Intake Manifold Vacuum Leak

[emerydc8]

While playing with my smoke machine last night I discovered a vacuum leak in the front portion of the intake manifold but I was unable to pinpoint the exact location. I tried using a mirror to see under the runners and towards the front but no luck. I hadn't looked at the attached diagram before I closed it up for the night but it looks like it could be the line coming from the electric change-over valve behind the right headlight (#92). I may have to remove the MAF and possibly the ETA to gain access to that area because it doesn't look like it is accessible from the front. All the smoke is coming from under the front area of the manifold.

I have recently seen a DTC 5 on pin 19 (EGR inoperative), so this line being loose or cracked would account for this and the smoke. Anyone remember exactly where this line connects under the intake? The diagram shows it towards the front. I'm hoping it's not a cracked donut seal that joins the lower and upper portion of the manifold.

EDIT: I just noticed from the video that the switch-over valve line connects on the exterior of the intake manifold, so what does that leave to be leaking underneath?

 

[gsxr]

Jon, from memory, the only tubes that go into the nether regions of the manifold are the EZL vacuum pipe which connects to the very back of the intake, and also the 8mm PCV tube that connects to the purge "MOT" valve next to the EZL. Both of these exit at the front edge of the manifold and then route below the driver side distributor. There's nothing else down there besides the ETA.

 

[emerydc8]

Thanks Dave. I was able to verify that those tubes were not completely broken but of course it doesn’t mean they aren’t cracked somewhere under there. I’ll have to dig deeper and remove the MAF and see if that gives me enough room to check it out. Have you ever heard of one of the intake runner donut seals getting hard and breaking, causing a vacuum leak?

 

[gerryvz]

Sounds to me like a full Top-End Refresh is in order here......

 

[emerydc8]

I wonder how many of those parts you used in 2020 are NLA. I’m almost afraid to check. It was good you did it when you did.

 

[gsxr]

Thanks Dave. I was able to verify that those tubes were not completely broken but of course it doesn’t mean they aren’t cracked somewhere under there. I’ll have to dig deeper and remove the MAF and see if that gives me enough room to check it out. Have you ever heard of one of the intake runner donut seals getting hard and breaking, causing a vacuum leak?

I've not (yet) heard of the donuts failing and causing a vacuum leak, but I do wonder if these start losing their ability to seal properly over 3+ decades. Pity it's SO much work to replace them. I need to smoke-test a couple of my engines to check the donuts...

 

[gerryvz]

I wonder how many of those parts you used in 2020 are NLA. I’m almost afraid to check. It was good you did it when you did.

I think that overall, parts availability is likely still pretty good.

I’ve yet to run into NLA snags with factory parts for my ongoing M104 project.

Which I need to get going on and make some updates here. Boating season has gotten in the way of me working on this project ……

 

[doolar]

I've not (yet) heard of the donuts failing and causing a vacuum leak, but I do wonder if these start losing their ability to seal properly over 3+ decades. Pity it's SO much work to replace them. I need to smoke-test a couple of my engines to check the donuts...

I replaced the donuts on my E420 and they were not leaking (yet) but were rock hard, IIRC one of them broke when I removed them.

A guesstimate is that from about now on they will start to give in, they won’t last forever and with 30+ years of heat cycles plus normal aging I think they’ll be a more common addition to the maintenance list.

While it takes some time to replace them, it’s not difficult, and a good time to clean and replace other things. Parts availability is probably the biggest concern, but with so many M119’s out there with a strong following, I hope it will be solvable.

 

[gerryvz]

The M117 uses the identical same donut part number to mate the two halves of its intake manifold that the M119 does.

I can definitively say that these donuts can and do lose their sealing ability, and with enough age and use will crack and break. As anything that is soft eventually does.

It’s a part that should be changed, I would say every 150K miles and/or every 2 years. For most — probably a once-in-an-ownership thing.

