Looking at a 300D possible purchase - PeachParts Mercedes-Benz Forum

pj67coll · #1 12-05-2012, 12:16 AM

My truck has died and I'm facing having to get a new vehicle by the end of the week.

Wondering if anybody can comment on a couple of issues that concern me on a 123 300D I'm considering purchasing. Car is a 77 with 230K on it. Odo is working and it appears to be correct. Quite a lot of blowby. The oil cap will dance a jig on it when it's loose though it won't actually shoot off out of the engine bay like my 240D's used to. So I know there's wear in the motor but my question has to do with the fact that when it's running there is what can best be described as "vapors" that seep out of the dip stick and emanate from the oil filler hole. It doesn't splatter oil the way my 240D did but at the same time I don't recall seeing this sort of steam for want of a better word before.

It's not a huge amount but looks to my untrained eye to be water vapor and is just enough to be noticeable. Anybody else have an idea what this is? Is it a manifestation of an engine on it's last legs? Oil pressure seems good staying above the halfway mark even at idle after a long freeway test drive but I've never owned a 300D and so I don't know if it's actually idling too fast or not and the idle adjustment knob is not connected so I can't adjust it to find out.

Second would the Chrysler combination valve abombination which is leaking a small amount of water have an effect on the vacuum in any way? The owner said he thought that would be the reason the vacuum is not working. Engine shut off has to be done manually from the stop lever and the door locks don't work from vacuum.

Any thoughts would be appreciated.

- Peter.

ontum · #2 12-05-2012, 12:43 AM

Blow-by is not a great, But what really matters on a 617 is the compression. Unless you compression test every cylinder when the engine is hot, you really don't know what kind of condition the motor is in.

-
Craig

vstech · #3 12-05-2012, 05:00 AM

the vapors out the tube are from the o-ring on the dipstick being worn. replace it.
is the valve cover vent line connected to the air cleaner? is the plastic line from the air cleaner to the vacuum pump clear/yellow or black? those older vacuum pumps tend to fail, and pump engine oil into the valve cover... any vacuum system broken can affect the vacuum system, best way to evaluate it, is to disconnect everything from the main vacuum line, and measure what the pump is putting out. hook things back up until the vacuum won't stay around 20... if the pump isn't putting out around 22, it's shot, rebuild kits are pretty cheap.
as for the oil pressure... are you saying it never goes above 1/2way? or that it never drops below 1/2way, and the instant you touch the throttle, it's pegged...

kerry · #4 12-05-2012, 07:49 AM

Water leak in the servo shouldn't effect the vacuum. Leaky servo is an expensive fix though. If you want AC you'll have to fix it somehow. New servo or its equivalent will set you back at least $600.

pj67coll · #5 12-05-2012, 08:37 AM

I didn't have time to check all the vacuum lines. They well may be problematic. As for the oil pressure. Oil on the stick was exactly halfway between the two marks and it remained at or above the halfway mark on the gauge when idling after a freeway run at speeds up to 80mph. Pegged at all other times.

Kerry I know about the cost of the climate servo. It would be nice to have AC but at this point I just need a reliable runner. I'm fated to never have C in a car it seems.

- Peter.

Air&Road · #6 12-05-2012, 09:01 AM

Beware of the problematic automatic climate control system in the early 123's.

Junkman · #7 12-05-2012, 12:54 PM

Quote:

Originally Posted by pj67coll

My truck has died and I'm facing having to get a new vehicle by the end of the week.

Any thoughts would be appreciated.

- Peter.

It is difficult to get a good deal when you have a short deadline. I use replacement diaphragms for single pods and try to use OEM scavenged diaphragms for double pods. So far every old(er) MBZ that I've bought has needed more work than initially thought upon inspection. Buy and drive doesn't happen frequently. You need a price where an unexpected $2,000 and time to repair still does what you want at a decent price. (Unexpected means 2k above what you see.)

Vacuum system can be a pita but not necessarily expensive. Climate including compressor etc and gas is expensive. Heat only isn't.

If it starts easily and drives comfortably enough, it should be reliable local transportation. You can rent for intermittent distance travel.

Pretty soon with short decision time, you get to price. How is your cash and cash flow.

pj67coll · #8 12-06-2012, 02:11 AM

Quote:

Originally Posted by Junkman

It is difficult to get a good deal when you have a short deadline. I use replacement diaphragms for single pods and try to use OEM scavenged diaphragms for double pods. So far every old(er) MBZ that I've bought has needed more work than initially thought upon inspection. Buy and drive doesn't happen frequently. You need a price where an unexpected $2,000 and time to repair still does what you want at a decent price. (Unexpected means 2k above what you see.)

Vacuum system can be a pita but not necessarily expensive. Climate including compressor etc and gas is expensive. Heat only isn't.

If it starts easily and drives comfortably enough, it should be reliable local transportation. You can rent for intermittent distance travel.

Pretty soon with short decision time, you get to price. How is your cash and cash flow.

I could get it for 1750. But I don't have that extra 2k spare to put into it on top of that and I know that at the very least it needs new engine and tranny mounts and engine mount shocks. Quite apart from the vacuumed issues. Looks like I will have to lose out and bite the bullet and repair my, truck. Sucks.

- Peter.

kerry · #9 12-06-2012, 06:54 AM

What happened to the truck?

pj67coll · #10 12-06-2012, 08:41 AM

Quote:

Originally Posted by kerry

What happened to the truck?

Clutch went out. I had to drive home rush hour traffic without a clutch. That was an experience to put it mildly. I'd be surprised if the gears are anything but mush, especially second. I managed to shift into the rest without too much trouble but first in to second was horrendous.

- Peter.

pj67coll · #11 12-07-2012, 02:03 PM

Oh well I' m out of time. Got to be mobile and back at work Monday so I had to repair my truck. 1600 bucks later and I'm out of cash. So too bad. I think the 300 is probably a fundamentally sound car despite the paint and vacuum issues but nothing I can do about it now.

- Peter.