Waterlogging in the passenger side rear battery well.

Since our purchase in 2016, we have loved our GL450, a 2008 model.
It had about 90K, no reported incidents, and a single owner prior. It has served us well and two years ago I got the Command center replaced with a CarPlay-enabled unit. This added tremendously to our driving experience. We have driven the car quite sparingly and the odometer is at about 115000 atm.

Two weeks ago, the car started with a large battery sign on the odometer display. The rear window slid down too. I rolled it back up and turned off the ignition, and back on. It must be a wobbly key insert, I told myself. The sign disappeared. We got on our way and drove from Contra Costa county to San Jose - an approx. 50-mile distance, without ANY issues. The window stayed up too.

On our way back home a few hours later, we drove the city for about 15 miles and hit the highway. Within a mile of ramping up to 75, my car was possessed!! The BIG engine light came on, the windows started going up and down, and a big tire-out sign blazed. The wipers started going off and stopping randomly. Then the handbrake sign came on. If it was the middle of the night and in the lone valley we are compelled to drive through, I'd have legit crapped my pants 😂

We took the next exit and got the behemoth towed. Diagnostics from a local dealership came back saying that the rear battery well was clogged with water (image above). They could not identify the source of the leak. So even after a $1900 fix, they would not guarantee the work. When we went to sign off the vehicle for towing to my regular Merc mechanic, a veritable god of Merc repair (and whom I trust implicitly), the car was making huge sloshing noises it never made before. The headlights refused to turn off and we had to disconnect the rear battery.

This morning he gave me the same diagnosis of battery well logging, but with loads of other sage advice. I thought I'd share that with you all and also gain some additional insight from other 'sagely' folks here

Ok! So the battery well is clogged, yes. But water logging is rampant in other places too. The front SAM is bust because of the water and needs replacement. Apparently, the Merc GL450 has a false bottom, and the carpets do not sit on a metal surface, unlike regular cars. Rather, atop other electronics that Mercedes crammed in that space. The carpet was soggy but no leaks in the sunroofs (there are two: one operable, another stationary). The water might not have immediately caused failures as it filled up over the months (don't know when this might have started because we've not had much rain here in N.Cali), but it will eventually fry circuits of random components. So there might be no clear diagnosis when random things start falling apart (wonder if I should have checked the battery well on a regular basis, now looking back).

His quote is more or less the same as the dealers'. But here is the benefit of contacting him. He advised us to go through our insurance as this kind of damage falls under comprehensive coverage. I called our insurance and they agreed! Oh, the relief!! Why would the dealership not tell us this, I wonder. He also said the water seeps in through the rear lights (wait wutt???)!! In a new car, rear portions are sealed with rubberized barriers which wear off, which is when this condition presents itself. According to him, this is a fairly common occurrence in the Merc SUVs apparently. Why aren't more people talking about this? And in his experience in a previous job, also with BMWs btw.

He too says that he cannot guarantee the work and my car will be sent to a water-flooding shop to identify the water leak. Chances are grim though that this will not be a repeat issue and he suggests my insurance might total the vehicle! I stand to lose my car friends. I cannot believe all this drama presented itself to us in just one afternoon with not a single warning. So torn and dismayed over the whole saga. The carplay cost me upwards of $1700, and we have been and plan to live debt-free. To buy a new vehicle in this economy just sucks. Truly heart broken.

 

Sorry to hear that you are having these problems. Though, people are talking about both of your issues (1. water in front passenger well and 2. leaking from rear taillight). Do a search here and you will find quite a few threads regarding the issue.

If your insurance is covering the repair, it may be worthwhile to have it done at Mercedes where the parts would come with a 1-year warranty.

 

Sorry you're having to go through this. Many have the same issues from sunroof drains or taillights on many different models. The real flaw is the locations of the controls. This started happening about twenty years ago as the boxes got closer to the floor, then in the floor. I had the issue on an Audi as well as an E55.