You can see my donut replacement / manifold rebuild in my M119 Top Engine Refresh thread here in “Project Journals” forum, and M117 Top End Rebuild thread over at 126board.com.

 

[emerydc8]

The M117 uses the identical same donut part number to mate the two halves of its intake manifold that the M119 does.

Going right down the parts list, it is not looking good. The right intake manifold gasket is discontinued and the left is "currently unavailable" as is the M117 part.

Screening x 8
https://www.getmercedesparts.com/oem-parts/mercedes-benz-shielding-1190700355

Seal Ring x 8
https://www.getmercedesparts.com/oem-parts/mercedes-benz-sealing-ring-1199970245

Intermediate Piece Upper to Lower Intake x 8
https://www.getmercedesparts.com/oem-parts/mercedes-benz-intermediate-piece-1171400265

Left Intake Manifold Gasket
https://www.getmercedesparts.com/oem-parts/mercedes-benz-gasket-1191411580

Right Intake Manifold Gasket
https://www.getmercedesparts.com/oem-parts/mercedes-benz-gasket-1191412680

 

[gsxr]

UGH.

The "screening" (119-070-03-55) is a nylon (?) bushing with O-ring for the injector-to-manifold. These are currently NLA, but people in the know in Germany claim these will be available again soon. 99% of the time you can re-use the old ones. If they don't come out of the manifold easily, leave them in there - it's difficult / impossible to remove from above without scratching the inner diameter sealing surface for the injector O-ring. Seal ring (119-997-02-45) appears to be available, the RevParts note "Currently unavailable" translates into "Has to be ordered from Germany". Note this O-ring comes with the "screening" bushing. It does NOT need to be replaced on your old bushings, and if you can get new bushings, those will include the new O-ring.

The manifold donuts ("Intermediate Piece", 117-140-02-65) appear to be available, but also likely need come out of Germany. Ditto for the one intake gasket that says "Currently unavailable". The donuts may or may not have a -64 suffix.

Fortunately, the intake manifold gaskets are still available new aftermarket, from Victor or Elring. It is surprising that these are headed for NLA from MB if still in production.

 

[emerydc8]

Thanks Dave. All good information. Do I have to mess with the injectors at all to change the intake manifold gaskets?

 

[gsxr]

Thanks Dave. All good information. Do I have to mess with the injectors at all to change the intake manifold gaskets?

I've never actually pulled the intake off an M119 (yet!). But I believe if you are only replacing the manifold gaskets (and 8 donuts), you can leave both the injectors AND the injector rail in place.

BTW - have the fuel tank close to empty if possible, or at least below half tank, to avoid fuel flowing out the hoses when disconnected. Also, DO NOT bend either of the hoses with stainless braided covers. Try to leave them in their "normal" position after disconnecting. If you bend them, the fossilised rubber inside can split. Don't ask how I learned this (2 weeks ago). I disassembled the cracked hose and need to take photos to document on the forum. They are all NLA now, of course, but can be rebuilt by a local hydraulic shop if needed. I'd like to see if AN fittings will bolt up to the factory ports so we can use bulk AN fuel hose & fittings are replacements.

 

[emerydc8]

If there is no evidence of injector leakage, I would probably not mess with them. I wonder if the @gerryvz replaced the fuel flex lines in the engine compartment when he did his top-end resto. Those 32-year-old lines are like a ticking time bomb.

 

[Oldcar]

While playing with my smoke machine last night I discovered a vacuum leak in the front portion of the intake manifold but I was unable to pinpoint the exact location. I tried using a mirror to see under the runners and towards the front but no luck. I hadn't looked at the attached diagram before I closed it up for the night but it looks like it could be the line coming from the electric change-over valve behind the right headlight (#92). I may have to remove the MAF and possibly the ETA to gain access to that area because it doesn't look like it is accessible from the front. All the smoke is coming from under the front area of the manifold.

