Hey everyone hows it going, I have a 85 300D with 200 000 miles on it and was just wondering if anyone can tell me what temperature the return hose coming out of the bottom of the rad should be, hot? cold? warm? ...see my dash gauge temperature is reading 100+ (before i turn on the heat) and its not like I'm using the aircon or cruising up mountain roads. I put a new thermostat in it, and checked it on the stove top, new coolant, new water pump, no fluid leaks, ...I also ran the garden hose through the rad to check for blockage and it was fine, and I pulled the drain plug on the block and ran the hose through the block with the thermostat out and there were no blockages there either.I was thinking the radiator might not be working efficiently but when I put my hand on the lower radiator return hose it is not warm at all, it's more like room temperature. Is this normal? I would think it would be at least warm if the rad wasn't working,??can i rule out a bad rad? other than that is there anything else I should check? ...........oh yeah and the clear fuel return line coming out of the injection pump, when i push down on the throttle linkage and give it some gas the fuel turns white like lots of little air bubbles, is this normal to have air in that return line coming out of the IP? thanks everyone!! -Robby

I would suspect the thermal fan clutch on the water pump. Most likely it has 200,000 miles on it and is either slow to lock up or not locking to help stabilize the temp. How old is the coolant cap? If old as well, possibly not holding correct pressure?

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81 300CD (sold) 1972 280 SEL 4.5 (sold) 1966 250 S 4 spd (sold) 1974 450 SL (sold) 86 BMW 325ES (sold), 1973 280C (sold) 1988 300 SE.

you have turbo model correct?

that hose might not get warm for a while. No reasonable amount of water 'flows' through there.

Assuming you are talking about line from expansion tank bottom to radiator.

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