Dreaded water ingress ML2.8 2008

[Cosmicjones]

Hi, after a frustrating couple of weeks I'm at a loss to see where water is getting in on the ML rear offside,I've changed the lens seals, poured water over joints and seals but to no avail. After heavy rain and parked up I can collect upto 300ml overnight! I've protected the SAM unit with a trimmed plastic takeaway dish so that works. Just can't see any water leaking in??? Any feed back appreciated

 

[Deesidecars7]

had exactly the same problem with mine, needed a new sam unit and back light seals, think it cured it, if you have a power boot lift make sure thats dry, mine was soaked and burnt the motor out, and you cant get a new one, and if you did £799 new,

 

[Cosmicjones]

had exactly the same problem with mine, needed a new sam unit and back light seals, think it cured it, if you have a power boot lift make sure thats dry, mine was soaked and burnt the motor out, and you cant get a new one, and if you did £799 new,

Hi, so annoying, changed light seals, fortunately after using a dehumidifier I got the SAM unit working. Just cannot see where water getting in, maybe rear side window or roof rail. Disappointing on a quality car. Feel like getting rid but just spent £1400 on MOT and B service. Not happy

 

[Deesidecars7]

Hi, so annoying, changed light seals, fortunately after using a dehumidifier I got the SAM unit working. Just cannot see where water getting in, maybe rear side window or roof rail. Disappointing on a quality car. Feel like getting rid but just spent £1400 on MOT and B service. Not happy

Hi, mines been nothing but trouble, this year alone its had new sam, 1 new glow plug 2 parking senors, seals, boot not working properly, and the worry of whats going to go wrong next, so tomorrow its going, back to a reliable but boring toyota lol

 

[Cosmicjones]

Hi, mines been nothing but trouble, this year alone its had new sam, 1 new glow plug 2 parking senors, seals, boot not working properly, and the worry of whats going to go wrong next, so tomorrow its going, back to a reliable but boring toyota lol

So annoying, not sure which route to go, these big diesels are not popular what with the expensive duty? I have fitted a water deflector to channel water away from SAM, shame because car goes smooth and powerful with reasonable mpg. Niggly things like this takes the edge off

 

[oldguy57]

So annoying, not sure which route to go, these big diesels are not popular what with the expensive duty? I have fitted a water deflector to channel water away from SAM, shame because car goes smooth and powerful with reasonable mpg. Niggly things like this takes the edge off

Don't know if the ML has a sunroof but drains to these can get blocked or the tube becomes detached and overflows internally. Are there drain grommets under the rocker panels- might need removing and clearing. If all else fails I'd be tempted to shove a smoke bomb in there (after covering seats and dash) and see where smoke leaks out.

 

[Bert_W164]

Have you changed the seal on the third brake light? I had my car in with Mercedes a couple of years back and a technician randomly suggested I change it, which I had done. Unfortunately nothing was suggested about the rear light seals and so my rear Sam died from its death a few months back.

I'm assuming new seals have been applied directly to the body rather than the light unit itself? And if so, did you tighten the nuts enough to ensure a good tight seal?

If you've ruled out third brake light, rear light seals, then through elimination it sounds like your rear window seals.

@Bobby Dazzler - any thoughts of other potential areas where our cars could be letting water in?

 

[Cosmicjones]

Hi, don't think it's 3rd brake light, more likely rear side window, there is moss around the edges? Seals renewed and sticky side on body nicely tightened

 

[Cosmicjones]

Don't know if the ML has a sunroof but drains to these can get blocked or the tube becomes detached and overflows internally. Are there drain grommets under the rocker panels- might need removing and clearing. If all else fails I'd be tempted to shove a smoke bomb in there (after covering seats and dash) and see where smoke leaks out.

Hi, no sun roof to worry about, there is possibly a grommet underneath that space below SAM unit, because there is one the other side. Not sure about smoke bomb, may get the wife to sit in to check when smoke bomb goes off

 

[Bobby Dazzler]

Have you changed the seal on the third brake light? I had my car in with Mercedes a couple of years back and a technician randomly suggested I change it, which I had done. Unfortunately nothing was suggested about the rear light seals and so my rear Sam died from its death a few months back.

I'm assuming new seals have been applied directly to the body rather than the light unit itself? And if so, did you tighten the nuts enough to ensure a good tight seal?

If you've ruled out third brake light, rear light seals, then through elimination it sounds like your rear window seals.

@Bobby Dazzler - any thoughts of other potential areas where our cars could be letting water in?

No, I’m afraid not, all the places that spring to mind have been mentioned. Side windows maybe?

 

[Cosmicjones]

Ok,as we speak I have just sealed off the rear off side window, as said before light seals done, the new ones have the sticky side to the body and not the lens which we know was the original Merc fault. So fingers crossed,rain forecast for tonight so let's see. I drew off 300 ml this morning,also it's very difficult to feel for any grommet as the SAM unit is in the way,underneath is also awkward as there is the exhaust shroud which gets in the way. Grrrrrr so annoying

 

[oldguy57]

Ok,as we speak I have just sealed off the rear off side window, as said before light seals done, the new ones have the sticky side to the body and not the lens which we know was the original Merc fault. So fingers crossed,rain forecast for tonight so let's see. I drew off 300 ml this morning,also it's very difficult to feel for any grommet as the SAM unit is in the way,underneath is also awkward as there is the exhaust shroud which gets in the way. Grrrrrr so annoying

Sorry, I don't know much about ML's. Do they suffer from leaking vents behind the rear bumper as other models do?

 

[Cosmicjones]

Sorry, I don't know much about ML's. Do they suffer from leaking vents behind the rear bumper as other models do?

Hi, I haven't experienced the vents leaking, this appears to come from above the rear light circuit? It's really obscure and nothing definitive! Taped off the offside rear window, completely sealed it and after raining a lot in the night there was certainly very little signs of water so maybe it's around the window seal, thing is how best to make watertight, the saga continues!!

 

[Cosmicjones]

Hi, having sealed the the osr window and it rained pretty much all night, found there was minimal water in the well beneath the SAM unit. I removed the homemade seal around the window and just checked after rain in the night I pulled off about 150ml of water, looks like the side window is leaking, so what to do, best seek professional advice rather than try and seal meself?????

 

[Cosmicjones]

Maybe time to draw to a close to the water ingress issue? Can't spend any more time on this so removed the wheel shroud and with a bit of fiddling found and removed the blind grommet from the location. Not really the answer but need to move on

 

[Flyinspanner]

Try “ Captain Tolleys creeping crack cure” (eBay/Amazon)

it’s a capillary action sealant, squirt it around under your window seal and it will seal them. It’s only about £6 a tube.
I used some to seal the windscreen on my Scimitar years ago, cured it immediately.

check no dirt/moss between glass And seal - clean with an old tooth brush. Let it dry, then seal. Maybe do the rear side windows, tailgate too, hope you cure it.

 

[Cosmicjones]

Thanks for the tip, will wait for a dry warmer day.

 

[Jigglyjohnson]

Hi you are correct the osr quater glass window is a common issue for leaking and letting water in and unfortunatly getting into the rear sam u it and causing electrical chaos. The rear window is bonded in but also has locating oegs i belive which have some sort of seal around them and thats what lets the water in. I would get yourself a windscreen fitter who can remove the glass. Im sure back in the day we used to replace these under warranty but to save the cost if he can remove and reseal it will be more cosr effective for yourself

 

[tombell]

where are the door drain holes on the 2012 ML250?