My 88' 240 wagon has 210xxx miles and in general is running well, aside from a rough idle which I will deal with eventually.

Of greater concern is a hollow knocking sound which seems to be coming from the block. I think Bentley suggests it may be piston slap.

A few people have listened and told me not to concern myself.

However, I tend to want to understand all of the little things going on.

Is there a way to check out this noise short of removing the oil pan?

If I were to get an oil gauge to monitor things would pressure or temp be a better indication if things are deteriorating?

The cylinders are within 5 to 10 pounds pressure difference (can't remember the values off hand). I change the oil regularly at 3000 to 3500 miles. Overall the car is running well, I just hate to think I may throw a rod sometime and want to prevent anything catastrophic if possible.

Thanks,

Mike