I have a 98 4runner with 130K miles on the 3.4L motor with the auto tranny. I have smelt oil coming from the motor for a month or two now (yes - neglect I know). There was no oil on the ground at my parking spot so I thought nothing of it. Took it to my mechanic, told me to change the valve cover gaskets, did that but the problem persisted. Now he's telling me the main seal has a very small leak, and the oil is burning on my exhaust causing the smell. Gave me an estimate of $700 to change it.

My question is, since this is a major job to change this gasket, should I be proactive here and change other gaskets while I am at it? Are there other gaskets to watch beside the valve and head gaskets? Otherwise the motor has been running great and no other indications of problems.

I guess the answer also relates to how long I want to keep the vehicle for, because I also need new brakes (rotors are a bit worn down). I was thinking this might be a good time to sell and upgrade (mechanic was hinting at this also), but regardless would need to get this leak fixed before that happens. Any thoughts?