Fumey Crank Case

[v6lux]

What do you guys think. I got a VR engine that is fumey for a fair while after shut-down. I note this from the oil dip stick tube. It is like this even if it is cold.

[Brett_jjj]

Check that the (PCV) Positive Crankcase Ventilation valve is not blocked.Im not sure where it is on the VN engines.My VS has it under the plenum chamber in the inlet manifold.The PCV scavenges any fumes from "blowby" that gets into the crankcase down past the rings, and directs these fumes to the inlet manifold to be sucked into the engine with incoming air,then burned off and consumed in the combustion process.Years ago before pollution gear was used,the crankcase was vented straight to the atmosphere.A worn engine usually creates a lot of blowby because of worn pistons, rings and cylinder walls.

[v6lux]

Thanks, will look for it!

[Brett_jjj]

According to a workshop manual the VN has it located in the rear of the inlet manifold, the VP has it under a cover at the front of the inlet manifold,and on VR models its in a hose near the throttle body.

[chrisdoesitbetter]

According to a workshop manual the VN has it located in the rear of the inlet manifold, the VP has it under a cover at the front of the inlet manifold,and on VR models its in a hose near the throttle body.

thats according to the haynes manuals, the vr pcv valve is located next to the thermostat housing undera big bolt. take the old pcv out and shake it. if it rattles its bust. dont forget the o-ring. from repco a new pcv valve costs $8.50

[deanos70]

its the 17 mm bolt in the pic for a vr

between thermo housing and alternator

[chrisdoesitbetter]

yep thats the one!

[deanos70]

its on bloody tight as well i had to use an extension to undo it

by the look of all the crap on it i'd say it hasnt been undone since the engine was built in 94

but the ball still rattled

[Brett_jjj]

As long as the valve rattles and is still free and not clogged up, should mean its still working ok then.Maybe the engine is getting to the stage where its gonna have blowby all the time and be a bit fumey no matter what.How many k's has it done?Maybe compression test the engine to check just how much wear the cylinders actually have.The minimum cylinder pressure is 689 kpa or 100 psi.The lowest reading on any cylinder should not be less than 70% of the highest reading on any cylinder.

[v6lux]

its the 17 mm bolt in the pic for a vr

between thermo housing and alternator

Thanks heaps. Just want I wanted to know! I'll get the spanner out in the morning!

[v6lux]

Maybe the engine is getting to the stage where its gonna have blowby all the time and be a bit fumey no matter what.How many k's has it done?Maybe compression test the engine to check just how much wear the cylinders actually have.

Thanks Brett, this engine was rebuilt by a mechanic in Brisbane (BRISBANE! - need I say more?) 6 months before I bought the car.

The engine only has 20,000 easy Ks on it since rebuild, but I'll check the PCV, then drive it till it fails! It already has a serious big end knock!

[Brett_jjj]

The engine only has 20,000 easy Ks on it since rebuild, but I'll check the PCV, then drive it till it fails! It already has a serious big end knock

Hmm,not good.It was probably not rebuilt properly if its knocking already which usually points towards bearing failure.A compression test will give you a good idea of the condition of the valves and their seats,the pistons,rings and cylinder bores.If the block has been rebored and honed,you might want to look into rebuilding it again yourself.20,000 is bugger all k's.It would only just be run in properly at 20,000.

[hako]

If it fumes from the dipstick hole or the oil filler cap after shutdown then it cannot be blowby which can only occur whilst the engine is running. However the knock or "death rattle" sure don't sound too healthy.

[v6lux]

Yeah, the fumes are not pumping, just sort of wafting out after shut down!

As for the knock, time will tell! I was thinking some real oil mixed with the normal on the next change to compensate!

[Brett_jjj]

The fumes you are seeing are left over in the crankcase from when its been running.It cant keep making fumes after the engine is shut down.As I said its just "blowby" gasses.