I have recently seen a DTC 5 on pin 19 (EGR inoperative), so this line being loose or cracked would account for this and the smoke. Anyone remember exactly where this line connects under the intake? The diagram shows it towards the front. I'm hoping it's not a cracked donut seal that joins the lower and upper portion of the manifold.

EDIT: I just noticed from the video that the switch-over valve line connects on the exterior of the intake manifold so what does that leave to be leaking underneath?

Maybe check ezl intake hose rear engine intake manifold Seam...no need to remove anything.....just reach down .....gsxr has pic

 

[emerydc8]

I'm going to check both lines running under the upper intake for cracks. There is zero leakage from the rear portion but I may replace that line too as it is looking a bit yellowish.

 

[Oldcar]

Jon, from memory, the only tubes that go into the nether regions of the manifold are the EZL vacuum pipe which connects to the very back of the intake, and also the 8mm PCV tube that connects to the purge "MOT" valve next to the EZL. Both of these exit at the front edge of the manifold and then route below the driver side distributor. There's nothing else down there besides the ETA.

Where does mot valve vacum line plug into at engine?

 

[emerydc8]

Where does mot valve vacum line plug into at engine?

Look at connection #35 in the diagram above. It taps into the larger Y fitting and then ducks under the front part of the intake runners and runs forward before turning left toward the fender well along with the line for the ignition (connection #44), which runs from the very back of the intake through to the front.

I think I found the problem with my leak. The center collar around the donut ring for the #1 intake runner (front right) is cracked in half. You can see it in the picture. I could easily rotate and remove the collar if I tried but I just left it in place until I can change them all.

Does anyone know if these center collars on new donut rings will rotate easily? I couldn't really get a good smoke test on it because when I took the MAF out to see up front I couldn't fit a rubber glove around the perimeter of the ETA and there was too much smoke coming out of it. Now I smell like burnt mineral oil.

 

[nocfn]

Yes the center ring is for rigidity support between the two halves. They can move with the samples I have in my order from MB to R?R the M117. Spacers if you will. If it is broken or missing, it may "not" be sealing as intended. There isn't any support of the very flexible, worn out rubber without the tight ring. There is only 1/8 of an inch "sealing" on either side of the ring. No plastic support, then that rubber is going to leak even if not cracked. Age, vibrations may just render this stuff useless. I looked at the ones on my spare m117 manifold and they spin too, indicating shrinkage in my view of the rubber over time (ring is plastic). Without those plastic spacers, or ones that freely move - it is my opinion that they all need to be replaced. (I take no joy in this as the M119 are original and my M117 was replaced in 2012 but there are other vacuum leaks on it so it would be foolish not to do it all at once. (they are justified consumables)


maybe you get a thick width zip tie around it and pull it taught and see if it still leaks.

 

[gerryvz]

On later cars (like my own) I don’t believe there is an o-ring [nylon spacer] that goes between the injector and manifold — it fits right into the manifold directly. It’s shown clearly in my Top-End HOW-TO. This is a 5-year-old memory so I could be mistaken on this, but I’m pretty sure there is a breakpoint where the early cars need an o-ring in the manifold’s injector hole, and the later cars don’t.

I did not replace the fuel lines. They were in fine shape 5 years ago.

ONLY get the Elring intake manifold gaskets. DO NOT get Victor Reinz gaskets.

Yes, the center collars of the donut rings will rotate around the rubber part.

You need to look at the emissions and vacuum diagram, but I believe the MOT valve line plugs into the ETA. I could be wrong on this, so please double-check.

As said it is possible to remove the intake manifold with the fuel rail and injectors installed. I recommend for a proper, full rebuilt, that everything should be removed. I detailed and documented intake manifold removal, cleaning, and re-assembly IN EXCRUCIATING DETAIL in my Top-End Rebuild thread.

I prefer to remove the entire manifold and then disassemble it on the bench, rather than trying to do it in the car. Of course you can remove the fuel rail and injectors with the manifold on the car, and this is not a problem.

