My crossover pipe keeps leaking where it joins the manifold. Not much but enough to spray a fine oil mist on the area around it, and make a mess.

Whats the best way to stop this? I don't want to tighten the bolts more I'll strip the threads. I already stripped one and had to fix it. Also the boost pressure sensor, which I replaced, with a new crush ring leaks slightly as well! If I get a new crush washer, take it off and sand the manifold a bit should that seal it up?

I have the entire manifold off, from the turbo to the head. I'm cleaning it and replacing all the gaskets...again... to stop the damn leaks!


RTV?

The leaks on these cars are a never ending battle. I'm down to the head gasket and IP weeping slightly, almost dry!

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

I have not had your problem with my '87 but would suggest RTV silicone seal on both sides of the existing gasket where the crossover bolts to the intake. Does it also leak at the o-ring seals on the passenger side of the crossover?

Defeating the EGR function would keep soot out of the intake. Soot tends to attract oil and make existing leaks worse.

Is the oil coming from your turbo? There shouldn't be much.

I never had a leak from the boost overpressure sensor; the most I ever did was to put on a bit of Teflon tape.

Have you measured the maximum boost your engine is seeing? Too much boost will make any leak worse.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

The little hump pipe coming off the turbo was leaking, I replaced both of those O rings. The new ones are real tight so NFW that leaks.

I never checked the boost, looks like no one has. So whatever the factory set, the preformance is excellent so its not down.

The EGR is long gone, and the intake is clean. I suspect the lack of sludge that most 603 intakes are full of is causing the leaks. EGR sludge is an excellent sealent! Seems like most 603 turbo's blow a little oil past them, just enough to make the inside of the intake wet.

I have had this thing apart at least half a dozen times, never seals perfect.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

I used silicone used on valve covers. It does the job fine. It's not a problem if you want to remove it later as easily peels away from the gasket once you have it off.

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1992 Mercedes 190D 2.5 turbo 5sp manual. EGT+boost gauges. Boost controller set to ~14.5 psi. 1 1/4 turns on full load adjustment. LPG injection. Next in the list is water injection.

I have used a thin rubberized gasket paper trimmed to fit.


For your boost pressure switch hole -- DO NOT OVER TIGHTEN it. It's a steal piece screwed into aluminum. My cost your lesson and the heli-coil kits are over $80!! (It's the rare 12mm x 1.5 thread) I have it for a reasonable rent/insert purchase. If you wrap the treaded part of the pressure switch in teflon tape it'll work like a charm.

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1987 300D (230,000 mi on a #14 head-watching the temp gauge and keeping the ghost in the machine)
Raleigh NC - Home of deep fried sushi!

Hatte -- FWIW, I used copper spray-gasket to excellent result in sealing an old Harley oil pump (which most likely leaked like a sieve when it left the factory).

Planning on trying it when I put the new head on my '87.

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1998 E300 +310,000K
1996 E300 +460,000K

JB Weld these weak points in the oil leaks.

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'06 E320 CDI
'17 Corvette Stingray Vert

JB weld? I want to get the thing apart in the future!

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Then replace the parts at that time, if they ever need replacing. Oil leaks.......or a hack saw and a file......?

JB Weld must work, because the owner lives in a big-ass mansion on I-30 near Sulphur Springs, Texas.

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'06 E320 CDI
'17 Corvette Stingray Vert

JB weld your intake together and report back on how well that works.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

.......but mine's not leaking...........

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'06 E320 CDI
'17 Corvette Stingray Vert

Hotdam, I must have passed by there this week, Saw a big house or two near there on I30. Nice community. Only one establishment in town with an open bar, Chili's.
I would NOT use JB Weld on those parts! Teflon tape on the sensor and a thin film of RTV on the gasket. Min show a tiny leak too FWIW.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Check the manifold end of the crossover pipe with a straight edge to see if it is truly flat,it may be warped and require a bit of work with a flat file to get the ends down to even with the middle.If that is the case once you get it flat make a new gasket and try not to over tighten it.A thin film of silicone gasket sealer cant hurt,but give it time to cure before you run the engine 1/2hour should be enough. My $.02 Don

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Red Green "This is only temporary,Unless it works!"

97 E300D 157000 miles
87 300TD ?141k? miles

I have been told that silicone can't be used on a catalytic-converter car because it will foul the cat??

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Gone to the dark side

- Jeff

Then JB Weld your fuel lines.....

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John