under
Menu #19 to see the details of the 'tick-tick' due to broken oil tube.
Not sure what the milage is on the '97 E420 but there's a few things that I would recommend that you try to see if you can fix it
yourself first.
1) Check the oil-tubes yourself or have somebody do it for you while you are there. If you have
low oil pressure at idle, then I strongly suggest that you check those tubes. It's a SURE sign of a bad tube or tubes!
2) If the tubes are ok, you may want to try this. Purchase a can (1 qt) of
engine flush just before you have your oil changed. This is best done at a "drive-thru" oil change shop. Idle that car at high idle 800-1000 rpm until the tick-tick stops; could take 20 minutes or so.
If it's a plugged lifter, this should remove the engine sludge and allow it to open to retain oil albeit temporarily. Drain the oil and refill with your normal oil.
3) If the tick returns, it's probably because there's some engine deposits that need to be removed. Check out "Auto-RX" website at the following link:
http://www.auto-rx.com/ I've used this product and endorse it 100%. It's a
unique formulation that WILL clean the engine deposits.
Follow the procedure. Briefly it's added to the oil with a fresh oil change and stays in up to 1000 miles depending on how much 'crud' is in the engine. All the details are on the site.
If it's a BAD (mechanically "bad") lifter, this procedure will probably NOT fix it. But in that engine, I've YET to see a bad one; just usually 'plugged' due to engine sludge.
This procedure will not only clean the engine but you will experience "new engine" performance again and no tick-tick. This will not cost you any significant amount of $$$, so you have nothing to loose.