What is this?

[chimchongdlight]

Might be a noob question. But what is this that all the coolant and radiator hoses go into? I want to know bc I'm slowly tracing where all this brown gravy is coming from in my coolant resovior. Pulled the whole thing out. And gonna probably replace some hoses too bc of it. Checked my trans fluid. Still red. I don't have any loss of oil. So I'm trying to see if I can clean it all out and perhaps get a new radiator. I've been reading and it says my radiator might be busted. I'm gonna try n clean and replace everything I see is wrong before I conclude that my head gasket is gone. Hopefully just my radiator needs replacing.

Anywho. I wanna know what this part is. So I can maybe either get another one Or fix it if it's broken

http://i40.photobucket.com/albums/e208/chimchongdlight/a5c068dd.jpg

[wichipong]

thermostat?!?

[Sulaco]

that's the thermostat housing that sits atop the water pump. Its a common place to leak. Make sure you use the proper gasket or sealant. Its a hard place to tighten, because it's aluminum. Too loose and you'll have a very annoying leak. Too tight and you could strip out the threads and be forced to drill out, tap, and use a new bolt (or replace the water pump!).

if you're certain oil isn't getting into your coolant, then you have rust gunking up your system. Drain and flush the ever living hell out of it. Be sure to open the drain plug underneath the exhaust manifold by cylinder #5. Its a 19mm bolt. Use a deep socket.

What I did on my other m104 recently was remove thermostat housing and thermostat. Stuck the water hose in there. Open up the drain valve by cyl 5. Car was already warm when I began (hot to touch, use gloves). Cranked car, turned on heater, turned on hose. Spent a good 10 minutes watching carefully the temp gauge and water level in the water pump to make sure it was getting a supply even to the amount that was leaking out. Seemed to clear up alot of the rust.

They sell coolant that inhibits rust. I recommend it.

I've just bought it at AutoZone, the green kind. Many swear by the oem stuff, but I've been using off the shelf green juice since 1999 and for 230k miles. My c280 has never had a rusty system and only runs hot in traffic because my aux fans died years ago.

[SD202]

Man sounds like your m104 run just like mine and i have only 178k . I had to replace the thermostat, fan clutch and radiator around 130k miles.

[chimchongdlight]

Anyone got a picture of the 19mm bolt? I can't seem to locate it.

[SD202]

it might be behind the belly pan if your car has one.

[Sulaco]

Passenger side of the block. Below exhaust toward the back of the engine, cylinder 5.

[tcles]

I might see if I can get a good picture of it for you, I gotta tighten my exhaust manifolds, maybe even replace the gaskets since they were just put on after the head gasket replacement. As soon as I get the car to actually turn over and stay on I'll need to work that out before I drive it anywhere and I'll grab that picture. Might be easier to see that bolt from underneath, but I would certainly NOT loosen it from underneath ;)