Beloit, WI
September 6, 2004

A case which has been baffling local Volvo authorities for weeks has finally been declared closed today. Saga, a blue 1993 Volvo 945 had been going through over a quart of oil every 100 miles or so, with no obvious signs of leakage or burning. Fred, Sagas part owner, and the owner of another 900 series Volvo, was stumped as to the cause of this missing oil.

"There were no stains on the driveway, or smoke out of the tailpipe" he was quoted as saying. "Absolutely no clue whatsoever where all the oil was going."

The case had many others scratching their heads. Everyone from professional Volvo mechanics, fellow owners on the Brickboard, and mechanical engineers were consulted, but no evidence of missing oil could be found, and none of the suggestions offered seemed to lead to the culprit.

This all changed one day on a trip to nearby Chicago, Illinois. Fred was driving down the I-90 toll road towards O'Hare international airport at around 70 mph. Suddenly. he was forced to stop rahter quickly due to a traffic incident. After coming to a complete stop, he noticed the tell-tale acrid smell of burning oil, and a wisp of blue smoke rising from the engine compartment. He immediately pulled over, popped the hood, and amazingly, caught the oil consuming culprit red-handed: It was his trusty oil cap.

It seems that when the car was at speed, oil was allowed to bubble out from under the cap, where it leaked onto the manifold and was burned off. Due to the fact that this only happened at higher speeds, the pungent oil smoke was blown out under the car, never to be detected by it's driver or passengers.

Fred stopped at a nearby Volvo dealer and took his old oil cap into custody pending further investigation, and purchased a replacement for $10.

Three weeks later, Saga is no longer missing oil, and all concerned are positive the true culprit has been identified. "She [Saga] has not lost a single drop of oil in the last three weeks." Fred reported. "It seems the old cap, while it seemed like a nice enough cap, was a bad apple who was just not with the plan. I guess my lesson in all of this is, for $10 a piece, investing in a new oil cap every year or so is a good idea. Also, look at simple things first. Just cause you're missing a quart of oil every 100 miles, don't go out looking for new engines just yet. Of course, we're all relieved that Saga does not have anything seriously wrong with her engine."

Saga, in a statement of her own, echoed Fred's sentiments. "It's quite a load off my miind that I don't have a ring, piston, valve or valve guide going out after all. I mean I only have 120,000 miles and I just don't think that could have happened to me at this age. I'm glad they caught the culprit stealing my oil, and am looking forward to being able to use synthetic now that my driver can afford to buy it for me."

The guilty oil cap, Angus, was recently convicted and required to serve an indefinite sentence in Fred's "junk box," where he will remain, possibly to stand in as a temporary emergency replacement should the need ever arise. He was mostly quiet and remorseless during his sentencing, only saying that he "would do it again" if he were ever used.

But, what we really want to know, have you found your sense of humour?

I recommend changing the oil cap sealing ring (part number 940096 the last time I checked) every other oil change or so. This is a very common problem and the dealers never seem to change it. The seal gets hot and hardens so before you look at it to check it make sure you have another one as it may break form being so brittle. The last time I bought some they were only about a dollar so I think you would have just had to change this seal!

i am VERY interested in this, cos i have a a very similar issue...

are you saying their was ABSOLUTELY no oil in evidence on the engine (i.e. if the engine had bean clean would you have noticed it)

in my case my engien has been degreased so such losses i would have THOUGHT would show up as spray on the cam cover...

as im baffeld as to my oil use...i will take any clues going

Most everything was being burned off by the manifold. the only thing I had noticed was a small slick of oil on the valve cover near the cap itself... this was disregarded, as we had to top off the oil every 100-200 miles or so, and would usually spill some whilst pouring it in.

the only other thing I see on the engine is a little oil near the filter, but not a lot. The engine is very clean, I wish I had a digital camera so you could see: it honestly looks like the engine compartment has been recently detailed.

When I was looking for this problem, I replaced all seals (and of course did the timing belt while at it. the seals looked good, but I did 'em anyway. I replaced a valve cover gasket. checked the oil pump, it was ok.... Checked compression to see if it was a head gasket/ring/valve: it wasn't. the whole pcv system was cleaned and recleaned. different brands/weights types of oil were used.

about the only thing not done was the IR dye thing, where they put the dye in the oil and use a blacklight to see where it comes from. had that been done, we might have licked this a lot sooner and cheaper.

after the weeks of anguish, two volvo dealers, one independant volvo shop, many brickboarders, mechanics of all types, and a Ph.D in mechanical engineering who worked with volvo for several years, it turned out to be the oil cap....

three weeks after the cap replacement, the car is missing neery a drop of oil.

