1992 300CE (M104 CIS-E)

I am trying to help my neighbor, she just purchased the car above. After about a week of driving it, there is a coolant leak. It only occurs when running, and starts a pretty good steady stream after about a minute or two. I jacked it up and looked from underneath, and removed the air cleaner assembly. The leak is on the passenger side. It looks like the leak is from somewhere above the starter, between the oil filter and cruise actuator area. I can see a hose in there from above (right between cylinders 5 and 6), that appears to connect to the block, but cannot see the rest of this hose to verify it is leaking. I suspect this hose, but not sure. I have searched and seen some mention of this hose being difficult to access, and requiring intake manifold removal. What if the starter is removed, can this hose be accessed from underneath? I could not find any good pictures showing this area of the engine, and I don't have the service manual for this car. What is this hose? Something for the oil cooler? The car has the cartridge type oil filter housing.

The car appears to have been neglected for the past few years, I already fixed some broken wires and found missing insulation, so I am aware of the dangers of disturbing the harness. I would really rather avoid taking off the intake and creating other headaches. Shall I remove the starter first? Please respond with your opinions and experiences in this type of leak. I don't think it is the headgasket. I didn't see any evidence of coolant in the oil or vice versa. No oil was leaking, just a good stream of coolant.

I appreciate all your help!! And so does my neighbor...

There is an o-ring on the lifting EYE on the left rear of the cylinder head...they leak & run across the back of the engine...I would start with a new o-ring there.

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I can see that lifting eye where the heater hose connects, but it does not appear to be leaking. Will check it again though and let you know if it's leaking. Thanks for the tip MB DOC! I appreciate all the help you offer to this forum.

Found these posts by glenmore that seem to describe the problem on this car. Thanks glenmore for posting this, it took me awhile to find it, but gave me some hope.

Please take a look and offer any comments you may have about replacing the hose in question. It is referred to in the online parts catalogs as "Cooling Hose", and is MB part number 104 203 03 82, WorldPAC SKU # G2021-71771. I purchased a new hose through Carquest using the SKU. It was 7.59 with tax.

Leaking coolant M104 W124 @ oil filter

Anyone with R&R M104 intake manifold experience

The tricky thing is trying to gain access. I want to avoid pulling the intake. And according to the posts by glenmore, his tech did the hose replacement from above. I am wondering if there is any special details to know about when doing it this way. It looks like you can get a bit better access by removing the throttle linkage because it blocks the path between the intake runners.

Thanks again, Brian

I just went out and checked the o-ring as suggested by MB DOC. It is not leaking there. I used a mirror, a piece of paper towel stuffed under the heater hose nipple, and checked from underneath. The dripping is really from the driver side of the block, not the rear as I had originally thought. And by using a dental mirror I was able to at least see the other hose clamp on the little v-shaped cooling hose at the oil cooler end.

Glenmore suggested using a flex-shaft 7mm nut driver to get the hose clamps. I have some small hook/pick tools I think I can use to get the hose off. Looks like I will have to remove the throttle linkage for access. It is held on by some Allen head bolts. Please God, don't let me break any of the bolts!

Hi,

There is no access from below, zero! I would not attempt this by removing the intake manifold. There are many many brittle things that you can break here. The sensors and wire harness, the throttle linkage, the EHA, the fuel distributor!!! In hindsight I was very lucky not to have damaged anything. After buttoning it back up I was tempted to do it from above but if I failed I would have had the car stranded far away from Mr. MB. The tech at Mr. MB did the repair rather quickly. There were two clamps, one regular screw type and one non-reusable type. He probably used a combination of picks and screwdrivers to yank, pry the hose off. A pair of long needle nose pliers, lube and that flex shaft nut driver would probably be needed to install the new hose. I was a complete novice when I attempted that repair, but now with a little more experience under my belt, I think I could have done what the tech did.

