W202 C180 Coolant leak
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Joined: Sep 2018
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C-class estate, W202, mod. 2000
W202 C180 Coolant leak
Hi, my first post here 
My coolant level indicator came on a few weeks ago. so I poured in maybe 1,5L of water. (I just added coolant today, to avoid damage.)
Checked underneath my car and noticed that, whenever the engine is running, water (and what's left of the coolant) is dripping down underneath from above the gearbox. It runs down both sides of the gearbox, right where the the flat part with the control unit for the gear box is located.
Now, I've checked the hose and plastic bits that runs through the firewall on the left hand side of the car, no luck. completely dry. I tried to look down at the transmission where it connects to the engine, and the coolant doesn's seem to run from the engine and down along the transmission either.
The water pump in the front of the engine is dry, and the black thingy beneath the reservoir is dry.
I can't think of anywhere else the water might be coming from..? Checked engine, no water in the oil. Transmission sounds and acts just fine, so i'm guessing the water isn't coming from inside the transmission either, since it's been leaking like this for a while. my last guess is that it's coming from the interior heater or something, but i haven't had the guts to rip out the dash yet.
Anyone have any idea how the coolant ends up above the gearbox?
Thanks!
My coolant level indicator came on a few weeks ago. so I poured in maybe 1,5L of water. (I just added coolant today, to avoid damage.)
Checked underneath my car and noticed that, whenever the engine is running, water (and what's left of the coolant) is dripping down underneath from above the gearbox. It runs down both sides of the gearbox, right where the the flat part with the control unit for the gear box is located.
Now, I've checked the hose and plastic bits that runs through the firewall on the left hand side of the car, no luck. completely dry. I tried to look down at the transmission where it connects to the engine, and the coolant doesn's seem to run from the engine and down along the transmission either.
The water pump in the front of the engine is dry, and the black thingy beneath the reservoir is dry.
I can't think of anywhere else the water might be coming from..? Checked engine, no water in the oil. Transmission sounds and acts just fine, so i'm guessing the water isn't coming from inside the transmission either, since it's been leaking like this for a while. my last guess is that it's coming from the interior heater or something, but i haven't had the guts to rip out the dash yet.
Anyone have any idea how the coolant ends up above the gearbox?
Thanks!
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Joined: May 2020
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2003 C230 Kompressor
draining coolant before replacing back hose?
Sorry - I meant to post the message below on a different thread... but I can't seem to delete the posting. If anyone sees this, and can delete it... please feel free to do so!
For anyone that has replaced JUST the back coolant pipe (part # 271-200-13-52), did you need to drain any coolant before removing the part? And if you didn't drain first - did much coolant pour out after removing it?
I'm just curious... since my hose is leaking, and the car has been sitting for a couple weeks - so I'm thinking that all the coolant in that area of the engine may have already drained out - so that if I disconnect the part now, no more coolant will be there to leak... and hence no need to drain any first. I also don't want to lose coolant all over the place, on the ground, when taking the part off.
thanks for any responses... I know most of the posts on this chain are very old, by now!
For anyone that has replaced JUST the back coolant pipe (part # 271-200-13-52), did you need to drain any coolant before removing the part? And if you didn't drain first - did much coolant pour out after removing it?
I'm just curious... since my hose is leaking, and the car has been sitting for a couple weeks - so I'm thinking that all the coolant in that area of the engine may have already drained out - so that if I disconnect the part now, no more coolant will be there to leak... and hence no need to drain any first. I also don't want to lose coolant all over the place, on the ground, when taking the part off.
thanks for any responses... I know most of the posts on this chain are very old, by now!
Last edited by brian1980; May 20, 2020 at 03:07 PM.
Senior Member
Joined: Jul 2018
Posts: 310
Likes: 49
From: AZ
the hose taking coolant that goes from the top of the head into the firewall to the heater core is probably needing to be replaced
*edit - or you might have a headgasket leak
*edit - or you might have a headgasket leak
Last edited by paste; Jun 6, 2020 at 03:37 PM.
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Joined: Dec 2020
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Mercedes W211
W211 2007 1.8 kompressor, same problem with coolant on gearbox. After I replace all the 4 parts, the coolant was still droping. The problem was what "Paste" said, the hose that go to firewall A 211 832 46 94.
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Joined: Jan 2021
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C 200 CDI 1999
Hi, my first post here
My coolant level indicator came on a few weeks ago. so I poured in maybe 1,5L of water. (I just added coolant today, to avoid damage.)
Checked underneath my car and noticed that, whenever the engine is running, water (and what's left of the coolant) is dripping down underneath from above the gearbox. It runs down both sides of the gearbox, right where the the flat part with the control unit for the gear box is located.
Now, I've checked the hose and plastic bits that runs through the firewall on the left hand side of the car, no luck. completely dry. I tried to look down at the transmission where it connects to the engine, and the coolant doesn's seem to run from the engine and down along the transmission either.
The water pump in the front of the engine is dry, and the black thingy beneath the reservoir is dry.
I can't think of anywhere else the water might be coming from..? Checked engine, no water in the oil. Transmission sounds and acts just fine, so i'm guessing the water isn't coming from inside the transmission either, since it's been leaking like this for a while. my last guess is that it's coming from the interior heater or something, but i haven't had the guts to rip out the dash yet.
Anyone have any idea how the coolant ends up above the gearbox?
Thanks!
My coolant level indicator came on a few weeks ago. so I poured in maybe 1,5L of water. (I just added coolant today, to avoid damage.)
Checked underneath my car and noticed that, whenever the engine is running, water (and what's left of the coolant) is dripping down underneath from above the gearbox. It runs down both sides of the gearbox, right where the the flat part with the control unit for the gear box is located.
Now, I've checked the hose and plastic bits that runs through the firewall on the left hand side of the car, no luck. completely dry. I tried to look down at the transmission where it connects to the engine, and the coolant doesn's seem to run from the engine and down along the transmission either.
The water pump in the front of the engine is dry, and the black thingy beneath the reservoir is dry.
I can't think of anywhere else the water might be coming from..? Checked engine, no water in the oil. Transmission sounds and acts just fine, so i'm guessing the water isn't coming from inside the transmission either, since it's been leaking like this for a while. my last guess is that it's coming from the interior heater or something, but i haven't had the guts to rip out the dash yet.
Anyone have any idea how the coolant ends up above the gearbox?
Thanks!
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From: Ireland
W202 C180, 2.3K swap. W210 E240, soon to be V8 swap.
Have to inspect the engine from underneath, you'll see coolant or staining where the head and the block meet if its the headgasket. Common issue with these. My headgasket is slightly leaking like this and my gearbox has coolant staining on it from the coolant running down the engine from the headgasket.
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