Brown Sludge in radiator fluid!!! - PeachParts Mercedes-Benz Forum

Scott98 · #1 06-27-2006, 10:07 PM

I opened the radiator cap on my '98 E300D and noticed the fluid was brown and there was a brown sludgelike substance inside. What is it??? My first thought was oil. I dipped my finger in and smelled it and it kinda smelled like oil but I really can't tell. The car uses no oil between changes, doesn't run hot and displays no adverse driving symptoms. Also, the oil on the dipstick looks fine. Doesn't look at all like radiator fluid has been leaking in. Also, the previous owner was a maintenance nut and had everything flushed regularly. I'm really worried. Anybody have any ideas???

Thanks,

Scott

aklim · #2 06-27-2006, 10:26 PM

It could be rust. Why don't you flush it out with water first, then use that citric acid rinse and see what happens after you refill it?

N41EF · #3 06-27-2006, 10:33 PM

I've never seen it in person, but have been warned that if you mix dex-cool (orange) with green antifreeze or the red VW stuff, it forms some kind of sludge. I have a friend with an S-10 that had a cooling system full of crud. Might be someone topped off with a wrong antifreeze and it gunked the system up?

I'd drain the radiator, and pull the block plug out and see what runs out. Fill the radiator with water to flush out what you can from the radiator and the block. The do the citric flush.

aklim · #4 06-27-2006, 10:41 PM

Could be that the tech saw the yellow stuff and dumped dex cool in but why bother? If it isn't oil then who cares at this point. GET IT THE HELL OUT OF YOUR SYSTEM. Then see if it reappears

#5 06-27-2006, 10:43 PM

Do check it out as recommended above, but be careful not to run it too much until you determine what's going on. If it is "milkshake" sludge, it is most likely oil due to a head/ head gasket issue. You don't want to do more damage.

aklim · #6 06-27-2006, 10:48 PM

Quote:

Originally Posted by Craig

Do check it out as recommended above, but be careful not to run it too much until you determine what's going on. If it is "milkshake" sludge, it is most likely oil due to a head/ head gasket issue. You don't want to do more damage.

I don't think it is a head gasket issue or there would be oil loss or coolant in the oil. Not going to gaurantee it isn't but I think somebody added some wrong stuff in it. I would think that there would be more oil than just brown water.

Scott98 · #7 06-27-2006, 10:56 PM

Quote:

Originally Posted by aklim

I don't think it is a head gasket issue or there would be oil loss or coolant in the oil. Not going to gaurantee it isn't but I think somebody added some wrong stuff in it. I would think that there would be more oil than just brown water.

Thanks everyone for the quick replies. I don't think it's a headgasket issue because there is no sign of antifreeze on the dipstick plus no oil consumption that I'm aware of. The other possibilities mentioned above never occurred to me. That is why I love this forum. My hunch is that's the problem. I will get it flushed immediately. I'll update everyone once I get it flushed.

Scott

aklim · #8 06-27-2006, 10:59 PM

Quote:

Originally Posted by Scott98

Thanks everyone for the quick replies. I don't think it's a headgasket issue because there is no sign of antifreeze on the dipstick plus no oil consumption that I'm aware of. The other possibilities mentioned above never occurred to me. That is why I love this forum. My hunch is that's the problem. I will get it flushed immediately. I'll update everyone once I get it flushed.

Scott

Make sure you turn the heater to the max while flushing. It might be good to run water in it for a couple of days then reflush. Some mild dishwashing soap before you drain it might be good to get rid of the crud.

Scott98 · #9 06-27-2006, 10:59 PM

One more thing... Where is the plug on the engine for the drain? I may attempt this myself rather than taking it to an indy. Do I drain it from both the radiator and the engine plugs? What's the proper procedure for flushing it with a garden hose? What's the proper procedure for refilling?

Thanks,

Scott

aklim · #10 06-27-2006, 11:17 PM

You drain it everywhere. Both block and radiator. Then you add fresh water in with a little dish soap to get out the oils in it. Heater on, of course. Then you can flush it with the garden hose. Now, if it were me, I would drain both the block and the radiator after washing it with dish soap and then fill it with water and run for a bit to make sure it comes out clean. Once satisfied, I would drain it, refill it, run the engine for a bit, drain it and refill, run again for a bit, then drain and fill it with distilled water.

aklim · #11 06-27-2006, 11:21 PM

Drain plug is at the bottom of the radiator on the driver side, IIRC. Either way it looks like a petcock. Then the block drains are on the side of the block.

Scott98 · #12 06-27-2006, 11:40 PM

Quote:

Originally Posted by aklim

Drain plug is at the bottom of the radiator on the driver side, IIRC. Either way it looks like a petcock. Then the block drains are on the side of the block.

How many block drains are there? On which side are they located? What do they look like? Also, how much fluid will it take upon refill?

Thanks,

Scott

aklim · #13 06-27-2006, 11:49 PM

Quote:

Originally Posted by Scott98

How many block drains are there? On which side are they located? What do they look like? Also, how much fluid will it take upon refill?

Thanks,

Scott

Not totally sure but I think there are 1 drain on the passenger side. 8.75 Litres. This is according to WIS and EPC.

Matt L · #14 06-27-2006, 11:52 PM

If it were mine, I'd not run plain water in it for longer than it took to flush. Definitely not a few days.

But you can get some water conditioner made for running without antifreeze, which is made to protect aluminum parts. Or some antifreeze that is also good for aluminum. If it's only there for a few days and is going to be completely flushed out after that, I wouldn't worry about running non-MB antifreeze.

And when you fill after each flush, use distilled water.

aklim · #15 06-27-2006, 11:56 PM

Quote:

Originally Posted by Matt L

If it were mine, I'd not run plain water in it for longer than it took to flush. Definitely not a few days.

But you can get some water conditioner made for running without antifreeze, which is made to protect aluminum parts. Or some antifreeze that is also good for aluminum. If it's only there for a few days and is going to be completely flushed out after that, I wouldn't worry about running non-MB antifreeze.

And when you fill after each flush, use distilled water.

Me neither but he does have sludge in it. I was thinking the soap would clean it out. Of course, it means he can't be taking cross country trips. Maybe a few miles a day to move the stuff around and not get too hot and then soak. Just not sure how long the sludge is there for and as such, how stuck it is. I know they use dish soap to clean out the oil after a head gasket failure.

Do you think it is bad to run plain water in it if he is going to dump it when he flushes the system to get all the crud out?