Who has the most miles on factory engine?

Post by **cn90** » 27 Nov 2012, 08:15

I am just curious, for people with 850, S/V70 +/- turbo, (B5254+ engines), if you maintain the engine well (replace thermostat, timing belt at appropriate intervals etc.) and don't ever let the engine overheats, what is the record mileage here?

My guess is 250K miles or 300K miles?

PS: I have seen posts where people have burned valves, what is the cause of that?
Also valve stem seals, when do they go bad?

Arnettii · Post by **Arnettii** » 27 Nov 2012, 08:29

I have 212k miles on mine and shes going strong still

Cheers

Post by **jblackburn** » 27 Nov 2012, 08:45

PS: I have seen posts where people have burned valves, what is the cause of that?
Also valve stem seals, when do they go bad?

The two are tied together. Leaky valve stem seals leave oil on the valve, which creates "hot spots" which in turn burns part of the valve away.

I think most of these engines have leaky stem seals to some extent by this age by the time you pass 150K. Mine does (220K), but you only get a quick blue puff of smoke on startup. Once it gets really, really bad, you'll need to do something about them - like the video below.

Post by **xHeart** » 27 Nov 2012, 09:12

1997 850 N/A - 123K-mi with exceptional acceleration after complete PCV and Cooling and Heating system replacement during the past summer.

Post by **rspi** » 27 Nov 2012, 09:20

Several years ago I was talking with a guy that had about 525,000 on his 850 but that was at least 7 years ago. He only had to replace a water pump other than normal stuff. I believe these are 500,000 mile motors without any major repairs.

The other enemy of these motors are the valve stem seals. They get hard with age, not so much from any neglect. My car is starting to smoke randomly and like the linked video above, if I let me car idle a while and rev the motor, I can get it to smoke. I believe the PO used regular oil, I use full synthetic (over the past 30,000 / 20 months). After pulling my hair out and doing a lot of research, as Matt said, I also believe that burnt valves are primarily caused by leaking valve stem seals. I initially thought it was because of carbon build up from low octane fuel but I have sence been converted.

I think you can go 500,000 easy with synthetic oil (or dyno for that matter). My compression is very high for 220,000 miles and the motor is strong as ever. Since I started smoking about 2 months ago (a little less with the vacuum fixed), I'm going to change the valve stem seals and replace my cams with NA cams within the next few months.

Post by **850 LPT** » 27 Nov 2012, 09:37

My 850 now has close to 233 k on it and is just starting to smoke a little on start up. I think it's good for many more miles.

My V70XC on the other hand smokes way more with less than half the miles, especially when it was parked for a little while

I guess that one might need some attention rather soon.

Post by **jblackburn** » 27 Nov 2012, 11:31

850 LPT wrote:My 850 now has close to 233 k on it and is just starting to smoke a little on start up. I think it's good for many more miles.

My V70XC on the other hand smokes way more with less than half the miles, especially when it was parked for a little while I guess that one might need some attention rather soon.

Clogged PCV system can also cause it to smoke if that hasn't been done

Post by **850 LPT** » 27 Nov 2012, 12:01

I know, but thanks for pointing that out.
The XC has just been done right before I bought it. It's a JRL car (by the way, I have not seen him here lately) and he did a real nice job taking care of everything.
I did the PCV on my 850 at 165 k and it should still be fine. Never hurts to check though.

Post by **rspi** » 27 Nov 2012, 15:23

Just to add a little to what I have already written. I have a little theory about the valve stem seals leaking... It's common knowledge that these cars do best with OEM oil filters. Running other filters sometimes cause ticky lifters. If other filters starve the lifters of necessary oil, they are also starving the valve stem seals of necessary oil. So, the use of poor quality oil filters may contribute to the failure of the valve stem seals. So, the guy before me may have replaced the oil every 3,000 miles but used sub-quality filters which may have caused the valve stem seals to fail. Just some food for thought.

nitehawk55 · Post by **nitehawk55** » 27 Nov 2012, 19:49

I think while the doner engine is out on my project T5 I'll do the valve seals . If has 280K km on it or about 170K miles . If 500K miles is possible it has a long way to go . If I recall there is a tutorial on doing the valve seals ?
?
I've been looking into clutch assys too as I want to do everything it will need while it's apart