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#1
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Air bubbles from injectors...
87 300 SDL...
I just noticed this and, of course, can't help but thinking this is not the way the injectors are meant to operate. I have air bubbles leaking from where the injectors screw into the block. Is there supposed to be a gasket between the injectors and the block? I don't see how. Perhaps just use some thread sealant? Maybe just plain old thread lock or teflon pipe sealant? I have tightened some of the injectors down and the problem is resolved, but others don't seam to respond to tightening. Thanks, Bill
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'87 300SDL, intensely modified Greasecar setup, with nickle plated heat exchanger, 3 valve setup, 312,000 miles '95 Suburban diesel, Greasecar basics, 16 plate heat exchanger, mercedes fuel lines, Racor filter '85 Renault Alliance converted full electric vehicle |
#2
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yes, it's called a heat shield.
about 2.00 each. get 12, cause you will need an extra set when you have your injectors pop tested. make sure you clean out the carbon that will be in there so the injector's threads don't get all banged up when you reinstall.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread "as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do! My drivers: 1987 190D 2.5Turbo 1987 190D 2.5Turbo 1987 190D 2.5-5SPEED!!! 1987 300TD 1987 300TD 1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere! |
#3
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Yeah it happens anytime you touch them.
Yank the injectors, and re torque them with new heat sheilds. They may leak a bit at first but should seal up in a few hundred miles.
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1999 SL500 1969 280SE 2023 Ram 1500 2007 Tiara 3200 |
#4
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Are the air bubles coming from the injector edge or from the ring under it? You could also be leaking at the prechamber. Not uncommon to have the prechamber seals burn out.
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http://superturbodiesel.com/images/sig.04.10.jpg 1995 E420 Schwarz 1995 E300 Weiss #1987 300D Sturmmachine #1991 300D Nearly Perfect #1994 E320 Cabriolet #1995 E320 Touring #1985 300D Sedan OBK #42 |
#5
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Answer:
Quote:
6010170060 Injector Heat Shield I suggest extras, they are easy to loose, and one shot = tighten to specification. Instant trash when you loosen the injector. Have a great day
__________________
ASE Master Mechanic asemastermechanic@juno.com Prototype R&D/testing: Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician. Noise Vibration and Harshness (NVH). Dynamometer. Heat exchanger durability. HV-A/C Climate Control. Vehicle build. Fleet Durability Technical Quality Auditor. Automotive Technical Writer 1985 300SD 1983 300D 1984 190D 2003 Volvo V70 2002 Honda Civic https://www.boldegoist.com/ Last edited by whunter; 07-30-2008 at 03:14 PM. |
#6
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What the?!?!?
OK...I've taken a better look and I understand what/where the heat shield is.
I don't think that's causing my leak but I want to relate what I see. The only good diagram I have is from Performance Benz, but even that doesn't truly match what I see. It appears the injectors screw into an "injector guide". The injector guide holds the heat shield in place. I have two new injectors to play with and they have a rubber sleeve, but I don't know where that goes. So my bubble leak is inbetween the injector and the "injector guide". I think I have to take the injector guide out to get to the heat shield. All of which I'd like to do to clean the crud out that I see. Is there a special tool to get this injector guide out???? Thanks!!! Bill
__________________
'87 300SDL, intensely modified Greasecar setup, with nickle plated heat exchanger, 3 valve setup, 312,000 miles '95 Suburban diesel, Greasecar basics, 16 plate heat exchanger, mercedes fuel lines, Racor filter '85 Renault Alliance converted full electric vehicle |
#7
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Their is no rubber gasket in their.
The injector screws into the prechamber, thats what you are seeing. The torque on the injectors is important to; I forget what it is off the top of my head I want to say 80nm.
__________________
1999 SL500 1969 280SE 2023 Ram 1500 2007 Tiara 3200 |
#8
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Ok... just got back from the dealer. The injectors screw into a collar which holds the heat shield in place which screws into the pre-chamber. I can't replace the heat shield without getting the collar out.
