They Said it Can't be Fixed - A Journey to the Inside of a Mercedes Bluetec

Took the EGR off and the ear that's farthest from the water port (and broken) was definitely not flat.  I cleaned up the surfaces a bit and heated that part of the EGR up and put it under the press to flatten it a bit.  It's not perfect, but it's less bad now.

(that's the "before" picture).

The threads for the EGR bolts are pretty well thrashed as well, so it looks like the valve wasn't quite torqued down enough, either.  Fortunately the bolt holes pass-through the intake manifold, so I can slip some slightly longer bolts through and pop some nuts on the other end instead of drilling and tapping it to an M8.  You can be assured that I will not be tapping it to an M7!

I also don't know if there's supposed to be an o-ring on there.  I kind of thought there was, but apparently I failed to put it on there.  I don't have EPC here at home and my shop time got cut short, so I'll have to look that up as well.  The kit from idparts was supposed to come with that seal, so I should have one somewhere.

It's easy enough to get that on and off right now, so I think I'm going to try to re-use the gasket, put some longer bolts plus nuts on there, and see what happens.  If that doesn't work, then maybe some of the red Right Stuff will find its way on there instead of a gasket.

I just need to find time to get out there and do that.  Sigh.

I had about 30 minutes today - not contiguous - to fiddle so I got the EGR reinstalled.  Turns out the oring was in place, it just fell to the ground when I pulled the valve out.  I'm able to fit a nut on the front bolt, but I tapped the rear bolt out to an m7 (yeah.  I know.  But I had an extra and the m7 fit through the bolt hole on the EGR while the m8 didn't) and got it tightened down.

Still leaks.

I'll try some Right Stuff next.

berkeley me, I think I know what the problem has been.

At some point I either couldn't find, didn't have, or lost the o ring for the EGR.  So I used one that I had.  I think it's too thick and it's preventing the valve from coming down low enough.

But I've got the Right Stuff smeared on there now, so maybe we try to go without the oring.

Wtf...  Still leaking.  But not from the EGR flange?  This is really starting to tick me off.

Un-berkeleying-believable.

I used my camera to scope around.  I think it's the oil cooler.  Possibly something above it, but I don't know of anything on the intake manifold that would leak in that spot but not anywhere else.

Ah, wait a minute...  The EGR cooler is directly above it.  I recall that I needed to put some serious pressure on it to thread the stupid intake flap sensor in to place.  Perhaps I jogged it too much.  Off to put the camera on that...

There is so much -stuff- on top of the engine and I just couldn't thread the camera around enough to really get a good look at anything.  With coolant pooled on top of the oil cooler, though, it is not likely that fixing the leak will be possible without at least pulling the turbo off.  So, last night I took the turbo off so I could look around.

With the turbo out of the way - and the wiring harness unbolted so it, too, can be moved around - I was able to get a little better view with the camera.  There's coolant around the front of the oil cooler as well.  Of course without the turbo attached, I can't start the engine, so I can't tell where the coolant is coming from.  But the flange between the EGR cooler and the intake manifold looks dry, so it's probably not that.  There doesn't appear to be anything leaking from the coolant temp sensor, and the thermostat housing seems dry.  The possible suspects, then, would be the oil cooler itself, something cracked on the EGR cooler, the oring on the other side of the EGR cooler, or the intake manifold itself.

While I'm a bit disappointed that I couldn't see an obvious cause of the leak, with the turbo moved out of the way I should be able to see what's going on if I can get coolant flowing.  I've never owned a cooling system pressure tester, and I think now's a good time to rectify that. 

I can stuff a bunch of rags in there to sop up the pooled coolant, blow it dry with compressed air, and then bring it to pressure to see where the coolant is coming out.

Oh, I hope it's not the FU barbell coolant connector thing between the intake manifolds.

In reply to Pete. (l33t FS) :

I'm not saying it it isn't that, but I did look at that before I pulled the turbo off and it appeared to be dry all the way around.  It wouldn't surprise me if it were leaking there, though.  That doesn't strike me as the best way to accomplish that crossover.

