boost very VERY strange problem
 

Well had a problem yesterday,
While driving on a trip heard a sound best would be to describe it as
a blunt impact (not too hard but I heard it)
and afterwards the car loost boost pressure. The turbo was not engaging.
There was no warning light, continued driving carefully cause I was in middle of nowhere, The car was acting like a ordinary diesel withput the turbo.
After a few miles the car was back to full power and didn't make any problems.
Checked the code today and there were no codes stored at all apart one for the heater which is on for sometime.
Visually inspected the pipes from above but they all seemed OK.

Anyone have any ideas what the f.. was happening and what should I check?
Thanks in advance.

Don't really know but could be turbo failure? Might have seized before freeing up again (after cooling a bit).

You could take off the air hose to the turbo (from the air filter) and give the turbo a wiggle in and out and up and down. Also see if it spins freely and without noise.

Also consider something seizing on the auxiliary drive belt side, alternator, aircon pump, or a pulley.

Ok thanks for the advice.
Will check the turbo first.

Take a look through this thread I posted a few years ago.
https://www.volvoforums.org.uk/showthread.php?t=179816

The issue I had was most the time, but would get boost occasionally, nobody else seems to have had this problem, but was down to a air shut valve which was letting air in, destroying the vacuum then creating no boost.

Finally got back from the trip will take a look as soon as the weather improves (no garage).
Car behaved normally on the way back.
I did notice some deposits on the air pipe from the air box to the turbo and around it.
And the deposits are not from the EGR or that shut of valve above the EGR.
Those places are dry.
Anyone have the idea from where the deposits are coming from?

Someone pointed to me to check the intercooler
Can anyone tell me how to drain the intercooler.
What pipe should I disconnect and where is it located?

Also what needs to be removed to take the intercooler of for cleaning?

Thanks in advance

The intercooler just receives air and cools it before passing it on for induction, so there shouldn't be anything to drain.

Ok thanks,
read somewhere that there could be oil in the intercooler so that is why I was asking.

Well it happened today again.
Again on the run after some 50 miles.
I've read on one Renault forum that it is the symptom of a bad brake light switch!!!??
Some of them reported that this is the cause on 1.9dci engines.
So next question is did anyone have this happen to them, and how do I check this bloody switch?