1980 300TD buying ?s & oil preasure concerns.
 

I am looking at a 1980 300TD wagon tomorrow. 178K miles non-turbo 617.

My concerns:

This car was passed over by another potential buyer because of the oil pressure. I asked the owner to start the car. At warm idle oil pressure was 1.5. I asked him to rev it to 2k rpm and he stated it read 2.5. Is this something I should be concerned with or is this normal?

I will of course check for blow-by.

I am also concerned when the owner mentioned that in the back of the car is a empty oil container by Quaker State that read 10w-40. This car belonged to his father who he said was a Mercedes enthusiast. This does not seem to be a diesel motor oil. I am hoping it was just back there to throw away and not used in the car. However if this car was run on non-diesel oil what should i look for besides blow-by?

That sounds a little strange. The idle pressure of 1.5 bars is good, but I would expect it to reach 3 bars at about 12-1400 rpm. My 617 lost oil pressure a few weeks ago (oil pump was failing) and it would not reach 3 bars until about 2500 rpm, but it was reading close to 0 at idle. I'm having trouble understanding why it would be OK at idle and too low at higher rpm. :confused:

When my 617 is warm it takes about 2000rpm to get to 3bar....but it also reads 0-.5 most of the time when warm. I have experienced no engine issues.....and I suspect it to be the oil pressure sender. Think thats what it is? Or should I be worried. I am replacing my oil pan in a month or so....so I'll be able to see how stuff looks in there...including that little intake screen. But the engine runs smooth and starts right up every time....so I wouldn't think the pump is bad. The gauge has been jittering and acting strange for quite some time. Maybe I'll just change the pressure sender tonight or tomorrow...as I am quite paranoid. :dizzy2: I have the new one, I was just going to wait till an oil change to do it.

I am wondering if the wrong oil was used that might explain the low lower oil pressure at higher rpm.

I am really hoping this engine is ok. It has been a long hard search for one of these cars for me but I don't want to buy a money pit.

Wrong oil or a weak pressure relief valve would be my guess.

Incorrect or defective oil filter can cause low oil pressure. Best to avoid the filters made in India.

I wish you good luck in finding a nice 617 powered TD, a large % of drivers swear by QS oil, the rest of us swear AT it... 10/40 oil was all you could get in the old days. qs is a good brand, I am sure it has at least CF rating, so as long as decent OCI was followed, that should not be the problem. the 123 oil pressure gauge is real, not sender, so that's not it. if it won't reach 3, as mentioned it could be a lousy filter, or it could be several other things. you may want to have the seller change the oil and filter and see where the op sits. if it was recently changed... walk away.
as a driver of a N/A TD, you may want to hold out for a turbo model anyway.
PNW is a lousy place to find them for good prices in good shape, but I am sure you will. I have 4... sorry we are so far apart... none of mine are cherry, but they were all affordable. check the Craigslists, check ebay, look around. you will find the one you want.

On the turbo charged cars it needs to be 3 bar by 3k rpm.

Its a very old engine, with a very old guage. As long as it hits 3 bar at 3k drive it. Put some tape over it, if it bothers you!

H is right. I've had a non turbo wagon- and loved it. It is not as slow as people tell you it will be, and last longer on average than the turbo model. Buy the car if the price is reasonable, and over the long run you will save money over the cost of other used cars, plus have the pride of driving a MB wagon.

IMO, the more important thing is how often the oil was changed. Also, I love driving my N/A 1980 300TD. This car has lots of pep and actually feels lighter than the turbos for some reason.

178k is low for this car, IMO. If the body is in good shape and the price is right, I'd seriously consider it. Of course you gotta look at the condition of other things (vacuum, exhaust, suspension (sls?), flex discs, axle boots, tranny, etc).

You're missing something here. 1980 wagons didn't have a tachometer. There was no way for him to find out if it's actually the RPM you wanted.

I truly love driving my 79 TD, due to it's spunky stop and go abilities. but on the highway the SD is kinda nice. I can't wait for my 85 Euro TD to get finished, so I can see how it is to drive.

Yup, spunky would be a good call.....another thing too with these circa is theres less stuff in the engine compartment to deal with:).

Good point, if he's just guessing at the rpm it's probably OK. It sounds like the idle pressure is correct, so it's unlikely to be a real issue. It's probably easier to tell while driving it. BTW, if you do end up replacing an oil pump, the parts cost is around $5-600.

:eek::eek::eek:

Sorry, it appears the oil pump is less expensive for the NA 617, it's a completely different part (shaft driven, not chain driven):

http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1CQ0J3JZ426C0MI5ZK&year=1980&make=MB&model=300-TD-001&category=All&part=Oil+Pump

I replaced my oil sender today, the old one was on so loose that when I put my wrench on it it came loose by merely pulling at it with one finger! :eek: is it supposed to be that loose? I put the new one on much tighter....not super tight, but good and snug. No leaks. And indeed did it make a difference. Started the car, pressure jumped right up to 3bar, idles warm now at 2bar, just like it did when I got the car. Lately it had been showing 0 to half a bar at idle, and wouldn't get to 3bar unless I rev'd it over 2000rpm. Now it jumps immediately, and the gauge is smooth like it should be. Very pleased with the results and I like knowing my engine has excellent pressure. :D

Here's a dumb question: Where is the oil sender? Pic anyone? :confused::confused:

How do you know the car actually only has 178K. These odometers are notorious for slipping and stopping. Is there any way to verify the mileage?
My newly aquired engine with 144K on it idles at nearly 2.5 bar when fully warmed up but it is a turbo engine.

How old is bottle in the trunk? QS used to be the best because it was Pennsylvania crude, same as Pennzoil was and Wolf's head before PA drilling operations shut down. Reputed to be finest oil in the planet.

