-w202-horrible-noise.html#post402192

A can of engine flush, new oil and filter sorted it for me :bannana:.
Since then I have flushed the engne at least once a year, it's now got over 155K on the clock with no engine problems.

 

[neilz]

My sound is a bit softer and quieter than that and seems to go away when I start driving, it comes about after a bit of a long drive, otherwise the engine is basically very raspy. But thanks for the idea, I was planning on using RedEx with a full tank except I usually just get £10 worth of normal petrol when I need it. I tried keeping the RedEx ratio but adding less with less fuel but it did nothing.

Kickdown still works on it and it pulls like a train so it's running fine, like I said earlier if you were deaf you wouldn't know anything was wrong, the noises don't appear to affect performance.

 

[neilz]

I'm going to take it in for that Halfords Auto-Centre fuel service when I have the time, as that includes running an engine cleaner and an oil cleaner:

Halfords Autocentre| Fuel Service. Better fuel efficiency guaranteed.

It won't be for a few weeks but anyone think it will make any difference?

 

[BoyracerAU]

Hi Neil, I notice in your first post you mentioned that the engine loom was slowly returning to nature. I would strongly recommend having it replaced asap. They do degrade and even worse they can cause further problems.

Our cars are about the same vintage, mine has travelled 130,000km (81,250 miles) yet the loom started to give problems early this year. Perhaps the hot Summers here helped things along?

At any event, I've recently had the wiring loom replaced and the ECU refurbished, apparently it had been spiked. The whole exercise cost $AU4,300 (GBP2,752).

So if you can save yourself the drama and cost of refurbishing your ECU, you'll be much better off.

For what it's worth, the car never failed to start. However after about forty minutes, it would be intermittently faltering under load, conking out at idle and the air conditioning would stop blowing cold air. Weird and seemingly unrelated symptoms (ie: the a/c problem), but I suppose a spiked ECU is capable of anything!