When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Weird, oil path/gallery between 2 components but no gasket
Gents,
Why do you think this is so ?
Let me explain the question.
I will be doing 10 years preventive replacement of the 2 o-rings + front crankshaft seal and all plastics used as timing chain guide , as discussed in this post : https://mbworld.org/forums/e-class-w...r-replace.html
So I am slowly taking my sweet time learning on how to do it properly.
Something is bothering me.
01. The oil filter reside on what is known as Timing Cover. Photo is below.
( 1 to 4 I would replace them )
The oil cooler is at the engine block.
My question is , why there is no gasket between these two oil path flanges ?
.
The oil flow is as follows : Oil Pump at engine block >>>> Oil Cooler at engine block >>>>jump over to Oil Filter at timing cover>>> jump back again to engine blockand distributed all over the engine.
This is 55 PSI we are talking about and if those 2 oil path flanges are not perfect, the engine block can loose oil pressure.
I seen some machining of two surfaces of two different component which are so good, gasket is not needed.
But is this the case for the M276 ?
Not sure if its needed or not but have scene many similar items on other vehicles. Depends on the pressure and flow and mating surface. If proper surface, a very very thin silicone or sealant will do a very good job.
That being said I just replaced rear shocks on my e250, why on earth would you use 4 different fasteners on the wheel well liner? I mean seriously, you have the 10mm plastic nuts, the push pin plastic guys (not sure of name), the T25 torx screw, and the 10mm wide body screw. Makes absolutely no sense what so ever and I have scene alot of different engineering type mechanical systems from steam turbines, JP4 turbines, gas engines of the rotary-opposed-v-inline, and the various setups they went into. Replaced aircraft fuel bladders, ship antennas, cleaned my fair share of heat exchangers, replaced motors-pumps-RO units-refrigerant systems-O2 generators.... list goes on.
Anyhow rant over. Its probably to save money, one less valley to machine for a O-ring.
It's probably fine if there's a little leak, pressure loss will be very low and any leak will still drip down into the sump.
If you want to perfect things, you can apply a small layer of sealant on the mating surface. Stay away from silicon, as this might harden and clog up the oil system. Products such as Loctite 574 or Hylomar Gasket 2000 are more suitable for this application. I'm sure that the Hylomar product breaks down in oil, specifically to prevent any clogging up. I think the loctite product has the same properties.
Hopefully the leak is very very small. I know it will go to timing chain oil wet area, I just want to make sure my crankshaft and camshafts and VVT sprockets get best oil pressure as design.
MB recommends this :Old gasket softener Loctite 7200
I just replaced rear shocks on my e250, why on earth would you use 4 different fasteners on the wheel well liner? I mean seriously, you have the 10mm plastic nuts, the push pin plastic guys (not sure of name), the T25 torx screw, and the 10mm wide body screw. Makes absolutely no sense what so ever.
LOL, I have removed that hairy liner like 10 times and the under the car long noise shield too, like 4 times. Front wheel well plastic liner, also at least 10 times.
I actually now understood MB "flavor" for fasteners ...the why and where
OMG that's another top notch study, thank you once again Master Surya. You have located another important aspect and potential gap in our engine design.
We likely have a pressure drop with full pump pressure right ahead of lubricating crankshaft journals. It's located on the timing cover before and after filter.
"carefully built"... self-sealed ?
The surfaces that get RTV next to those that don't get any sealant GUARANTY PRESSURE LEAKEAGE.
This will be a proven true statement if these seal surfaces are machined on the same level plan. Fair enough ?
MB specifically wants no gasket and no sealant - Go figure...
connector for oil pump solenoid
Small world.... isn't this our new friend: the oil pump solenoid harness?
I guess if we have numerous losses then it is our best interest to have normal oil pressure instead of low, true? What is Mercedes up to....?
-- Do we want to seal these oil conduits to preserve pump pressure ?? Good old paper gasket perhaps instead of silicone ??
MB oil filter use to have its own leaky gasket job, like the heat-exchanger. I wonder if the best insurance is not to drive with dipstick port actively venting??
+++ Does Master Tasos not pay attention to this leak? He's seen hundreds of these covers (different filter housing on M153/7)
+++ Incentives: filter + 5W40 grade
the inlet eye being so much larger than outlet means it's going to be sensitive to back pressure from dirty filter cartridges - Standard leak will resume with clean cartridge because non-existent seal won't get destroyed.
Tasos does run high viscosity oil in UAE heat. ✌️
LOL, I have removed that hairy liner like 10 times and the under the car long noise shield too, like 4 times. Front wheel well plastic liner, also at least 10 times.
I actually now understood MB "flavor" for fasteners ...the why and where
The only MB flavor I think is saving money, or they squished several engineers plans together and wanted them all to get credit for contributing lol.
Damn, this quest for I-NEED-TO-CONFIRM-LEAKY- FLANGE-OR-NOT is time consuming, but I will do it.
Most people won't care, but I do care because that is how my brain is wired when it comes to a product I held dear in my heart....my Learning Lab called an E400.
