My 1975 MB 240D is overheating. I've had the radiator reaired, it has coolant in it, the radiator cap is fine, i've replaced the thermostat with a new one, but nevertheless it continues to overheat.

The main radiator hose(s) never seem to get very hot. As if no steam/water/coolant is passing thru the system. There are no visible leaks, but i still suspect it may be the water pump. Before i change the water pump, i wanted to run it by you guys.

p.s. how do i know if it's a blown head gasket or cracked head? how hard is it to fix a blown head gasket? please help fellow MB brothers!

Teddy
1975 240D - 244k

Well, let's see. Check the radiator in the center after the car has warmed up. If it's cooler than the block or head then you've got circulation problems. As always, to eliminate some components it is easier to remove the thermostat and see what happens when it gets hot. if it's not too hot, then the t-stat is no good. If it remains hot, the you gots to keep looking. with the t-stat out, remove the clamp from the upper radiator hose (being careful to do this with the cap off and the engine stopped so you don't burn yourself). Start the engine and if the water pump is functioning, you should see a rather substantial gush of coolant leave the end of the hose. If not, then you've found your problem. Good luck and please be careful. BTW, when you say the radiator was repaired, what was done to it and was it checked by the shop after they finished the repair. That could also be a problem. Also, you might just have a ton of air in the cooling system and it's air bound. Check that slso...

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Jeff Lawrence
1987 300e
1989 300e
1987 BMW 325

[This message has been edited by jeffsr (edited 07-14-2000).]

If the head gasket is blown at a point were the coolant pasage is then the coolant will get contaminated with combustion residue. Also you could look for bubles in the coolant but they are hard to see. Leave the rad cap off and let the car warm up while you watch the coolant. As the engine warms up (and the thermostat opens)you should see the coolant flowing thru the rad.