Good Luck,

glenmore
1991 300CE
2000 C280
1990 LS400

glenmore, I certainly appreciate your help by responding. I found a flex shaft nut socket driver to try. Got one at Harbor Freight in a screwdriver set for about $5. Hopefully it will work. I tried without it earlier, using all different combinations of extensions and 7mm socket or phillips bit, and could not get anywhere. There was not enough space to turn the ratchet even if I could engage the hose clamp well enough. Tomorrow I will try again.

Well I struggled with it more today. I was able to use the flex shaft driver to get a phillips bit onto the hose clamp, but it kept slipping off when I tried to turn it. The hose clamp is positioned so close to the intake pipe above it that I can't get a socket on it. Even if I could successfully remove the hose clamps, I don't know if I would be able to install the new hose satisfactorily with such limited access. My hat is off to Enrique who supposedly did this on glenmore's car. I would like to watch it done. If the hose clamp was positioned slightly differently, it would make some difference. The only other thing I can think of is grinding a socket to get it to fit in and engage the hose clamp under the intake.

I am now closer to plunging in and removing the intake. It is so frustrating working with just fingertips through a cramped space in between the manifold runners, in the heat and not making any progress.

I am going to order an intake manifold gasket, EHA seals, some power steering hose, and perhaps some O-rings for the various pipes at the oil cooler, and the heater hose nipple that M.B. DOC mentioned. Also, it needs a new oil pressure sender. Any other suggestions on what to replace are welcome!

You can do it! I would give it several more tries before going the intake manifold route. If that tech can do it, you can do it! Yes, one clamp was so close to the manifold that you can't get a normal socket on it. The one piece flex shaft driver I had, had a fixed 7mm thin walled socket on it. The tool was made for hose clamps. I think the tech probably used a pry bar of some sort to spin the clamp around. And since the second clamp was the crimp on kind, he probably just pried the hose off.

Good luck,

glenmore

A thinwall socket would probably be key. But I didn't try getting one because I decided to go ahead and remove the manifold to get a good opportunity to clean the hose nipples and renew the miscellaneous o-rings. I wanted to see my work and it was so frustrating trying to do it from the top.

So the manifold was removed a few days ago, and I have done the following:

1. Clean the EGR port and tube with pick, wire, Seafoam spray
2. Replace leaking power steering return hoses
3. Repair cracked insulation on crank position sensor harness
4. Replaced O-ring per MB DOC
5. Fabricated a replacement for an air pump hose that broke upon intake manifold removal due to brittleness. Used 5/8" heater hose and 3/8" fuel line.
6. Replaced fuel distributor O-ring
7. EHA O-rings
8. Attached control module behind battery-missing bolts replaced
   
9. DROPPED an intake manifold dowel sleeve into the OILPAN through the dipstick hole.

Gahhhh, I could have retrieved it but didn't realize what it was when I noticed it balanced precariously in the dipstick hole. I accidentally knocked in the dowel sleeve when I tried to cover the hole with a temporary plug.

Anyway, now I have the oil level sender out to replace its seal, and I used a magnet on a retractable wand to seek the sleeve, to no avail

I guess there is a windage tray there that the little piece could have fallen int and become trapped without landing in the oil. I want to get this out. The car is on jackstands nose up in a garage.

Help me out. Should I try to remove the oilpan? Or drop the oilpan enough to reach in there. I would have to jack up the engine and maybe drop the trans lower to create clearance for the oilpan.

Any good schemes or comments about what you might do or have done?

Thanks everyone so far. Glenmore, I appreciate your input. That must have been a good tech who had done it a few times. With the right approach I can see it working. I probably should have let someone else do this.

Yeah!

Thumbs up for Mr MB...

It would be nice for you if the dipstick led straight into the pan
but my fear is it may not...

Arrgh

Good Luck!

Tried a few different magnetic pickup tools to no avail. It looks like the windage tray comes close to the dipstick tube, and the little piece may have landed on top of the windage tray, suspended below the crank, but above the oilpan.

Maybe now I'm looking at pulling the oilpan. Let me know any pointers I should know.