I am looking for any information about oil sludge problems or turbo failure resulting from following the 7500 mile oil change schedule the owner's manual recommends for the V70 with the turbo engine. I am also interested in similar problems for other recent model volvos with turbos. I know toyota had similar problems with some of its high performance engines on an extended oil change schedule and don't know if this is a unique problem or others are having similar issues with the 7500 mile schedule. HELP!

6-10 k oil changes are common recomendation in the UK..some cars are even going to 20k!

I have run cars to 300k with 6 k services with no issues....

My 940 turbo (which I suspect has been VERY negelected in the past) has had to have a new turbo and is very sludged....but thats at 140k..and as I say I thnk it has been neglected...I am currently 'dealing with it'..which is fun (not!)

My 2c..would say 7 k should be fine, but for peace of mine drop it a 5k...

However!!!! if you use the car for short journeys a lot I would drop it far sooner...my mechanic years ago (who i trusted implicitly as he used to get my cars to 200k plus WHATEVER make...said to me 'with the motorway miles you do you know we could just change the oil whenever ...it really wouldnt matter...'

but then again he did change it every month (say about every 5-6k miles)

I now have 133,000 miles on my '98 T5, I've changed oil every 5000 miles as per the recommended schedule, I use Mobil-1 10W30 synthetic and the car still uses *absolutely* no oil between changes. It even looks pretty clean when it's drained out. I've heard the Toyota stories but I've heard no similar Volvo stories.

-Sam

"...I use Mobil-1 10W30 synthetic and the car still uses *absolutely* no oil between changes."

Not trying to be arumentative, but it ain't possible. Even a brand new engine will consume some oil.

Is it necessary or wise to do so? I'm concerned because we go from hot weather, 10W/30 oil during summer to 5W/30 during winter. Will leaving the 10/30 summer oil in the cooler while changing the rest of the oil to 5W/30 for the winter lead to any damage? (I've heard that mixing oil grades should not be done, though I've never heard of consequences as a result of doing so.)

Thanks

use synthetic oil on your turbo volvo. it costs more but provides superior protection. mobil 1 synthetic. have 62k on my t-5, some of that was with chip, perfect motor performance, and i beat the shit out of my car. 10w-30 for southern climate, may want to try the new 0w-40 if its cold where u live. dont do 15-50, have heared its too thick.

The sludging problem occured in regular Toyota engines...the kind you see in Camry's. It is my understanding that Toyota more or less caved in to a lot of pressure and never really admitted anything was wrong with the engines. The settlement applied to those with failed engines who could prove they changed their oil at least annually. A low threshold for sure.

My own opinion is that Toyota purposely designed an engine that ran somewhat hot, for emissions purposes. It wouldn't fail if owners adhered to the prescribed oil schedule. My guess is they didn't leave enough margin to account account for the sloppy maintenance habits of many car owners.

I've never had a sludging problem...heck my cars after 200k miles show no sludge in the camshaft cover. But I change the oil at 3,000 to 3,500 miles.

Volvo, like Toyota and all other car makers play a numbers game with maintenance. They know consumers watch the annual maintenance cost number computed by one of those consumer mags, so they keep required maintenance at a minumum to hold that number down.

Toyota's engine was not thier high-performance engine. It
was their jack of all trades engine. They modified it to
improve oil circulation to fix the problem.

I found a site that lists these as primary causes of sludge
(I was surprised at the number of possible causes):

Faulty head gasket, allowing coolant to leak into oil system

Unburned gasoline contaminating oil

Inadequate oil circulation

Infrequent changes of oil and filter

Poor quality or nondetergent oil

Oxides of nitrogen from emissions system contaminate oil

Engine runs too cool in spots, causing condensation buildup inside crankcase

Engine runs too hot in spots, causing oil to break down faster

Seal on oil filler cap fails, allowing moisture to enter engine through valve cover

Too many short trips or frequent driving under adverse conditions

I can't answer your question, but I change the oil in my turbo and non-turbo every 3K. This is my choice, but interestingly enough when I bought my new 97 the dealer recomended the 3K interval instead of the 5K which was stated in the manual. I would never feel comforatble running to 7.5K on dino juice with a turbo. I don't think any of the lifers here would either.

My buddy bought what he thought was a nice 97 Trooper with 50K on it. One year later one of the OHC's froze on the v-6 and detroyed the engine. Cause was a bad design for oil flow and poor maintanence! Bottom line with any engine is sound consistency on your changes and good quality oil. I also run a quart of Risolone in my engine every other oild change. I have always used Dino oil and have never had problems! Its the abusers that make a bad name for the Dino oil. Also some bad designs recently like the Isuzu impact as well. My brothers 94 Turbo 850 wagon went 190K before needing the turbo, always run on Dino oil but changed religiously at 4K!