Will I still Get Filtered Oil If I Block Off My Oil Cooler Lines or Ports?
 

There was a question a Month or so ago if for some reason you had to completely block off the Oil going through the Oil Cooler Circuit; if when the Oil Cooler Thermostat opened; Oil that was supposed to go through the now blocked off Oil Cooler Ciurcit would have no place to go but through the Oil Filter Bypass Valve (and that would give you unfiltered Oil).

The answer is yes you will get filtered Oil.

The answer is on page 5 of the Manual section 18-005.

LOL, have you considered putting your researched answer on the end of THAT THREAD ?

My turn to be Lazy.

Actually I do not remember enough about the other thread to search for it in a reasonable time.
Also to day I am trying to get my Car back together after removing the IP and the Oil Filter Housing.
(on both the Gaskets leaked Oil where they attached to the block.)

This thread is at least as interesting as the "here are pics of my new 300D I just bought Threads.

I'm still unsure whether that will always be the case

My copy of the FSM has been badly scanned - so it is hard to see - but have a look at this diagram which is on page 11

http://www.peachparts.com/shopforum/...1&d=1303234961
I understand that in the world of the ideal OM617 the oil filter housing is meant to behave as described in the FSM but I was thinking that in the real world it may (just MAY) behave differently.

The oil enters at arrow "a" as shown above - it goes through a "star valve" that's number 16 (you can hardly see that from the crappy scan though).

The star valve acts as a non return valve so the oil filter housing doesn't empty via this route when the oil pump (=> engine) is stopped.

The control valve (12) and the thermostat (11) would normally open to allow flow via "A" round the oil cooler and back to "B" at a temperature of about 95 degrees Celsius and higher.

If "A" is blocked then the oil should in principle flow upwards through the little gap next to the spring for parts 11 and 12 and into the coarse filter part of the of the filter element and back into the engine. If there is enough pressure the oil should also reach the fine filter part of the filter element above. I understand from the FSM that this gap is smaller than the normal route to the filter - the normal route is restricted as the flow is encouraged to flow via the cooler. I'm not sure about how big this gap is though as I haven't been able to get hold of the special tool to remove the thermostat housing to check.

I've been worried that if people just block off the flow at "A" the pressure relief valve could be fooled into thinking that there is a blockage in the filter as the flow is already restricted going into the filter (as described in the FSM and above). On an older car with less than ideal conditions in may (just MAY) cause the pressure relief valve to open and so you then get unfiltered oil flowing back into the engine.

That is why I think it is probably safest to either remove the thermostat if you block off "A" or alternatively just connect the two unions "A" and "B" together with a bit of pipe.

If you join the two unions "A" and "B" you can be assured that the filter housing is working as well as it should be albeit with a really crappy "oil cooler" (<= just a bit of pipe that runs down the side of the filter housing).

I too am skeptical that all the downsides are realized...MB does not do anything halfway or without a reason... I did not read Army's post , sometimes things are designed where only when something else messes up... gets blocked lets say for this example... that the engine might not be toasted as a result of the backup design element...

The thing about getting it to the other thread END is so people who find that thread will see your excellent answer.... sorta the purpose of some of these threads... LOL

I used the 617.952 manual.
The whole outer portion of the Oil Filter is exposed to the same amount of Oil Pressure.

With the exception that there is a spring loaded Valve at the bottom tube that extends from the Oil Filter Cap; when that spring tension is over come the Fine part of the Oil Filter also has Oil flowing though it but at a low flow rate due to a single less than 1/16" hole at the top of that tube that restricts the flow.

I am guessing that at Idle speeds no Oil is going through the fine bypass section of the Oil filter but have no way to tell if that is true or not.
The Bypass Valve reacts to a difference in pressure between the inside and the outside of the Filter.

Unlike a simple Pressure Relief Valve in normal use the Bypass Valve has Oil Pressure on both sides of the Valve; Oil pressure on the dirty Oil side and the clean Oil side.

The manual has the Bypass Valve opening at 3.5 bar (about 50psi) of differential pressure.