Some tips from an electronics hobbyist.

Water does not inherently kill electronics. Running electronics that are wet kills them. So if anything is every suspected of being wet, the first rule is to turn it off and dry it.
Drying can also mean pulling every module that got wet and spraying it with something like electronics cleaner, alcohol, or vinegar with the first two being better. If the moisture caused corrosion, clean first with either the cleaner spray or vinegar. Make sure they are DRY

Spray all connectors as well. You can improve water tightness of the connection by adding some dielectric grease in the fitting/bushing.

The module will now work as long is it was not shorted. Replace any bad modules with used modules and program as needed.

In terms of checking the car, it takes only a few minutes to pull the rear tail lamps and check the seals. Very easily replaced. Do not use silicone as its not needed or correct.

The sunroof drains are also very easy to check. While someone is looking under the car starting at one corner, one person pours water or uses a hose to direct water to that corner of the sunroof tray (sunroof open) when directing water towards the driver front wheel, there should be an exit of water under that area. Do this at each corner with the rear being a little harder. Do not overwhelm the tray, not really much water gets in there during a rain. Sunroofs are not totally sealed and are meant to pass this water. If any of the drains appear clogged, research how to clear. It could be as silly as a leaf in the tray, mud on the flap at the bottom of the drain, kinked drain, etc.


This is all to say that you don't need to Total your car (unless its really totaled this time) and these are the things to keep it running correctly after the initial repairs.

Good luck

 

Funny, I just canceled my comprehensive and collision insurance.

My GL is garaged, though, and I live in dry Idaho. The former generally keeps the rain off it, but also helps the rubber gaskets remain intact.

I am seriously considering installing water intrusion alarms. They are cheap.

 

Thank you so much for your reply. I just joined here moments ago. Did a search but was not successful. Maybe I did not look for the right keywords. Sorry about that.
We towed the car 3 times now - highway to dealership to shop. All tow services used up for the year Would still take up your advice but the insurance might total it. Dealer did not mention that option so thinking this might be best.

 

Sorry these issues happened to you; they are known issues that can occur at any point in a GLs life. If caught immediately it is possible to salvage some or possibly all of the electronics - but what wasn’t known to me is that this could be carried by a comprehensive policy.

I never thought of it that way and thanks for the update.

Although I would imagine the ins company would rather just total the car and then give you a a check to fix it, and then you buy it back at a reduced rate - leaving you in a car you fixed yourself with a branded title but at this point the latter doesn’t matter. Once it an event like this happens, it is the beginning of the end and driving a branded title GL into the ground with a nice maintenance slush fund courtesy of the insurance payout isn’t a bad way to automobile.

 

Thank you thank you thank you for your positive and hope-giving post. If not totaled I am going to make sure I do all of the above.

Very grateful to you and people like you who take the time out to help complete strangers.

 

Wow thank you. I did not know there are sensors/alarms for water leaks. Where are these installed? Is this a diy type of thing or do I need to get them installed professionally?

You are too kind to thank me for a minor bit of information. You are welcome

 

We are only nice to newbies. I had quite a problem about a year ago and everybody just told me it was my fault and I should give up.

Seriously, though, it is daunting but recovery from flooding is possible.

You probably won't be able to get comprehensive or collision insurance on the vehicle after it gets a salvage title, but like I said, I suddenly woke up to the fact I had paid thousands over the years for insurance I really did not need.

 

Here is such a search on Amazon.
I bought the Topico for my an attic-installed water heater. I put it in the overflow pan. I am overdue to install something similar in my cellar, which is where all my water stuff now is. The problem is, the cellar is a great big tub that would fill completely with water and probably wreck the foundation.

