98 V70XC 2.4 Turbo -- Turbo Kicking in at Wrong Times?

MBinEugene · Post by **MBinEugene** » 04 Apr 2010, 20:00

My turbo on my 98 V70XC has started making a noise. I notice it when the engine is cold and I am just starting out of my driveway. It seems to wind up once and then I no longer hear it at road speed. It also occasionally kicks in when the car is just sitting idling. The car was in my garage the other day idling for at least 5 minutes when the turbo kicked in. At least I assume it is the turbo; it's a semi-loud winding up noise that last for 15-30 seconds or so then shuts down. The noise comes from the back of the engine. It's not the radiator cooling fan as I can hear and see that kicking in when it is idling with the hood up and it is normal sounding.

So, question: Is there some kind of control on this turbo that could be bad, causing it to come on at odd times? Or is this normal and it is just the sound of a turbo going bad? Or both (most likely, with my luck).

I an pretty familiar with engines but this is my first turbocharged car. The noise is definitely a recent development. I've owned the car for almost 4 years and just started hearing this noise, so something is definitely wrong. Thanks for help!

Post by **JDS60R** » 04 Apr 2010, 20:18

The turbo on your car is always providing a low level of boost (2psi) . Even whe idling. If you "are" hearing the turbo sto pand go occasionally then I would suspect that something is mechanically stopping it like an oil restriction.
I would run an engine flush and change oil just to be sure.

Is it possible that the noise is the blower motor under the dash?

MBinEugene · Post by **MBinEugene** » 04 Apr 2010, 20:23

I've been pretty religious about the oil, changed every 3-4 K with semi-synthetic, but I bought the car with 91k miles on it, so who knows how it was treated before me? So it may well need a flush. I know I need to do the PCV system.

I'm pretty certain it's not the blower; I can hear it whine from inside the car when it's cold. I never run my heater blower on Auto, and, believe it or not, the blower system is still working perfectly (the car has 145 k).

Post by **JRL** » 04 Apr 2010, 20:52

It's not your turbo, it's your secondary air pump gone bad

MBinEugene · Post by **MBinEugene** » 04 Apr 2010, 21:39

Searched, found this post : https://www.matthewsvolvosite.com/forums ... y+air+pump

Indeed it does sound like the secondary air pump. I will test it by unplugging it, then try to find one at a junkyard as I am already spending money sending my ABS module out to be repaired...Thanks for the help!

Matt

Post by **JDS60R** » 04 Apr 2010, 23:07

That's much better - Glad it wasn't your turbo