Skip to content
MOTRS

850 / 850 T-5R / 850R

1991-1997 / Sedan / Estate / Sweden

All 850 / 850 T-5R / 850R problems All workshop issues
Common Engine

PCV System Oil Leaks and Breather Box Failures

Symptoms

Oil everywhere, particularly around the back of the engine and firewall. You might see smoke at idle or a rough idle. In severe cases, the turbo oil feed line can blow apart because the crankcase is pressurised like a balloon.

Cause

Volvo's PCV system is baroque. The breather box (flame trap) sits on the back of the block and clogs with sludge over time. When it blocks, crankcase pressure has nowhere to go, so it forces oil past every seal it can find. The turbo cars are especially vulnerable because boost pressure exacerbates the problem.

Fix

Replace the breather box/flame trap assembly.

This is a bastard of a job on turbo cars because access is appalling.

Budget half a day and skinned knuckles.

The box itself is around $100-150.

While you're in there, replace all the associated hoses, they'll be brittle.

Check the oil trap in the inlet manifold as well, it's part of the same system and often overlooked.

Do this every 100,000 km as preventive maintenance.

Cost mentioned in fix
$100-150

Know something we don't?

Owned a Volvo 850 / 850 T-5R / 850R? Share your experience with this issue. What worked, what didn't, costs, tips. Help the community.

Submit an update
// More 850 / 850 T-5R / 850R problems

Other known issues

Critical Engine

Timing Belt and Water Pump

The engine suddenly stops. If you're lucky, nothing else happens. If you're not, you've just destroyed pistons, valves, and possibly the head. This is an interference engine.
Critical Engine

Oil Consumption (Turbocharged Models)

You're adding a litre of oil every 1000-2000 km. Blue smoke on startup or under boost.
Common Engine

Turbo Failure (T5 and 850R)

Loss of power, screaming noises, oily exhaust smoke. The car feels gutless and the boost gauge stays flat.
Common Cooling System

Radiator and Expansion Tank Cracks

Coolant loss, overheating, the temperature gauge climbing past 12 o'clock. You might see pink coolant pooling under the car or steam from the bonnet.
Common Cooling System

Cooling Fan Failures

The temperature gauge climbs in traffic or at idle. The radiator fan doesn't spin up when it should.
Common Cooling System

Heater Core Leaks

Sweet smell in the cabin, fogged-up windscreen, wet passenger footwell. Coolant loss with no visible external leak.
View all 26 850 / 850 T-5R / 850R problems