as regulars will know i am batteling truely awfull oil consumption figures (up to 1tr per 100 miles)..and having spent in excess of $1000 trying to solve this I now wonder if its the fact that I have been buying oil that is too modern for this engine...

basically i use oil on long fast motorway runs and have filled with mobil 0w40 as this should (my thinking) be nice and runny to get to that turbo faster...however I now note that Volvo recommend 10w40, and indeed for runs such as these recomend 15w40 or 20w40...

Anyways being unable to get mobil 1 10w40..yeh i know i should be able to get it but no one stocks it....I am going to try good old fashioned part synthetic 10w40...but has anyone else tried 0w40...and had issues or can i rule this out...?

I must say this is pretty much the last throw of the dice for volvo ownership for me...I have been so disapointed in the car....it drive great, lovely to sit in but so unreliable....and requiring so much work (which lets face it a 135k miles car just shouldnt...)

well just wondered if i might be onto something..at least if someone could confirm or deny the suspicion...

thanks guys...

well that kinda spoils that idea...I think i will just give up...and get shot of the car...oh well sems buying a brick wasn't such a good idea after all..(well at least a 9xx one at any rate)

Kick - sorry to hear the trouble continues. I've only used Mobil 1 10w30... never had to add any except when changing the filter. I've only had the car for ~8500 miles, though.

Did you make any more progress on the theory of plugged cat = back pressure = turbine seal oil leak = oil burns up in cat = more plugged, more backpressure, etc?

- Brian '93 945T 108k

hi brian,
thanks for the comiserations...

i didnt make a lot more progress on the cat for 2 reasons...1 - lack of information, 2 - cant get the bloody thing off!

i did a series of high rev WOT tests to read back preusre off various points on the system and came back with a maximum peak of 5psi pre cat and 2.5 psi post cat...

THe problem is no one seems to know what it SHOULD BE...but for subaru impretsa turbo's i understand 16psi is not abnormal so i doubt that 5 psi is the issue...but like I say without figure who the hell knows!

this oil thought is pretty much my last throw of the dice ...I just cant defend pooring any more time or money into this...no one seems to be able to offer any SOUND diagnostics..people just hear half the story...the nmber of people who say 'turbo's gone' when it uses exactly the same oil on the old turbo and the NEW turbo is unbelievable....(as say piston rings when the compression test is fine....)

It really is a shame but I think it has just got to the point where I hate the damn thing....

I tought about trading it against another brick, but honestly I just cant face this level of grief again..so its either take it to the dealer..and spend yet MORE money...of just trade it a gainst soemthing like a toyota or honda which at least wont burn oil...and demand my every spare hour is spent on them

Did you see the 'Cat bypass pipe' thread in the 700 forum? I thought of your situation when I read that... Here's a link to the thread, and here's one post that has a good method of removing the cat without messing with your rusty flange bolts:

+++++

You may be able to cut the converter right after the flange joint using a hacksaw or Sawsall. Then find a pipe that slipfits on the remaining stub (or cut the downpipe and lose the flange flex joint). If worse comes to worse, you may have to have a shop expand a pipe slightly to make a perfect fit. Seal it with exhaust paste and a clamp. Same deal at the other end. Alternatively, band clamps are more expensive but can allow you to work with off the shelf pipe diameters. There are also a variety of adapter pipe sections available. Doing exhaust work right takes time and patience. You could also buy a new 2.5 inch converter for about $70 and have pretty good flow. It would be aftermarket (Summit and JC Whitney sell Walker and Catco for under $100 in 2.5) and you would have to do some adapting to fit.

+++++

You might also take one more stab at getting backpressure info from someone here with the Volvo green manuals. I would post in the 700 forum, and title the post something like "Green Manual info needed." There are a few BB'ers out there with complete sets, and I'd be shocked if the turbo/exhaust sections in those books didn't have something about backpressure.

Probably not a bad idea to try dino 10W40 for a bit... even if that keeps disappearing, it's less $$$ down the tubes, so to speak!

Best of luck to you,
Brian

Thanks for the thoughts brian..

I did actually catch the cat by pass thread...my worry is ending up with a car that i HAVE to spend money replacing the cat on because of a botched bypass...at least now I can trade the car against something else without spending much money on it....

I just dont know what to do...if i could just find a dignostic measure that pointed at something in particular i would be inclined to go after it...but I am NOT going to spend money on a 'it might be this' type thought...

basically I am commign down to try the oil change combined with an overnight soak for the cylinders in redex (might help unstick a ring or 2) and do a oil cleaner product - these are all low cost items...

if that doesnt show a marked improvement, sell the damn thing and go buy something else..right now it wont be a volvo!

thanks for the thoughts..

