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Over the past several months, I have been getting the "check coolant level" message about every few weeks; the level keeps dropping in the expansion tank, however there are no visible leaks and an Indy shop tested and confirmed no coolant in the engine. It's mostly an inconvenience since I have to keep mixing and refilling the tank. Any ideas on the source of the leak?
2025 AMG E 53; 2018 GLC300 4Matic; 2003 360 Modena
Check for coolant in the transmission. W203s suffered from bad radiators - although C55s may or may not have not been affected. I caught a 2003 C240 early on and saved the transmission - my C55 had the same radiator as the C240 and I immediately changed over to an OEM Behr radiator.
Check for coolant in the transmission. W203s suffered from bad radiators - although C55s may or may not have not been affected. I caught a 2003 C240 early on and saved the transmission - my C55 had the same radiator as the C240 and I immediately changed over to an OEM Behr radiator.
The radiator was replaced a few months ago, and I just had the rear main seal replaced 3 weeks ago (includes draining ATF) I feel like the shop would have noticed if there was coolant in there... I guess Ill check the brand on the radiator to see if its oem
Yes pressure tested and everything checked out as functional at the shop. I just took it on a 3 hour cruise pushing it hard and it held up fine. Just kind of annoying knowing there's a problem I can't fix.
Bad coolant reservoir cap? Cooling system pressure test wouldn't show this if the test kit screws onto the coolant reservoir. You may eventually see residue around the reservoir cap, but not necessarily. This happened to me before on another car. I never saw any residue before I finally figured out it was the cap after several weeks of having to refill the reservoir every couple days or so. Otherwise, there's only a couple places the coolant can go if it's not leaking out anywhere externally. You've said indy verified no coolant in engine oil but you only "feel" like they would have caught it if it were in the tranny. I'd go ahead and make certain. You/your shop can use a trans dipstick and check in a matter of seconds whether your trans fluid has become milky looking. You're losing coolant and internal leaks can cause catastrophic damage. It's not the time to assume anything.
BTW, perhaps it's implied when you said "no coolant in the engine" but are you getting any white smoke from your exhaust? Possibly headgasket.
Last edited by brauhaus313; Jun 1, 2022 at 04:39 PM.
Pjmac, what side is that y-pipe on under the cowl? Ill check it out. I also noticed this small hole on the top of the expansion tank where the cap goes. Its above the o-ring seal, but could it be the cause? I find this hole odd as the expansion tank was just replaced only 6 months ago at an indy shop...
So update: I tried taking off the wiper assembly and it wouldn't budge off (used wd-40). Even worse, the threads are destroyed from banging the stud so now the nut wont go back on. Don't know why they gotta make it so dang tight even after removing the nut. Anyways, I'm not sure what I can do other than take it to an Indy shop and possibly have to replace the entire wiper assembly.
Are you saying you can't get the wiper arms off? AFAIK, the wiper assembly is held on by bolts but the wiper arms are held on by nuts. I don't know what the clearance/access/visibility situation is like under the wiper assembly but if you've got the cowl off, can you use an inspection camera to try to get a look at what's going on? Would suck to pay an indy take off the wiper assembly and the problem isn't even there.
I watched a walkthrough video on Youtube for taking off the wiper arms; the guy pops them off with little effort. No so much with my car. The nuts come off easy, but the assembly won't budge at all, meaning that I can't get the cowl off. It appears that the only way to get to the cowl is by taking off the one part that won't move; I'm worried if I push any harder, it will break the cowl from leveraging the prybar. Obviously never been taken off before as they are really on there.
Wiggle the wiper arms back and forward but first put it in the service position.
When it comes to the cowl, start at the corners. I will share the video that helped me when I find it. It was a pita to figure out on my own because it seemed impossible.
I'm hesitant to try now, since the threads are destroyed on the stud for the nut on the wiper arm. If i manage to pry off the wiper arm, I won't be able to re-screw the nut back on... And im pretty sure I would have to buy the whole blasted wiper assembly as I can't find just the stud for sale...
Have you considered a split die thread chaser? Find out the thread pitch and if a split die is available in that size you could be back in business. Perhaps you've figured this out by now, but if you are going to bang on the end of a stud, loosen the nut to the end of the stud and bang on the nut, not the stud.
Worse comes to worst, I think a new wiper assembly is less than $100.
I'm hesitant to try now, since the threads are destroyed on the stud for the nut on the wiper arm. If i manage to pry off the wiper arm, I won't be able to re-screw the nut back on... And im pretty sure I would have to buy the whole blasted wiper assembly as I can't find just the stud for sale...
Trust me that's better than a coolant line blowing up under there and filling your cabin with hot smoke and possibly even coolant.
Luckily it is the highest point of the coolant system so just shutting the car off should prevent further leakage and damage but still not something Id want to deal with.
Trust me that's better than a coolant line blowing up under there and filling your cabin with hot smoke and possibly even coolant.
Luckily it is the highest point of the coolant system so just shutting the car off should prevent further leakage and damage but still not something Id want to deal with.
i managed to get the nut to hold (sort of), so im about to attempt removing the wipers and cowl; ill update with what happens.
i managed to get the nut to hold (sort of), so im about to attempt removing the wipers and cowl; ill update with what happens.
tried with a prybar. Still wont budge; if i pur any more pressure, ill just shatter the cowl. I slid off the cabin air filter and tried to get a side view of the part behind the cowl, but I cant really see enough to confirm its the issue. On a more depressing note, I think I might have oil in my coolant. The expansion tank looks darker than usual and the substance is rather oily😬... The shop told me last month that they checked and confirmed no coolant/oil mixing.
Why not use the right tool for the job instead of prybars and hammers around your windshield and on parts that aren't supposed to be hammered or pried? Not trying to be a jerk but you've been held up for how long now because you can't get a wiper arm off? Hope your headgasket isn't leaking. Good luck.
Last edited by brauhaus313; Jun 18, 2022 at 05:18 AM.
My tank is pretty dark too but I dont see signs of oil.
When removing the cowl, you are gonna want to start from the corners. Its snapped in and is in there good. Get under it using some sort of plastic pry bar and lift the corner and youll have to pull on it good
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