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Oil Leak INSANITY!!!!!

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Old 07-04-2018, 12:12 PM
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Oil Leak INSANITY!!!!!

I'll try and be brief. Engine is 5.5L M273.

6 months ago I had an oil leak at the back of the engine on the passenger side. It turned out to be a leaking oil separator.

I thought lets go ahead with preventative maintenance and replace the 3 cam plugs back there. Well that was a bad idea.

Next day the oil leak on the passenger side is gone and I have a leak from the driver side.

I have replaced the small driver side plug 3 times in the last month and it still leaks. I run my hand behind the engine near the small and large plugs and only the small one has oil on it.

Last weekend I replaced the plug a 4th time. I even slathered on Ultra Black gasket maker. Let it sit for 24hrs.

Next day did a 20km drive and the leak is back. I GIVE UP.

Recommendations please.
Old 07-04-2018, 12:44 PM
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Damn man, that sucks to hear. I've been putting off the connector seal replacement between the engine and transmission on mine, just because it's a $$$$ labor job and I just had the transmission serviced. Drip isn't bad, just enough to bother me ever so slightly. (My mechanic says I'm too OCD, but he gets it)

Did you add lubricant to the back of the plugs, so that they slide in completely?
DId you clean the insert and the surrounding areas with brake clean or something in case there is any gunk preventing a tight seal?
Was the cap seal clean?
Did you push in the seal when it was level? Pushing when it's at an angle can bend the plastic, or snap the teeth depending on the cap.
Did you push in with a screwdriver to remove them? Could be that it pushed/buckled the metal surround a little

Those are the "go-to" points that come to mind whenever something is leaky after I tamper with it.

I'm sure you're certain but, could the oil be coming from somewhere else?
Old 07-04-2018, 01:31 PM
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Where is the connector seal located out of curiosity? I don't think the leak is coming from anywhere else. Its driver side rear. Right in the middle of the steering wheel as you look at the car.

Every time there was oil under the small plug.

Only thing I haven't done is oil up the new plug. Every time it when in flat. Last two times I put a lot of pressure on the cap. The hole is clean, I spray it down and run my finger in it and on the lip. All looks good.

Thanks for the insight bud.
Old 07-04-2018, 02:35 PM
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my first gut reaction is to think that the oil is not coming from where you think it is coming. Did you steam clean the engine and then drive it to track it down?
Old 07-04-2018, 02:43 PM
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Originally Posted by flybd5
my first gut reaction is to think that the oil is not coming from where you think it is coming. Did you steam clean the engine and then drive it to track it down?
Yea I spray it down with 3 bottles of brake cleaner. Spray from the top all the way down. Same location under the car every time. Same oil behind the stupid small plug.
Old 07-04-2018, 03:18 PM
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Brake cleaner??? Thats not steam...

How about a picture?
Old 07-04-2018, 03:31 PM
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Originally Posted by OUZO Power
Where is the connector seal located out of curiosity? I don't think the leak is coming from anywhere else.
Thanks for the insight bud.

Hmmmm.... Curious as to what is leaking. Can you try leaving a paper towel around the plug overnight? That way if anything leaks you know how much, based off the spread, and from where.

The connector seal is the part where your engine is mounted to the transmission. Basically the marriage point. So the axel, transmission, and engine have to be moved to get it off, cleaned and re-sealed properly. Hence, very labor intensive (aka $$$$)

Since I just serviced the transmission, I don’t wanna do it right this minute. When it gets a little worse then I’ll address it. Maybe I’ll throw in some upgraded clutch packs at that time to make removing the transmission worth it.
Old 07-05-2018, 12:31 PM
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Originally Posted by OUZO Power
Yea I spray it down with 3 bottles of brake cleaner. Spray from the top all the way down. Same location under the car every time. Same oil behind the stupid small plug.
Did you already replace the oil seperator? My ml550 had a bad seperator and it was building up so much pressure in the engine that it was blowing oil out of the oil cap seal.. I replaced the seperator on the back of the engine and that took care of it. I wonder if high pressure from that is blowing your plugs out?
Old 07-05-2018, 01:36 PM
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Originally Posted by flybd5
Brake cleaner??? Thats not steam...

How about a picture?
Brake cleaner does a great job at breaking down the oils and cleaning them off.
Old 07-05-2018, 01:38 PM
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Originally Posted by Anthony550
Did you already replace the oil seperator? My ml550 had a bad seperator and it was building up so much pressure in the engine that it was blowing oil out of the oil cap seal.. I replaced the seperator on the back of the engine and that took care of it. I wonder if high pressure from that is blowing your plugs out?
Yes. I replaced the leaking Oil Centrifuge Separator and all the cam plug. And the next day the small one on the left drivers side keeps leaking. I have replaced them 4 times.

You think the new Oil Centrifuge Separator just didn't work from the get go?