Fred

ok, thanks for the detailed reply, i dont think this is my issue as my engine compartment is spotless and no slick (even misting!) on the rocker cover..

my list of attmpted fixes is somewhat longer than yours including a replaced turbo!

hey ho that nice saab i have just been offered sounds better and better

Dear the kick inside,

Good p.m./a.m. and may this find you well. Refresh my memory, if you will. After you park your car, is the floor always spotless? Further, once you've done a good distance on the motorway/highway, do you need to top up. It may be that oil leaks from around the filter or the oil pan gasket, but only when the car is rolling, and the oil system is "pressurized".

Oil pan bolts do work loose over time. My rule of thumb is one-hand snug, plus 1/8 turn.

Hope this does not go over old ground (pun intended).

Yours faithfully,

spook

car spotless, ground spotless...

do 100 miles o nthe highway...say godbye to 1/2 litre of oil..

engine has been cleaned to the point a dead fly on it looks like a pimple on a super models face - there are no (and i do mean no!) external leaks...nice try though

Sounds like your crankcase ventilation system is plugged up. Have you checked cleaned your flametrap, vacuum hose, intake nipple?

Worth a look.

Jeff Pierce
--
'93 945 Turbo ( one kickass family car ! ), '92 Mercedes 190E (my daily driver), '53 Willys-Overland Pickup (my snow-plow truck/conversation piece -- sold to a loving home), '85 Jeep CJ-7 w/ Fisher plow

all that gets cleaned every 3000 miles. i clean the pcv system at each oil change.

that was the strange thing, there was nothing wrong with this engine that anyone, even professional volvo mechanics could find.

As for angus, well, he looked fine, the gasket looked good and everything.

all evidence of what was happening was burning off the engine.

Fred

That is indeed peculiar. Just goes to show you that you ain't never seen it all.

Good catch.

Jeff Pierce
--
'93 945 Turbo ( one kickass family car ! ), '92 Mercedes 190E (my daily driver), '53 Willys-Overland Pickup (my snow-plow truck/conversation piece -- sold to a loving home), '85 Jeep CJ-7 w/ Fisher plow

Maybe Angus could go on tour speaking to high school assemblies about the dangers of oil addiction, assuming of course, that he gets clean of the addiction and truly is remorseful. Maybe after languishing in your junk box for a time, he'll be ready to reform.

Do you have a lot of gunk, or stains on your engine masking this?

The only evidence left was a small oil slick surrounding the cap, which was written off as spillage since we had to put a quart in every 100-200 miles or so and are both somewhat clumsy. everything else burned off on the the manifold.

This is not the famous "710" cap of urban legend.......?

Dunno about 900s but the oldtimers have a rubber seal that gets
worn/squashed thin so it doesn't seal well. Also the locking tabs
sometimes get bent up. Wish I had a nickel for every time I have,
as a "field expedient", bent the tabs toward the cap to get a little
better sealing.
--
George Downs, Bartlesville, Oklahoma, Central US

Another good trick to use in a pinch: Remove the rubber seal, and re-install it flipped over. Generally, the problem is that there's a ring pressed into the seal. The other side is still flat, and can give you months of leak-free service. Plenty of time to order a replacement with your next parts order.

Jeff Pierce
--
'93 945 Turbo ( one kickass family car ! ), '92 Mercedes 190E (my daily driver), '53 Willys-Overland Pickup (my snow-plow truck/conversation piece -- sold to a loving home), '85 Jeep CJ-7 w/ Fisher plow

I wonder what it would be like to just double up the gaskets? Using 2 gaskets to make for a tighter fit?

Anyone try that?

I notice a little misting of oil around the filler cap sometimes.
I can't imagine how the cap itself could be 'broken'.

I don't know how it could be broken either.... maybe dropped and bent, warped or some way knocked out of kilter.

like I said, for $10 a piece for oem oil cap at the dealer, i don't mind buying one every year for each car.

fred

What was the gasket like on the old cap? They get old and brittle, and don't seal so well after a while. The replacement gasket is maybe $0.75 from your favorite partshouse.

--
alex