S70 Engine

[Thomas and Judith Lilli]

Hey,

We’ve discussed briefly my issue with my 99 S70. My conundrum is that I’ve spent lots of money on some repairs and now I found I have a scored cylinder. Brief review.
Nov/16 Tune up resulted in broken plug in #5 cylinder. Removed head, found spark plug debris in valves. Removed and replaced both valves, lapped, reassembled. Later noticed high oil consumption. Mar/19 Suspected turbo, replaced turbo and PCV system. Oil consumption remained. July, burnt #5 cyl exhaust valve.
Removed and refurbished head with new exhaust valve. Noticed scoring in cyl 5.
Reassembled and running car with oil consumption. 1 qt/1000 miles.

I’ve got new drive train, turbo, head, exhaust system and many other consumable parts have been replaced. Body is without rust.

I’m considering a replacement engine for the oil consumption. Would you all rebuild what I have or buy a remanufactured unit?

[Thomas and Judith Lilli]

Neither. Were it me, I'd try to find a lowish mileage used unit and replace with used.

I am certainly no engine rebuilder, but I haven't heard much about honing cylinders to remove scoring. Most of the time when these engines are opened up for valve replacement, people comment that the original cylinder machining marks are clearly visible still, even after a couple hundred thousand miles. Not sure whether you'd have to overbore to remove the scoring, or even whether oversize pistons are available.

I think Bob Elwood of Elwood Industries in FLA. (seller of replacement Volvo seat covers) may have rebuilt a white block.

You may want to reach out to him. Good luck and let us know what you end up doing.

On the other hand, if money were no object, I'd get a crate engine from Volvo if available, just know that when you clip that first you won't get your money back on the insurance claim.

[Thomas and Judith Lilli]

I’ve got a decent short block up here. High miles but from a good runner

For a 1999 turbo you will need a pn engine with exhaust VVT to work with your ECU

[volvolugnut]

Call me a red neck, but if it runs ok and looks ok, I can carry oil and put in oil every 1000 miles. At that consumption, it likely still does not embarrass you by smoking on acceleration.
volvolugnut

[Thomas and Judith Lilli]

This is waht I did when my 1998 S70 GLT with 190K had a burned valve #3 and trans losing reverse, I sold the car to a used car dealer for $300.
I bought a nice 2004 V70 with 100K for $4200.
On the long run, you are better off with a P2 car with 2.5T.
Don't sink money into P80, especially when the odo > 180K.

What is your odometer reading?

[Thomas and Judith Lilli]

On reflection, I'd part it out. That's likely your best economic return, though it may take some time.

The reason I would do so is threefold:. If you haven't already fixed the throttle body, you will need to do so eventually (XeModex rebuild runs close to $500), pretty soon there will be few buyers for P80 parts due to most of them coming off the road, and it will become increasingly difficult to source replacement parts if you are banking on running the car into the ground.

So, part out, or top up oil every 1k seem like your most sensible options.

[Thomas and Judith Lilli]

hey all, sorry, didn’t get notifications to your responses.

We’ve got 185000 on it. I’ve owned it since it’s had about 40,000 miles and have done nothing but run mobile one it it and routinely maintained it. Very little corrosion and other than oil consumption, runs strong. I’m wondering, with a scored #5 cyl, would oil consumption be due to increased crank case pressure from blow by at the rings during compression and combustion blowing some oil out the breather and then back into the intake manifold through the turbo?
I have been concerned about burning a valve again in a year or two but, maybe that wouldn’t be the case. Also, is there a plausible explanation for some sort of issue causing burning valves in this engine that I could keep ahead of such as fuel injectors, lousy gas etc? (I’m running premium fuel).

If I can get my moneys worth out of these repairs, (18 months, then I’ll be happy, if it makes it to 2024 that would be a blessing)

[Thomas and Judith Lilli]

My own, entirely unscientific suspicion with burned valves is that failing to replace front O2 sensor as a maintenance item at 100,000 miles is a contributor, as is low octane, generic gas use and overly extended oil change intervals.

P.S. #5 valve is not usually the one to go. Generally #2 or 3. I think most commonly #3.

Ok, reading back through I see that you've already burned one valve in that engine. Accordingly, I'd either keep running it as is and adding oil, or pull and replace with a used engine. Engine swap is going to be about 18 hrs labor charge from mechanic. Cylinder head is about 15. And, of course, if you DIY, the labor is "free."

[Thomas and Judith Lilli]

Do you run light (5000 miles per year) or heavy (20,000 per year)?


It isqalmlst is almost always cost effective to repair a light running car vs buying a new set of problems.

My gut feel is valve burning seem pretty rare and uncorrelated. Evans factors above definitely will put things in your favour at low cost of repairs.

There are lots of examples here if people who burn valves, pull the head, replace just the one valve , rework the head, d drive another 100k

[crlande]

"isqalmlst".......I would try to scrabble the living daylights out of that one on the college smarty!!