Hi Scotty,
I have a Toyota Rav 4, from year 2006 with about 145K miles. My Dad is the original owner. I don't believe he has ever has had the spark plugs changed, the car has been fairly well maintained. It runs fine, but I'm concerned that I'm past the spark plug change interval - and if one fails, they'll be "welded" to the block and impossible to get out.
I believe this is a 3.5 hour of labor job. Is it worth the money to change, have you ever seen these get welded to the block or should I rather wait till the performance gets degraded or a spark plug actually fails causing a misfire?
Thanks!
Even with modern spark plugs 18 years and 145,000 miles is pushing things a bit. You could pull a plug from the side of the engine where they're easy to get to and check its condition. However if the vehicle is still in good shape and you plan to keep it going as long as possible I'd probably bite the bullet and change the plugs and you'll be good for another 145,000 miles. On the other hand if it's a rusty beater on its last legs I wouldn't bother if it's still running OK.
Unfortunately there's always the chance especially with an aluminum head that removing spark plugs after so long may pull out the threads in the head.
