Diesel Forester Turbo Hoses

[Pecky]

I have had failures of two turbo hoses on my 2010 Forester Diesel. I know of two other club members who have had similar problems.

The first failure was at 124,000 km in January 2016. Driving along at 80/90 in 5th gear the car would start shuddering going up a slight incline and the fuel consumption had also started to get worse. Backing off the throttle seemed to ease it and it was repeatable in similar circumstances. I found a split in the hose from the intercooler to the throttle body. As it was just before a trip and I didn’t have time to get to a Subaru dealer I replaced it with a $35 aftermarket silicone hose that is 70mm diameter with a 45 degree bend. The intercooler had to be removed to get at the hose but it was a straight forward replacement and all I had to do was trim the silicone hose to the same length as the original. I consider the replacement to be a better part than the original and I would encourage people to do the same.

The second failure was at 139,600 km in September 2016. As I accelerated whilst overtaking on a hill I heard a pfft noise and the engine lost power but the car was still drivable. I limped back to the nearest town and had to get the car transported 200km back to Perth. The symptoms were obviously turbo related and the fault was found to be the hose from the turbo to intercooler. The end that is clamped onto the turbo outlet had separated completely.
It appears to be a very poor design as there are fingers on the end of the hose that are clamped to the body of the turbo. The problem is the fingers are much thinner than the wall thickness of the turbo hose and the end of the hose had broken off the fingers completely. The fingers remained clamped to the body of the turbo along with a cylindrical spacer.
I didn’t want to replace the turbo hose with something that appeared bound to fail again so I got a 51mm diameter straight silicone hose and filed down the outside diameter of the end of the rigid plastic turbo hose until the silicone hose fit over it and provided a flange for the hose clamp. The spacer was placed back onto the turbo outlet and hose clamps used to secure both ends of the silicone hose.

I hope this prevents others having similar problems.

cheers

 

[Kevin]

Thanks for the heads-up and the solution!

 

[PauSum]

Yes, thanks for sharing this - preparing the same to happen to my diesel outback

 

[Pecky]

The third failure was in May 2019 at 202,500 km soon after I had the clutch replaced and the intercooler had been removed, but I don’t think that was a contributing factor. I noticed an unusual noise when accelerating.
I pulled the rigid pipe from the turbo to intercooler off and found that the concertina section that is near the intercooler had a split in the bottom of one of the grooves.
I cut the concertina off, leaving the first bulge which I ground down to fit a straight silicone 57mm to 51mm reducer. The reducer was trimmed to length and the 51 mm end was cut at a slight angle to get the clamp to fit nicely.

 

[Kevin]

Good job!

 

[ABFoz]

Thanks for the update. This is similar to my experience with turbo diesels from other manufacturers. Just replace the the intake hoses with high-grade silicone ones. 1KZ-TE also has this problem, as well as the cult classic 4JB1-T. Just imagine how expensive those hoses were in the 90s but they solve so much boost drop issues.