Yet when I put a test Gauge on my Engine and was getting 97 psi after first starting my Oil Filter Bypass Valve was not opening and given me dirty Oil during idle; because it had nearly the same Oil Pressure on both sides of the Valve.

So If you Oil Filter is OK I do not see any reason that a blocked Oil Cooler Outlet port would cause the Oil Filter Bypass Valve to open.

So you're not playing ball because you feel this information is in the wrong place?

I don't quite go along with the first statement that you made about the outer part of the filter being exposed to the same amount of pressure.

This is an oil filter not a bled hydraulic system. Without the presence of air I would guess that to be true - but I think the oil filter set up will be more variable. I haven't been able to check this though - but I have big plans! (I've always got big plans I'm still sourcing equipment to measure glow plug output voltages...)

As for the second statement that I've highlighted I agree so long as the filter is OK you are unlikely to have any trouble - BUT how can you measure the condition of the filter when it is in the housing? Service intervals are set to so many thousand miles / kilometers after which it is assumed that the filter is old and so it gets changed. Would you have to change the filter more frequently because the flow through the filter is not as good as it should be? I think perhaps anyone who just blocks off the oil cooler unions ought to think about that!

I am some what perplexed by this. We have 2 very knowledgeable members with opposing views.
I have heard from many MB trained mechanics that one should never block the cooler lines.
I first heard this for a 280 motor. Something makes me think it even gets a mention in that stuff I sent you Army. I thought that the oil thermostat actually restricted the flow bypassing the cooler once it heated. A bit like the coolant thermostat. Not having ever needed to pull one to bits, I cant say for sure.
Maybe its a rule that applies to some of the MB motors & not others. As a rule, I would be against removal of the oil cooler anyway. I guess that we dont need to consider it if the cooler is kept in the system.

Thanks for the input layback40 - from the information in the FSM (thanks) it does say that the thermostat diverts the oil from the usual route to the filter towards the oil cooler.

I'm probably not being clear enough about my opinion:-

(and it is only an opinion!)

I'm saying that under ideal circumstances blocking the oil cooler unions off probably won't do any noticeable damage - but - if things are less than ideal (say dirty oil / leaking O rings in the filter housing / dirt / bad luck etc etc) then people who simply block off the unions could (and I stress COULD) possibly be in a position where the system no longer functions as it should:-

Filters may not be useable for as long as prescribed by the FSM; in the worse case scenario the filter doesn't filter anymore because the relief valve operates because it thinks the filter is clogged due to reduced flow induced by the thermostat.


Deep breath! Here's the punch line!


If you wish to remove the oil cooler I'm advocating the addition of a pipe that runs from the bottom union to the top one so that the filter housing assembly operates as it should.


PS I don't think that I have even a quarter of the experience of diesel911 - but it is flattering to suggest that I'm on the same playing field. I'm still a newbie!

I've only ever owned one Mercedes.

The bypass valve responds to pressure differential through the filter, not to reduced flow rate to the dirty side of the filter. It should not "think" anything unless the full-flow filter element is obstructed. (The relief valve serves an entirely different function, which is to control the upper oil pressure limit.)

Uh oh I feel a slap on the wrists coming on - I've done it again - the bybass valve is the one I'm talking about... (relief valve is on the pump - not even in the filter housing)

I understand what you say about the filter element being obstructed - and I agree - but - the obstruction could also come from the operation of the thermostat control valve couldn't it?

In the picture I posted the bypass valve is number 9 (this opens with a differential pressure of 3.5 bar)

The control valve is number 12 this one works in combination with the thermostat.

This is frustrating - I'm getting the impression I'm not communicating effectively!
 

Let me try another way of explaining.

The control valve (12) controls the way in which oil will flow into the filter.

When the oil is cold the oil flows through the control valve and above into the filter from below.

When the oil gets warm enough that the thermostat opens the control valve the flow of oil can go two ways:-

Way one - as before straight up

Way two - round the oil cooler and back into the oil filter housing





Eventually when the control valve is completely open the the flow of oil via "Way one" is restricted to a small amount that has been calculated by Mercedes to be enough oil for the engine if the oil cooler line is temporarily blocked by cold viscous oil.



