Burned Valve Database DATA ONLY or a P0455 code will be set

[mecheng]

Great data everyone, and kudos to the moderators for applying the sticky. I don't want to be hasty and draw conclusions, but I'm starting to see a trend and can rule out items people once thought were the root cause

[101]

a) 1998
b) V70 GLT
c) 211K
d) 211K (I'm the original owner)
e) 87, but I do use 89 or 93 on longer highway trips
f) Shell or BP
g) (50% city/ 50% hwy)
h) Average Driving Behavior
i) Varies - But on average two occupants
j) Cincinnati area. 10K - 12K miles per year, evenly distributed year round. Ambient temperatures range from 0'F to 90'F
k) No evidence of leaky valve guides or oil smoke.
l) Prior to 80K - 10W30 dino oil, 2.5K change interval. Since 80K - Mobil 1 10W30 high mileage formula, 5K change interval.
m) Failure happened on the interstate, 250 miles into a 450 mile trip. I was going up a 6% grade with strong headwind at 75MPH in 4th gear. About 55'F outside. About half way up the hill, I noticed a miss in the engine and loss of power and the check engine light began flashing.
n) TBD # of valves, cylinder #3
o) Volvo coolant always, changed every 2-3 years. Most recent change was 1000 miles ago.
p) Removed cylinder head and rebuilt the engine. I found two exhaust valves badly burned (one each on #1 and #3) and a third one showing distress. The cylinder head had the full complete valve job / pressure check / valve stem seals / surface milling treatment.

Other possible contributing factors - I had an exhaust leak at the back of the cat converter due to a split pipe for the past 3000 miles and what sounded like an exhaust leak at the manifold. Both oxygen sensors have 150K miles on them, but no issues with check engine lights. The cat is original.

Other findings - To prevent future issues, I had the fuel injectors rebuilt. Two of them were missing the plastic disc at the bottom and the o-rings where they mount in the intake manifold were degraded (possible vacuum leak). The turbo CBV diaphram had a small hole in it and was replaced. One Evap check valve was flowing both ways and needed replacement. The turbo vacuum lines were replaced and a new o-ring put on the base of the vacuum tree. I'll be replacing both oxygen sensors and verifying the fuel pressure is within spec.

[E Showell]

So mech -- you're thinking low octane fuel?

[mecheng]

So mech -- you're thinking low octane fuel?

Yes, that was my original theory and I put that in the first post. Thus far, the data it is showing it to be possible and you can potentially rule out the common thought that it was leaky valves (posed by many members of MVS). I never bought this because the leaky valves are only during start up and there is a lot of time to burn that oil off.

It is also common that they are all on highway trips, not sure what to make of that as there is always air raming into the engine but the engine develops a full 'heat' during a long highway trip and some have posted it was during a grade climb.

Also intersting, as the non turbo cars use different exhaust valves (non sodium filled I believe) and they are not immune.

Perhaps, the car can not compensate enough for the low octane to reduce the pre-ignition and heat.

[cmblackburn]

a)1998
b) S70 T5 Auto
c) 241,039
d) 35,000
e)93
f) Kangaroo
g) Driving Cycle (25% city/ 75% hwy)
h) Average, mildly aggressive
i) Typical Load in Vehicle: Single occupant
j) Boone, North Carolina- Cold climate, snow/rain
k) Does the car have leaky valve guides- It did.
l) What kind of oil do you use- Mobil 1 High Mileage Synthetic 10W30
m) Ambient temperature was 35 degrees,freezing rain...throttle load was light- turning about 2k rpms @60mph on the highway during a 200 mile trip. Going up a mountain. Incredibly strong headwind, the rain was pouring down so I couldn't hear how it was running. CEL started flashing and eventually flashing very rapidly. Attributed it to a wet coil causing a misfire. Disconnected fuel injectors for 3 and 4 and continued the driving the 65 miles I had left on 3 cylinders, really keeping my foot down because it was straight up the mountains.
n)2 exhaust valves, cylinders 3 and 4
o)Prestone green extended life- 2 years and 15k old.
p) I replaced the cylinder head with one I pulled off of a 98 V70XC 2.4 with 101k after resurfacing the head and replacing the valve stem seals. Car is alive and well.
And here's a picture of the carnage.
https://www.facebook.com/photo.php?fbid ... =3&theater

[101]

I updated my other thread with disassembly findings. https://www.matthewsvolvosite.com/forums ... =1&t=74171

[woodsytf]

my engine isn't a full-on burned valve, it just leaking and worn the H@ll out.

a) 1995
b) 850 wagon
c) 278000
d) 175000 miles. i am the second owner and picked it up with 103k
e) 89 most of the time, my wife forgets and uses 87 sometimes, but usually 89
f) shell, kroger, etc. whatever...
g) Driving Cycle (% 50 city/ % 50 hwy)
h) Average Driving Behavior, but the climbs around here give regular revs above 3k RPM
i) usually a single occupant, & teenage kid taxi
j) SW Virginia, USA, some hills/mountains
k) yes, leaky valve seals, smokes at the traffic light or while idling, EGR valve is plugged solid
l) synthetic, usually mobil 1
m) Describe in detail how it happened: summer car trip, it just didn't like climbing a long hwy mountain with a full load and luggage on the roof. power became weak. pressure checks showed

DRY RESULTS
1) 170
2) 165
3) 175
4) 165
5) 125...
WET RESULTS
1) 255
2) 245
3) 255
4) 235
5) 185...

n) cylinder 5 is suspect.
o) prestone coolant, changed about a year ago
p) i am getting ready to either rebuild the head or swap out the block with a reman/rebuilt unit soon.

