Engine Oil & Filter Change 280SL '71

[Mike K]

I'm planning to do an engine oil & oil filter change on my 280SL over the weekend. I've purchased the filter and all necessary seals etc.
 
I have 2 questions.
Other than draining the sump:
1. Do I have to also drain the oil from the oil cooler attached to the radiator?
2. Do I have to remove the sump pan and clean that out as well? Thankfully this car doesn't shed a drop of oil and I'm concerned about starting something I can't finish.....

I've spent a great deal of time searching on the Site but don't seem to able to find a definitive answer on this.

FWIW, I've purchased Elf HTX Retro 2 Mineral 20W50      http://www.lubricants.elf.com/products-range/classic-cars.html

Any advice and input is greatly appreciated.

Thank you,

Mike

[ctaylor738]

I have read that draining the cooler is recommended "every second" oil change.  If you decide to do it, don't put very much force on the drain plug because it is easy to tear the cooler body and then you have an expensive mess on your hands.  Personally, I would leave it alone and just change the oil and filter.  But with the filter out, take a good look at the gasket/seal where the filter fits to the housing (PN 000 184 33 80) to make sure it is in good shape.

No need to drop the pan unless you think there is something going on it there.

Cheers,

CT

[Larry & Norma]

I always drain the cooler as there is a new washer supplied with the filter.
As said be careful with the drain bolt, hopefully it has been torqued correctly
and will undo easily, replace with correct torque on refitting.

[66andBlue]

... hopefully it has been torqued correctly and will undo easily, replace with correct torque on refitting.

And the correct torque is?

[ctaylor738]

Just to be complete, Haynes says (in Nm):

Oil pan drain plug - 41
Oil filter bolt - 41
Cooler plug - 25

[Bonnyboy]

Mike, if you haven't changed the oil before - beware of the volume of oil that comes out when you remove the plug.  It overflowed my funnel and container and went all over my arm and my neck the floor and ...you get the idea.   Now I remove the plug just slightly and hold it at the hole to reduce the flow of oil - just so my funnel can keep up.  If the oil is hot this could be a problem.  

Remember to look for and replace the sealing washer on the filter housing - a friend tried to put the filter cover back on with two washers and it didn't work too well.

[Cees Klumper]

I also drain the oil cooler contents each oil change. And I make sure the engine is hot so all the oil is nice and fluid and comes out easily - indeed make sure you have a large enough container to catch all the old oil and get your hand out of the way when it starts to poor. I'm sure you know about the 'garden hose washer' that is supposed to be inside the oil filter housing, or the new filter will not have much to do. And make sure there's not more than one large thin round seal in the oil filter housing.
Good luck, it's an easy but important job to do at least annually.

[66andBlue]

Just to be complete, Haynes says (in Nm):
Oil pan drain plug - 41
Oil filter bolt - 41
Cooler plug - 25

I was interested in the number for the cooler plug because I could not find it in the Mercedes "Technical Data Passenger Cars" (probably because it is not a MB part).

Checking up on the other numbers in the MB data book reveals a difference from the Hays data:
Oil pan drain plug - 5 mkp = 49 Nm
Oil filter bolt - 4 mkp = 39 Nm

[Mike K]

Thanks to everyone for their valuable input, it's a great help and much appreciated.

Best,
Mike

[ja17]

Actually the oil coolers on the 280SLs are steel and and brazed together. They are hard to damage. The coolant radiator is copper and soldered together,  the drain plug on it can rip the lower copper tank if it is stuck. I prefer to pull the lower radiator hose rather than unscrewing the drain plug for removal of the engine coolant. I have not had any issues with plug removal on the steel oil coolers.

The most important thing on an oil change is to use a good OEM quality oil filter, and absolutely make sure the inner rubber filter seals are installed and are fresh. These inner rubber seals do not come with the oil filter like the other seals. They must be ordered separately. See the tech manual, there is lots of info and part numbers. If these inner filters are not in place the engine oil will not be filtered. About half the cars have these inner filter seals missing!

[m300cab]

be careful not to over torque the oil filter housing, they can crack.

[ja17]

Yes the oil filter housing is especially prone to crack when they have two O-rings  accidentally installed.

[Mike K]

I did the oil change over the weekend; drained the Sump, Oil Cooler, Filter Housing and changed the oil filter, all rubber and copper washers.
BYTW I was pleased to find that the rubber washers in the oil filter housing were all in place including the ”garden hose” washer.

Problem:
On refastening the the Oil Cooler drain bolt I encountered a problem. The recommended torque setting for this is 25Nm, which I set the torque wrench to, and just as the bolt was starting to tighten the threads stripped and the bolt started turning freely. This bolt seems to be an 11mm or 7/16 in. thread bolt which appears to be a non standard size here in Europe.

After about 15 minutes of cursing,    I composed myself and with some plumbers hemp and Loctite Copper Gasket Maker covered the bolt threads. Using a spanner, NOT a torque wrench, I managed to turn the bolt slowly and gently until it fully tightened.
Problem solved no leaks!

Moving on to the sump plug, in order to avoid a repetition of this near-disaster, I covered the sump bolt threads with Hylomar AF non-hardening sealant, placed the copper washer over it and hand tightened the bolt with a normal spanner. Again all nice and clean, no leaks.

Tightened the Oil Filter bolt the same way, (without using any sealant), only the small metal washer. Again no leaks at all.

The bottom line- my .02c  to anyone doing this job, be aware. I’m not sure about the recommended torque settings for these bolts.
As pointed out earlier in this thread, there’s a discrepancy between the torque settings in the BBB and Haynes.

Hand tighten with a spanner and some sealant around the bolts seems to have worked perfectly.

Thanks to all for their input.

Best,
Mike

[Cees Klumper]

Good going Mike, sorry you had the issue with the oil cooler plug. I never use a torque wrench on bolts like this, hand tighten by feel with new (crush) washers and have never had a leak. I guess you will just repeat the hemp/gasket maker trick each oil change.

[Mike K]

Thanks Cees I'm with you.  Hand tighten by feel seems the best way.

Best,
Mike

[Mike K]

Update- When I did the oil change I replaced the old 15W50 Shell oil with Elf Retro2  20W50.
Prior to the oil change there was a slight amount of oil seepage around the oil pan gasket.
I'm pleased to report that this oil seepage has since completely disappeared and it's all bone dry.
FWIW, in my instance it reinforces the idea of using higher viscosity oils in these cars.

Best,
Mike