Help needed quick, please - PeachParts Mercedes-Benz Forum

The Warden · #1 07-05-2002, 06:56 PM

As I've mentioned, I'm looking at an '85 300D. I'm currently in Dallas, and have had a chance to look the car over.

Everything seems okay, except for one major thing. With the engine running, if I pull the oil filler cap off, I'm seeing quite a bit of blow-by, and it seems to be puffing out (at a fairly quick pace) as opposed to calmly steaming away as other "okay" diesels I've seen do.

I'm not sure exactly how much is too much, and, being the day after the 4th of July, I have yet to find a shop that knows anything about the W123 diesels that's open. I honestly don't think I'm going to find a shop at this point, and it's about 6pm Central Time, I believe.

Again, other than that, the car seems okay...the tranny shifts a bit weird unless I put a lot of pedal into it, but the engine thing is the big issue. I basically have two choices...either drive it home to CA or hop on a plane and forget it.

Thoughts pretty quickly would be appreciated...thanks in advance! Please respond to this post, as I don't have access to my E-mail at this point.

Again, thanks!

#2 07-05-2002, 07:28 PM

First of all, how much is it? If we are talking about several thousand dollars, I would wait and get a compression test if you have any concerns. Also, what exactly is the tranny doing (or not doing)? How many miles?

If its really cheap, just go ahead and drive it home then worry about it. Worst case scenario, you drive it another 50,000 miles before it dies instead of 200,000 miles.

The Warden · #3 07-05-2002, 07:55 PM

The price is $2500 minus my cost to fly out here and drive the car back (special deal; the current owner's a member on this board and wants to help

).

I don't know when I'd be able to get a compression test done; I have to be home by Monday night no questions asked. I don't know what availability's like during the weekend...

The tranny seems to be shifting into a higher gear too early, unless floored, but I'm honestly not sure. The fluid looks okay offhand. FIrst time I floored the engine, I got a nice big cloud of black smoke, but it seems to have been burning pretty cleanly since...

I tried blocking the blow-by, and got varying results...3 times, with 16 seconds, about 10 seconds, and 8 seconds (last time). I also noticed some cracks near the fitting on the valve cover...also, I smelled the exhaust and it smelled a bit sweet...no white smoke whatsoever, and he says he's never needed to add any coolant...the water temp's been varying between 80°C and 100°C, varying probably due to the hot and humid weather...also, the electric fan in front of the radiator appears to be dead. There was a little bit of oil in the intake, and the air cleaner was downright disgusting...it needs to be replaced before I leave if I buy the car.

Not sure if I left anything out...

engatwork · #4 07-05-2002, 08:02 PM

Warden - how many miles are on the car? If there is no rust and the body/interior look good go for it. I am of the opinion that even if the engine was brand new you would get some blowby. I'm sure the severity of the blowby is in direct proportion to the milage. My 300D shifts into high gear by the time it is at 30 mph no matter how I drive.

The Warden · #5 07-05-2002, 08:10 PM

The car's got 223K miles on it, I believe (original engine/trans, as far as I know). I couldn't find any rust...it's apparently been in Texas all it's life. Very clean underside.

The body looks great (other than a few minor dents that I didn't even notice at first); the interior's okay...could use some seat covers, along with something for the center armrest.

I know that some blowby's to be expected, but I'm not sure if this is too much or not. Also of concern at this point is the "sweet" exhaust...I"m worried that that may be a harbinger of problems on the horizon...or should I worry about it? I've only seen this smell on one other vehicle (also a diesel), and that one turned out to have a cracked piston, hence my concern.

Other than these issues, I'm happy with the car.

psfred · #6 07-05-2002, 08:11 PM

Hmmm. Sounds like my 220 only not so bad.

If you decide to get it, buy a case of oil and stop frequently (at least once an hour) for a while and check oil level -- if you have bad rings you will have high (less than 100 miles to a quart) oil consumption on the highway.

That blowby can be either rings or valve guides, probably rings if it kills the engine quickly. If the blowby is overwhelming the oil separator, I'd pass unless I was planning on an engine overhaul.

Shifting problem can be the bowden cable or a dead vacuum modulator, or stuck modulator push rod -- its plastic.

Peter

The Warden · #7 07-05-2002, 08:22 PM

I don't know on the rings...I haven't noticed any blue smoke. Only smoke I've seen was black.

He also has an '85 300SD (he's selling the 300D 'cause he bought this), and he told me that he switched air filters between the two 'cause he wasn't driving the 300D, and that the air filter looked as bad when he switched it as it does now. There was some oily residue on the inside of the air cleaner housing, but, again, I don't know what's excessive...I wiped it all up and didn't get a whole rag dirty.

I will admit that the filter looks much dirtier than the housing, so it makes sense...

Thoughts? Especially on the exhaust? Maybe I'm just being unrealistically optimistic (or was being paranoid earlier), but maybe the blow-by isn't as big of an issue as I had thought? Going by some revious posts, even 8 seconds with the breather tube plugged killing the engine, is in the "okay" range...does that sound right?

Ugh I wish I knew if a shop would be open early tomorrow morning...

Holson Adi · #8 07-05-2002, 08:36 PM

Take it to a dealer.... the local MB dealer here is open on Saturdays..