So in principle all should be OK in an ideal world. No arguments from me here!



However, we don't live in an ideal world so I'm suggesting that if you wish to permanently remove the oil cooler - hence always having a blockage there! - then perhaps it is worthwhile considering that you are putting your system purposely in an emergency design situation (albeit a situation designed by Mercedes). Wouldn't it be better to either

1) Remove the control valve - so the flow of oil is always going to be as good as it could be?

2) Put in a pipe on the outside of the filter housing so that there is no "blockage"?

Interesting! I've never looked closely at the oil circuit and just took a look at FSM 18-005 Oil circuit, oil pressure, pressure relief valve and oil filter. Pretty sophiscated oil filter!

From the diagram and description, it does appear that if the oil cooler is blocked or bypassed (note the oil cooler is essentially blocked by the thermostat with a cold engine), the engine will still get filtered oil via the main flow filter component (24a), which is separated by a seal to the bypass filter component (24).

Up until now, I didn't know there are 2 separate filter components in the filter element. I'm gonna have to cut one open to have a closer look and see how it is constructed.

I don't think so. That's not going to cause a differential across the filter element. But, bottom line, I am not at all convinced that blocking the oil cooler plumbing is an acceptable strategy.

The bypass valve and the bypass element are two entirely different concepts that share common nomencleture. One has little to do with the other.

I agree with ya. I did not say they are the same. One is a valve, the other is a filter element, 2 entirely different items. The only common nomenclature is the word "bypass".

If you remove the Oil Filter Cap and look inside and then remove the Filter you can see that the Oil inlet and the whole outside of the Oil Filter is exposed to the same Oil. So what ever pressure that Oil has is around the Whole outside of the Filter.

This is a different subject from the above.
I have measured the Oil Pressure of the Oil from the Center of the Oil Filter Cap and that would be the Oil that has gone through the Bypass/Fine section of the Oil Filter and also the Pressure out side of the Oil Filter and with a New Oil Filer the Pressures were the same.

Ihave other stuff hooked up on the Oil Filter Cap now but in the pic you can see where I drilled through.

I agree with that too! But that's not really the point - that's been handled in the "original" thread that diesel911 talks about in post#1 - not that I can find that bloody thread now of course!

I think it will / could cause a pressure difference across the filter as the amount of oil flowing through the control valve and up (Way one as I've called it above) is restricted. With an oil cooler in place there would be additional supply via the oil cooler (Way two) which would make up for the restriction.

If there is no supply via Way two then the filter just isn't getting as much oil as it would... blah blah blah (Sorry I'm trying to keep this short and sweet - honest)

Interesting set up there - have you got any data?

As for the way in which the oil goes into the filter from the outside in - I have seen that and it is clearly shown in the schematics in the FSM as well. I still don't think the pressure would necessarily be the same at all points all the time though - I'm a stubborn git I know!

However, I'm not so stubborn not be interested in your measurements. I am very interested in your measurements.

If the Manual is to be believed the Thermostat Control Valve does not block the the Oil Flow when it is completely opened.

I think there must be some poor translation wording in the Manual that is making things more difficult.

The Mercedes I have is the only one I have ever owned. In the 3 years + I have owned it I have had to Cram to learn stuff about it. Apparently the learning never ends.

Does anyone know what the micron ratings are for the 2 filter sections?

1. Main
2. bypass

It sounds like they are physically separated and requires a seal (25) on the clean side so they get routed to the proper ports b (engine bearings) and c (oil pan).

I think it would be more correct to say that the normal flow is not completely blocked. That leaves the possibility that the resulting partial flow might not be all that ideal on a permanent basis.

Are the internals of the filter housing rebuildable? i.e. can it be disassembled? I have access to a spare filter housing and would be interesting to have a look inside.

Mercedes clearly did not make it as easy to get at the Thermostat as they did the Bypass Valve that has a sloted Retainer.

What amazes me is that the ports the Oil passes through are not very large.

