I recently bought an 87 300D (134K miles) in FL and drove it back to Cleveland, OH. It sounded very quiet at idle and ran good, until the little pre-filter clogged with algae. Drained tank, cleaned the tank screen, replaced both fuel filters added some Bio-Kleen to tank. Changed coolant with Zerex G-05, new lower rad hose and new t-stat. Changed oil, Rotella 15W40 and new oil filter. I filled the main filter with fuel to help with the starting process. It still took a lot of cranking to finally run. After it started I checked for leaks, none. Noticed a spray pattern of black soot on my driveway from the tailpipe. Drove car around neighborhood to get the t-stat to open. Temp right at 80c. Opened hood to look around one more time, engine sounds like there is a handfull of ball bearings loose in it, especially near #1 cylinder. I have read numerous post about nailing and will crack lines on each injector to see if noise stops.
I drove this car 1,200 miles in two days and it never made this sound.
What happened???

Quite likely just a little air in the fuel system. Everythign tight? Start okay?

__________________

Gone to the dark side

- Jeff

I did not see any fuel leaks, I will check again when I get home. It took a lot of cranking initally. After I drove it around the neighborhood. I shut the engine off and started it several times. It started immediately everytime.

If I do not have an air leak. Do you think driving the car will make the noise go away?

I would expect it to, yes, if it's fuel related. Plenty of oil pressure, right?

__________________

Gone to the dark side

- Jeff

Oil pressure gauge is pegged at 3. I am curious to know why so much soot came out the tailpipe when I was trying to get fuel flowing?

Some cylinders were running, others not, bubbles compressible and causing timing to be off, until all cylinders were running properly you were not burning the fuel well.

__________________

Gone to the dark side

- Jeff

Thanks for your help.

If it does not come down at idle the sending unit has failed. Very common issue.

__________________
1986 300 SDL - rolling parts car and test bed.
1987 300 SDL - semi daily driver.
1977 U1000 Unimog
2007 Ram 2500 6.7l

If the instrument cluster has been reinstalled and someone forgot to reconnect the oil pressure connection, the pressure will stay pegged at 3.

__________________
1993 W124 300D 2.5L Turbo, OM602.962
2000 Chevrolet Cavalier, 2.4L DOHC
2002 Ford Explorer, 4.0L SOHC
2005 Toyota Prius, 1.5L

http://www.fuelly.com/sig-us/40601.png

Sorry, should have said that oil pressure gauge reads O when not running, rises to 3 as soon as engine starts. When I was cranking the engine to start it after changing the fuel filters the oil pressure was rising just from the starter turning the engine. This is a new development, it was not making this sound until I removed the tank strainer fuel line and installed new filters. Maybe running unburned fuel thru the injectors has one or more of them fouled. I will crack the lines when I get home and see if I can determine if an injector is the problem. Replacing the injectors and the glow plugs was on my maintenance to do list, maybe sooner than planned.

Search for threads about the problem vacuum pump on this engine. It can lose its bearings, which fall into the timing chain and destroy the engine. Driving it will not make that noise go away!

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

I started the car this afternoon and it was not making the same hammering sound, but is still making a lot of noise. I cracked all the injector lines, no real difference. Put the big wooden screwdriver on the valve cover, injectors and vacuum pump, nothing. I think the vacuum pump has been replaced. It has screws on the front cover vs. rivets and I can still read the sticker on the front of it. I also put the screwdriver against the water pump, nothing.
Wedged the screw driver against the shock absorber and spring connected to the idler pulley. Sound disappeared. Put the screwdriver on both bolts attaching the shock and spring to the head, hammers like hell thru the screwdriver. I find it hard to believe that the idler pulley bearing could make that much noise.

Also, today no glow plug light on dash, waited about 20 seconds with key "on" and then "start", engine started immediately. Glow plugs must be heating.

I can't help but wonder what the next test will be.

Oops, the tensioner shock is a common problem and noisy. Are there plastic bushings in each end of the shock still?

__________________

Gone to the dark side

- Jeff

Yes, but the one on the bottom has a fair amount of play in it.