Replaced the oil cooler lines this weekend- some hints - PeachParts Mercedes-Benz Forum

tenknots · #1 04-03-2006, 06:42 PM

Not as bad as I thought, but still a PITA. I took the advice of several of those before me, thanks for your posts.

Helpful hints:
Drain the oil the night before and let it drain overnight – get all out you can. It’s a messy job and the less oil the better.
Cut the old lines close to the oil cooler – I used a hacksaw. Place your oil drain pan under that area because it will drip.
Remove the oil cooler – top and bottom bracket; it comes right out.
Take it to your shop or an outside work area. Use a Dremel tool to cut the rest of the lines off, just at the nut. Then use the Dremel to cut a slice up and down on 4 sides of the nut just deep enough to get to the threads. Having the hose cut right at the nut allows you to see how deep you need to make the cuts. Use a screwdriver to pry between a cut and the nut will peel off in 4 pieces. I’m convinced that trying to unscrew the nut would have ruined the threads; despite using PB Blaster every day for a week it was still corroded on the threads. New oil cooler are $350+. Clean up the threads for the new hoses.

Jack up the driver’s side until the wheel is almost off the ground and use a jackstand.. Remove the two clips that hold the fan shroud to the radiator and remove the little clip that holds the throttle linkage that comes through the firewall to the engine- you’re going to lift the engine and these will bind otherwise.
Remove the driver’s side engine shock (there is a flat spot on the bottom shaft to put a wrench to keep the shaft from turning as you loosen the nut). Take off the 10 mm bolts on the top and it comes right out. Remove the 8mm engine mount allen screw from under the car. Jack up the engine about 3 inches using a large piece of wood and a bottle jack under the oil pan. You’ll wish you done these steps if you don’t – just do it; it makes the job much easier. There are two brackets that hold the lines in – one 10mm screw on each. With a big gap at the engine mount and no engine shock, it took all of 15 minutes to get the two hoses out. Remember the order because it matters. Reinstallation of the hoses took another 15 minutes. I would take pictures if you don’t have another car to look at as I did. Lower the engine (search for engine mount tips if you need more information about them) The rest is just buttoning up.

All told, it took me 5 hours, not including cleaning up, which took some time. I went through 6 pairs of gloves – I recommend them. My arms were dirty, but my hands were OK. Refilling took 8 quarts due to the oil in the cooler draining out.

My wife’s car had oil all underneath the car from the leak. The last two weeks she was adding a half quart between fillips. I have no doubt these lines would fail catastrophically very soon, likely taking the engine with them.

dieseldiehard · #2 04-03-2006, 06:52 PM

nice write-up! I learned the hard way about the need to slot the nuts. I've used a dremel tool for that.
I now use a dab of No-corrode stuff on the threads, so some mechanic 20 years from now can get them off without resorting to all the stuff you just went thru

(can't help but think these cars will be collectors items in 2025!)

Diesel Giant · #3 04-03-2006, 07:44 PM

Those are some great tips!

How fast do you think you could do the job the second time around?

kmaysob · #4 04-03-2006, 08:27 PM

think it would be quicker on a lift?

Hit Man X · #5 04-03-2006, 08:41 PM

My plan is to remove the motor mount too, glad that's the way to fly.

After court tomorrow I'll probably do my cooler lines, motor mounts, and trans mount... as well as an oil change.

tenknots · #6 04-03-2006, 09:00 PM

I think I could knock an hour off of it next time, maybe more. Having a lift would be nice, but a lot of the work was done from the top; it would help with the motor mount and shock. I'm certain my Dremel tool has paid for itself many times over.

mplafleur · #7 04-03-2006, 09:09 PM

You got me beat.

Mine's taken over 2 months now and still counting...

Still haven't replaced the oil filter housing I broke. But I'm getting close!