With consumption that high the grade or make of oil used will have no appreciable effect. You have a mechanical problem in the engine (or turbo) and minor changes in oil type is not the answer. Since you have been careful with maintenance you have to assume that somewhere in the car's past it was abused, or repaired improperly, etc. All Volvos are created equal - but after they leave the factory, who knows? As you can tell from this board most of us are getting good service from Volvos even after much greater mileages than yours. Sorry to hear of the bad luck.
--
Bob (81-244GL B21F, 83-244DL B23F, 94-940Sedan B230FD)

I bought my 91 940 SE Turbo about one year ago. At the first oil change I switched to Mobil 1 15-50 because of the Turbo and the heat we have in Texas. I have 105K on the car now and oil consumption is 1 quart per 5000 miles as that is the interval I am changing the oil and filter.

I was using Mobil 1 10w30, using a quart on 1000 miles and the engine was a bit noisy on starts, switched to 0w40 and I'm using .5 quart on the 1000 miles and the engine quite down some, next I'm trying 10w40 or xxw50 which ever I can find.
--
1996 964 139,200 Miles

No, wrong tree. Mobil 1 and the B21/B230 are almost exactly the same age. ca 1975. The oil is fine for the engine and many red engines consume almost none of it between changes. Good luck finding a better 135,000 mile car to rely on.

Through a winter run of this oil, temps 0F at times and a lot of cold starts, it used 10 ounces in a 940 Turbo, which is the first time this car used any oil. The sudden usage I attribute to the numerous cold starts with a "0" weight oil. Previous oil fill was M1 10-30, dino 10-30's earlier. On the plus side with this 0-40 weight the engine ran the smoothest and quietest (including noiseless COLD startups) that it ever ran on any oil in its life of 107K. Oil analysis revealed wear metals were basically cut in half compared to the M1 10-30 previously used at the same mileage interval. In 3,600 miles it sheared down to a very high 30 weight, which is a characteristic of this particular oil. This is not a problem with me. Continued usage and with additional miles the oil will slowly thicken back up to about it's original viscosity - a mid to low 40 weight. Will I use it in the future? Probably, since the car performs so well with it, but I have to try a run of Redline 5-40 first, just to see how it works out.

The 0-40 is still in, over 4K now, with a first time load of "Auto-Rx" added to slowly and safely clean out the internals for several hundred miles before the change to Redline. The level of solids in 3600 miles indicated that the oil was cleaning up the internals and using up it's additive properties. I suspect the ring pack is being cleaned. In your case absent tailpipe smoke, leakage, or cheap oil burn-off, the ring pack may possibly be the cause of your excessive usage. Auto Rx is safely used in many low and high mileage engines with this trait, including certain Toyota engines, Saturns, and Cadillacs to name a few.

In your particular situation your engine would most likely benefit greatly from Auto Rx. It isn't snake oil, it's cheap for what it accomplishes. Visit the site Auto-Rx.com.
--
92-944, 94-944, 97-960 - Silverstar headlights, Green Diamond Tires

unfortunately this product isnt apparently available outside the US otherwise i would have given it a punt...

I am a little puzzled though, if it is a ring problem (assuming not compression rings due to decent compression test results so lets say scraper rings)..why do i see NO smoke...certainly absolutely no smoke at idle, maybe - and thats a maybe - a tad under full boost if you follow behind in a car...

surely that much oil beign burnt SHOULD smoke (must be being burnt if its passing the rings in to the cylinders - or am i guilty of wrong thinking?)?

I assume you've checked the FAQ-especially crankcase vent stuff-can you say "oil trap"?If it's not a case of excessive crankcase pressure,check for leaks-I had a strange leak on my 940T that only ocurred at speed-bad seal on the turbo oil return line (my fault after I replaced the exhaust manifold gasket and messed up the reinstall of that stuff).Actually,I'm not sure if you have a four or six cylinder car-if a six,try thicker oil (10W-40 or thicker)if this helps,OK-if not,you may have stuck oil control ring(s)-try some kind of snake oil to break 'em loose. Don't give up-it's probably a good car! sredwine 94 944T 135K,98 V90 63K

Thanks for the thoughts...unfortunatley not that helpfull as:-

1. new turbo

2. new turbo drain line

3. after 3 attempts the mechanics managed to actually get the drain line to hold oil and it now definately doesnt leak

4. I have overhauled the PCV system so many times im bored - and so is it including replacing all the 'replacement' componants on the basis maybe i had got a duff new componant - plus i get -1psi at 2500 rpm measured at the dip stick..interestingly its almost as thought the PCV was workign too well!

5. if its burning the oil (and a sizable amount of oil) why doesnt it smoke?

6. looked at snake oil...but which one...none of them here claim to be able to free stuck rings .....

7. I am going to try 10w40 out of desperation and fro ma post on turbobricks where a guy was reporting oil usage in the litre per 300 miles range until he STOPPED using sythetic and moved up a weight at which point the oil usage disapeared!

8. If that doesnt work I am going to go and buy a puegeot as my previous experience of that engine is it just doesnt go wrong and uses no oil at 300,000 miles let alone 130k...i think my brother might join me my experiences are making him decidely nervous about his 740....