The Warden · #9 07-05-2002, 09:10 PM

I'll try the dealer, but they're already closed here...so I'll call tomorrow.

I'm running on 2 hours' sleep, so at this point I'm going to find a motel and crash for the night...I ought to be back tomorrow. Any thoughts, comments, etc would be greatly appreciated. Thanks in advance!!

TimFreeh · #10 07-05-2002, 09:48 PM

The blow-by sounds pretty typical for an engine with 223K. That said I suspect it would run fine but would use a quart of oil every 500-1000 miles. If you can live with this I think you should buy it. I've looked at lots of W123's here on the east coast and rust-free examples are starting to get a little rare. The 85 turbo W123 is supposed to be one of the best years (if you don't get the ones that have the california trap oxidizers)

The price seems about correct if the car is as you describe.

Good luck

Tim

leathermang · #11 07-05-2002, 09:49 PM

If it were not for that " monday night" deal I would invite you to Austin for Sunday morning... TCane will be here and I am sure he has the diesel compression gages...and knows all the other symptoms one might want to look for...

But absent the required time to do that I would vote with the rest who have posted.. change the oil, drive around the block to check for leaks... then carry plenty of oil,water etc with you...

And leave early enough so that you do not have to drive like a bat out of Texas to get there. Check your tires with them stone cold the morning before you leave.. and let us know your route... maybe forum members along the way could post and offer assistance if something happened... Good luck,,, Greg

dabenz · #12 07-06-2002, 07:11 AM

Sounds like you'll get a rust free car for less than $2000. If you don't like it and you think you can get it back at home, then you've gotten a free road trip and a good learning experience out of it.

An old trick for water in the oil: Put a lighter to the oil on the dipstick. If the oil "spatters" then it's wet. Also look at the dipstick for signs of water like corrosion pits or white sludge.

Beagle · #13 07-06-2002, 08:56 AM

Your best option obviously is compression test. First cold, dry and then wet, then when hot again dry and then wet. In the absence of the necessary equipment there are still a number tests you can do that will give a very good indication of the engines condition.

I’ll just mention 3 of them here:

1) Idle.
If the engine has a smooth even idle when cold (no missing) this is very good news. This tells you that the pump calibration is 100%, the injectors are at least reasonable and there are no SERIOUS compression problems. Next push back the manual STOP lever slowly letting the revs decrease until it finally stalls. If it keeps firing smoothly on all 5 better news still! A rough idle is not necessarily bad news, could be just one bad injector or pump cal.

With engine hot and idling crack open each injector pipe in turn and retighten. The rough idle when you do this should sound the same on all 5 cylinders.

2) Blow-by.
a)First check that the breather pipe is securely connected to the rocker cover and induction manifold – no leaks
b) With engine hot and off remove oil filler cap. Wipe cover clean and smear grease around the filler hole. Take a piece of thin polythene sheet ( an old bag is fine) and lay over the filler hole sealing with the grease. Start engine and let idle. The sheet should not have blown off. Now increase revs slowly to about 2000 and the sheet should now progressively be sucking into the engine indicating a negative crankcase pressure. In other words the manifold is sucking off the blow-by faster than it is leaking past the pistons. Obviously blow-by vol. increases with engine load but should never be positive.
Briefly if the sheet blows off you have excessive blow-by and consequently poor compression.

3) Oil control rings.
Find a hill steep enough to over-run the engine at 50mph in 3rd gear (2nd for auto) preferably about ½ mile long. Accelerate away on half throttle at the bottom. If you see blue smoke in your mirror you got a problem!!

The 617 engine will give you fantastic service if you look after it -but everybody here knows that don't they? My ’82 300D manual has over 670,000km on the original engine, burns 1 ½ pints of oil to oil change at 5000km and still gives me 7 litres/100km – still as good as the day I bought it!

Ridge · #14 07-06-2002, 11:39 AM

Warden,

Go to the local parts store and buy yourself a compression gage with the adaptors to fit the glow plug holes and do your own compression test.

Above all, don't push the limit, there's always tomorrow. There's a European 300D here in the Bay Area with a 4 speed manual transmission, euro a/c, heater like the 240D, manual windows and 110k on the engine. Asking $3200.00 but I'm certain he'd look at lower offers.

Ben

The Warden · #15 07-06-2002, 01:35 PM

Quote:

Originally posted by leathermang
If it were not for that " monday night" deal I would invite you to Austin for Sunday morning... TCane will be here and I am sure he has the diesel compression gages...and knows all the other symptoms one might want to look for...

Greg, I've actually decided that, were I to buy the car, getting back by Monday is probably unreasonable...so I'm actually up to that meet. Any chance it could be done today?

The local Benz dealer wants $500 to do the compression check. I decided to pass...and don't know of a shop that's open. The current owner says it uses up about a half a quart of oil in 3000 miles, which is actually better than my van was.

Again, Greg, if possible, I'd love to do that meet, preferably today...and I'll try Beagle's tests. At this point, barring bad results on these tests, I think I'm gonna go for it...

Thanks!

{added in edit} Just did Beagle's shut-down lever test (no grease so I couldn't do the bag test), and it was firing nice right up to shut down, so I feel better.