Intermittent rattling noise, car in ICU

[Ct3833]

On 8/21/2023 at 3:39 PM, Beehive3783 said:

I wonder if a cylinder compression test would have helped to narrow down the problem? From your description, seems like none of the workshops did a cylinder compression test?

Actually it will likely be able to catch it but not sure how many engine specialists will do this for problem isolation these days  

[Beehive3783]

On 8/21/2023 at 3:49 PM, Ct3833 said:

Actually it will likely be able to catch it but not sure how many engine specialists will do this for problem isolation these days  

IMO, it is one of the very basic tests that need to be done before even considering opening the engine. If nothing wrong with the engine compression, why open? Something along that line. It will help to narrow down or eliminate a lot of potential issues. 

Edited August 21, 2023 by Beehive3783

[Mkl22]

On 8/21/2023 at 3:49 PM, Ct3833 said:

Actually it will likely be able to catch it but not sure how many engine specialists will do this for problem isolation these days  

compression test is actually very quick. just remove spark plug and disable fuel pump and crank. viola done. but lazy ass SG workshops use eye power and just quote.

[Jamesc]

Monkeys with wrenches

Eye power is all you need.

Eye power diagnosis can always charge more.

Who needs OBD scanner?

Eye power is never wrong.

[ER-3682]

On 8/21/2023 at 3:54 PM, Mkl22 said:

compression test is actually very quick. just remove spark plug and disable fuel pump and crank. viola done. but lazy ass SG workshops use eye power and just quote.

Use Compression Gauge will do.

Edited August 21, 2023 by ER-3682

[Mkl22]

On 8/21/2023 at 3:59 PM, ER-3682 said:

Use Compression Gauge will do.

need to do my mentioned above steps yah?

[ER-3682]

On 8/21/2023 at 4:00 PM, Mkl22 said:

need to do my mentioned above steps yah?

No need..if all 4 Cyls have correct Pressure.

[Beehive3783]

On 8/21/2023 at 3:59 PM, ER-3682 said:

Use Compression Gauge will do.

Hang on a minute. You still need to crank the car for the compression gauge to show the cylinder compression.

1. Remove spark plug

2. Screw in compression gauge to spark plug screw hole

3. Disable fuel pump (removing relay/fuse)

4. Cranking engine

Don't expect to see anything on the compression gauge if there is no cranking. 

[Gnahp]

On 8/21/2023 at 9:01 AM, Ct3833 said:

Misfiring can be due to many causes too, from plug, coil, injection head etc. it happened to my altis before, just replace the high tension (ignition )coil for $65🤣

yes, many faults will give misfire symptoms 

my ex M271Evo engine car, same engine as yours I believe, gave misfiring symptoms for the following faults

1. at 225k km, too much gunk/carbon at inlet ports, very common for direct injection cars, the engine (cylinder 4) will misfire briefly during acceleration. I swapped the ignition coils and spark plugs around but the OBD still reporting cylinder 4 misfire. I told Jason about it, he hooked up his scanner and went for a drive with me, his scanner also showed cylinder 4 misfire. His diagnosis was spot on, walnut blasted the inlet port, engine all well and happy after that.

2. at 235k km, engine will run on 3 cylinders during first start in the morning, if I switch it off immediately and restart, it will run normal. A week later, check engine light on and my OBD scanner shows P2300 P2301 indicating the ECU primary ignition circuit fault. I did the usual elimination exercise by swapping the coils and plugs around to make sure it is not the coils or plugs. At the end change the ECU at Chip Soon, car running well till I traded it in.

3. at 263k km, the engine will missed a beat or two during idling but normal when driving. it was intermittent and random, no specific pattern so I didn't do anything and wait until it get worse. about a month or two later, the car went into limp mode, can only drive up to max speed of 20 km/h then it threw P2118 code when I reached home. it was due to the worn plastic gears inside the E-throttle, at idling when the e-throttle trying to adjust the idling speed, sometimes it couldn't catch the gears because of the worn teeth and that made the idling a bit erratic and felt like a misfire. That part of the gears at idling region get used a lot because of idling speed trimming. replaced the e-throttle, all well.

 

[Ct3833]

On 8/21/2023 at 3:54 PM, Mkl22 said:

compression test is actually very quick. just remove spark plug and disable fuel pump and crank. viola done. but lazy ass SG workshops use eye power and just quote.

@Gnahp 

Thanks for sharing. I will  leave them to focus on the repair first, i will ask him for more details when i collect my car. 

[Gnahp]

On 8/21/2023 at 3:54 PM, Mkl22 said:

compression test is actually very quick. just remove spark plug and disable fuel pump and crank. viola done. but lazy ass SG workshops use eye power and just quote.

need to keep the throttle fully open too

if the compression is lower than the spec, put a few drops of engine oil through the sparkplug hole and repeat. if that bumps up the compression, the leak is at the piston rings

[Gnahp]

On 8/21/2023 at 4:18 PM, Ct3833 said:

@Gnahp 

Thanks for sharing. I will  leave them to focus on the repair first, i will ask him for more details when i collect my car. 

if you look at the mileage, most of the problems surfaced after 200,000km 

I will try to dump my current car around that mileage if possible 😁

 

[Beregond]

On 8/21/2023 at 3:49 PM, Ct3833 said:

Actually it will likely be able to catch it but not sure how many engine specialists will do this for problem isolation these days  

Have la. Those ws that overhaul engine or fuel pump sure have the gauge to check compression. 

