Oil leak (almost) disaster

[VeryNoisyPoet]

Started getting a strange, intermittent "burning smell" when at stoplights, but by the time I got to destination and opened hood, it would dissipate and I couldn't locate source. Didn't smell like smoking oil, and instead smelled almost like diesel exhaust. No obvious leaks besides the residue from past leaking. Then one day I got to work and the smell was really strong, like I was right behind a badly tuned diesel puffing soot at me. Opened the hood with engine running and was greeted by the signs of oil pouring from under distributor, along with puffs of crankcase vapor, which explained the hot oil smell. In the minute I ran the car before shutting down, it left a puddle about 10 inches in diameter on the road.

I already had replaced a weeping rear cam seal on the exhaust side around a year ago, so I was 99% sure I had a major failure at the intake side cam seal now. I ordered parts for quick delivery without tearing into it first, and thankfully I got it right. The old seal completely fell out when I took distributor rotor off. I replaced seal and checked PCV system, which seems to be functioning normally. The old seal just decided it wanted to walk off one day with no other signs of excessive crankcase pressure or abnormal blowby.

Somehow in all of this, I'd only lost half a quart of oil, though maybe as little as a cup or two since I haven't added any oil for at least 1500 miles. Even so, this is the closest I've come to needing my oil pressure gauge to warn me the sump's going dry before I fry my engine on the freeway.

 

[CharBaby]

Well done!
Glad you quickly found the source of the leak and nothing disastrous happened.

 

[demarpaint]

 

[Astro14]

Usually, when a cam seal goes on a white block Volvo engine, it's being pushed out by excess crankcase pressure.

How's your flame trap? I know that you said you checked it (PCV), but since it's under the manifold, it's not easy to actually look in the passages. The "glove" test is not really that useful...in a turbo car, there are actually two complete PCV routings, one for low pressure and one when the engine is under boost. The "glove" test only checks the low pressure circuit, not the other.

If you've not replaced the flame trap components, particularly the box itself, I would do that now, along with your cam seal, or you'll find that another seal blows, and soon as the pressure finds the weakest point through which to vent...

IPD sells a kit, which is not expensive, for your car that includes all of the PCV components. Clean the passages in the block, too, while you're in there.

https://www.ipdusa.com/products/11269/124712-pcv-breather-system-kit

 

[VeryNoisyPoet]

Originally Posted by Astro14
Usually, when a cam seal goes on a white block Volvo engine, it's being pushed out by excess crankcase pressure.

How's your flame trap? I know that you said you checked it (PCV), but since it's under the manifold, it's not easy to actually look in the passages. The "glove" test is not really that useful...in a turbo car, there are actually two complete PCV routings, one for low pressure and one when the engine is under boost. The "glove" test only checks the low pressure circuit, not the other.

If you've not replaced the flame trap components, particularly the box itself, I would do that now, along with your cam seal, or you'll find that another seal blows, and soon as the pressure finds the weakest point through which to vent...

IPD sells a kit, which is not expensive, for your car that includes all of the PCV components. Clean the passages in the block, too, while you're in there.

https://www.ipdusa.com/products/11269/124712-pcv-breather-system-kit


Back when it was my mom's car, the PCV system was replaced by a shop at 150k when it clogged. Perhaps that pressure event partially ejected or weakened the old cam seal which finally let go now years later. Certainly blew the dipstick out of the tube and made a mess of the engine bay back then, along with turning car into self propelled mosquito fogger.

I had manifold off about 15k miles ago when I installed the oil pressure transducer. Took apart PCV system to clean it while under there. Ports into block were clear, and I soaked and flushed out flame trap and hoses with carb cleaner. Only a little bit of brown liquid came out and all connections flowed freely. If it had gone 35k without much buildup at all, do you think it's already clogged after another 15k of highway cruising?

 

[andyd]

Every vehicle's liquids should have a low level warning light. It is a very simple float and a few wires. The ones on my 528e saved me a few times.

 

[Astro14]

With that work done, no, I think your PCV is fine.

They generally take a while to clog up.

And they clogged up so often on these cars because Volvo NA didn't educate dealers on what oil to use when Volvo went to a 7,500 mile, then 10,000 mile OCI. Most Volvo dealers used a bulk 5W30 dino when ACEA specs were called for. No problem under warranty, but a real problem around 100K miles...

We bought my wife's 2002 XC with 92,000 miles on it. Dealer serviced. It got Pennzoil Ultra Euro oil for the first couple of years that we owned it, and still blew out a camshaft seal. Once the hard carbon sludge builds up in the PCV, no oil will remove it. Only a mechanical cleaning. By the way, that car passed the "glove" test not long before it puked out the seal.

I just pulled the PCV system off a 2001 V70. A 72,000 mile car - and it was near spotless. I suspect because it got so few miles/year that the oil was changed at short intervals, it never stayed in there long enough to turn into low TBN/acidic, which is what causes that sludge to start forming.

I didn't know that you had all that work done on the PCV on you car.

Keep a good ACEA A3/B3 oil in there, and you'll never have to worry about it again.