Here is a logic test :
01. On all sides of this timing cover, MB wanted sealant of BEAD WITH A HEIGHT AND WIDTH OF 3MM ( +- 0.2MM TOLERANCE ).
This is a flexible sealant, not metal one, so it will compress.
The tightening torque is 20Nm, how much will that compress a 3mm thick Loctite sealant 5970 ? Let say 1mm reduction of thickness/height.
02. So in theory, the 2 oil flanges/path/gallery must be "taller" for its surfaces combined ....to 2mm than the timing cover side mating surface which needs gasket of 3mm before compression... Make sense ?
Assume +1mm extra "taller or thickness " of each side of the oil INPUT and OUTPUT flanges.
Why design such a risky thing ? If zero leak is the target or controlled leak ?
MB is not consistent. Attached 3 PDFs.
In M276 3.0 or 3.5, the sealant bead thickness/height and width is 3mm, but in M278 and M157 ( same platform ), they wanted 2mm ? WTF ???
==============
Anyway, I will find ways to inspect how the mating surfaces of the two oil flanges behave in terms of its mating surface pressure points.
I can get 1, 2 and 3mm Polyurethane sheet to act as simulator sealant for the timing casing perimeter
I then buy this FujiFim Prescale pressure monitoring paper.
This special Fuji Prescale paper I will put on the 2 oil flanges surfaces and see , do both side mate well at 3 different thickness of the simulator side sealant at 20Nm ?
> Using marking film:
I really like the way you want to test surface contact using a type of sensing film.
I just came out of the dentist chair recently for a crown cap. Dentists use the same technic to visualize bite gaps with a sort of blue paper to adjust contacts surfaces - - that is what you're doing!
> Combination of Block vs. Cover surfaces:
It may be the cover surfaces are all machined on the same plan BUT the block is machined on two separate plans to allow for a almost good flange contact while outside surfaces get Loctite.
> Surface height details:
The matching of surfaces height is what dictates the gap remaining at filter flange.
1-- Block surfaces match cover height = serious leak!
If all surfaces height are matched then there is NO room for Loctite sealant AND filter in/out flange to stay in contact - The sealant guarantees concealed internal leak where we want it the least.
2-- Block or Cover not match height = limited leak
if all surfaces height are not matched then there is room for Loctite sealant while filter in/out flange also stays in nearly good contact.
> REMEDIATION fixing
-- Even if we can prove surfaces are allowed to almost butt well similar to chain tensioners, will we be satisfied without any seal or do we want to seal our oil pump output for maximum available pressure ?
fastener location vs. flanges
If surfaces are expect3d to sel-seal, the fasteners ate poorly distributed around flanges. No particular effort is evident to distribute torque down, specially near upper part of Inlet flange.
-- WHY is MB carefully not sealing the flange surfaces around filter base??
- Is it to prevent chunks of silicone lips from plugging crank passages ? This is a known killer issue! Using a shaped custom O-Ring then is perfectly good as us3d by Honda on oil pumps.
- Is it to let pressure drop when dirty filter back pressure is too high?
- If the flange allowed to leak in order to protect pump seals in case filter gets compromised... if pump has seals.
The one classy solution would to use a cone shape fitting: "no seal, no leak". It's 100% impossible to have four cones of that shape match.
-- It sounds like this is going to be a perfect case to recommend not keeping dirty extra old filter with long-mileage oil.
Combine that no-seal condition with pump solenoid to get amazing results.
WHY bias all systems with poor attributes to fail shortly?
I think I know that one
On a similar topic:
have you seen how Tasos has redesigned a better thermostat for high heat countries? I think he has it for sell.
T-stat cannot be removed. Tasos explains it provides a necessary bypass when installed.
✌️
Last edited by CaliBenzDriver; 11-07-2023 at 06:40 PM.
For my US brain thats almost 1/8" down to 5/64" roughly, thats a pretty big gap IMHO. Granted at the pressures it sees doubt it would break a relatively wide line of sealant. If proper surface prep and dry time that stuff can be pretty resiliant.
Off topic but had a mechanic blue checking a turbine half (steam turbine) and it ended up leaking. When we redid the blue check found out he put too much blueing on so it gave a false positive, once we did a miniscule film of blueing it showed the small valley <1mm deep by 10-12mm wide. Had to stone that area flat and replace the top half. These operated at pretty high pressures and were torqued to something like 1500 or 3000 ftlbs (cant recall which it was).
For my US brain thats almost 1/8" down to 5/64" roughly, thats a pretty big gap IMHO. Granted at the pressures it sees doubt it would break a relatively wide line of sealant. If proper surface prep and dry time that stuff can be pretty resiliant.
Off topic but had a mechanic blue checking a turbine half (steam turbine) and it ended up leaking. When we redid the blue check found out he put too much blueing on so it gave a false positive, once we did a miniscule film of blueing it showed the small valley <1mm deep by 10-12mm wide. Had to stone that area flat and replace the top half. These operated at pretty high pressures and were torqued to something like 1500 or 3000 ftlbs (cant recall which it was).