I CAN'T GET THE COLLAR OUT! YIKES!!! The dealer admits there's a special tool to do this but says he'd probably just take a screw driver and try and whack it with a hammer. I thought of that too, but you can't get the angle on it without taking off the intake manifold. Making a special tool seem awfully enticing. The collar does have a wide slot all the way across it for some sort of tool, but I don't know where to find that. My searches so far have been fruitless. Thanks, Bill
__________________
'87 300SDL, intensely modified Greasecar setup, with nickle plated heat exchanger, 3 valve setup, 312,000 miles '95 Suburban diesel, Greasecar basics, 16 plate heat exchanger, mercedes fuel lines, Racor filter '85 Renault Alliance converted full electric vehicle |
#9
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You only need to remove that collar if you want to remove the pre chambers. Since you said the leak is between the injector's and pre chambers you don't need to do that. The heat sheild is under the injector, yank an injector and you will see it.
You also need to get a FSM because this is all covered with pictures.
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1999 SL500 1969 280SE 2023 Ram 1500 2007 Tiara 3200 |
#10
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Thats under the injectors, thats the heat sheild.
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1999 SL500 1969 280SE 2023 Ram 1500 2007 Tiara 3200 |
#11
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OK... taking your word. The sucker must just be stuck on there then. Can't get the friggin thing out without bending it up. So when the dealer said the collar was on top I didn't argue, maybe I led the dealer to that conclusion.
Although all this has me wondering if I SHOULD pull the prechamber to clean it out. There must be some good carbon build up on it. I appreciate your patience and all your advice. I'm going to order the heat shields now since it looks like I won't have to order anything else. I actually bought an FSM off eBay, but it was a pirated copy and the installation instructions are impossible!!! What's your thought on pulling and cleaning the prechamber? Bill
__________________
'87 300SDL, intensely modified Greasecar setup, with nickle plated heat exchanger, 3 valve setup, 312,000 miles '95 Suburban diesel, Greasecar basics, 16 plate heat exchanger, mercedes fuel lines, Racor filter '85 Renault Alliance converted full electric vehicle |
#12
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with the injector out, spray a LOT of PB blaster all over everything, and let it soak for a few hours.
then get a thin screwdriver or a dental pic and chip all the carbon that has been leaking past the shield off of it and the prechamber. it will be smooth in there once the carbon is out. the shield will come right out once the carbon is cleaned out. then before you put the injector back in, spin the motor over good to be SURE there is no liquid PB blaster left in the cylinder.
__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread "as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do! My drivers: 1987 190D 2.5Turbo 1987 190D 2.5Turbo 1987 190D 2.5-5SPEED!!! 1987 300TD 1987 300TD 1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere! |
#13
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I always get my heat shields out by turning over the motor, just make sure you are not in the exit path as they will fly with a good amount of speed.
__________________
http://superturbodiesel.com/images/sig.04.10.jpg 1995 E420 Schwarz 1995 E300 Weiss #1987 300D Sturmmachine #1991 300D Nearly Perfect #1994 E320 Cabriolet #1995 E320 Touring #1985 300D Sedan OBK #42 |
#14
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Quote:
Easy FSM to use = http://www.alldatadiy.com Special Tool: A three inch long 1/4 lag bolt works great for pulling heatshields. Have a great day.
__________________
ASE Master Mechanic asemastermechanic@juno.com Prototype R&D/testing: Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician. Noise Vibration and Harshness (NVH). Dynamometer. Heat exchanger durability. HV-A/C Climate Control. Vehicle build. Fleet Durability Technical Quality Auditor. Automotive Technical Writer 1985 300SD 1983 300D 1984 190D 2003 Volvo V70 2002 Honda Civic https://www.boldegoist.com/ |
#15
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Why not on the PC? They are regular inspection items.
__________________
http://superturbodiesel.com/images/sig.04.10.jpg 1995 E420 Schwarz 1995 E300 Weiss #1987 300D Sturmmachine #1991 300D Nearly Perfect #1994 E320 Cabriolet #1995 E320 Touring #1985 300D Sedan OBK #42 |
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