Mr. Bible, when you give this advice, I assume you are talking about SCHEDULED oil changes?!? I am sure that is good advice, but for the second time in 2 weeks we have had the oil pressure line blow off. Result: An oil change whether we want one or not!

Both times it has been kind of 'good news/bad news'. The first time it happened was in the driveway. A mess to clean up, but at least no damage done, and no tow. Today, we had gone for a long Sunday drive, all the while patting ourselves on the back about how many improvements we have made on the car in a short time. It's running very well. If it had happened on that trip, it would have cost us a fortune. We even took our 2 big dogs (doubt they would have allowed them in a cab), went for a ferry ride (we would have been so popular if it had happened THERE) and were considerable distance from home (and of course it's Easter Sunday). Anyway, no problem at all then (thank God), but later my husband and daughter went to go and fly a kite. They were only a mile or so from home, on a fairly deserted road with a wide grass boulevard, when it happened this time. So, not GOOD news, but it certainly could have been worse!

I had some concerns about the line after the first incident, but hubby felt it was pretty secure (and it's not like he hasn't been busy with other repairs). Apparently it did not come apart where he had put it together last time, but at a different spot. He's off now trying to find a 12mm bolt so he can just plug the thing and get it home.

On the upside, I guess we're giving the engine a good flush!

__________________
Natalie

It sounds like you need to have both oil cooler lines rebuilt. They can do this at any industrial hydraulic hose shop. More than one engine has been ruined by failure of these lines. Even if you have to buy complete brand new lines at the exhorbitant replacement price, it will be a small price to pay to prevent catastrophic engine failure.

Good luck,

After reading about a number of issues with oil lines, I wonder has anyone gone to braided lines or setup any low oil level alarm?

__________________
1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it

No, it wasn't the line to the oil cooler, it was the oil pressure line that goes in to the firewall and dash. I think it must be under a lot of pressure. Has anyone heard of a retrofit for these cars to the newer electrical style pressure guage?

So, we ended up using Mary to tow the car home. I thought the poor old girl might just split in 2 (she's pretty rusty), but it was no problem whatsoever. It was only about a mile or so, but we had to start the car one more time to get it in the driveway.

My husband took the oil pressure line off our parts car, and will install it today. Hopefully that will be the end of THAT problem.

He found a couple of interesting things when he took the instrument panel off the parts car. For one, there are a couple of security boxes... one says broken window sensor, I forget the other one. Was this standard equipment in 1981?? Or is that after market? Also, there were some electrical lines wrapped in cloth tape, and the tape is oily?? I'll try to get a pic today. Not that important, as it's only the parts car, but I'm curious. I guess it has to be from the oil pressure line, but it seems kind of distal to that.

Such an adventure owning these cars!

__________________
Natalie

It's shouldn't be too difficult to swap the electric oil pressure gauge system from an 81-85 300SD into a 300D.

Things you'll have to consider:

- fidgeting with the gauge itself if the temp-fuel-oi pressure gauge combo from a 126 doesn't fit the cluster of your 123.

- figuring a way to wire the gauge.

- fitting the sensor to the 123 filter housing or fitting a 126 filter housing. That's not a lot of fun.

Sixto
91 300SE
87 300SDL
83 300SD

I've installed a lot of manual oil pressure gauges and never had a line blow off. I've never read of it happening on this forum either. This leads me to suspect that you need to do some close diagnostics. Why did the line blow off (twice!)? I've never had the line off on a Mercedes, but on the ones I have installed myself, there is a brass ferule that slides over the line and a nut holds this to a fitting. I'd be suspecting that someone was messing around with the line at some time and left off a ferrule or something like that. Compare the lines on the two cars and see if you can find any difference.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Check the threads at the oil filter housing. This connection is at an odd angle. I can see how an experienced person could easily get this crossthreaded which would ultimately prevent the line from tightening securely.

If it is cross threaded, rob the oil filter housing from your parts car.

I've never had such an issue with one of these mechanical gauges. Actually I prefer them, it's a KISS thing (Keep It Simple, Stupid.) There's nothing more simple or accurate than a mechanical gauge.

Good luck,

Yes, you're right, there was a difference. With the one that failed, there was a softer rubber hose coming out of hte oil filter housing, and a harder plastic line coming out of the firewall. The first time it failed, it was the connection between the two that let go. The second time, the rubber itself split apart. On the parts car replacement, it is all one continuous hard plastic line. So, all should be well now. Whew! The previous owner only owned the car for 6 months, but he did a few daft things (though it must have given him problems for him to mess with it in the first place).

We did find something odd under the dash though. On both cars, the electrical tape wrapped around the wiring is wet (slightly) with oil. Since it was the same on both cars, it seems like something common? Where is it coming from? Just deposited vapours? Or maybe coming in from a vaccuum line? Sounds like there is a vaccum leak if that's the case. Anyone have any ideas? I'll post a couple of pics.

Attached Thumbnails

 

__________________
Natalie

The first pic was to give you a reference where you are looking. This is the wet tape...

Attached Thumbnails

 

__________________
Natalie

Couldn't that oil just be dripping from the fitting at the oil pressure gauge on the instrument panel?

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Yes, I suppose. But it is under a lot of pressure, right? If there was a leak there, wouldn't it be more of a spray all over? (rather than a drip running down the wires). It is not 'everywhere', just on the tape. I actually wondered if it wasn't oil, but some sort of fire retardant. But, it really LOOKS like oil, so maybe I'm the only retardant .

__________________
Natalie

Have found this on my '83 300D as well. In fact it went all the way down to the back of the radio and ash tray. The PO changed out the " ign" switch, so I am suspecting the item behind the switch that activates the IP shut-down with the key. Think it leaked during his ownership and this was just some of the drippings.

__________________
1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150

While mine was not a "D" my 1984 123 200 had a severe leak in the oil pressure guage which caused a small rivulet of oil to dam up against the inside of the clear plastic on the instrument binnacle before flowing down the side of the center console to cause a sizable and thorougly unpleasant swamp in the floor mat.

Replacing the guage fixed this on mine but hearing about all these leaks emanating from this area I wonder if the guage/line/connector is not a weak point on 123's? I have not heard of it happening on other series and my 108 and 116 were fine despite being older and having much higher mileages.

- Peter.

Makes me think that the next time I am behind the cluster, that I should use tie wraps as a clamp around the rubber line.

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

I had this exact problem on my 240D. In my case, that actual brass oil pressure gauge was to blame, and I was in fact getting drips everywhere. The previous owner new nothing of this, so my drivers side carped was thoroughly steam cleaned to take out the oil Anyhow, the actual gauge may be at fault. Although this sounds dumb, I currently have the line plugged until I put in a new gauge, which I may in fact do today (since I have many lying around from a junkyard) Anyhow, don't ever put anything out of the picture. It could be a faulty or plugged gauge.