Newbie wanting purchase advice! - PeachParts Mercedes-Benz Forum

twinturbo · #1 12-29-2004, 09:50 PM

Hi,

I've been perusing the forums for about two months now trying to learn the basics about the turbodiesel models. Today went to look at an 82 300d, (the 3rd I've looked at) and the seller and I settled on a very cheap price.

Many of you here have vast knowledge regarding these things and I wanted to run a few questions by.

Mileage is 208,000, upon driving noticed the odometer not working. Checked blowby and it seemed to be blowing pretty bad out the oil filler cap. Car started easily and it was dead cold, fell into a good idle after about 2 or 3 seconds. Full oil pressure when cold , Idled at 2 bar when warm.

Body is a rust free California, interior no rips. Paint needs a good cleaning along with the interior.

Drove O.K. Tranny seems to shift early and would not always kickdown, but no flaring at all. 1-2 shift is harder than the rest, all other gears smooth.

Problems: Vacuum system is a mess. Car wont shut off unless he pulled some hose under the hood, brake pedal pretty hard, although stopped O.k. I had a light on the dash come on.. yellow idiot light next to the battery light when braking. Assume this is fluid level in master cylinder? Heater seems to work, did not know how to operate AC, so didnt check but he said it works. Temp seemed abit high maybe high to 90's.

Anyways negiotiated on 1200.00 bucks. Should pick up in the next couple days. There is time to pull out of the deal if you guys think I am over my head. This will be my daily beater as I do not want to run my Porsche daily. I consider myself to have decent mechanical aptitude so fixing things will be done by me. Does the deal seem fair?

Any advice?
Thanks in advance!

Hatterasguy · #2 12-29-2004, 10:19 PM

First I am no W123/617 expert but vacuum system problems are common. Get a tester and go at it, the hard brake pedal could mean a bad vac pump. Is their any rust? Is the car still in CA? Blowby would bother me, that would be a deal breaker for me. A compression and leak down test would be a good thing to get. I looked at an 1985 300D last year that had almost no blowby. The AC was dead but the vac system was perfect everything seemed to work. Paint needed to be cleaned up but the interior was in great shape. It needed a steering box the guy would have let me have it for $1,200. It had a ski rack on the roof to.

kerry · #3 12-29-2004, 10:41 PM

You'll probably find a lot of different opinions on the blowby. It seems there are big differences in the amount of blowby on engines that seem otherwise to be fairly similar. At the price, which is good, I don't think I'd worry about it.
Shifting oddities could be related to the vacuum problems.
Yellow brake light probably indicates a need for new front pads.
I'd probable bite if it looked good.

Wodnek · #4 12-29-2004, 11:00 PM

If it runs and drives good I would bite. There is a vacuum book on **************.com that I here is pretty good for figuring vac problems. Mine runs temp 80 in winter (wisconsin) and 90 or a little higher when its over 70 degrees outside. If you can drive it trouble free for a year it would be worth $1200. The brake pads are very simple to change on these and only cost $20 for the lifetime warranty ones at autozone. Be sure to adjust the valves. (2 hours my first time)
Enjoy!

twinturbo · #5 12-29-2004, 11:33 PM

Thanks for the comments.

I must admit I am a tinkerer by heart so projects lend themselves to me rather easily which is why I am asking for objective advice.... but, a few minor projects are expected.

The seller is probably in his early thirties and he told me the car has been in his family for quite some time. His mother drove the car and I guess his dad is a MB diesel head, so there is some understanding of operating sytems and maintainence through the years. The car has sat for 3 months when the mom moved up to a 300sd, so I think it just needs to be driven. There was no exhaust smoke at all and it sure did idle well, but the blow by concerns me!

Anyways maybe it just needs an italian tuneup?..

Cheers

Wodnek · #6 12-30-2004, 09:28 AM

I give mine an itallian tune up every day! And it runs so much better than when i bought it. The big change came when i put 5 gallons of B100 in it. That must have cleaned the injectors like diesel purge.

KCampbell · #7 12-30-2004, 09:52 AM

The vacuum system really isn't that tough to fix, it sounds as if you have a total lack of vacuum, which could mean the vac pump is gone. There are many write ups on testing the vacuum system, all you need is a gauge and some hose.

The simplest thing to check would be to pull the rubber 4 way connector off at the check valve and see if there's any hissing, indicating that you actually have a functioning pump. Bolted right on the front of the engine is the vacuum pump, it has a large, shiny, black hose that comes up past the PS pump and heads for the vacuum booster on the master cylinder. Just before the master cylinder is a white check valve with a rubber connector attached - this is where I'm suggesting you test for vacuum.

You'll need to pop the hood and press the red STOP switch that's part of all the throttle linkage on the valve cover in order to stop the engine every time, and your central locking won't work.