The Oil Filter Thermostat is around $40 each.
The Pic of parts shows that there are part numbers but that does not mean parts are available.

Yeee ha! That's what I'm saying / trying to say!

Yes in principle you can take it apart.

I was planning to do so and then publish an expose... in my opinion there isn't enough information about the filter housing on the forum - I'm glad this is now in the process of being remedied.

Anyway I fell at the first hurdle - I couldn't replicate the special tool to remove the end screw caps to get into the guts. Also I'm running out of cash for this project and can't justify ripping that bit apart as well was the rest of the car. I'm quite sure I've found the one bit that is OK.

So funola if you have a spare one that you are planning to pull apart please post pictures of the guts and gore.

Oh yes - when we've finished talking about the specific oil cooler removal pros and cons can we talk about why the filter has coarse and fine element sections? If I remember correctly I've got some good information about that. (I'm checking my source tonight - bed time reading - how sad!?)

All of this could just possibly be an over engineered system.

Most cars branch a good volume of pressurized oil through the one element filter, and be done with it. Some have and in-line oil cooler that is always-on, not thermostatically controlled.

MBenz has two section oil filter, pressure bypass, temperature regulated oil cooler diversion, and ?? whatever else... yadda yadda.

But what I'm really wondering is why anybody would want to bypass the oil cooler if the car has one? I mean pinching off in case of a leak I understand, to get home... but beyond that why?

Maybe this over engineered oil filter system has something to do with the legendary longevity of these engines?;)

no doubt part of the equation!

There is 2 big long Oil Filter Threads (in the DIY section) that talk about them nearly to death.
Rather oddly the Filter Companies only can tell you what Micron level the Paper Element part of the Filter is.
The companies that make Filters that use "Cotton Jin" in the Upper/Larger/Finer part of the Filter seem to have no idea how well it works.

List of the Microns of some filters (617.952 types)

http://www.peachparts.com/shopforum/showthread.php?t=247597&highlight=Bosch+Oil+filters&page=3

When you take apart the Filter take a look at the item 53 circled in Red. It is a plate that devides the inlet from the Thermostat and acts as a spring seat for both.

If you notice the plate has cutouts in it for Oil to flow. Also because of the cutouts the Thermostat cannot block the Oil Flow.

The Plate barely shows up in your scanned cross scection of the Oil filter.

In the last thumbnail item 53 is pointed to by the Blue Arrows.
The Oil Flow through the plate is the Red Arrows.
I am betting there is plenty of room for Oil circulation because the Thermostat cannot block the flow going through the plate and does not appear to block the Passage going towards the Filter Element.

The problem is that we can speculate and speculate until the cows come home.

We need some measurements.

Has anyone ever come across the oil equivalent of a leak down tester?

http://en.wikipedia.org/wiki/Leak-down_tester

Does it exist or do I have to invent it?

It's hard to see the details from the poor drawings but it appears the holes in the plate (item 53) is to allow oil to flow to the thermostat (item 86). The actual seal / valve of the thermostat is at the tip (item 86).

Does anyone know what the oil filter housing is like and what internal components it has if the vehicle came from the factory without an oil cooler?

Thats a good question. All I know is the oil cooler line attachments are not drilled out. I would love too know what the difference is inside, but not enough too take either of mine apart:D

So you've got both then? An OM617 with an oil cooler and one without the oil cooler then?

I know it is difficult considering how far apart we live but just park both cars outside my house for bit won't you... (I don't need the keys!)

I don't but my guess would be that it is the same but without the control valve and thermostat.

Actually my Euro 85 240D was imported from Rotterdam, had a plaque on it "J. VanDisk&Zn.B.V.,Rotterdam" with the MB star so I guess that was the dealer. I dont know when, I've owned it for about ten years.

I put a Euro O/F housing on an 80 engine that I rebuilt for my 79 240D a few years ago and the 617 in my TD, of course has an oil cooler.

My cars are under cover and guarded with Bangle tiger traps and the trunk monkeys are kept well fed :D

Cloak and dagger @ peachparts.com
 

The following information has fallen into my lap.