[MadeInJapan]

a. '98
b. S70 T5
c. 220K miles
d. Owned for 125K miles at the time of the burnt valve incident (bought the car with 95K miles on it)
e. Premium gas (92 or 93)
f. Various- Shell often but off-brand too
g. 80% city/20% highway
h. Average to Aggressive driver- only get aggressive occasionally like I did when the valve burned.
i. Typically single occupant
j. Tennessee (the south)- mild weather typically, but it was cold on the day of the incident.
k. Could have had leaky valve stems- rebuilt now so not sure- let's say there was a suspicion- all valve stem seals were replaced.
l. Always synthetic Mobil-1, 5w/30 in the winter and 10w/30 in the summer months- changed every 5K miles religiously.
m. Speeding up a hill and I gunned the engine to hit high psi on my turbo and the car immediately misfired and was not the same after that
n. Only one valve- cylinder #5
o. I've bought Prestone but topped off with cheaper Autozone brand- always the green stuff- Ethylene glycol. Last time it was replaced was a few years before the valve was burned.
p. I had the head taken off, all valves lapped and the bad valve replaced with the correct Volvo sodium valve. while it was off the PCV was done for the second time I've owned the car.
Let me add that the valve was an exhaust valve and that there was a hole in it as if a pencil went through it- the incident happened during the winter- Dec. 2014 if I recall and it was a cold night, but the car was warmed up properly and I was driving home from across town and had almost made it home- I hope that this information helps. Recently my son's '94 850 also burned a valve (intake valve on cylinder 5 spewing most of his oil out and rendering his older car totaled) and it happened at 245K miles on the interstate with no warning. He too has taken care of his car religiously but it had been wrecked and band-aided together several times so we did not feel like it was in anyone's best interest to fix it up and continue to drive it after the valve was burned leading to him losing most of his oil in the engine at high speed.

[rspi]

my engine isn't a full-on burned valve, it just leaking and worn the H@ll out.

a) 1995
b) 850 wagon
c) 278000
d) 175000 miles. i am the second owner and picked it up with 103k
e) 89 most of the time, my wife forgets and uses 87 sometimes, but usually 89
f) shell, kroger, etc. whatever...
g) Driving Cycle (% 50 city/ % 50 hwy)
h) Average Driving Behavior, but the climbs around here give regular revs above 3k RPM
i) usually a single occupant, & teenage kid taxi
j) SW Virginia, USA, some hills/mountains
k) yes, leaky valve seals, smokes at the traffic light or while idling, EGR valve is plugged solid
l) synthetic, usually mobil 1
m) Describe in detail how it happened: summer car trip, it just didn't like climbing a long hwy mountain with a full load and luggage on the roof. power became weak. pressure checks showed

DRY RESULTS
1) 170
2) 165
3) 175
4) 165
5) 125...
WET RESULTS
1) 255
2) 245
3) 255
4) 235
5) 185...

n) cylinder 5 is suspect.
o) prestone coolant, changed about a year ago
p) i am getting ready to either rebuild the head or swap out the block with a reman/rebuilt unit soon.

Is this vehicle turbo?

[erikv11]

... you can potentially rule out the common thought that it was leaky valves (posed by many members of MVS). I never bought this because the leaky valves are only during start up and there is a lot of time to burn that oil off.

It is also common that they are all on highway trips, not sure what to make of that as there is always air raming into the engine but the engine develops a full 'heat' during a long highway trip and some have posted it was during a grade climb.

Also intersting, as the non turbo cars use different exhaust valves (non sodium filled I believe) and they are not immune. ...

Unfortunately we are going to need a whole lot more data than 10 or whatever, to try to make any conclusions! But maybe we are on the way with this thread. And there could easily be more than one common cause, for example the local indy has seen at least a couple that were definitively due to a clogged injector, yet I don't know that I've seen any/many of those cases here at MVS.

Leaky valve stem seals leak pretty much all the time. Which means that any time the car sits some oil may pool up on the valves (to cause a puff), for example when idling at every stop light. Just because you only see a puff of the smoke at certain times, doesn't mean that is the only time there is oil leaking.

Actually, Sodium-filled valves (yes, in turbo cars) are supposed to help prevent this problem, the sodium diffuses heat better.