I have owned a 1991 SD previously and are familiar with heat problems etc.
I've had this car just a few weeks and are going thru the paces of getting the bugs out. As my wife and I were beginning on a 300 mi trip Sun AM, we had just commented that we liked car better than our two previous, lights came on the dash, first I saw was ABS light plus a couple of others, my first thought was an electrical problem, I traveled a few hundred yds and pulled over then noticed the heat gauge was in the red or near, I immediatelly turned the engine off. Upon raising the hood I could hear a boiling sound just to give an idea about how hot it got. I discovered that my accessory belt was off and the reason was the pulley on the alternater was loose. Upon my mechanic friend arriving, taking the alternater off, tightening the pulley, reinstalling and driving back home all seem to function normal, temp and everything. Considering this cars track record, are there are any particular symtoms to look for in the event that there could be more serious damage to the engine, like blown head gasket etc.
This really made me sick to the stomach as this was the one thing I didn't want to happen to this engine.
Thanks in advance,
Frank

Keep an eye out for loss of coolant over time...........or oil in the cooling system............the engine will let you know if it's got a problem if you're paying attention to the details.

An oil analysis is the definitive test if you want to blow the $20.00 on it.

Brian,would you suggest the radiator hose check after this ? Johnny

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85 300sd SOLD ,85 745i,95 740i,1972 Suburban,1938 International

You could do that as well........but........it may not be obvious for awhile. The head does not crack and offer symptoms instantly. The crack is very tiny to start and then slowly gets larger over time.

Just keep an eye on it.............it will tell you if it has a problem.........coolant will disappear.........or oil will appear.

Okay now I understand the wait and keep an eye on things,thanks for the explanantion,Johnny

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85 300sd SOLD ,85 745i,95 740i,1972 Suburban,1938 International

Not to worry, I'm in the same boat.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Thanks for all the info, my mechanic friend tested the cooling system with a pressure pump for obvious leaks, there were no apparent leaks.
Could you pass along the details of testing the oil, size of sample, container, and where to send.
Thanks again,
Frank

As described in previous post, I purchased this car weeks ago with 75,600 miles. I was expecting the temp to go high on me which it would approach
120 degrees in severe driving, I started my campaign to correct this by getting AC aux fans to work properly, replacing thermostat, radiator cap, flushing coolant and finally new radiator, water pump, fan clutch, new coolant (G-05). Upon test driving the last few days she hasn't gotten over 100 degrees, I did have an immediate problem with the level (light coming on)in my expansion tank, this was resolved when I followed someones recommendations drive car onto ramps and let sit overnight and while cold the next AM disconnect the small hose(at top of radiator) from the expansion tank and with funnel add coolant, after adding about 1/3 gal, even though it appeared to travel into the expansion tank through the hose at the bottom, it appears to have corrected the problem of coolant level fluctuating in my expansion tank.
It appears that I have overcome my first obatacle in owning an SDL, my next I am working on is a skip and smoke when cranking cold in the AM, I've run a couple of bottles of Red Line through it which appeared to help initially but lately the problem seems to have gotten worse, it runs perfect after a couple of minutes. I'm taking to a dealer today to check if the glow plugs are working properly(the car has new plugs), also check the injectors.
Hopefully there's an end in sight, we love the SDL as we owned an SD and had problems with cooling, unfortunately the color was black and my wife hated it so we traded for a 98 LS-400, one of the best cars I've ever owned but there's something about the Mecedes SDL that I couldn't get out of my blood, we had sold the LS-400 and ran accross our current car, I just hope we can get many years of enjoyment from this great driving vehicle.
Frank

Frank, since the dealer is going to have those injectors out and it is a 350 engine. Why not have the compression checked if cheap to do. Should be done with those injectors out anyways.

It's possible, if you are unfamiliar with the 603, that you're starting procedure is not ideal.

Normally, folks will start the engine when the glow plug light goes out. However, if you try this with a 603, you get the most horrible stumbling and banging that you can possibly imagine........and it lasts for nearly 1 minute.

So, try this:

Turn the key to the glow position and wait 25 seconds. Then start it. Report back with your results.

The time of 25 seconds is variable........sometimes 10 seconds will do the trick when it's 80 degrees........sometimes you need the full 40 seconds when it's down near 0°F.

mr. carlton, thank you. my 603 does the 'stumble' after i engage the starter immediately after the glow plug light goes off. i for one will try your suggestion. have a great day/weekend.

Yep, happens to all of us........let us know how you make out with a procedure change.

I have to remember which M/B I'm driving. The 617 starts instantly without stumbling after the glow plug light goes out. The 603's don't. Apparently, it's a characteristic of the aluminum soaking up the heat of combustion much faster than the cast iron.

Since I've got an appointment today already with the shop(these folks have been reasonable with charges) I won't have an opportunity to try a cold start as recommended by Brian. I will get them to check compression. I have also sent off an oil sample but don't have results yet.
Thanks,
Frank

Brian,
I am sorry that I won't be able to test your suggestion since I already have an appointment at 1:00 PM, I will feel better having the compression checked anyway. I will be sure to report back on findings and also my oil sample.
Thanks to all,
Frank

Since I do not own one of these engines I was happy to read Brians post about their cold blooded startup and initial running problem. It sounds all too reasonable as the probable cause. An awful lot better than a potential rod being bent for sure.