Oil Pressure at Oil Cooler for the 617 motor, Anyone know?

[warmblood58]

Removed my oil cooler as a result of an accident and since I have an extra oil cooler, I took it to a radiator shop to have a drain brazed in. Owner of shop seems concerned that oil cooler is "high pressure" - how high is pressure here anyway? I have been loosening my lower oil cooler hose and draining this way -even after the sump is just dripping I still get a quart or more of oil. I don't over tighten lower hose mount but since those threads are soft, I would rather just pull a drain plug as this is quicker and less taxing on the soft aluminum threads. Anyone know what pressure is in psi at the oil cooler? Can't be much I am guessing -

[vstech]

should not be much pressure. it drains into the return for the bypass I think. it's going to be less than 100 psi though. I am pretty sure the oil cooler hoses are THIN, so they can't hold much pressure!

[warmblood58]

Originally Posted by vstech

should not be much pressure. it drains into the return for the bypass I think. it's going to be less than 100 psi though. I am pretty sure the oil cooler hoses are THIN, so they can't hold much pressure!

hmmm . .. when I think about it, they are both tough and seem to be high pressure material, in fact, I had them made once and they failed so I went oem replacement with no problems.

[vstech]

I just changed my hoses with OE, and the rubber is very thin and flexible. I was expecting much tougher hose. probably rated at 250psi or the metric equivalent

[warmblood58]

thanks vstech, ok, who has the definitive answer on oil cooler psi?

[79Mercy]

There is a drain plug on the bottom of the oil cooler on my W115, i drain the oil cooler at each oil change. Dunno if that helps you in with decision or not.

[warmblood58]

Originally Posted by 79Mercy

There is a drain plug on the bottom of the oil cooler on my W115, i drain the oil cooler at each oil change. Dunno if that helps you in with decision or not.

not on my cars otherwise I would not be going thru this effort -

[aaa]

Somewhere around 100psi (90?) is the max for the oil pump, it has a relief valve that limits the pressure. Oil cooler sees the same oil pressure the rest of the engine does, when the thermostat's open.

[charmalu]

You probably don`t want to braze the cooler, it is aluminum, and you would want to alum weld it. Iam pretty sure the ends of the cooler are probably fairly thick to weld on. there may be an alum brazing rod, when i think braze, Iam thinking of the bronz brazing with gas.

here is a picture from the "Nipple repair thread" shows the thickness of the tank in the one picture.
http://www.peachparts.com/shopforum/members/jdr01-albums-oil-cooler-nipple-rapair.html

Since you are removing the lower hose to drain the cooler, probably a good idea anyway to weld on a drain. eventually the steel threads of the hose will wear on the alum threads of the cooler.

The replacement oil cooler line hoses seem a lot thinner that the originals I removed a few years ago. then maybe they seemed thicker because of the age, 18 yrs of being cooked under the hood.

I since replaced them with Parker Push Lock, using their blue hose. it been on there at least 6 yrs w/o any problems.

Charlie

[warmblood58]

Originally Posted by aaa

Somewhere around 100psi (90?) is the max for the oil pump, it has a relief valve that limits the pressure. Oil cooler sees the same oil pressure the rest of the engine does, when the thermostat's open.

excellent, thanks!

[Jeff B]

You could just put a "t" in the lower hose, & plug the extra port in the "t" as the drain.

[t walgamuth]

Given the potential for massive damage in case of any failure I would avoid modifying any portion of the oil cooler and hoses.

If the MB engineers didn't think it was worth putting it in why should we?

Having torn the thin aluminum of a mb oil cooler accidently when removing the lines I am wary of anything around them. Adding a drain plug seems like a fool's errand to me.

[layback40]

Originally Posted by t walgamuth

Given the potential for massive damage in case of any failure I would avoid modifying any portion of the oil cooler and hoses.

If the MB engineers didn't think it was worth putting it in why should we?

Having torn the thin aluminum of a mb oil cooler accidently when removing the lines I am wary of anything around them. Adding a drain plug seems like a fool's errand to me.

X2
For the sake of draining 1/2 a pint of oil, it has no merit.

[warmblood58]

Originally Posted by layback40

X2
For the sake of draining 1/2 a pint of oil, it has no merit.

Sorry, it is always more than a quart even after sump has slowed to a drip rather than a pint. Mercedes did put drains on other oil coolers, just not the 617 - a pretty low tech solution and common out there in the automotive world.

[layback40]

Originally Posted by warmblood58

Sorry, it is always more than a quart even after sump has slowed to a drip rather than a pint. Mercedes did put drains on other oil coolers, just not the 617 - a pretty low tech solution and common out there in the automotive world.

I find that if I have the motor nice & warm when I do a change, most of the oil in the cooler drains back as the thermostat on the cooler is open.
It works for me. I have tried blowing the cooler & lines out after draining & only ever get 1/2 a pint out.