boost leak

pajeroboy · Post by **pajeroboy** » Tue Jan 09, 2007 10:27 am

hey all,

just got a little prob on my pajero 2.5 turbo diesel,it seams to have a bit of a boost leak,seams to be coming from round the top of engine on drivers side,it not from the block (i think) more round the stuff that sits above the turbo,hope it not the turbo,only seams to do it when the foot is buried and boosting at 13 then sometimes starts hissing and drops back to 11 psi.

it very stange,if anyone has any ideas or theorys as to y and where would be great,still drives fine,only seams to do it randomly,was thinking some sort of release valve maybe.

matwelli · Post by **matwelli** » Tue Jan 09, 2007 6:05 pm

There is a safety blow off valve around that area, Its probably that passing under boost.

reasons - 1/ its getting old and tired and needs to be replaced (the springs getting soft and lifting early) -2/ your boost gauge is wrong and your boost is to high and the valve is doing its job.

Just a couple of thoughts, also check the hose connection between your turbo and intercooler, make sure they are tight.

pajeroboy · Post by **pajeroboy** » Tue Jan 09, 2007 9:37 pm

thanks man,will look into it,wouldnt think it be the gauge because it only couple months old,mite have to find some info on boost system

NJV6 · Post by **NJV6** » Tue Jan 09, 2007 9:50 pm

Further to that from Mat - I am new to the 2.5Tdi but from what I gather there is a safety valve right at the rear of the inlet manifold on th highest point. Maybe air is leaking out there at high pressure. Otherwise just what mat suggested

There is the wastegate actuator which has an air line running into it and a shaft going down to the exhaust side of the turbo

To the front of that is what looks like some sort of controller for the inlet manifold pressure which has a opening from the inlet to dump excess boost into the exhaust which is vacuum operated by a electric over air solinoid. I haven't actially worked out how this controls boost......

NJ

matwelli · Post by **matwelli** » Wed Jan 10, 2007 8:33 pm

OK, could not find a photo on the web, so braved the Hawera night and took a photo from the wifes engine bay.

Easy to check if the safety valve is leaking, go to a plumbing store and get a bung that is the same thread - only a temporary measure, as this valve help protect the engine from the wastegate on the turbo failing.

NJ - that thing on the front you were refering to, I think you are talking about the egr valve, it allows a certain amount of exhaust gas back into the inlet to reduce emmisions.

Pajero boy - this "hissing" noise, do you hear it with the bonnet open and standing next to the paj, or is this sound when you are driving ?

These turbos are old tech, no water cooling and no ball bearing, they can make quite a bit of noise when they get older, seriously this may be the noise you are talking about ? (they spin at about 20k rpm at idle and up to 110k rpm at full boost.

Hope this helps

NJV6 · Post by **NJV6** » Wed Jan 10, 2007 8:48 pm

Ah - that makes sense - someone prior had disconnected the vacuum line to it and pluged it so it did nothing except gather oil (like yours by the looks) and crap. I plugged the hose back into it but it seems I needn't have bothered!

P.S. Mine is cleaner under the engine bay than yours

Edit - Ah Bingo - good picture, I have found out where a bracket goes that I had left over after putting it all back together! (the flimsey piece that the rocker breather hose clips into that yours isn't cliped into......) CHEERS!

matwelli · Post by **matwelli** » Wed Jan 10, 2007 9:05 pm

Its the wifes truck, dont care about the oil buildup

Do care about the leaking fuel pump

Thats the next project (wof's due this month)

pajeroboy · Post by **pajeroboy** » Wed Jan 10, 2007 9:42 pm

thanks for the big help guys,as it was raining today didnt get under bonnet to look but thats the area that the noise is coming from,it only does it when driving and at full boost,there is a bit of oil spary forming round that area,when driving round town (low boost sort of stuff) i can hear the turbo spoiling up in the snokel,but it not the new hissing sound.

mud_slinger · Post by **mud_slinger** » Wed Jan 10, 2007 10:03 pm

its def dumpin boost at speed i'd agree and go wit the relief valve sounds more like it than anythin else cos its only random. bit of rain aint guna melt ya :lol:

red-devil · Post by **red-devil** » Sat Jan 20, 2007 11:26 am

pajeroboy bring ur truck around and we'll have a look. i think i know were its leaking and there a easy fix for it.

ur boost controler/wastgate may not be closing correctly, i had the same problem and fix it.

jono

pajeroboy · Post by **pajeroboy** » Wed Jan 24, 2007 4:07 pm

sorry all havent been on in a bit,yeah jono i mite cum round soon,kinda gotta get warrent first and need to do hand brake b4 i go cos it bloody useless at mo. how ur truck going?still playing up or sortded now