S40: Odd Turbo Boost Noise

[VolvoS4]

Car:
Volvo S40 1.6D (Ford DLD Engine) 55 plate.

Hi,

I have recently noticed that the turbo makes the same noise as the interior fan when under load, I have checked for leaks but cant find any... I am truly stumped, Does anybody know what could be possibly causing this?


Cheers,
-B

[VolvoS4]

I have just realised this is in the wrong s40 category, could a mod kindly move the thread to the correct section.

[Kaptin Orsum]

When you say same noise as the interior fan, do you mean a whistle or a clicking?

If it's a whistle tpe of sound, it could be a blown intercooler (IC). Any loss of power? Smoke on wide open throttle (WOT) ? increase in turbo boost rpm, 1,800 before and 2,000 or 2,200 now?

My intercooler is split and I notice a whistle around 2,000rpm, much like running an open air filter. I thought that's what it was and the garage verified it for me. No biggie, just goes with age.

Is yours remapped? This can cause the IC to go on WOT as more boost is stressing the IC, causing it to split.

[Volvoline]

On mine, if I throttle up hard and let the turbo engage, and after half a second release all throttle, I'll get something that sounds like a turbo backfire. Like a turbine doing wush wush wush.

This is a new turbo.
Normal ?

[VolvoS4]

Originally Posted by Kaptin Orsum

When you say same noise as the interior fan, do you mean a whistle or a clicking?

If it's a whistle tpe of sound, it could be a blown intercooler (IC). Any loss of power? Smoke on wide open throttle (WOT) ? increase in turbo boost rpm, 1,800 before and 2,000 or 2,200 now?

My intercooler is split and I notice a whistle around 2,000rpm, much like running an open air filter. I thought that's what it was and the garage verified it for me. No biggie, just goes with age.

Is yours remapped? This can cause the IC to go on WOT as more boost is stressing the IC, causing it to split.

Its not a whistle but like a woosh kind of noise, like the interior fans blowing on setting 4 on the LCD dial, the turbo is full chat when I hear the woosh, under load, whilst accelerating.

What I have noticed is that the pipe running under the turbo (LHS of the engine that leads to the intercooler) expands whilst revving/turbo boosting, and there is a small but noticable escape of engine oil around the join.

Also there is no noticable loss of power and I havent noticed any unusual smoke from the exhaust but I will double check this again to be sure.

I have not long had the car, and I dont know if it has been remapped but the car is completely standard so I would hazard a guess that is has not been tampered with, but I can't remember this noise being present before today as I remember the car was behaving silently whilst accelerating through the gears.

The only thing that bothers me is I need this use the car the next couple of days and I hope I do not cause any unecessary damage to any mechanical parts.

Thanks for the reply Kaptin Orsum, if I have any new information, I shall keep the thread updated.

Regards,
-B

[Kaptin Orsum]

Hmm, sounds to me as though you can hear the turbo spooling up and down, compressor surge/air flow?

Have you had it serviced or any work done on it of late? Maybe the air box is open?

Does it sound like this...

http://www.youtube.com/watch?v=7Pk3dvMJ2FU

[Kaptin Orsum]

the only damage you'll do is if you're running the car at full tit all the time, however even that will be minimal. The turbo, if it is a leak in the boost circuit (pipe work feeding from the air filter, turbo, intercooler and inlet manifold) will just be boosting that little bit harder to achieve the same power. Drive it, but don't go racing until you get it sorted.

If you're seeing oil vapour collecting it sounds as though your boost pipe may be split or perished, or the jubilee clip (if there is one?) could be loose.

It's sounding like a boost leak, much like my split intercooler, which I've had whilst I covered 1,200 miles this week.

[VolvoS4]

Originally Posted by Kaptin Orsum

Hmm, sounds to me as though you can hear the turbo spooling up and down, compressor surge/air flow?

Have you had it serviced or any work done on it of late? Maybe the air box is open?

Does it sound like this...

http://www.youtube.com/watch?v=7Pk3dvMJ2FU

Thats the noise, around 44 seconds in. but very noticable in the drivers seat

No service has been undertaken since my ownership, but I am keen to do this soon.

[VolvoS4]

Originally Posted by Kaptin Orsum

the only damage you'll do is if you're running the car at full tit all the time

Its only a 1.6, although nippy, its not worth raggin' the t!ts off it

Originally Posted by Kaptin Orsum

If you're seeing oil vapour collecting it sounds as though your boost pipe may be split or perished, or the jubilee clip (if there is one?) could be loose.

Shall do some further investigating on this tomorrow, there is a jubilee clip present and from memory, it seems to be unique to the pipe, so I'll try not to lose it

Originally Posted by Kaptin Orsum

It's sounding like a boost leak, much like my split intercooler, which I've had whilst I covered 1,200 miles this week.

Hopefully it is an easy fix, I will remove the dubious intercooler/turbo pipe tomorrow for further investigation.

Once again, thanks for your help
Regards,
-B

[Kaptin Orsum]

I would go and check the air box, ensure it's clipped in correctly. However as you mentioned the boost pipe work it could just be a split pipe or loose jubliee clip.

You'll be OK.