Engine: D5: Leaking intercooler

[dalhousie2008]

some chaps pressurize the system with an air hose and check

[ianbr]

Also had the intercooler fail on an 04 D5 so same engine and didn't get a limp home moment even though it got so bad that I left a couple of poor souls in a cloud of black smoke on the way up a motorway sliproad one evening. Must admit after that I backed off quite a lot to avoid the cloud until I got a new one and swapped it out. Went at about 100k miles (about 3 years ago) but was showing weeping oil from the bottom of the radiator for about 40k beforehand (just out of warranty of course!!) Interestingly the replacement (original volvo part) is still pristine with no signs of bowing some 73k later. Have they been beefed up or some other reason? I guess time will tell.

[stutgart69]

I was under the impression from reading other threads that a leaking I/C was a common cause of Limp Mode, but two out four people who have replied to me have said that theirs were leaking for thousands of miles without causing any limp moments ... Since mine is only a slight leak im now thinking it might be some other cause . I will try working my way through the list of possibles in the link that Robbie provided , if i ever get the time..working 60hrs a week is no use

[stutgart69]

I was under the impression from reading other threads that a leaking I/C was a common cause of Limp Mode, but two out four people who have replied to me have said that theirs were leaking for thousands of miles without causing any limp moments ... Since mine is only a slight leak im now thinking it might be some other cause . I will try working my way through the list of possibles in the link that Robbie provided , if i ever get the time..working 60hrs a week is no use

[Vaho]

well, you can count me in also. My intercooler was leaking oil and had many holes. It didn`t hold so much pressure. Nevertheless I drove with the car some 20 000 km before I changed the IC and had no problems with limp mode, only mildly black smoke when accelerating hard. After the swap there was an improvement of throttle response and no more black smoke. I think the intercooler must me completely bust to cause the limp home mode.

[Diesel Convert]

Originally Posted by stutgart69

Since mine is only a slight leak

Hi
How do you know it is only a slight leak? Mine had done 69K and I thought it had a slight leak. It is very difficult to see the intercooler as it sits between the Coolant radiator and A/C radiator. When I changed it it looked like someone with a shotgun had taken a pot shot at the lower section. My fuel consumption and performance also improved once replaced.

[stutgart69]

Originally Posted by Diesel Convert

Hi
How do you know it is only a slight leak? Mine had done 69K and I thought it had a slight leak. It is very difficult to see the intercooler as it sits between the Coolant radiator and A/C radiator. When I changed it it looked like someone with a shotgun had taken a pot shot at the lower section. My fuel consumption and performance also improved once replaced.

Thats a fair point, it is hard to see it , but the car isnt using any oil and there is no real oil stains on the driveway to cause any alarm. I have noticed though that the trip computer says im getting 42mpg but in reality its only 36mpg.
Was yours causing limp mode ?

[stutgart69]

Mmmm..... I stand to be corrected here, but could it be that the extra pollution being thrown out because of the intercooler leak could be causing a build up of soot or carbon inside the turbo and thus sticking the vanes? I remember reading somewhere that intercooler failure precedes turbo failure. Could this be why ?

[outnumbered]

yes that could be a reason why but you do not no that you really nead the code then you can establish where to start.
mike

[RobbieH]

Dunno about pollution but think of it this way:

The ECU calls for a certain quantity of air based on the engine load

The turbo spools to a given level based on the air demand command to give the required air output

Some of the air leaks out from the i/c which means less air gets to the engine

The engine sees less air than it should be getting so calls for even more work by the turbo

Catch 22, vicious circle...............

How hard do you want to work the turbo? I'm led to believe that certain "high power" output remaps can only attain such levels by over-speeding the turbo and there are instances I know of where turbos have expired (prematurely).

Do you knw how much a new VNT turbo plus actuator will cost vs replacing an i/c?

Apologies for my simplistic view on this or if I'm talking bowlocks.

oh, and forget the on-board computer, it lies. Over the last two 2000 ish mile run to the Alps and back mine's out my ~4mpg.

The stuff that comes out of the i/c and shows the leaks is mainly soot and condensation. There might be a little bit of oil that gets through the turbo seals but unless your tubo bearings or seals are shot it shouldn't use any noticeable amount. Mine was checked by blanking off one of the boost hoses and pressurising it with a bike (track) pump. It whistled nicely.