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Oil Consumption/Smell

dualcitizen

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Jul 1, 2018
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Just wondering aloud here what I should start looking for. I got this 940 a few weeks ago and I've noticed a baked oil smell whenever I come to a stop after a drive. I thought it wasn't a big deal as the car has a pretty thick coating of rust protection (oil based) treatment, and it's normal for theme to smell a bit. But I checked the dipstick and it almost didn't read any oil. I put it about 1.5 quarts to bring it up.

Also, when I opened the oil cap, there was a fair bit of smoke/steam coming from there together with that smell. Maybe that's normal, I don't know. Don't recall that with the R.

The car drives great as far as I can tell, and the turbo spools nicely.

I'm thinking I should clean off some of the gunk around the turbo and manifold to see if there's a leak somewhere. I've head about people cleaning the flame trap box. Not exactly sure where this is, but I suppose that should be done or at least inspected. I'm going to do a timing belt change here shortly, anything else I should check? I'm new to the RWD redblock scene but I've been reading and trying to learn as I go along.

Also, any Quebecois here who want to buy my R? :)
 
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The oil separator box (F) is under the intake manifold. Not sure what it's like on a turbo, but I've read you can change it without pulling off the intake manifold. I've also read that the aftermarket ones tend to split, so go with genuine Volvo.

While you are doing the timing belt, it may be a good idea to install new camshaft, crankshaft and intermediate shaft seals as well.
 
I couldn't see anything like that under the manifold, but what is this canister thing? Is this part of the PCV that should be clean?

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Here from another angle:
Notice the cut hose at the bottom. Is that normal, and if not, to where does it connect?

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On the R motors there is a "glove test" that is done by placing a latex glove over the oil cap to see if it gets sucked down or inflates. Sucked down = good, inflates = bad. Does this carry over to the redblock? It seems like it should to me. I just tried this, and the glove inflated. There was also air coming from the dipstick hole. I know if the PCV fails on the R, it causes high oil consumption; do you think that is the case here?
 
That's the charcoal canister, you can ignore it.

The PCV box is under the intake manifold, some say you need to remove the manifold but you can get it off with some extensions. Clean it out thoroughly and get a new o ring.

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If it's been a while, the PCV box under the manifold may blend in really well. It's tucked in there pretty well, but can be removed and cleaned/replaced without removing the manifold.
 
That's the charcoal canister, you can ignore it.

The PCV box is under the intake manifold, some say you need to remove the manifold but you can get it off with some extensions. Clean it out thoroughly and get a new o ring.

Thanks for that picture. I found it; it looks like it will be a nightmare to get that out! What o ring are you referring to?
 
It's this o-ring:

https://www.ipdusa.com/products/5700/107230-oil-separator-box-o-ring

That sits on the bottom of the PCV box.

Just remember to buy that when you buy a Volvo branded PCV box, and you should be good to go. It's a bit of a bear to get to the box without pulling the manifold, but it's doable, I put some string around the wiring harness that sits right above the box, and had a buddy pull up on it for clearance, then I was able to fit the box back into the block.
 
Thanks for that picture. I found it; it looks like it will be a nightmare to get that out! What o ring are you referring to?

It's honestly not that bad. The two ways to make it "easy" but more work are...

Order an intake manifold gasket, and remove the IM to slide it out.

Or... (probably also AND) order a throttle body gasket and remove the throttle body.

If you're gonna take the TB off, order a bunch of valve hushers as well. Those are what they use to seal the throttle plate to the body and get a bit leaky over time...
 
I'd rather keep it simple and just do what I need to. Just ordered the box from Volvo Sherbrooke. Was about $63 CAD. Also ordered the O-ring as recommended above. I hope this solves the the consumption issue and the burned smell.

Where does the oil go if the PCV system is clogged, or how does this affect consumption? I don't fully understand how the system works.
 
If the PCV system is clogged, the crankcase pressure will be higher than normal, and you may start to see oil leakage around seals and gaskets, sometimes the cam seal at first, and usually the rear main seal eventually if not fixed.
 
I'd rather keep it simple and just do what I need to. Just ordered the box from Volvo Sherbrooke. Was about $63 CAD. Also ordered the O-ring as recommended above. I hope this solves the the consumption issue and the burned smell.

Where does the oil go if the PCV system is clogged, or how does this affect consumption? I don't fully understand how the system works.

It's basically an OEM spec "catch can" that is designed to work WITH emissions. It's just a baffled chamber. You get blow by into your crank case that requires the pressure go somewhere. Rather than just venting it to the atmosphere, OEMs draw a small vacuum on it and suck the vapors back into the combustion side of the motor.

Consider that when I mentioned simple earlier. I think it's probably "simpler" to just remove some crap thats in the way. BUT... it DOES require more "work".

Also, pro tip. KEEP YOUR OLD BOX! That way, if/when the new box you ordered blows itself up... you've got your old one as a backup. You can clean them out with some diesel or other such solvent and a lot of shaking it about.

Don't forget to check your flame trap as well. (the little "white" or metal basket that may be the ACTUAL thing thats clogged. (item C in the above diagram)
 
Both... this is in fact the specific component of the whole thing that's SUPPOSED to be cleaned like... every other oil change or something.
 
Cleaning the engine should take care of the baked on smell. I like to use rubber safe engine cleaner. Don't forget to replace the oil cap gasket and the valve cover gasket. They are cheap and easy to replace. This helps keep things sealed at the top.

This PCV stuff is very important if you have a block mounted distributor. The crankcase pressure in the head can get high enough to work the rear cam plug out of position and leak your engine oil out very quickly.
 
ALWAYS make sure your oil idiot light is lighting up during the startup procedure. lol...

Now we're all just like... you're gonna die for a question that basically amounted to "change your flame trap".

I'm a fearmonger.
 
On the diagram above, does hose A connect to something? I pulled this flame trap hose assembly thing off from the catch can and this hose looks like it was cut or broken off.
 
If memory services, Hose A connects into the intake manifold, just on the other side from the throttle body. Should be a little brass fitting to push the hose onto.
I just quickly modified this picture from another post here on TB:
24SDwjJ.jpg
 
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Yes, I found it. Thanks. That hose was broken so I made a new one on from some silicone vac line I already had. I'm a little confused though. I apparently don't have the flame trap with all the little holes in it that get clogged. Mine was just a 15 degree or so elbow with that nipple off the side for the vac line. I was pretty dirty but not completely clogged. I cleaned it out anyway, put it back together and the glove still inflates. Mind you, I haven't taken the oil separator box out yet and replaced it. Just thought I would do this ahead of that since it looked easy. Are there other parts of the PCV that might need cleaning or inspection? And why do I have that different looking connector with no mesh in the middle?
 
I think some if not all models equipped with a turbo don't have a flame trap in that location, like you're seeing. Anyone feel free to confirm or deny, seems to me I remember reading that when looking into the PCV system on my NA.
 
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