ND cold engine noises

Technical Area Engine, Transmission, Exhaust etc
1
  1. My model of MX-5 is: __ND 2 2.0l
  2. I’m based near: __High Wycombe
  3. I’m looking for technical help or recommendations on: __Cold engine noises for first 1/3 mile driving

In cold weather (mainly) on the first start of the day, I get a piston slap type of tap/knock noise on starting the car (even AFTER the initial higher idle speed when the ECU tries to warm things up quickly). The volume of the noise seems to increase with engine load (e.g. when pulling away). After 1/3 mile or so it quietens down and all is fine for the rest of the day, through multiple starts.

I’ve read these type of noises can actually be injector related but in any case is this type of noise typical/normal, or is further investigation needed?

2

Hey, I’m wondering the same things. I don’t know if mine started recently or I just recently noticed it, does yours sound like this? https://youtu.be/vA0Ioq6-GhU?t=95&is=1rzLkiT7b5VVHOru

If you check the video you can tell a tapping noise that then disappears. Once the blue coolant light goes out you don’t hear it at all I think.

3
  1. My model of MX-5 is: 2016 ND1 2.0
  2. I’m based near: __
  3. I’m looking for technical help or recommendations on: Tapping noise with cold engine

Hey everyone,

I’m noticing an issue with my ND1 that I don’t know how much I should worry about.

My car is a 2.0L 160 hp european ND1 with about 103k miles.

Recently, I’ve started noticing a tapping noise coming, from what I can hear, from the engine top end, after the cold start.

I know that the first 20 or 30 seconds the idle is high and the engine sounds very rough, I’m used to that and I also know that when the idle lowers but the blue light is still on, the engine sounds very clattery and diesel-y. I also know that the injectors are very noisy on this engine. But the noise I’m noticing seems a bit different than all those sounds.

I would say that it sounds almost like the NA lifter tick, albeit slightly slower.

I do have a video of the noise: https://youtu.be/vA0Ioq6-GhU?t=87&is=1CnTOkTXnlW08nUk

At about 1:45 you can hear that the tapping noise suddenly disappears, but comes back a few seconds later, although it’s a bit harder to tell. It’s quite rhythmic and the speed of the noise does increase a bit with revs.

The noise completely disappears after the blue coolant light turns off and the engine is warmer.

I’m not sure if the noise has always been there of if it started recently. You can’t usually hear it if you have the top up and the windows up, and usually when I leave the house I just wait for the idle to drop and then I start driving so I don’t usually leave the car cold idling for long.

The noise happens more easily if the car has been sat overnight, and if the morning is colder than usual I would say. If the car does the cold start procedure if the car only sat for 6-7 hours I can’t hear any tapping noise.

I change the oil every 6 or 7 thousand miles with 5w-30, my current oil level is slightly lower than the full line, and I always wait 5-10 minutes after startup before revving high.

Is this noise normal and a quirk of the Skyactiv-G engine or should I worry? I’m planning to keep the car for about another 100k miles so I would like to fix potential problems as soon as I can.

It does sound to me like it’s valve train related, a bit like NA MX-5s lifter tick. I know that some Skyactiv engines with cylinder deactivation might suffer with bad HLAs, but the MX-5 doesn’t have it and I couldn’t find a single TSB for hydraulic lifters issues.

4

Yep, same

5

Just wondering: how many miles does yours have? Did you notice it as soon as you got the car or only recently?

6

13000m.

Only really noticed it after its 2yr service, but I was looking for odd things as the Mazda dealer had put the wrong oil in! There’s another thread on that.

Anyway car was in for a laundry list of potential warranty issues today. I was told the noise if definitely normal.

(But they will be fitting a new gearbox! Another thread on that ;-))

7

Normal

8

Oof, the gearbox one is painful. Lucky for you it’s still under warranty. I was a bit worried because mine hasn’t got any warranty anymore,but if the dealership is reporting it as normal let’s hope it is.

9

Just asking: did you get a chance to check the video I posted? Is that tap tap noise that suddenly goes away normal? I know the injectors tick, but that’s usually much faster than what I’m hearing.

10

When I bought mine and started it, I thought it sounded awful. There was another one next to it so asked for the keys to that one as well and it sounded the same. I think its doing something with the timing to heat up the Cat,

11

I’m very familiar with the warm up procedure, where the revs go high and the car sounds very different, a lot more noisy. After that procedure you can hear the car getting quieter and the revs dropping, but the car is still noisier than normal. The sound I’m referring to is the one in the video a few messages above, if you click on the link https://www.youtube.com/watch?v=vA0Ioq6-GhU&t=87s you get taken to the noise I’m talking about: that rythmic tap tap that seems to be coming from the top end. At about 1:45 that tapping noise suddenly disappears, sometimes it come back but with less intensity, sometimes it stays silent. This noise completely disappears once the engine starts warming up. Once the blue light goes out, that noise stops. I can’t tell from other videos if other NDs do that as well. Normal cold start videos are only 30 seconds long and usually last until the revs drop, which isn’t enough to check for that noise.

12

I did watch your video, Sorry I couldn’t help more. Hopefully someone else can.

13

Normal. Same as mine. Goes after about 1/2 mile for me, and seems loader under a little load.

14

Thank you. I’ll assume it’s normal and it’s just that I only recently noticed it. Also if your does it as well with almost 1/10 of my mileage (I’m at about 105k miles) I don’t think that it should be an issue.