The thing is for  example your case even if show 1 cylinder less compression.  But how can we be sure that is the cause of the rattling?  

[Ct3833]

On 8/21/2023 at 4:28 PM, Beregond said:

 

The thing is for  example your case even if show 1 cylinder less compression.  But how can we be sure that is the cause of the rattling?  

I hope so, he seems confident.  Will update when i hv more info.

 

[Sdf4786k]

On 8/20/2023 at 6:06 PM, Ct3833 said:

My 14 year old W212 had this intermittent rattling noise from the front when decelerating to about 40kmh to 20kmh, it will happen when engine is heated up. The rattle noise sounds like a rotating mechanism knocking or marbles hitting some metal walls. The problem is difficult to troubleshoot  due to the intermittent nature of the noise and only when the car is moving . I have to highlight that I am one who will not save on maintenance, so it is not due to lack of servicing. 

Let me share the trouble I have to go through to nail the cause, or at least, I believe the mechanic have found the cause. 

It started off with the intermittent noise, to rule out some of the possible causes and guess work, I want to highlight that I have  replaced engine mounts , transmission mounts, belts , tensioner, cam adjusters, timing chain etc,  even the drive shaft bearing and bracket was replaced. Most of those mentioned items were replaced as part of wear and tear or as preventive maintenance along the way during various servicing schedules till my car has reached 200k km now, except for the drive shaft bearing and bracket , it was the one that I told my workshop to replace it as part of problem isolation. I also asked the mechanic to check if there was metal parts like heat shield or exhaust  that may come very close to contact with other metal or mountings, but there was none.

2nd workshop

Since the first workshop couldn't pin point the problem, I asked another of my regular workshop, the mechanic heard the noise and told me could be auto transmission and he will have to open up the autotrans and service the whole unit, I was not convinced that it could be the autotrans but  I could not fault the mechanic since he had only heard the noise for the first time. I told him more likely to be the engine and asked if he could check the valve lifter etc, but he didnt think so.

3rd Workshop

To validate the findings form the 2nd workshop, i sent the car to an autotrans specialist that i repaired my Odyssey gear box before to get a 2nd opinion, incidentally, the car came up with a engine check light when we rev the engine hard during the test drive, he had also heard the noise. He told me my ECU was having problem after reading the code from OBD. Again i was not convinced the noise can be caused by ECU, I didnt want to speculate why the engine check light first. I check the error code when i reached home, it was indicating cylinder 4 having fault. 

4th workshop

Not convinced with the autotrans specialist, I sent my car to another autotrans and engine specialist workshop, the guy heard the noise, check the code, he didnt know what happen, asked me to leave the car with him. After the next full day, he told me he could not find the problem, I asked him to open the engine block to check, look out for hairline cracks, valve lifters defects etc, he asked me if i was sure that I wanted to open the engine block, i told him to proceed. Another day had gone and he said still no fault found, I was a little panic then, I told myself cant be so complicated or bad luck. Fortunately, on the 4th  day, he told he he found the knocking, it was due to a piston that was slightly loosen and was knocking against the cylinder.  With that,  I was more convinced with the finding, at least it was likely the cause of knocking and it explained why only when the engine was heated up. 

Those who know about engine would know what happen next, the engine will have to be overhauled. He told me that will need at least 5k, but that was not my concern, I am hoping that the problem could be resolved once and for all. 

My experience indicates one thing, one needs to have some car knowledge in order to drive an old car, otherwise, otherwise one maybe taken for a ride by workshops. Not that they will cheat but the problem is when they only get to see or hear a problem for once, their diagnostic and conclusion may not be accurate, especially when a problem is intermittent, the owner who drive the car everyday have to provide feedback accurately, take the input from mechanics and decide if the findings make sense.

Now on the workshops, one may think that I anyhow find a workshop to diagnose a strange problem, no i did not, all the workshops that i engaged are not fly by night workshops, they are reputable and very experience workshops , just that the problem i had was unique and more difficult to troubleshoot. 

The repair should be done by mid to late next week, I really hope the problem could be resolved and I personally think so. Meantime I have to be contented with my Altis.🤣

 

perhaps a old phone tap to the car on recording mode may be more useful in recording the nosie, else a cheap fake go pro or the In car camera may help to identify the nosie.

Bear in mind that I had the same set of difficulty saying thats the noise Unless it can be identify with a certain behavior, like under hard acceleration or up hill.

if its only on the move that the sound can be heard , then tough luck. Else look for a wall with the car park facing the wall with the bonnet up can help amplified the noise

 

[Sdf4786k]

On 8/21/2023 at 4:31 PM, Ct3833 said:

I hope so, he seems confident.  Will update when i hv more info.

 

well.. if its not within specs, then even if its a wrong diagnosis, its already proof that the cyinder has a leak.

[Jamesc]

Now I know why so many owners sell me their W212 

when its reaching the 200,000k mark.

W124 never had this kinds of issues even at 500,000k mark.

Those were build to last forever.

[Mkl22]

On 8/22/2023 at 4:25 PM, Jamesc said:

Now I know why so many owners sell me their W212 

when its reaching the 200,000k mark.

W124 never had this kinds of issues even at 500,000k mark.

Those were build to last forever.

That’s why Mercedes didn’t make that much money. So now must make it spoil, then can earn more from parts.