Thanks for all your help guys.
Old 07-05-2018, 04:09 PM
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Originally Posted by OUZO Power
Yea I spray it down with 3 bottles of brake cleaner. Spray from the top all the way down. Same location under the car every time. Same oil behind the stupid small plug.
Watch out with that brake cleaner my friend... It's not meant to be used on many different rubbers and silicones. It actually strips plastics/rubber of their embedded wax/silica properties that keep them soft/flexible. It accelerates the dry rot of hoses and housings.
If you do use it, make sure to thoroughly clean off all plastics with a strong jet of water to minimize damage from the residue. A strong, concentrated degreaser is preferred.
PM me if you want a list of great degreasers that don't damage plastics and rubber. I can also suggest some water-based products that will actually rejuvenate the plastics making them last longer if you're interested.
Old 07-06-2018, 05:50 AM
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Originally Posted by OUZO Power
Brake cleaner does a great job at breaking down the oils and cleaning them off.
No, it does NOT. That's like saying what WD-40 is a great lubricant, when it is absolutely not. WD-40 is intended to displace moisture, hence WD = Water Displacement. It also attracts a ton of dust which ruins locks, etc. Brake fluid (otherwise known as hydraulic fluid) is intended to be used in the internals of a brake system, and not for "breaking down the oils." Like has been said already, it has a bad effect on other things in your engine compartment. Like SunnyT said, I strongly suggest you go steam clean the engine to remove any trace of that fluid.
Old 07-06-2018, 10:34 AM
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Originally Posted by OUZO Power
Yes. I replaced the leaking Oil Centrifuge Separator and all the cam plug. And the next day the small one on the left drivers side keeps leaking. I have replaced them 4 times.

You think the new Oil Centrifuge Separator just didn't work from the get go?

Thanks for all your help guys.
Maybe check to see if there is a lot of pressure when you take off the oil cap. There is also a plastic black box on the drivers side valve cover that I replaced that is part of the Oil seperator system that could be clogged or something.
Old 07-06-2018, 03:37 PM
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Originally Posted by flybd5
No, it does NOT ... Brake fluid (otherwise known as hydraulic fluid) is intended to be used in the internals of a brake system, and not for "breaking down the oils." Like has been said already, it has a bad effect on other things in your engine compartment...
I believe there is some confusion in the description.
Brake Cleaner ≠ Brake Fluid. Two very different fluids. Although flybd5 is correct in stating that brake fluid is used within the internals of a brake system, it is not brake cleaner as OUZO Power talked about.
Brake cleaner works wonders on metals, just not plastics or rubbers (not saying you can't use it, just saying it's not recommended). It cleans very aggressively and efficiently and therein lies the problem. It is too aggressive for most plastics and painted surfaces.

OUZO Power:
Any progress on why it is leaking?
I'm about to change the oil sensor next week. So useless, but the message is oh so annoying...

Last edited by SunnyT; 07-06-2018 at 03:41 PM.
Old 07-07-2018, 03:41 AM
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Ah, so he is using Tetrachloroethylene? Well, isn't that precious. He should read up on what happens when you expose yourself to that, especially when it is heated.
Old 07-09-2018, 10:19 AM
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THIS IS INSANE.

So the leak stopped. The latest plug with the Ultra Black Gasket sealer worked.

But a day after another leak showed up. 1.5 foot forward near the front driver side.

Its the dreaded Rack & Pinion Leak. This one is going to cost. I hate this car.
Old 07-09-2018, 10:36 AM
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Originally Posted by OUZO Power
THIS IS INSANE.
So the leak stopped. The latest plug with the Ultra Black Gasket sealer worked.
But a day after another leak showed up. 1.5 foot forward near the front driver side.
Its the dreaded Rack & Pinion Leak. This one is going to cost. I hate this car.
Don't you mean love this car? Because it always lets you know it's there and wants your attention?

Try the refurbished market from reputable sellers. Great way to save a lot of $$$$$ on the parts, usually come with all internals replaced and have a warranty. From a quick Google, the refurbs are half the cost of new. Then only labor cost is your real enemy.
My refurb purchases/repairs have not let me down so far.
Old 07-09-2018, 10:46 AM
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Originally Posted by SunnyT
Don't you mean love this car? Because it always lets you know it's there and wants your attention?

Try the refurbished market from reputable sellers. Great way to save a lot of $$$$$ on the parts, usually come with all internals replaced and have a warranty. From a quick Google, the refurbs are half the cost of new. Then only labor cost is your real enemy.
My refurb purchases/repairs have not let me down so far.
Did you replace yours? Mine has the Parametric Speed Sensor. It will cost.
Old 07-09-2018, 12:17 PM
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Originally Posted by OUZO Power
Did you replace yours? Mine has the Parametric Speed Sensor. It will cost.
I have not replaced mine yet. So far I've been lucky. Just checking some of the websites I usually get parts from the rack with steering sensor runs under $1k (US)
If you do some searching, I'm sure you can find a well-priced one that will soften the blow.

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