What could have leaked?
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Junior Member
Joined: Aug 2007
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W163 ML320
What could have leaked?
I started my ML this morning, and while waiting for it to warm-up, I began smelling something burn. I looked out the windshield to see what appeared to be smoke spewing out from under the hood. I immediately cut the ignition and got out. After some time, I popped the hood open to find it still smelling like burning rubber, but intact, there didn't seem to be any damage. I asked my neighbor, a mechanic for the transit authority, and he left it on for a few minutes, but it seemed to be fine. I took it for a drive, went up to 60mph, and it ran smoothly. My neighbor told me that some liquid must have leaked, and I figured that because the smoke was greyish rather than black, it must have been a leak. He also said that the water hose was soft, though he wasn't sure. I don't want to drive it unless I know the problem has been fixed, any similar experiences or suggestions? By the way, its an ML320 with 65,500 miles.
Thanks in advance
Thanks in advance
Super Member
Joined: Nov 2001
Posts: 864
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ML
Geez, tough one. I first thought harmonic balancer, but don't recall burning incidences. I would start with the hoses - check them all. Keep the truck outside overnight to see if the cold would trigger something. If there were no fluids on the floor, I wonder why so much would burn to bring that much smoke. It's not fuel otherwise you'd be takling about a burnt ML. Is it possible that a night creature got caught in the engine bay - look for signs of cooked animal!! I have no idea!
Thread Starter
Junior Member
Joined: Aug 2007
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W163 ML320
update
So, I ended up having to drive the car today, (Yes, I know that was a bad move) but I noticed something. The thermostat shoots up from zero to about 80 degrees within 5 minutes, which indicates the engine cooling system radiator etc. Now of course I didn't drive long enough for it to get any hotter, but at least I found something.I have an appointment for this Saturday at the local shop, but want a heads up before going, any idea how much replacing the hosing and possibly the radiator can cost? Also, anyone know if something like this can affect the transmission? The engine was revving highly, I think I saw it go to almost 5500rpm before shifting out of 1st on level ground!
Any help is appreciated
Any help is appreciated
Super Member
Joined: Nov 2001
Posts: 864
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ML
The high RPM is most likely the motor trying to pump in as much coolant into the system as poissible. Could it be a stuck thermostat? Then why the burning? Something is restricting flow. First, check the coolant level in both the overflow tank and the radiator - you can start vehicle with radiator cap open and see if coolant is flowing by via the coolant cap opening - I believe you can also have the cap on and observe the reservoir, there should be some fluid motion in there - experts, please help!!!!! Don't open radiator cap after starting vehicle, please. If fluid is flowing, then there's either bad fluid or insufficient flow. You can check bad fluid visually or by using one of those $3 coolant checkers from auto parts stores. If coolant is flowing OK, that means water pump is working. If you don't see any flow, the problem gets more complicated - water pump, thermostat or some deranged sensor? My guess is thermostat - I don't even know where it is on the ML and I have no idea how you replace it. If it's neither thermostat nor water pump, you have a much bigger problem at hand, including faulty sensors that may be causing things to close up quickly. Still, all this doesn't explain the smoke, unless you just ran so hot the first time that something started to melt, just due to the heat!!
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From: Philadelphia area
2010 ML550, 2010 E350 4M, 1966 Corvette Convt C2
The high RPM is most likely the motor trying to pump in as much coolant into the system as poissible. Could it be a stuck thermostat? Then why the burning? Something is restricting flow. First, check the coolant level in both the overflow tank and the radiator - you can start vehicle with radiator cap open and see if coolant is flowing by via the coolant cap opening - I believe you can also have the cap on and observe the reservoir, there should be some fluid motion in there - experts, please help!!!!! Don't open radiator cap after starting vehicle, please. If fluid is flowing, then there's either bad fluid or insufficient flow. You can check bad fluid visually or by using one of those $3 coolant checkers from auto parts stores. If coolant is flowing OK, that means water pump is working. If you don't see any flow, the problem gets more complicated - water pump, thermostat or some deranged sensor? My guess is thermostat - I don't even know where it is on the ML and I have no idea how you replace it. If it's neither thermostat nor water pump, you have a much bigger problem at hand, including faulty sensors that may be causing things to close up quickly. Still, all this doesn't explain the smoke, unless you just ran so hot the first time that something started to melt, just due to the heat!!
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W163 ML320
I went to the mechanic, he told me a clamp was coming loose and he tightened it, so the problem seems to be fixed for now. One oddity I seemed to have just noticed is the odometer, which, at startup, shows a little wrench and 22 d. Last night, it was 23 d, so I assume its a service sign, and it would have shown up around the day this incident occurred. I guess its telling me to get something serviced within 22 days, but what? No OBDII codes showing, no other signs. I'm going to get the oil changed right now, maybe that's why, it has been 2800 miles since last change, so I thought maybe this was the reason. Any other ideas or ways to reset this meter? Thanks in advance.
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Super Member
Joined: Nov 2001
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ML
I went to the mechanic, he told me a clamp was coming loose and he tightened it, so the problem seems to be fixed for now. One oddity I seemed to have just noticed is the odometer, which, at startup, shows a little wrench and 22 d. Last night, it was 23 d, so I assume its a service sign, and it would have shown up around the day this incident occurred. I guess its telling me to get something serviced within 22 days, but what? No OBDII codes showing, no other signs. I'm going to get the oil changed right now, maybe that's why, it has been 2800 miles since last change, so I thought maybe this was the reason. Any other ideas or ways to reset this meter? Thanks in advance.
