engine knock under load

Forum for Engine, Exhaust, Drivetrain, ECU
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jimmy156
Posts: 4
Joined: Sun Aug 15, 2021 4:02 pm
Qashqai Model: Mk.2 Qashqai - J11 (2013–2017)

Post by jimmy156 »

Hello all,

I am one of those new members signing up and instantly asking for technical help, so sorry about that!

We have a 2014 Qashqai with the 1.2 petrol engine. I have noticed that occasionally, under load at around 2k RPM (so low revs but not straining the motor near idle) I get a knocking noise from the engine. It is very intermittent so I am reticent to take it to the dealer as I can almost guarantee they won't be able to replicate it.

It is definitely not the "rattle" that there is a lot of YouTube videos about, associated with the timing chain / tensioner. It's a distinctive knock, not dissimilar to the sound you get as an engine is stalling. It lasts a few seconds (or until you lift off throttle) and is not associated with any hesitation or loss of power from the engine. It does not happen every time you go through the revs, it does not seem to be gear dependent and as I said it is very intermittent. On a recent 6 hour drive, I reckon I heard it 6-8 times.

Before I am relieved of £50 for diagnostics only for the tech to tell me they can't replicate the fault, has anyone got any ideas?

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gloucester
Posts: 5173
Joined: Sun Apr 03, 2016 7:04 am
Location: Gloucestershire, England
Qashqai Model: Mk.2 Qashqai - J11 (2013–2017)

Post by gloucester »

Welcome to this forum

Sorry can't help with this one
(2015 Nissan Qashqai Tekna DIG-T 1.2 sold 15/6/18) ~ 2018 Suzuki Ignis SZ5 - 2018 Yamaha MT-07 ~ (2024 Volvo EX30 ordered)
jimmy156
Posts: 4
Joined: Sun Aug 15, 2021 4:02 pm
Qashqai Model: Mk.2 Qashqai - J11 (2013–2017)

Post by jimmy156 »

Thanks for the welcome gloucester.

Yes its a tough one to diagnose on the 'net! I found this video posted by a forum member earlier this year, same motor, sounds pretty similar to what I can hear. Unfortunately he only had one reply to his post and it was only to say that the video was too short to be helpful!

lewisbryant
Posts: 336
Joined: Sat Feb 23, 2019 7:27 am
Qashqai Model: Mk.3 Qashqai - J12 (2021+) New Model

Post by lewisbryant »

Is it like a "donk" and just 1 done not like rotational where you get a knock knock knock one after another until you let off?

Also can you replicate it at idle by blipping the throttle up to around 2k and letting off? Does it do it as you let off?
jimmy156
Posts: 4
Joined: Sun Aug 15, 2021 4:02 pm
Qashqai Model: Mk.2 Qashqai - J11 (2013–2017)

Post by jimmy156 »

Hi lewis bryant,

Sometimes I get a couple of "donks" other times its repeated "donk, donk, donk" until you lift off, or for a few seconds. It is not necessarily linked with engine speed, its pretty hard to tell.

Pretty sure it only does it under load, I have never heard it by blipping the throttle
lewisbryant
Posts: 336
Joined: Sat Feb 23, 2019 7:27 am
Qashqai Model: Mk.3 Qashqai - J12 (2021+) New Model

Post by lewisbryant »

Difficult one, unless its easy enough to replicate then its going to be hard to diagnose
jimmy156
Posts: 4
Joined: Sun Aug 15, 2021 4:02 pm
Qashqai Model: Mk.2 Qashqai - J11 (2013–2017)

Post by jimmy156 »

Yeah i knew that would be the case. I've booked it in at the local dealer for to have a look and try to diagnose. Worst case its £50 for a valet and health check to be told they couldn't replicate it!
Qashowner
Posts: 564
Joined: Wed Apr 17, 2019 10:07 am
Qashqai Model: Mk.2 Qashqai - J11 (2013–2017)

Post by Qashowner »

I would not have thought it was a rotational thing as 2000 rpm is 34 per second and would probably sound like a buzz than a donk. It may well be the engine leaning a bit with the load and straining the engine mounts or knocking the exhaust on something. Which ever it is hard to reproduce and almost impossible to find.
Past cars Mercedes B Class, S Class, E Class Estate, E Class Coupe, G Wagen, 260E interspersed with Peugeot 406 and Audi Coupe.
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