As said make sure coolant and fuel are drained or at very low levels. A

An alternative on the fuel lines is to purchase a pair of screw-on fuel line plugs for the ends of the fuel lines. I have a pair of these and they are actually screwed into the ends of my M104 G-wagon fuel lines under hood at the moment. They work well. I think I got mine from Baum Tools some years ago. They do come in handy for fuel work either under the rear of the car at the fuel pump package, or under hood at the feed and return fuel lines.

 

[emerydc8]

@nocfn — Thanks for all that information on the intake donuts/spacers. Mine are definitely petrified and need replaced. In the mean time I might give your zip-tie band-aid a try and recheck for smoke.

@gerryvz — When I printed out the parts list from the EPC I didn’t check the footnote for the cutoff point but I’m sure you are right and I shouldn’t need the screens on my ‘95. Now to decide whether I want to mess with pulling the injectors out of the manifold. There is no evidence of external leakage; I’m not planning to send them out to be cleaned; and with my luck I’ll probably break one of them in the process of removing them just to install new O~rings. After reading the discussion in a @gsxr recent thread about how a new (unpaired) injector could cause an imbalance versus old injectors with 270,000 miles on them, I’ll have to think about it. Since this is my daily-driver I don’t really want to be down for more than a day if I can help it.

The screw-on fuel line plugs are a good idea. All I could find on a search of Baum Tools’ website was for BMW and they were $266! I also realized it would be nice to find a plug that will seal off the ETA for doing smoke tests with the MAF removed. I saw a plastic cover on my spare MAF that might fit snuggly enough into the ETA if I use a rubber glove to seal it. I’ll check tomorrow.

I presume the factory donuts are Elring?

Genuine Mercedes 1171400265 Intake Manifold Gasket; Upper Intake Manifold to Plenum Chamber - Mercedes | 117140026564

Find Genuine Mercedes Intake Manifold Gasket; Upper Intake Manifold to Plenum Chamber 1171400265 at discount prices in our extensive Mercedes auto parts catalog. AutohausAZ offers a large selection of Genuine Mercedes parts online. 8 per car. CLOSEOUT ITEM! Limited availability. Fits Mercedes...

www.autohausaz.com

 

[Oldcar]

Look at connection #35 in the diagram above. It taps into the larger Y fitting and then ducks under the front part of the intake runners and runs forward before turning left toward the fender well along with the line for the ignition (connection #44), which runs from the very back of the intake through to the front.

I think I found the problem with my leak. The center collar around the donut ring for the #1 intake runner (front right) is cracked in half. You can see it in the picture. I could easily rotate and remove the collar if I tried but I just left it in place until I can change them all.

Does anyone know if these center collars on new donut rings will rotate easily? I couldn't really get a good smoke test on it because when I took the MAF out to see up front I couldn't fit a rubber glove around the perimeter of the ETA and there was too much smoke coming out of it. Now I smell like burnt mineral oil.

Look at connection #35 in the diagram above. It taps into the larger Y fitting and then ducks under the front part of the intake runners and runs forward before turning left toward the fender well along with the line for the ignition (connection #44), which runs from the very back of the intake through to the front.

I think I found the problem with my leak. The center collar around the donut ring for the #1 intake runner (front right) is cracked in half. You can see it in the picture. I could easily rotate and remove the collar if I tried but I just left it in place until I can change them all.

Does anyone know if these center collars on new donut rings will rotate easily? I couldn't really get a good smoke test on it because when I took the MAF out to see up front I couldn't fit a rubber glove around the perimeter of the ETA and there was too much smoke coming out of it. Now I smell like burnt mineral oil.

Maybe use some type of sealer that wont get sucked into intake on crack for a temperary fix ? What year119s have those donuts? The only donut I've seen is under maf and inrake manifold......I'll have to pull airbox and take a look

 

[gsxr]

I presume the factory donuts are Elring?

