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MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4317
Experience:  Mercedes Benz Qualified Diagnostic Technician
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2007 SL350 (R230). What can I do to stop water getting into

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2007 SL350 (R230). What can I do to stop water getting into the boot and killing the PSE that powers the central locking amongst other things? I've just had the PSE replaced by an MB dealer and it was expensive.

This is quite a common problem on the SL & in the first instance a water test may be needed to trace where the water is coming from.
However in around 90% of cases the leak comes in through the lower rear screen seal where the rear of the boot makes contact - try giving this a slight pull in a few areas, if it comes away easily then this is the likely cause of the water ingress & will need to be replaced.

I would say to leave this to a dealer or specialist used to this repair as it is a repair that takes a bit of experience to get correct as needs treating & butyl cord (a sealing strip) applying before the new seal goes on and needs pressing into place with a special roller. Costs from memory would usually be around £300-350 as a rough idea if this is the cause of the leak.

There are other possibilites & we have a water test rig at work to help identify the leak source but in most cases this seal is the biggest problem.

Best regards, Paul
Customer: replied 3 years ago.

Thank you, ***** ***** is helpful. I assume the seal fails because it is rubber and therefore perishes with age and use ?


After I'd had the PSE replaced (to fix my car's central locking problem that I needed resolved in a hurry as I was going away on holiday so needed convenient access to the fuel filler cap) I was quoted - by a dealer - £2000 and being without the car for 6 days for "replacing the boot seal". [I won't identify which dealer unless you ask !]. That seems somewhat excessive compared to your mention of £300-£350. I do recognise the advantages of a dealer repair (especially as you mention the need for particular tools and equipment). Can you suggest to where I might take the car for a repair at or nearer the cost level you have mentioned ?


Are there any drain holes I should be aware of (other than the ones at the left and right hand side of the boot just behind where it joins the rear screen) ? I've taken care to keep these two unblocked, but I'd like to ensure any others are treated similarly.

Wow! that appears seriously excessive for just the lower screen seal! Costs were a rough quote from memory, I would have to check for exact prices but would not be far from what I said.

We done one today in my workshop - its around a 2 hour job if it is just the seal that needs replacing. Sometimes more if there are complications but as long as it is just the lower seal then nowhere near the costs you are being quoted. As said there could be other causes & more expensive problems on the roof but if they are just quoting for that one seal then definately find another dealer or specialist!

The main problem is the seal detaches from the frame below the rear screen.

The 2 drains either side of the boot channel are just the ones than need cleaning although a good clean of all the seals every now & again to get rid of algea build up is also a good idea.

Where are you in the UK?

Regards, Paul

Customer: replied 3 years ago.

I live in NW London ... but I'm mobile (at least, for the time being). Where are you ? For a reason that must be obvious, I don't mind travelling for a repair (or so that the car and its actual seal can be examined). I do try to remove algae, moss and other detritus as I really like the car and want it to last a few years yet. By the way, the aforementioned dealer said that my Tier 1 MB Warranty (for which I pay, having had the 2007 car for 3 years myself) doesn't cover seals: I'm not 100% convinced they're right about this when I read the policy document; but you know the purpose of ALL Insurance is to take your premiums then niggle over the small print when it comes to paying out so they might be right.


Im in Canterbury - Kent.

With regards ***** ***** Tier 1 warranty I would have to check that but they are usually quite good & cover most things. I think from memory we may have even done some under Tier 1 but would have to run it past my warranty administrator to be 100% - he is off for a week now.

If you want to travel to us then this is where I work: Vikings Canterbury - we are a small Mercedes approved independent retailer.
Ask for me by name & can get you booked in, however what I do on here is seperate from my work & would ask you did not mention this website at my place of work.

Seeing the car would certainly be better to see what the cause may be - as said sometimes we do need to check on a water test rig to find the cause but you could check yourself just by pulling on the seal. If it feels loose then it will almost certainly need to be replaced as the first step.

Best regards, Paul
Customer: replied 3 years ago.

Thanks for the website link, Paul.

Sturry is only about a*****away from where I live (via M25), so that wouldn't be a problem and I presume I could get a train home if I needed to and decided to leave the car with you after an initial inspection (or return another day having booked it in). I fully realise that your role on the justanswer website is unrelated to your "day time job" so rest assured discretion also wouldn't be a problem. There are potentially advantages to both of us (&/or your employer) if a repair can be carried out under Tier 1 Warranty. I have a £250 excess so know I'd have to pay that personally. If you ARE able to check with your warranty administrator in advance that would be helpful - even if I have to wait a week or so.

I'm reluctant to pull too hard on the seal in case I break it or detach it - then I'd really be screwed as the car isn't garaged, it's street parked, but I'll give it a gentle examination tomorrow in the daylight.

I'll be away from my computer for the rest of the evening, but will get back to you tomorrow whenever you respond. Rod

Hi Rod,

If it is something we can claim for under Tier 1 then rest assured we would do this for you.

If loose the seal usually just pulls away & can be gently pushed back into place. No need to pull really hard to check it.

I will certainly check with my warranty admin once he returns - you can either follow up on here (a gentle reminder next week would be good as I usually have lots going on & may forget!) or if you are happy to do so you could just call me at work.

If you are happy with my answer then you can either rate it now or leave it open until next week - either way you can still reply to me at any time.

Best regards, Paul
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