Engine / Gearbox question: Clicking when accelerating from low RPM

[petetherock]

Dear friends

I notice a clicking sound under the conditions:

- low RPM and I press on the gas firmly

- especially if it's an incline 

- around 1100-1200 rpm 

- doesn't happen if I above 2000 rpm - if i kick down and the gear shifts down

- seems to happen more with SPC than other brands of fuels..

- more often when the engine has been running for a while

- the sound come from the engine bay area 

Thanks bros for helping! 

[jtang]

Sounds like your engine is Pinging aka knocking. What RON petrol is this? U need a min of RON95.

[petetherock]

I was using SPC 95 due to a promotion. 

Now some may say it doesn't matter but She'll didn't seem to give me this issue. 

So you may be right bro!

trying some Esso 98 now.. seems less

saw a series of posts in HWZ on this and some others have also experienced this when they use SPC. And I just realized it's now owned by Petrochina!

I will keep using Esso 98 or shell for while and I also bought Techron concentrate to see if it helps ..

Thanks bro and if you think of any additional tips, please sound out ! Cheers 

[petetherock]

Just an update:

Been using Esso 98, and that sound seems to be much less if any at all. Added a bottle of Techron Concentrate, will see if the sound goes away totally, thanks again for the tip  

[dyeeng]

Indeed it could probably be the knocking.....choose your fuel carefully bro...otherwise, inject some additives to see if it help the boost...

[kingfisher07]

On 10/6/2017 at 0:18 AM, dyeeng said:

Indeed it could probably be the knocking.....choose your fuel carefully bro...otherwise, inject some additives to see if it help the boost...

Having the exact experience for my w246 face lift.

Was on esso95 for first 10,000km, then switch to Caltex Ron95 between 10,000km till today 50,000km.

Started to hear a very mild and low sound volume dull thut-thut engine sound specifically only at 1200rpm (the peak torque rpm) when speed is 50-60km/h for eco, comfort and sports mode. Other rpm is still smooth sound acceleration. This seems to imply that car do not favour light footed slow acceleration at 1200rpm.

Last week went pandan loop service centre to check, technician test drive and say its engineer pinging and ask me to try ron 98. Car specs stated need Ron95 and not ron98 leh...does this mean if enginee down due to pinging on Ron95 means we can claim warranty?

 

[tanwill]

Bro, i had been using 98 Esso since the last advise 9 yrs back from Ah Boon of AutoSprite on my w211. Till today, so far so good, no pinging/knocking.

The reason why many owner had to hv a top overhaul (some as new as 3 years old) mainly due to knocking/pinging.

The Kompressor or Turbo engine (compressed charged engine) is relatively hot and demand the best fuel to suppress engine knock. More so if its been boosted up or ECU tuned for ignition advance.

Its a Mercedes Benz, use the best you can afford.

[petetherock]

Thanks bro, I think even among the brands, there's a difference. 

Anyway, my service rep suggested Esso 98 too.. 

After the switch back to Esso, and the Techron, it's been pretty smooth.. Hope it remains so.. 

Interestingly, I was using Shell 95 with no issues at all, until I went over to SPC 95.. 

[kingfisher07]

recently drove the CLA180 SB on Ron95 and it also had the same mild and low sound volume dull thut-thut engine sound at 1200-1400rpm when cruising at 60-70 km/h or when accelerating on a slop...perhaps its the enginner behaviour the As Bs CLAs.

[tanwill]

Bro thats engine knocking ; and its not good.

Suggest you pump 98 and mix into the 95 when nearing 1/2 tank to raise up the octane level.

[kingfisher07]

On 1/21/2018 at 10:59 AM, tanwill said:

Bro thats engine knocking ; and its not good.

Suggest you pump 98 and mix into the 95 when nearing 1/2 tank to raise up the octane level.

The funny thing is the CLA180 SB was courtesy car when I send in my w246 for the low tut tut engine sound and also squeaking sound from the front wheels (bushings). When I drove the CLA180 SB out from service centre (haven't top up tank yet),  immediately I experience the exact same 2 issues which I reported for my w246!? LOL

[tanwill]

Probably the previous loaner uses the cheapest petrol money can buy.