Cooling system
 

Just did a cooling systen flush on my '83 300D(shout & citric acid), replaced thermostat and refilled with Zerex G-05 coolant. The problem I'm having is that it it running hotter now than it did before. Its now running at 90-95 were as before it ran at 85 and at the most 90. My upper radiatior hose is hot but it wont get hard so I think I'm not building up enough pressure. Is is possible I still have air in the cooling system? My heat works great. I've read where the cars are difficult to get any air that is trapped out. My radiator cap seems fine. I dont hear any air coming out of the overflow wich could happen if it was leaking by the cap.. Any ideas?

When fully cold:

Raise the front of the vehicle or put it on ramps.

Remove the upper hose at the radiator and add coolant to the hose until the head is completely full. Quickly install the hose back onto the radiator while attempting to minimize any coolant loss.

Brian is right, but be careful doing that. The radiator neck can be brittle if it is original.

I'll try that Brian. I also think there may have been an issue withe the new t-stat. I checked it in boiling water and it opened, but it seems to be slightly different than the old one. For one the new one doesn't have the bleed hole and also the "disc" part (the side facing the engine block) is smaller in diameter than the old one. Oh well, I guess I'll leave the old one in. Shouldn't the air be pushed out on its own through the top of the radiator and into the tube that goes to the expansion tank?

It's not a good design because the thermostat housing height allows air to remain in the top of the head...........it doesn't get pushed out.

When you pour coolant from a higher point (the top of the hose above the radiator), you've got a better chance of displacing any air in the head.