Just got the news about my '98 V70 AWD (217K miles). Burned valve on #3 cylinder. I am wondering two things: Can this have happened by running the car a quart low on oil at interstate speeds (Daughter was driving when the check engine light started blinking, but oil light did not come on)? Also, is a valve job a DIY for a mediocre mechanic? I love the car--best car I have ever had. Bought it in 2004 with 54K miles. About $1800 work in the last year (new heater core in February, wheel bearings in May, climate system blower motor last weekend). Hate to part with it. Looking for wisdom, as I am not objective about this car I love. About $2500 for my shop to do it; they say I should look for a new car. Thanks, as always!

Repairing a valve requires head removal and machine shop to repair valves. Think again about cost. Your mechanic is very expensive! Head removal/install should be around $1,000. Machine shop in the hundreds, depending on what they find and if the valve guides need to be replaced(probably).

The blinking CEL happens when multiple misfires occurs. So I would assume that more than one valve is involved. Another option is a remand head with all new components, also about $1,000 plus R&R.

You might want to investigate a 'new' car for your daughter. A Toyota or Mazda, both easy to work on and reasonably reliable.
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Keeping it running is better than buying new

I'm in agreement with Klaus. A 21 year old Volvo is not worth dropping that kind of money on.