I drove a beautiful '87 300 SDL today and...

[oilslick]

I am in love! The car is very nice! It has 201, 800 on the odometer. After sitting all weekend in 30 to 40 degree weather she fired immediately and ran smoothly. Everything works except the electric headrest on the driver's side.

I do have one concern though. While I did not see any coolant/oil mix in the coolant resevoir or on the oil dipstick the low coolant "idiot" light stayed on for the entire test drive. The coolant level was fine when checked cold and after the test drive. BTW, after testing the car for an hour I removed the oil cap and there was NO, and I mean NO, signs blow-by. I was VERY impressed with this car but I am concerned about the low coolant warning light.

If the light is just "flaking" out would this car be worth the $3995.00 that is being asked for it?

Kevin

[nhodges]

Yes...and more.

[franklyspeaking]

Everything works except the electric headrest on the driver's side.

Sounds like you found something else that doesn't work!

Good luck!

[oilslick]

I see said the blind man!

[sixto]

The headrest problem is typically a dirty switch contact or broken riser clip. Neither is an expensive repair.

The coolant warning light staying on when there's adequate coolant in the reservoir typically means a corroded harness connection to the sensor. Pull off the connector, clean the contacts, and it should be fine. If that doesn't do it, replace the sensor.

How do you test for blowby by removing the oil cap after a test drive?

Sixto
95 S420
87 300SDL

[CSchmidt]

Oilslick,

Sounds like you may have found a gem. I bought an 87 SDL 2 years ago with 210K on it and a few observations that "may" apply. My headrest adjustment didn't work and my seat spring was bad. When the spring went it sliced the wiring for the headrest. Not sure yours will be the same.... I had some gauges acting up. At the suggestions of some wise members of this group I removed, cleaned, and reseated all the relays in the fusebox. This fixed a number of unusual symptoms. Again, please check your situation. ( a later side thought here... is it the washer fluid level light you are seeing? Mine sinks in alcohol based washer fluid. I now use the water based MB stuff and the sensor floats).

The SDL is a way cool car. Mine was $3500 and I have about another $2K in repairs over the last 50K miles. Still cheap compared to a new car payment and a lot more style. You have to decide if you want to continue to invest time and / or $ to keep it going. Overall it has been a great experience for me. Especially the help and expertise from the forum members here.

Chuck

[oilslick]

I didn't do any scientific tests to check blow-by.

On my 300D you can remove the oil filler cap and watch the whisps of smoke rise with the engine running. On the 300SDL there were no whisps of smoke, no chuggs of smoke, and I felt no air blowing out of the oil fill hole.

The seat springs are in great shape. Very comfortable! Firm but not too firm. Very supportive.

I do not have the cash to purchase this car but my local credit union will finance 100% of the retail value of this car for up tp 72 months! Not that I would do that but that to me says these old MB's are not your "run of the mill" automobiles!

Kevin

[DieselAddict]

I'm confused. Hot oil seems to always produce some visible vapor whether the engine is on or off. I think a better way to evaluate the overall condition of an engine is to monitor oil consumption, but of course you can't do that with just a test drive. Sounds like you found a really beautiful car. Also check underneath the car for signs of seepage. If it's dirty but dry I'd be even more impressed.

[Hatterasguy]

Sounds like a nice car I hope you get it.
Sixto its a field test. If you pull the oil cap and see smoke coming out you have blow-by. For example my Toyota has some blow-dy when I crack the cap. But the Mercedes with 100k more miles has no trace of it. (In disbelief I checked a few times) Conclusion MB makes a better engine than Toyota.

[Tymbrymi]

Originally posted by DieselAddict
I'm confused. Hot oil seems to always produce some visible vapor whether the engine is on or off.

Agreed, but an engine (like my 617) that has lots of blowby will puff/blow/chug all the oil vapors out vs. the slow occasional wisp that you would get from just the hot oil. It *is* a very crude test, but it does give you a little bit of info.

John
'79 300SD

[rickg]

My SD engine only has about 40K on it, and it still chugs out "stuff" if I take off the oil cap. (And it also did so with only 7k miles on it). I'm not sure that this is a bad sign.
But that's getting off track here. Keep us posted if you buy it, and post pix

[oilslick]

I went back to test drive the car and put some money down for the man to hold the car until Friday. Here's something for discussion.

The low coolant light is still coming on and staying on in spite of the fact that the coolant level is not low and I did clean the contacts on the sensor and it's plug. The coolant level (tank) goes down while the engine is running. The engine temp only gets to 60 degress c after 4 or 5 miles of driving. Once the engine is shut down the coolant level comes back up.

I removed the tank cap today before I started the car (the car had not been started since I drove it yesterday) and there was no pressure on the system which I thought was a good sign but this light is scarring me away from purchasing the car. I know nothing about these 6 cylinder diesels and have heard too many tales of heads cracking on them and even some with rod problems. Am I passing up a super good car over something that might turn out to be a $25 sensor or should I just keep walking?

Kevin

[djugurba]

do you have an indy mechanic?
well worth a hundred bucks for a pre-purchase inspection. they'll know for sure...

I bought my '87 sdl with no inspection. so far... I've replaced the injector return hoses, washer nozzles and hoses, new brakes all the way around... nothing major. all levels and indicators are spot on, and it starts in 20 degrees cool no sweat. all this at 282k miles and with the original trap oxidiser still on there! (being replaced this week or next btw. at local dealer)

get an inspection and you'll be happy and know for sure.

enjoy it!
K

[mplafleur]

The coolant sensor in my 190D used to do that. I replaced it with a new one and it's fine now.

[oilslick]

and I hate to walk away from it if it's only a sensor. Is there any sure fire, shade tree, way to test the sensor? You don't find them this nice around here.

Kevin