My first time here. I recently acquired a 1990 560SEC with 55k from Florida. The SEC has been my dream car since 1982. I found the perfect one for me. Black with palomino.
It has been in storage since November. I have been starting the 560SEC every month or so and let it run for 15 minutes. Never had any problems. The last oil change was before winter and it has 1000 miles on it. I check the level and it always on the money. And no oil leaks or drips on the garage floor.
Yesterday, it was warm out so I decided to start it up and drive it around the block. To make sure everything is in good working order. This is a vehicle that I will only use in nice weather. I stored it for the winter. I started it and let it run. Shut it off and checked the oil dip stick. It was in the middle. Right on the money. I let the car warm up nice and good before I drove it. After about 20 minutes into my drive the engine started making knocking and tapping sounds. I shut if off immediately. I let it sit one hour and stated it up again. It knocked for a minute and then it was fine. So, I figured I would drive it straight home. I drove it slow and everything seamed fine. No warning lights. After about ten minutes the noises came back and I checked the oil pressure gauge and it was just under one bar. I pulled in to a gas station and shut if off. I checked the oil dip stick and it was showing the same amount of oil. I took the oil cap off and it looked empty. I put a quart in and started after 30 seconds the noises stop and it was normal but the oil gauge did not really move like I am use to seeing it move. I was a few blocks from my house at this point so I drove it home. Once I reached my garage the engine started making the noise again. The car never lost any horse power or seamed weak in any way. And the oil warning light never came on. I checked the warning light when I start the car and everything works. However, no lights to warn.
In retrospect, I remember turning on the heat and it has a faint smell of burnt motor oil.
Today, I opened the hood and checked everything for leaks or evidence of bugs or mice. Everything looks good and clean. I started the 560SEC once again. It made the same engine noise from yesterday for about 30 seconds and then the noise stopped. The engine seams fine. I only let it run for a minute or two. While the engine was running and not making noise, I opened the oil cap and watch the oil pouring out on top of the cam lobe as it should. It was a steady stream. I looked deeper under the valve cover and saw the second lobe was receiving the oil just like the first one. Then I checked the oil level and now it's to high. (I'm sure it's from the oil I added last night.) I plan on taking some out in the morning. The oil gauge went to 3 bars and did not move at all during the ideal. Something seems off. I know the sound of the car and something if just not right.
I started it again this morning and it made a tapping noise for about 20 seconds and then every thing was quiet. I let it run ideal for 20 minutes standing by listing to the engine. It was fine but after 15 minutes the oil gauge dropped from full 3 all the way back to just under one. A few minutes passed then the knocking and tapping started up again. I let it cool off for a few hours and tried it one more time and it knocked and tapped for a few seconds then it was quiet.
I recently noticed that the valve covers are slightly leaking on to the headers. That must be the cause of the burnt oil smell. Looks like that will be added to the "honey do list."
If you would please take a moment and think about what I should do next. Or guide me to a website that may have some information it would be greatly appreciated. I am in no rush. I want to take the time to do it right.
When I bought it last October, I took it straight to the mechanic and had them inspect it and changed the oil and proceeded to drive it home. One thousand miles, without even a hiccup. I enjoyed the drive home. Just touch the gas and off we go! It was worth the 20 year wait.
An over-full crank case can turn into foam due to the crankshaft, depending on how far over you are, it may be very important to address immediately.
I don't know the viscosity of the oil, but if you check your owners manual it calls for pretty thick oil in warmer climates. You mentioned Florida, but I am not sure what kind of weather you consider "Winter". Here in Michigan winter means below zero conditions for days on end with snow and ice.
After the vehicle is warm the oil pressure will read just under 1 bar, however this is usually with the vehicle in gear, with your foot on the brake. It should also immediately hop up to 3 bars when accelerating and at cruising/highway speed.
The tap could be a chain tensioner wearing out, or even a lifter. Sometimes the followers wear out and sometimes a cam lobe can wear out. Since you said the valve covers are leaking a bit I would buy the gaskets and pull the covers off and inspect the timing chain, guides and tensioner. I would also consider having the plastic oil supply rail clips replaced (Depending what they look like).
You could snap some photos while it's apart and upload them. I'll tell you what I think. A worn follower/cam lobe is very easy to spot where as a noisy lifter might take a little more effort to pin down.
The amount of wear on the guides, along with their color will say a lot about what may or may-not need to be done. 55,000 miles is VERY LOW miles for the amount of years that have passed. Mercedes do not take well to sitting, they like to stretch their legs. Rubber parts get brittle, like the valve cover gaskets and lose their seal. After 21 years it could be time to replace some of them rubber seals and make sure them chain guides haven't gotten brittle.
I would be getting the oil level in line, examining the oil, checking the filter and pulling off the valve covers. Let us know how it goes.
__________________
What is to give light must endure burning -- Viktor Frankl
Very good advise. I should clear up that I live in Chicago, IL and the 560SEC was from Florida.
From the advise I gathered I am going to drain the oil and take the lower oil pan off for inspection of the oil pump, strainer, oil level indicator, and it's two O-rings. The chain and one tensioner. I will take some pictures to share. Once that section is complete, I will remove the valve covers and replace the seals and take a few pictures of that to.
I believe the knocking and tapping is from the lack of oil pressure. Like something is blocking the oil from lubricating the engine. I believe this because since I bought it she has never made any noise like this. And it is not continuance. Only when the oil pressure gauge reads lower that one bar for a few minutes. Before I parked her for the winter, she ran fine with out any problems. I started it a few times and let it run for 20 minutes or so. the one day it was really nice out I decided to take her around the block. During that small trip that's when I noticed the noise and the oil pressure gauge not working properly.
Thanks again for your advice. I sure do appreciate it. I will keep in touch. I am looking forward to this challenge. Yesterday, it was so nice out and now today it is snowing. LOL!!! I to am use to the two seasons winter and construction.