I think you might find it interesting even though the author felt it was repeating what has already been said: I think it gives a bit of an insight into how Mercedes have tackled the design of other engines - even if they are petrol and not diesel.

We diesel heads like to think that we are alone and special - but the manufacturer will of course use the knowledge / components used in other products... so here goes:-

<Start quote>

Hello Army,quite an interesting and important discussion !
Managed to find a pic of what the most recent oil thermostat supplied by MB looks like( MB 1171800175):

http://www.hehlhans.de/280ge/bilder/...el-thermo2.jpg

…this one is used in OM616,617,M110(vertical thermostat arrangement),M102,M116,M117

Source: http://www.hehlhans.de/tipp98-8.htm#b12

Just for a comparison,this is the thermostat of a M110 engine(horizontal thermostat arrangement, see pics)-A1101800075(used only on M110 engine).

http://www.hehlhans.de/280ge/bilder/...hermo-alt2.jpg

The more interesting scheme is that of M110(horizontal t-stat):

http://i1201.photobucket.com/albums/...g?t=1303426132

Note the special cutouts of the t-stat control valve, serving to divert the oil flow as the element expands. The M110 oil filter top also has a small bore (f) from the oil channel to the filer bottom(my guess is that it serves the same purpose as the small space the OM617 t-stat valve leaves-to compensate for a possibly hindered flow thru the rad at low ambient temperatures because of the quicker cooled oil).But the small bore (f) on the M110 filter top cannot guarantee adequate flow to the filter element when the t-stat is fully open AND the outlet to the cooler is plugged. Moreover, the by-pass valve on M110 is located in the oil filter top section(and has no direct entry to the oil coming from the oil channel-the oil has first to pass thru the t-stat arrangement or ,God forbid,the small bypass bore !).Block the cooler, let the oil heat up, rev it -disaster strikes(hence the warning in the FSM).

Here is M110 filter with vertical t-stat setup(om617 t-stat):

http://i1201.photobucket.com/albums/...g?t=1303426303

As you suggested, although the OM616/617 by-pass valve is exposed directly to the incoming oil from the pump, it’s better with the oil radiator to remove the t-stat too (or connect the outlet and inlet bores by a tube) in order to prevent the introduction of unfiltered oil.

<End quote>

The schematics and pictures are of particular interest

Enjoy!

You could also argue if you take away the over engineered systems then you end up with a bloody Renault!


Ahhhhhhhhh why buy German and turn it into a French car? Pah!

I was wondering if you guys know whether it matters which of the oil cooler hoses went where? By this, I mean you have two oil cooler hoses coming from the oil filter tower going to the oil cooler....one goes to the top fitting on the oil cooler and one goes to the bottom fitting on the cooler. I took off the oil cooler lines to drain the oil cooler last night.What would happen if you got them mixed up and reversed them?

I just cut open my NAPA gold oil filter last night. I changed to a Baldwin filter...it says made in the U.S.A on it and was half the price. They are different, in the way they are constructed, but I am not sure if the difference is significant or not. The tube that goes through the middle of the Napa filter is hollow all the way through, whereas this baldwin filter is split in the middle with a rubber boss so that the rod from the filter tower lid goes through. I'll add some pictures of what I mean when the Balwin filter comes out.
I drained the oil cooler when I did this latest oil change and when I went to check the lines coming to the oil cooler.... they felt cold. I went for quite a test drive and I don't think that I am getting oil to the oil cooler and am wondering if I got the lines reversed or if this Baldwin filter design has something to do with it?

Also did a coolant flush and changed to Zerex G-o5 and adjusted the valves. The engine felt hotter than usual. but shows normal coolant temp.? maybe the oil cooler is air locked? Is that even possible?

I doubt if swapping the hoses at the oil cooler end would make much of a difference - but I'm surprised you've got enough hose to do that.

I'm very interested to see pictures of the oil filters when you get them dissected.

There is a procedure in the FSM to check whether the thermostat is working or not chap 18-120 (one whole long page long). Basically you stick a long thermometer into the dip stick tube and see if you get a sudden change in temperature at about 95 degrees C