Diesels can produce a fair amount of blow by, I wonder how much yours has in comparison to others? Is there oil running over the valve cover from the filler cap? It might be good to look inside the air cleaner, as that's where the crankcase vent goes. If it's really, really oily in there it might be a bit more serious.

I had a Vauxhall diesel in the UK with poor compression, it started OK when cold but would not start when hot. Putting your hand over the oil filler hole was like putting your hand over the tail pipe! Based on my experience I would say make sure it starts when it is good and hot.

Kevin

Rick Miley · #8 12-30-2004, 10:05 AM

At that price, if it started fine when cold then don't worry about the blowby. Go for it.

#9 12-30-2004, 11:17 AM

Pay attention to the condition of the suspension and steering components. Very expensive to replace, and they need to be in reasonable condition for the sake of driveability and safety.

That said, $1200 for a rust-free, running car is a good price IMHO.

Pete Burton · #10 12-30-2004, 11:36 AM

yellow idiot light is sensors in front caliper grounding on rotor, indicating the pads need replacement. Blowby will aggravate vacuum issues, because the vacuum pump can't create a strong vacuum if it has to pump its discharge into a significantly pressurized crankcase. A running, rust free MB should be worth most of $1200, but with a significant amount of blowby, you should expect it to get worse, and that will eventually affect starting. How you drive, how much and how you maintain it will determine how long that engine will last.

twinturbo · #11 12-30-2004, 01:27 PM

Are you saying that the blowby is excessive enough that I may never get the vacuum system operating properly?

I may be jumping to conclusions but that seems resonable.
Like I said, the deal is not completely done if it seems this motor is too far gone. The other stuff on the car is easy to fix but not significant compression loss! The body is perfect except for the banana yellow factory paint that was hideous to begin with. This will never be restored, just used to haul me and my dog around to and from work.

Thanks

Pete Burton · #12 12-30-2004, 01:43 PM

Quote:

Originally Posted by twinturbo

Are you saying that the blowby is excessive enough that I may never get the vacuum system operating properly?

yes, that's what I meant. Here's a quick test: Disconnect the vacuum line between the metal pipe coming from the vacuum pump and the hard, semi-flexible live that leads to everything else. Put a vacuum gage there. (this eliminates all other possible leaks in system from giving a false reading) try revving it up a bit and remove oil filler cap. If you don't get much vacuum until you remove the cap, I would pass on the car unless you can live with the consequences.

franklyspeaking · #13 12-30-2004, 02:00 PM

I think I would take it to an independent mechanic for a compression test. Blowby is not a very objective test. Compression tests tell you if you have general issue across all cylinders or whether one is causing the problem. A smooth idle is not indicative of a huge variation in compression.

On the other hand, if it idles well and starts easily when cold (although cold may not be very cold in California), it may not be in bad shape relative to $1200 car. I personally would not be afraid to buy it for this price, if I needed a car and just take my chances. The other issues you have cited are minor.

Good luck!

#14 12-30-2004, 02:07 PM

A couple of items from my experience with 1980 300 TD: Until vacuum system is fixed, you'll shut off engine with stop lever. On mine, this works fine IF the idle is adjusted all the way down.
My odometer had stopped at 229,000, I don't know how long before I got the car in Oct. 2003. After a few months I fixed it by following instructions found in archives on this forum. The odo drive gear had become loose on its shaft. Move gear, knurl shaft, push gear back; or use Loctite on shaft.
When you take off the oil filler cap on valve cover, don't put it down upside-down. This lets a few drops of oil get up into the cap and drip down
on valve cover later, making it look like blowby is worse than it really is.
I'm looking at a vacuum pump rebuild myself, as the following symptoms showed up all at once a couple of weeks ago: hard braking, engine won't stop with key, strange shifting (revs up pretty high in 1st before going to 2d), door locks stopped working, extra oil turned up in air filter canister (not from blowby).

twinturbo · #15 12-30-2004, 02:59 PM

Thanks again guys.

I will try Burton's quick test to see if the vacuum pump seems to be working before I outlay the cash.

This car has spent its life in the Central Valley of California and it gets hot as hell here in the summer, I know that any rubber components or seals in the car are brittle so vacuum lines are easily replaced... also the rebuild kit for the vac pump seems cheap...easy fixes if they are the problem?

About the blowby..., I did not hear excessive puf..ppuf..puf when removing the cap, just a good amount of smoke. This is after about 6 minutes of driving. Not exactly empirical evidence but an indication nevertheless.
Just need to talk my wife into taking me down to Modesto sometime today to pick it up. The owner sure was hesitant to move down on price which I view as a good thing, hopefully things pan out.

Again, thanks for the replies.