Yes 5/64" = very close to 2mm and that is a big gap indeed.
I have seen propeller techy using that blue contact dye to see propeller shaft cone/taper to propeller hub machining precision, I did not know that it can be as thick as you described...wow thank you.
1,500 ft-lbs..DAMN !!!
Good thing the FujiFilm Prescale is a fix thickness. Supposedly both papers are 0.18mm thick. http://www.spare.it/prescale-lettera...e-addendum.pdf
I have ordered the 2 sheet type. Up to 85psi and up to 350psi version.
This is more for my itchy hand and mind
> Using marking film:
I really like the way you want to test surface contact using a type of sensing film.
I just came out of the dentist chair recently for a crown cap. Dentists use the same technic to visualize bite gaps with a sort of blue paper to adjust contacts surfaces - - that is what you're doing!
> Combination of Block vs. Cover surfaces:
It may be the cover surfaces are all machined on the same plan BUT the block is machined on two separate plans to allow for a almost good flange contact while outside surfaces get Loctite.
> Surface height details:
The matching of surfaces height is what dictates the gap remaining at filter flange.
1-- Block surfaces match cover height = serious leak!
If all surfaces height are matched then there is NO room for Loctite sealant AND filter in/out flange to stay in contact - The sealant guarantees concealed internal leak where we want it the least.
2-- Block or Cover not match height = limited leak
if all surfaces height are not matched then there is room for Loctite sealant while filter in/out flange also stays in nearly good contact.
> REMEDIATION fixing
-- Even if we can prove surfaces are allowed to almost butt well similar to chain tensioners, will we be satisfied without any seal or do we want to seal our oil pump output for maximum available pressure ?
fastener location vs. flanges
If surfaces are expect3d to sel-seal, the fasteners ate poorly distributed around flanges. No particular effort is evident to distribute torque down, specially near upper part of Inlet flange.
-- WHY is MB carefully not sealing the flange surfaces around filter base??
- Is it to prevent chunks of silicone lips from plugging crank passages ? This is a known killer issue! Using a shaped custom O-Ring then is perfectly good as us3d by Honda on oil pumps.
- Is it to let pressure drop when dirty filter back pressure is too high?
- If the flange allowed to leak in order to protect pump seals in case filter gets compromised... if pump has seals.
The one classy solution would to use a cone shape fitting: "no seal, no leak". It's 100% impossible to have four cones of that shape match.
-- It sounds like this is going to be a perfect case to recommend not keeping dirty extra old filter with long-mileage oil.
Combine that no-seal condition with pump solenoid to get amazing results.
WHY bias all systems with poor attributes to fail shortly?
I think I know that one
On a similar topic:
have you seen how Tasos has redesigned a better thermostat for high heat countries? I think he has it for sell.
T-stat cannot be removed. Tasos explains it provides a necessary bypass when installed.
✌️
Honestly I am kinda confused on how and why MB does what it does on the no-gasket for oil flange/gallery
I took a look at M278 timing cover and its more complex....but seems the same concept, OIL path get no gasket nor sealant.
It has its oil cooler on the timing cover and not on the engine block.
The oil cooler gasket #20 ( not DIY sealant ) below seems to only for coolant section.
.
.
If anyone failed to read the sealant path of M278 timing cover WIS, it will be a distaster !!!
At a glance that small channel , all of its entire length seems like a nice place for sealant .
In reality we need to seal only like 2-3 cm of each ends, as that channel is for coolant between those 2 holes. Why so complex ?
Yes Cali, I seen Tasos done some tropical climate thermostat. I forgot the detail though.
Wow, actually there is a TSB for that seal item 20 on M278 timing cover. https://static.nhtsa.gov/odi/tsbs/20...99679-0001.pdf Coolant leaking into the engine oil via the molded seal between the timing case and the cylinder crankcase.
Among others, we are especially lucky to have you two, @CaliBenzDriver & @S-Prihadi on this and several other forums.
THANK YOU, for not just your help but the level you take your research and sharing is beyond reproach.
Measurements that should be done:
1. height of the non-sealed oil passage flange compared with the oil filter housing mounting face to the engine block or front cover
2. height of the mating non-sealed oil passage flange compared with the mating surface on the engine block or front cover
By measuring 1 and 2, it allows calculation of the clearance, or interference, at the non-sealed flange interface. This should support the data collected by the pressure sensitive paper.
I seen EPC and the M276 teardown video a few times, but I did not spot the "missing" seal or o-ring.
Here is another oil transfer flange with no seal or gasket. And this belongs to the OIL PUMP ...damn !!!
So we pray it is a very good precision fit........
.
.
.
I was exercising my mind for when I have to replace that plastic guide of the oil pump chain, item #80.
So I took a closer look
How the hell did I miss this. I bought the plastic baffle for oil pump INPUT and its spare o-ring, and I missed the OUTPUT side of the oil pump ...LOL
11-05-2023, 06:27 PM
.
