Guys

I would appreciate some real-world advice here. I am slowly working on my 1983 300SD to bring her up to daily driver standard - she only has about 88,000 miles on her.

The "standard advice" is to ALWAYS replace the cooler lines - but I've noticed that the most strident advice to do so comes from the folks who sell the parts. And the job sounds like a bear.....

There are NO signs of leakage on my lines anywhere - so should I replace them right away? Is this a must do because the old lines are prone to blowing with no signs of leakage? I am planning some reasonably long haul trips in the old girl over the next year.....

I would only consider replacing your oil cooler lines if the rubber portions are rock hard and full of cracks or visibly leaking. If you see no evidence of leaks or weeping, they are fine.

My lower hose was leaking and the rubber portions were hard and cracked, but I was able to drive a bunch of miles while they were in that condition. You just have to watch your oil pressure like a hawk. If it drops more than what it does when the oil cooler opens, shut off the engine IMMEDIATELY.

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Chad
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys

Oil cooler lines always give warning before they blow. Usualy they get wet, and maybe even start to drip. A hose just doesn't blow, if they are clean and dry they won't.

However on my cars if they look original they get changed, even if they look perfect. They are to cheap to risk an engine over. More so for the 617 powered cars they are only like $200.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

You might want to consider a low oil pressure alarm. Here are some threads (my thread is in the middle):
http://www.peachparts.com/shopforum/search.php?searchid=2761188

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84 300D, 82 Volvo 244Gl Diesel

If you are going to replace any, be veeeery careful not to strip the threads on the oil cooler.

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

The scrap aluminum value of the oil coolers covers a lot of the cost of buying a used one. Works out pretty well.

We're in the process of replacing lots of oil cooler lines. We bought two new ones for the project SD, but at $260 for the pair, thats steep....the other cars we are going to see if a local place we go to can replace the hoses and re-crimp them....they probably can. So the other two cars we will be going that route. Costs have sure gone up! When I replaced my oil cooler lines with OEM about 3.2 years ago they were $215 for the set.....now they are coming up on $270! Its probably all due to the dollar conversion vs Euro though.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

If I'd found the place that made up my small a/c hose earlier, I'd have just replaced the rubber portions. If the ends are ok, a place like I found locally - Hose fast, could probably re-do them for $75. The $45 dryer-to-condenser line I needed was made up with new fittings for $20....

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Sharing my partner's 2012 Forte 5dr SX til I find my next 123 or 126..
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Do I miss being a service advisor ???

Find a local place that can crimp them on. I should have done that with the SDL.

My uncles Volvo 160 has some nice 350bar pressure lines that would have worked just fine for an oil cooler.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

dont forget to tell him that you can EASILY strip out the oil cooler when you remove the lines. If they dont leak & look good leave them alone. One of the common ways for them to blow is the power steering belt sawing into the line (this can be from a collapsed motor mount making the belt & lines coming together or a loose belt). I would definitly make sure there is good clearance between the belt & hoses. Also not a bad idea to place something on top of the hoses like a old heater hose cut in half with a few zip ties, this way it will cut that instead & you can moniter it.