Hello All,

Greetings from Chicagoland.

Just wanted to share my experience working on the oil cooler line on 850 Turbo. This may help someone who's going to work on the oil cooler line, as I could not find a procedure in Haynes' (not surprising) or anywhere, not even at Volvospeed.

I had to change the oil cooler outlet hose, as it was leaking oil from seams. This was close to a nightmare with full of Volvo wonderland features (Torx screws, impossible-to-reach components, etc...).

Disconnecting the clamps at the oil cooler is easy (a pair of snap-ring pliers are helpful), but doing so on the other end is a bit messy and there are things you need to know before proceeding.

First, expect some oil to drip. Not too much, but have at least a quart of oil and plenty of newspaper/oil drain catcher. Also, make sure to have new seals/O-rings for all connections, though Volvo's rubber seals seem quite durable and may be re-useable. Here's the procedure:

1. Jack up the front of the car and take the pax-side wheel off. Fold back the fender inner liner and keep it there with a vise grip.

2. Loosen two Torx screws that hold the thermostat housing (The cylinder-looking device on the right of the crank pulley). Make sure to use the correct size torx (I believe they are T40). Oil drips from here. There is a square-shaped rubber seal in the thermostat housing.

3. The 1st fun part. There is a 10mm bolt that holds both inlet & outlet tubes, and it's attached to the cylinder block in the middle of nowhere. Access is extremely limited here. Use universal joint or whatever helps you to get to this bolt. I later found that you can actually get straight access from under the bumper. Check with flashlight and if you can see the bolt from a tiny gap, you'll have much easier time than I did. Taking this bolt makes the hoses moveable

4. This is the 2nd fun part. There are two metal tubes attached to the thermostat housing; inlet & outlet. To take them off, you have to unscrew one Torx screw that holds a metal hold-down plate. This screw is almost impossible to reach, unless you remove the thermostat housing and twist the entire housing sideways without causing damage. Expect this screw to be very tight, mine actually stripped and I had to resort to Volvo-servicing expertise; a chisel & a hammer. This frees all components for the oil cooler lines.

5. Re-installation is the reversal of disassembly...no way, it ain't that easy. First, clean all mating/connection surfaces. Now, connect the hose-to-cooler connections first. This keeps the hoses from moving around too much. Next, connect both inlet & outlet tubes to the thermostat housing. Put new O-rings before connecting, and use a bit of liquid gasket around the connection. When both tubes are attached, re-install the thermostat housing on the engine block. Again, you might want to put liquid gasket outside the square seal ring.

6. Put back the 10mm bolt. Mine had stripped female threads so right now the hoses are hanging loose, though there isn't much play.

7. Start the engine and check for oil leaks.

8. If you find a leak, don't be discouraged. Mine is now dripping oil from the thermostat housing-to-outlet hose connection, so I'll have to do it again (I used new O-rings and made sure the connection was tight, but I had to do this before I re-installed the thermostat housing). Also, the new hose, genuine Volvo made in Sweden, is already seeping oil from the same seam as the one that failed, though this time it only looks wet and is not actually dripping oil.

9. Call/write to Volvo and report your misery. If they get enough complaints, the future products would be improved (though I plan to by an Acura someday).

Good luck if you must service the oil cooler lines.


Best wishes,


JPN