Mazda 6 engine noise

jayz76

Hi, my Mazda 6 2.2 diesel 15 reg starts to make a noise when I start it, it appears to be coming from the engine and lasts for about 3 to 4 minutes then its gone.
If I left the car for 6 or 7 hours and started it there would be no noise but if I leave it for a longer period 12+ hours I would hear it.
Any advice on what might be causing this..thanks

ongarite

What kind of noise?
A hard mechanical knocking or belt screeching or air escaping/hissing?

The Mazda 2.2 diesel is know to have some serious reliability issues.
Have you checked the oil level on the dipstick?

jayz76

I left the car in the garage last week when I first heard it, they serviced the car and said they couldn't find any thing wrong with it. I have left it in again so they can hear it when it first starts after overnight.

Its sounds like a knocking noise.

bazz26

Not trying to be smart but I don't think anyone here could diagnose "a noise". It could be anything really.

jayz76

I know just I find it strange that it only happens when not driven for long period of time.. 12+ hours

greasepalm

Wonder if its the warm up system in operation.

https://www.youtube.com/watch?v=esKADKbFaXw

Plenty of diesels starting from cold have a bypass valve and you hear a wheeze from cold and as it warms up it fades away
and shuts off,might be a way of reducing high carbon building up before car is driven to expell it out the exhaust.

Vicxas

Does it sound like something loose when it's cold and goes when the car warms up?

If so i had the same on my 11 Mazda and it was the Alternator tensioner belt. Needed to be replaced.

jayz76

Yes it does and goes as soon as the car is warm..3 to 4 mins

greasepalm

Do a video with sound.

Cee-Jay-Cee

Have you checked the oil level??? If it only happens when the car has been sitting for long periods then it sounds like a dry chain and it takes a few minutes for the oil to circulate and lubricate it properly but that's just a guess. If its something that it didn't do previously and the oil level is normal then bring it to a mechanic and get it properly diagnosed.

jayz76

I had my mazda 6 in the garage and they are telling me one of the heat sheilds are loose around the exhaust/DPF area of the car, when I start the car I can hear a knocking noise and it lasts for around 3 to 4 minutes and the is gone. They say they cannot fix it as they cant open one of the bolts.Has anyone had a similar problem with heat sheilds?

greasepalm

Sometimes vibration can make things break and high temp and low temp can have a bearing on what is happening.

Older cars have those issues but years is fairly new but wonder quality of parts and have they rusted so seized in.

Sounds like they need a hot torch to loosen seized bolts.