Otherwise test drive it from stone cold start if yer lookin at it tomorrow. And ask the seller to start the car while you first listen under the hood to hear the engine kick then sniff smoke out the back. Heat it up on expressway at full throttle then see if oil pressure drops when slowin down on exit ramp. If it does, NOT a good sign. And when idling warm the needle oughta peg fast when you hit the pedal.

How much they askin for this old wagon?

Actually my post was kinda irrelevant to the W123....as its mechanical....but on the high tech 126 we get an electrical oil pressure sensor. :D Its on the back of the oil filter canister at the bottom. :D

Speaking of an 80 TD...
 

What would you pay for this one?

Odometer stopped at 248K, maybe has 300k now. Black int is in good shape. Drives nice, some rust around the door bottoms, below rear window.
AC 'needs charge';)...
Its sluggish but shifted and handled well when I test drove it.

AMG wheels are from a W208, I believe.

IMO, I would start at bet $800-$1200 but no more than $1500 due to mileage.... there could be other surprises :eek:

Not what you wanted to hear, eh Danno? :D:D
Tell that guy to quit over-valuing his wagon and sell it to you!

Ahhhh, gotcha. Thanks for the clarification. See, sounds like I need a W126 so I won't have questions like that..... :o
:D

I guess he's not wanting to sell then.

I really like the color combo.

It is a mechanical guage with a plastic tube from the filter housing to the guage in your dash.

I have never seen a ten w forty oil that is diesel rated.

I think your motor is probably fine.

The na diesel three hundreds are not as fast as the turbo but they are fast enough imho. And the engines if cared for about cannot be worn out.

Tom W

Here is the scoop...
 

I bought the car. $2700

It came with a maintenance stamp book stamped by dealers or German auto shops from it origin until 11/2001 135k miles. No stamps after that. Removing the oil filler cap while running was uneventful. It just sat there barely moving. Removing it produced a little smoke exiting from the hole on a regular basis.

The interior of the car is flawless except for carpet stains and worn fabric on the door pillars. I am not sure if anyone has ever sat in the back seat. There was a wrapped lollipop under it so maybe someone had. Only bad was PO was a smoker leaving a faint smell.

The exterior is rustproof except for a thumbnail sized spot on the underside of the rear hatch door. Original paint will look beautiful with a little buffing with only a couple of rocks chips as damage.

PO lived in CA and had 5 MBs including a 6.9. This was the last the son was selling. The PO is an American that lives in Germany 6 months a year. I bought it from his son.

I hope I will not regret the following. The oil pressure was actually lower than I expected. At warm idle it sits at 1. Hwy speeds it sits just a tad over 2. I changed oil and filter in the guy's driveway before I drove the car home. Oil pressure did not change. I drove it 230 miles home the way it was. It will sit until I can figure out what is wrong.

Following are a few other issues I will address after I first try and find the answers that might already be on the board. If not, then I will address them individually as posts.

1.Oil pressure

2.Shifting issues : Shifter seems misaligned with the shifter having to be a little farther back than the notch for the transmission to engage. The transmission will only up shift after you pull you foot off the pedal. I have experienced this before in a car with a vacuum problem. I hope it is that or linkage. It down shifts with no problem. Driving in traffic is a pain because it is constantly down shifting right after I get it to up shift.

3.Drivers side door will not lock/unlock with key. Looks like someone tried to pick the lock.

4.SLS system does not seem to work properly.

Yeah, that's not too good. The oil pressure needs to be pegged at 3 at highway speeds (2500+RPM).

Warm idle is OK, but the high speed numbers are not. I might look into the oil pump if we're sure the gauge is OK.

low oil pressure
 

Some members have found that by changing the tiny O-rings, cleaning out the little holes on the oil filter cover stem, and blowing out the crud in there they suddening improved their oil pressure. How or why this worked is not something I understand but it's easy and worth a try.
Go to:
http://www.peachparts.com/shopforum/diesel-discussion/93364-low-oil-pressure-idle-changed-o-rings.html?highlight=oil+filter+holes

and read down from about #10 or #11 past #24 or so
good luck

First hook up a mechanical guage to see what you really have. You can't trust old guages.

IMHO, hold out for a turbo. You'll be glad you did.

You DID see the post that said he already bought it, right???? ;)
{see post #28}

1 at warm idle is not bad, it's the 2 at higher rpms that gets me... try the orings on the filter shaft, but don't hold your breath for it to work. at idle looking down through the oil filler hole, do you see lots of oil spraying around? are the cam lobes nice and clean, well the black colored oil is fine, but is there any gunk on them? try the known good mechanical gauge and see if the pressure is still at 2 while driving.

rr, I can't really add anything that hasn't already been said here. Just wanted to throw out that when warm my '80TD has a tick over 1.5 bar at idle and pins at 3 bar while driving.

I joke about how slow it is, too, but it is surprisingly responsive when it needs to be.

It's getting tougher to find these in decent shape. The fact that yours is relatively rust free and the interior is in good shape is a plus. The oil pressure, SLS and the tranny (if not vacuum or linkage related) might be causes for concern.

Hopefully you can get those questions answered quickly and move on to just enjoying the naturally aspirated TD life :)

on a wagon, the tailgate is first to rust. be sure the drain holes work on the bottom of the hatch and caulk the window seal with black silicone if it is not already.

Sounds nice.

I am betting there is something wrong with the guage.

Tom W

on a wagon, the tailgate is first to rust. be sure the drain holes work on the bottom of the hatch and caulk the window seal with black silicone if it is not already.

Sounds nice.

I am betting there is something wrong with the guage....unless the mileage is all wrong.

Tom W