Genuine Mercedes 1171400265 Intake Manifold Gasket; Upper Intake Manifold to Plenum Chamber - Mercedes | 117140026564

Find Genuine Mercedes Intake Manifold Gasket; Upper Intake Manifold to Plenum Chamber 1171400265 at discount prices in our extensive Mercedes auto parts catalog. AutohausAZ offers a large selection of Genuine Mercedes parts online. 8 per car. CLOSEOUT ITEM! Limited availability. Fits Mercedes...

www.autohausaz.com

I don't think the factory donuts are Elring, but if Elring is available, they could be reboxed OE, maybe? Also, the OE/Genuine are $7.75 list, <$6 each discount. I have no idea what AHAZ is smoking with their $17 price on a "closeout" sale. Note that aftermarket "AJ USA" brand is made in Taiwan.

What year119s have those donuts? The only donut I've seen is under maf and inrake manifold......I'll have to pull airbox and take a look

All years M119's (and, M117 + M116) use the same donuts. They are not easily visible.

 

[Oldcar]

Ok how many donuts are there on m119 engine 1992.......?

 

[emerydc8]

Ok how many donuts are there on m119 engine 1992.......?

8 required.

 

[gerryvz]

Maybe use some type of sealer that wont get sucked into intake on crack for a temperary fix ? What year119s have those donuts? The only donut I've seen is under maf and inrake manifold......I'll have to pull airbox and take a look

.As said it is possible to remove the intake manifold with the fuel rail and injectors installed. I recommend for a proper, full rebuilt, that everything should be removed. I detailed and documented intake manifold removal, cleaning, and re-assembly IN EXCRUCIATING DETAIL in my Top-End Rebuild thread.

Duuuuuude……..If you look in my aforementioned Top-End Rebuild thread, you will find. Full removal, disassembly, and re-assembly of the intake manifold with new factory parts, including all rubber donuts and temperature sensors. The full process is documented in excruciating detail, backed up with extensive close-up photographs.

Thread 'RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh'

Apr 4, 2020

What with the current "self quarantine" imposed, I thought it a good time to begin a very long-standing project -- the complete refresh and cleaning of the top end of my M119 engine. Note that my E500 has 143K miles on it.

There was ZERO issue with running, other than the following small issues:

1. a small but annoying engine oil leak from the valve cover, resulting in oil dropping onto the exhaust manifold and smelling
2. a persistent set of two codes being thrown over the past few years -- an EGR code and an "air injection inop" code, resulting in a CHECK ENGINE light being lit...

• gerryvz
• m119 vacuum
• Replies: 613
• Forum: Member Roadtrips and Project Journals

• 
• 
• 

Let me get you the specific posts pertaining to the intake manifold rebuild:

Post 1 - Removal & Disassembly
Post 2 - @JC220 intake manifold disassembled
Post 3 - Reassembly (with extensive donut photos)
Post 4 - More re-assembly

We create these HOW-TOs and have a world-class search function here for a reason …

 

[emerydc8]

Hi Gerry,

Forgive me for my ignorance on this but your RESTO PROJECT M119 is so epic that there were plenty of times I remembered your covering something but didn't know which page or post it was on and a subject matter search brought up other posts as well. Is it possible to use the search feature only within that specific string / thread?

 

[nocfn]

Gerry IS THE WORLD-CLASS SEARCH FUNCTION.

 

[emerydc8]

I think I found the answer to my search question: If I go to the thread RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals and before inserting the search terms I scroll down and insert only posts from @gerryvz, then back up to search this thread only all the results are within that string. That will be helpful.

 

[gerryvz]

Hi Gerry,

Forgive me for my ignorance on this but your RESTO PROJECT M119 is so epic that there were plenty of times I remembered your covering something but didn't know which page or post it was on and a subject matter search brought up other posts as well. Is it possible to use the search feature only within that specific string / thread?

Yes, you can search by thread title or author. The "Advanced Search" button provides additional options for filtering the search (date range, etc.).