 

wow I had no idea. I would love to save it because all else is very reliable in the car. But is the car legal to drive at this point? With a salvage title, won't the insurance prices shoot up? TIA

 

Similar thing happened to mine. Massive rainfall, water intrusion, rear windows rolled down, interior flooded. Woke up to see my car smoking from burning electronics on the inside and headlights on. Car would start and then immediately shut off. The ending was a totaled GL450 that worked perfectly for 14 years. The X164 GL's leak from the rear taillights, rear pop out window, front sunroof, and rear sunroof drainage channel as well as the rear sunroof cracking in the middle. If they dry it out and not fix the leaks, it will happen again and I'm not sure you can feasibly fix all the leak points.

 

😂

Overpaying in health insurance atm is killing us softly. There is nothing we seem to able to use and its is just net $15k a year. Sorry, I know it is off topic, but I know what you mean.

So quick question. If my car is hit by someone - no fault of mine - what happens? And what about liability to the other driver if I hit them?

 

I am so sorry it happened to you also. I read somewhere that one of the dangers of a wet battery is an explosion. Before this issue, I'd have lived my life ignorant of that fact. It was so sudden and so without warning, that it shook us when we thought of alternate scenarios. Sometimes it feels like we all live on borrowed time. Scary stuff.

When the shop gets cleaned up with the current damage, they are going to send the car to a garage that works exclusively on water damage. I will know more then and update here.

 

Every state is a little different but I've gone through this process before. Once they issue a salvage title you have to have the state inspect the car and issue a rebuilt title. My state just wanted to see that it had headlights, turn signal, seat belts, horn, that sort of stuff. Their main interest was in looking at receipts for parts to determine that I didn't steal anything. That's Kentucky. Other states have different requirements. Once you have a rebuilt title, you can get the car re-registered for operation on the roads. You will be able to get regular liability insurance so that if you hit someone, the damage to their vehicle is covered. I was able to get collision insurance but not comprehensive (or maybe that's vice-versa. I'd have to check) because of the branded title. If someone were to hit my rebuilt car, the insurance value would be much, much lower than for a non-branded car. Now, for me, it's a 1997 Dodge Neon so there isn't much value there anyway and it's the race car not a daily driver, so I don't really care.

That's really interesting, though, that they'd consider that a covered loss. I guess they treat it as a flood? Hopefully that brings you at least a somewhat happy ending. I know that with all the electrons that cars are zapping all over the place now, flood cars can be a real challenge to make right. Moisture gets wicked through the insulation on the wires and harnesses get corroded from the inside, ground points start rusting, and you just never know if you've gotten everything clean or if there's still some resistance somewhere that will come back to bite you later.

 

Thank you Wae. Your post inspired me to do some digging. Here is what I found out about Cal-specific salvage title laws:
https://www.metromile.com/blog/how-t...re%20Statement.

At first glance, the rules appear fairly similar. Although it remains to be seen who might insure me.

Thank you everyone for the options available to me. This might be the route we go if the Inspector assesses salvage on my GL.

 

So, back to our regularly scheduled progamming..........

There are several threads that address the 'water intrusion' issue. Likely sources are:

1. Tail light gaskets as OP mentioned
2. Sunroof drains
3. Clogged charcoal air filter intake drain (passenger side, behind engine fuse box, big plastic air intake)
4. Roof rails (if they easily wobble with a bit of force, the seals are likely no longer water-tight and allow water through the rail gaskets. The water will quickly find it's way down the A pillar and under your front seats; or over to the spair tire well).

Search: 'water intrusion' for additional threads on the topic.

 

You can forget about collision or comprehensive insurance. Not only will you probably have difficulty finding coverage, the coverage will be minimal (because salvage vehicles have low value), and since you have a track record of bidirectional money movement with your insurance company, which they absolutely hate, preferring to only take your money, not give it back, they will probably charge you a lot.

Keep a few thousand in cash to cover the cost of buying a replacement vehicle, drive defensively, and park carefully. You will recoup this cost in a few years anyway.

Just my anonymous opinion from two states away, worth about the energy you took to read it.

 

If the insurance company totals, give them the car and be done with it.