I picked up a used 1999 turbo and it goes like a rocket. It doesn’t use oil, starts when it’s 10 below zero, runs perfect , but starts really hard after it has set for a little while when it’s hot. If I start it within a minute it’s OK but if I wait 20 minutes or so the problem shows up.
I had and old Oldsmobile diesel that acted this way when the compression rings wore out but it also had a problem starting cold. I sure don’t see how this could be the problem with a Benz that only has 100,000 miles on it.

This one has me stumped. I sure hope someone has seen this before and knows what is causing the problem.

Fuel Leak, allowing air into the system??

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'95 E300 Diesel, 264,000 Miles. [Sold it]

If it is a fuel leak a cold start should become difficult as well. Last November the o-ring on the fuel shut-off (which is mounted to the head) developed a smaller than hair line crack, but it was enough for it to become difficult to start. Drop the belly pan and see if fuel has dripped onto it.

Ya know...when I got the car it seemed like I could smell fuel now and then. I will check the pan. Any ideas as to why it would start properly after it cools down?
This car seems very powerful. I think people would change their minds about diesels if they had an opportunity to drive one of these cars.

Realize that the fuel passes through the engine head. Heated fuel is expanded fuel. When you shut if off the fuel colds and contracts. Where there is a leak it will draw in air thus making it hard to start.

Also, look for air bubbles in the clear plastic fuel hoses. If you see any bubbles, than you do have a fuel leak.

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]

Here is the full thread from when I had the same problem.
http://www.peachparts.com/shopforum/showthread.php?t=135970
Check the fuel shut off first. See if it is wet underneath it.

Such a hard/no-start condition could be that you have a glow-plug relay fuse that has broken at the molecular level [ em-brittle-ment ] and the warming up causes the fule to loose continuity over a certain range of temperature. If my guess is wrong, the only thing you are out is the ~$2.00 cost for what is a good idea anyway... a spare glow-plug relay fuse !
Mine had similar symptoms like yours and when I tested the fuse it looked OK for continuity... and then it snapped when I lightly touched it with my finger!
Let us know what you eventually find !
Sam

Tasma,

I hope your problem isn't (or wasn't if it's corrected by now) the same as mine. Last winter I had a problem where in extremely cold weather, when I left the car parked over night on a driveway with about a 25 to 30 degree slope with the back end lower than the front, the car, also a 1999 E300 Turbo Diesel, wouldn't start in the morning. At first it just wouldn't start no matter what I tried and I had to have it towed to the MB Dealer. They replaced the plastic fuel lines, filters, etc. and all was fine for a while. Apparently during the night, a leak in the lines allowed the fuel to drain back into the tank, virtually starving the engine.

Then in January 2006, another cold spell and the problem appeared again, but not as bad. At least I could eventually get it started. But this time if at some point I let the car parked on the incline, nose down, I found small spots of diesel fuel in the driveway.

I took it back to the MB dealer thinking something was wrong with their guaranteed plastic fuel line repairs. But this time they replaced the metal fuel lines, and everything has been fine since. No more leaks, but the cost of these repairs was out of site. For me it was worth it because I wouldn't want to attempt work like that, even though it may seem simple to some. But I didn't have the time or the inclination either. Plus there's something to be said about having work done professionally by qualified MB mechanics, if you can afford it.

Jack525

Thanks everyone for info. Now the problem only shows up if the engine is really hot The weather has not been hot enough lately for it to be a problem. It is most pronounced if the air conditioner has been running and the engine temperature is slightly above normal.
I have switched to running home brew biodiesel and it seems to help a bit.

I will be sure to report what I find.

Another thought I have is a weak battery. When the engine is hot the compression is higher/the engine is harder to turn over fast enough. If the other stuff doesn't fix the problem check the battery.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

Had the exact same problem with my 99 and did the exact same thing...no problems thus far..