I often use "Top-End Refresh" or "Resto Project" as title thread to narrow down the search to display that thread.

 

[emerydc8]

Cross-posts. Thanks!

 

[gerryvz]

I will create an initial, "index" post that provides the post(s) in the thread where each job is done. That way, people can go to the initial post and search the index for the specific job they are looking for, and then click on a link and go right to it.

It may take me a couple of days to go through every post and log what it covers, and then translate that into an index post, so stay tuned.

 

[emerydc8]

I was going to ask earlier if an index could be created but I know it’s a lot of work considering there’s the removal, possibly additional work on the component and then the reinstallation. Thanks for considering an index. It will be better—and more comprehensive—than the FSM.

 

[emerydc8]

ONLY get the Elring intake manifold gaskets. DO NOT get Victor Reinz gaskets.

Any tips on where to find a set of Elring intake manifold gaskets? Autohaus only sells Reinz and FCP shows one side on indefinite back order.

I was just able to order the intermediate donuts from MB Laredo for $5.66 each once I confirmed they could order them from Germany. But they said the right intake manifold is discontinued. Part 119 141 26 80.

 

[gsxr]

I fished out my pair of NOS intake manifold gaskets, and confirmed the OE/Genuine are made by Elring in Germany. Photos coming soon.

In general, Elring and Victor-Reinz are both reasonable quality. I'm going to order some Reinz gaskets and compare to the OE and see if I can tell any difference. FCP says the Reinz are made in Turkey now.

 

[gerryvz]

I have consistently over the years heard from experts and mechanics alike, that Elring is always preferred to Victor Reinz (although for some items, Reinz is an MB OEM). If Elring isn't available, then I would use Reinz. For an intake manifold gasket, I think it should be fine. But I'd google to see if Elring is available somewhere.

 

[emerydc8]

I have consistently over the years heard from experts and mechanics alike, that Elring is always preferred to Victor Reinz (although for some items, Reinz is an MB OEM). If Elring isn't available, then I would use Reinz. For an intake manifold gasket, I think it should be fine. But I'd google to see if Elring is available somewhere.

I ordered the Victor Reinz from FCP Euro.

Do you remember the size of the fuel line plugs you got from Baum Tools? I can't find them on their website. Anyone else know the size of these plugs?

 

[gsxr]

Do you remember the size of the fuel line plugs you got from Baum Tools? I can't find them on their website. Anyone else know the size of these plugs?

Jon, here are photos of the Baum Tools plugs. I got them on a clearance sale a few years ago, I have a feeling they don't make them anymore. The thread is M14 x 1.5 and it fits the fuel hoses in the engine compartment.

I would LOVE to find an equivalent tool with M16 thread (and, larger ball seat) to seal the ATF cooler hoses when disconnected from the radiator pipes!

 

[emerydc8]

Thanks, Dave. The transmission line to radiator plugs would be nice too. I guess it’s going to be the rubber glove and tie-wrap solution instead. I didn’t see anything like this tool on Amazon. Maybe I’m not using the correct search words.

 

[gerryvz]

I think I got the same plugs on the same closeout sale. Honestly, I've also just used small flexible plastic cones/wedges, or even a small cork, in the past before I got these, with pretty good results.

Perhaps you can do a search on Amazon or Google to find something that will work.

 

[gsxr]

I use the red plastic caps a lot, but they don't seal 100%. These metal threaded plugs are really nice. Schwaben should make a copy of 'em...

 

[sheward]

I keep all sizes of rubber corks on hand for these situations. Found at most hardware stores they do not degrade or crumble. rubber bolt caps are also useful for this and come in various sizes and are female vs. the male corks but can be used either way.

 

[emerydc8]

I have assorted rubber stoppers so I will try those. Thanks.

 

[gsxr]

I fished out my pair of NOS intake manifold gaskets, and confirmed the OE/Genuine are made by Elring in Germany. Photos coming soon.

Pics attached of the NOS OE/Genuine gaskets.