In reply to wae :

It probably is the best way, as it allows the intake to be installed in the first place.

It is not a BAD idea, just a potential leak spot.  At least it is not plastic like, say, the barbell on the oil cooler on a first generation Audi V8.

Wait a minute.....   is there any reason why I couldn't use my smoke machine to test the cooling system?  I'd have to pull the coolant out first, but if I dropped the lower radiator hose, collected the coolant, and then injected smoke from the bottom, I should be able to see exactly where it's failing to seal.  There might be a little mineral oil residue left in there, but that shouldn't hurt anything.

I could also smoke test the intake and see if I have a leak at the intake manifold.  Which could explain things.  It has a little bit of a stumble that I assumed was extra air coming in at the EGR flange.  Now that the EGR is sealed, it's still there a little, but not all that bad.  I assumed that it may have something to do with either all the sensors that are missing with the DPF, but an intake manifold that isn't sealed up right could be causing both problems.

I don't see what that wouldn't work!

In reply to wae :

If you have a smoke machine, absolutely you can test for coolant leaks with it.  Also oil leaks.  Used to do that all the time to verify oil-tightness on project cars where pulling the engine back out to reseal the oil pan is a pain.

It doesn't work all that well for minor leaks like intake gaskets that seep coolant through the fiber material but it will catch major ones.

It was too hot to come out here during the day yesterday and my wife isn't feeling well so last night was better spent at home with her.  This morning, though, I got up early and came over to the shop while it was still - well, not cool, but not heatstroke-inducing.  I'm getting more and more interested in the idea of installing a mini split out here.  I really like the super hot weather, but it seems like it drags me down faster the older I get.

Anyway.... 

Dropped the coolant, stuffed the smoke hose into the lower cooling system neck, and started making smoke.  As expected, it started blowing coolant out of the disconnected hose, so if you're going to do that, be prepared for more coolant to spray.  I had left the hose directed at a bucket, so all the coolant was preserved and I didn't get soaked.  After pulling out the fuel filter and getting more fuel lines and wires out of the way, I could snake my camera around in there looking for the source. 

It appears to be coming from the front of the engine.  I get heavy smoke up there before there is anything in the back and if I blow the smoke away from about the midpoint forward, the rear smoke kind of disapates until the front smoke catches up to it.  The connector tube isn't smoking, so I got that part right.  It looked like the EGR cooler tube might have been the source at first, but I can't tell.  There's still just too much "stuff" in the way to get a good look.

I'm having a cup of coffee and a think right now and when that's finished, my next step is likely to be to remove the intake tube that goes from the throttle body to the intake manifold.  That will give me more room and also allow me to put smoke into the air portion of the intake.  If I still get smoke leaking, then I know that the problem is the intake manifold not mating to the head correctly.  If that's solid, then I'm still leaning towards the EGR cooler tube, but at least it will be easier to see.  Either way, I'll need to head back home before too long to get some real work done.  (I mean, I will of course be at my home office and doing my clickity-clacks by 8am!  Hi, Boss!)

It is definitely the EGR cooler and it's coming from the back side of the pipe.  Maybe the oring is damaged, maybe the pipe is bent.  I'm out of time to screw with it right now, but next step is to pull the cooler.  I don't really remember how that's done, but I think it has to come out with the left intake manifold.  I'll see if I can get sneaky.

Had to take a little break due to sickness taking the family off-line for a while, but back to it today! 

This is a little bit of a backwards step, but the turbo, fuel lines, throttle body, swirl motor, five billion electrical connections, and the intake manifolds are out.  Again.

There's really no way to get sneaky and pull the cooler without pulling the intakes.  But you do not have to take the EGR valve off to do any of that.  This is good to know for a car that's got some miles on it and the EGR gets a bit stuck in there.  It isn't in the way of the turbo, the swirl motor, or anything else.  If you pull the electrical connection and un-do the coolant lines, it'll come out just fine as part of the left intake manifold.

Now we take the EGR cooler off and look at that O-ring in there:

When I put the pry bar on the EGR cooler to make room for the swirl flap sensor, I managed to do a number on the O-ring.

