Date registered: Jan 2003
Vehicle: 1990 560SEC Euro
Location: Windermere, Florida
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Quoted: 0 Post(s)
TIME FOR A SECOND OPINION.
Maybe what the man at the shop "smelled" was money!
First, do you work on your own cars? If so, buy a copy of the shop manual:
Passenger Cars Starting 1968 108/109/111/113.
You can find clean copies on eBay for about $50. US. That will help you countless times.
Sort out the safety-related items first. Make certain the steering and brakes are safe. These cars have kingpins for the front suspension, rather than ball joints, and sometimes it's difficult to tell if the front suspension is worn to the extent it has become unsafe. Get an alignment at a shop which is skilled in these cars. They also can comment on the condition of the suspension--if it is badly worn, they may diagnose the problems for free. Like I said: 2nd opinion time.
Provided the car is safe and can be aligned--or can be made safe with modest expenditure--then put it in daily use. Change the oil, and watch its level. Watch the oil pressure...it should peg at 45 psi (3 bar) off idle and stay that way, and should fall no lower than about 10-15 psi (0.7-1.0 bar) at idle. If it is not using oil, and produces no blue smoke (except possibly a puff on starting), then the engine probably does NOT require a rebuild. If not, an honest shop can diagnose "top end" (head/valves/cam) wear versus "bottom end" crank/rods/pistons) wear.
EVEN IF the engine is using oil, at a rate of 1 quart per 500 miles, or less, and is not smoking objectionably, just keep it oiled, and enjoy it. Even so, change oil frequently, as the "blowby" of a worn engine contaminates the oil much faster.
If you only see black smoke from the tailpipe, then you may have fuel injection issues. I don't know BEANS about the fuel injection on the 6-cylinder cars...ask some others.
If the car is smoke-free, the suspension is safe, and doesn't use oil, then you've proven the man at the shop wrong on most counts.
I drove a 280SE 4.5s as my daily driver for many years, and just loved it. I rebuilt the front end during my ownership, and that was over $1,500. Otherwise, it cost me little. There was the occasional item (window regulator, engine fan clutch, disk caliper) but I did the work myself, and bought used parts or deeply-discounted parts. You'll get to know the parts sources. Are you in the US? Many sell parts all or in part on eBay.
Lastly--KEEP THE SUSPENSION LUBED. These cars were intended to have a lube job VERY frequently. About every 2 months wouldn't be too often. There are over a dozen fittings, as I recall.
Don't be too worried yet--for a few dollars of diagnostic work, you can see how things really stand. Best of luck to you!
1970 300 SEL 6.3
1979 450 SLC 5.0
1990 560SEC Euro Conversion