Hey guys,

My GL450 has had the check coolant message come on a few months ago . I took to service and they said it just needed topping off. but today it came in again and I see that from the hose that goes from reservoir to radiator is white and shows coolant on the lower larger hose and on upper housing . Is this a difficult repair to do on my own. Warranty has expired. I have added pics. Any help I will really appreciate it.

 

It is unclear where it leaking from. Relatively easy to replace hoses. Try to wash it off and see again in couple days where it is leaking from (may be a crack?)

 

Thanks for the response. I’ll do that. And try to pinpoint it

 

Well while I was wiping it down the smaller hose that goes to the reservoir started make noise as if air is escaping when it moved the hose it stoped a bit or became less. Is that normal? Or is this the problem?

 

based on your photos alone and from your description ... you have leak in hopefully just the lines ... 14 months ago (still under ELW) they replaced my return line ... 3 weeks ago, they found Both lines (I'm assuming supply and return) leaking ... not at home, but can try and scan in both service tickets ... if I forget, remind me :-)

 

hhhmmm, definitely got to clean it all off, fill up the reservoir and be diligent about popping the hood constantly to find where the leak is form....

my '12 ml63 had a leak in the radiator.... standing in front with the hood open drivers side right on top under that cap...

i'll post a pic of the area....

 

The cap in blue comes off... that's where my radiator leaked and it appears might be your issue as well...

 

Thanks for information, if the leak is under that cap can it be fixed or does the radiator need to be replaced?

 

New Radiator per dealer... but I didn't get a chance to really look into it... was leaving a few days later so ended up trading it in... if your a diy guy, night be worth popping the cap to see...

 

I’ll take a look. But yes might be my option also definitely a pricey replacement

 

When I tried to remove the cap and pushed on it a I see bit coolant coming up. Which tells me that’s where the leak is from.

 

The radiator is in the $400 range. Not cheap, but not out of the normal range. Also generally not that hard to replace. Just need to be patient and remove everything that needs removed, to access the radiator.

 

That's 90% of your issue is finding it Know ya get to decide do i get dirty or i pay somebody else to get dirty

 

I have exactly the same issue

 

Kindly help me what exactly you did to resolve this issue

 

Based on your both pictures i think that you need to replace thin plastic hose. It cost about 60 bucks. To replace it all you need is to pull steel spring on connections with small screwdriver. Be very gentle taking it out. Of course you need to do it on cold engine - so you wont get yourself burned with hot coolant.
Part number 1665001091
Example https://parts.keyesmercedes.com/oem-...ose-1665001091

 

Maybe for the other guys, they will have to check.... but for me, under that cap was a crack in the seem of the radiator... fix was new radiator....

 

So my wife has a 2013 GL550 with a coolant leak in the exact same spot as the above pictures. I should say that the residue left behind looked just like the above pics. I initially thought it was leaking between the plastic tank and aluminum core. I worked at a radiator shop as a teen and thought no big deal, I will just replace with a new one. I downloaded a service manual for the car and step three was to vacuum down the A/C system. It turns out that the condenser and the radiator come out as a package. I'm like red team bail, I'm out. Took the car to the dealer and they wanted $4500 to replace the radiator and everything else associated coolant wise including the reservoir. Turbo coolant lines were 2K BTW with the radiator out!! I was like umm, NO and picked up the car. In the old days we had a tool to re-clamp the tank to the core but needle nose vise grips would do the same. I thought, what could it hurt to try this before taking the vehicle to an independent mechanic.

Now the fun part, I removed that mounting cap and cleaned up the all the residue, washed everything down and let it completely dry. Later, I started the car and drove it to operating temperature with no leaks found. I let the car run in the driveway with the mounting cap removed for an hour after the drive and lo and behold I found the leak. It was coming from the cavity inside the mounting stud! See the pictures. Craziest thing I've ever seen but the stud was full of coolant. What did I have to lose right? I dried and sanded the inside of the stud, swabbed and cleaned it with alcohol and filled with JB Weld radiator epoxy. That stuff comes in a kit with a repair patch which was not needed.

We've driven the car a couple hundred miles with no leaks. One more tip is that I heated the stud with a small heat gun used for heat shrink tubing. This may help with adhesion. Main thing is making sure the inside of the stud is competently clean. See the before and after pics. The first one is when I discovered the leak. Second is after I cleaned it and the third is after the repair. If this repair fails, buy a rubber radiator hose cap maybe 3/4" and a worm gear clamp. Remove the rubber surrounding the stud and install. I think it will fit and save you $1k's.

I hope all of this helps someone else.

 

nice fix.... $4,500 ? yikes.... they wanted $2,700 at Sarasota MB....

 

had a coolant leak but only in warm weather,i would get a check coolant message every 500 miles,as it got colder it stopped,i insisted that the shop does pressure test and they said new radiator.
New denso radiator 800$ installed with 2 year warranty from local shop.Hopefully it will stop the leak.

 

This really helped me, thank you @Probablecause! I was able to follow these instructions and now after couple test drives the leakage has stopped!!

 

So is it just the top of that fitting that is cracked? My wifes GL450 started leaking fluid and it appears to be in the same area. I have not pulled that cap off, does it just 'pop off' or do you have to depress those little tabs around it?

Chad

 

Well ****, broke one of those little tabs off, but I got it off and that hole there is full of fluid;
However;
Found this too;

I'm thinking this might be an issue!!

Chad

 

Chad

 

P/N 166-500-10-91
or
P/N 1665001091

You guys are awesome, thanks for the help!!

Chad