A three-cent part buried under 6 hours of labor broken by a dumbass.  Kind of like the story of my life.  Ah well, lessons learned, my friends, lessons learned!  For those of you following along at home, put the damned swirl flap sensor on first and THEN attach the EGR cooler.

Time to have some lunch and then get back to it.  Chicken pot, chicken pot, chicken pot pie!

With a new o-ring, it has passed the smoke test!  So now I just need to put it all back together.  Unfortunately, the new intake manifold gaskets are at home, so I can't get that far with it right now.  But at least I know that I don't need to replace the EGR cooler itself.

Whomever decided that the turbo needed to be supported with these two bolts should be slapped with a grouper. 

I spent some time on Saturday getting the intake manifolds put back on, hooked up the fuel lines again, re-installed the swirl motor, and got the fuel filter installed.  Before I ran out of time, I was able to get the turbo positioned and all four of its bolts finger-tight.  Those two in the back are absolutely brutal to get to.  The one on the right side of the engine (left side of that picture) isn't too bad:  I used my little claw-type pickup tool to lower the bolt in to place and then zipped it in with an E12 socket on an extension.  Since you can actually see that side, it's pretty easy.  The other one, though, is down there, but you cannot get a visual on it.  I tried a bunch of different things, including putting the truck back in the air and coming in from the bottom - that doesn't work even a little bit - and it took me about 30 minutes of screwing around before I got it in.  The answer, though, was really quite simple and I should have thought to do this much sooner:  I taped the bolt to the socket-on-an-extension and just came straight down on the back of the turbo using my little endoscopic camera for a visual. 

I also was able to find one of the coolant hose clips, so I'll use that instead of bailing wire for the lower hose.  The thermostat is actually integrated with the housing for some reason, so I bought one of those to put on and it came with a coolant hose clip as well, so no more wire.  I was fearing that wire coming loose some day and the thing just dumping all its coolant while I'm going down the road. 

Later on, when I've got time to get back to it, I'll go ahead and get the turbo torqued down and all the exhaust bits reconnected.  Then the only part left to put back on is the throttle body and "mixing chamber" or whatever.  Hopefully that will take care of it and I can focus my efforts on figuring out what's up with the rear suspension.

In reply to wae :

Pocket magnets are indispensable for those bolts.  Unless those are the ones that are non magnetic

In reply to Pete. (l33t FS) :

I'm fairly certain they're magnetic, but my magnetic tool is a poor, broken, piece of garbage that I should probably replace.  I actually got a decent one back when I had to do the oil pickup tube on the truck but I have no idea where I put it.  Usually I wind up sticking them to something when I'm finished, so it's probably hanging on something, hiding in plain sight somewhere.

Almost back together!  I smoke tested the cooling system and the intake and they both passed that test, so that's encouraging!  I'm going to need to run out and get some blue coolant and maybe more distilled water, but hopefully I'll be able to give it another test before I head home for the night!

No leaks!  And I found where that one spare electrical connector goes.  I forgot that one of the air filter boxes has a sensor.

Now I need to put the fender liner on, fill it the rest of the way with coolant, put the undertray on, close up the battery, and figure out whats up with the rear air bags.

Shoot bro I thought my 03 Duramxx LB7 was a tangled bag of snakes, you got me in spades with this mash up. How many 10mm 's reside in this mess?

In reply to 759NRNG :

No 10mms get lost in that motor.  Just E10s because Mercedes doesn't use regular hex bolts like some sort of peasant!

I'll work on a Mercedes (any Mercedes) over a Duramax anything any day of the week...  Everything is well packaged and fairly simple, in comparison.

I also am a fan of inverse Torx fasteners

Well, the heat is on now.  The local Mercedes dealer just called me begging me to bring it in to get the brake booster and airbag recalls done along with the AEM.  Rather than put them off again, I decided that nothing gets my ass in gear faster than a deadline.  The first available loaner car (because, yes, I am going to make them give me a loaner!) is July 20th, so at 9am the truck goes in!