Is it normal that the engine gets hotter after flushing the radiator? Used MB coolant mixed with plain water to fill it up.

Before flushing the engine would not get hotter then 175F, now after just driving two blocks it's already almost in the red.

I was thinking that maybe the coolant and water needed to be mixed and that that's the reason for the overheating right after flushing the radiator (?).

I did not touch the thermostat. Any suggestions, Thanks.

1978 300CD

How did you drain the old coolant? Did you drain the block too? If you didn't mess with the t-stat but drained the block then its possible that you filled the radiator but not the block. I did that once. I'm glas it was on a w123 series with cast iron head and block. Very forgiving.....

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2001 Dodge Ram 2500 Cummins Turbo Diesel - 4x4, auto, 3.54 gears, long bed
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'92 300D 2.5 Turbodiesel - sold
'83 300D Turbodiesel - 4 speed manual/2.88 diff - sold
'87 300D Turbodiesel - sold
'82 300D Turbodiesel - sold

I was thinking about that, but are the radiator and block then not connected?

how do I fill the block, now that all the coolant is in the radiator?

Thanks.

Jorn


You may have some air trapped in the system. I think you have a 13mm vent bolt on the T stat housing ? Did you vent the system when you put in the coolant? It is NOT normal to get hotter after a flush. Your car should run a little hotter than 175, as thats at the low end of the range, it never got any hotter ?

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

I'm betting the thermostat didn't open yet. You are not getting an accurate temperature reading since there is no water in the block. You car will not be in the "red" after a drive around the block with no water.

Let it idle and feel the engine for heat, don't pay any attention to the needle. Let it idle for 10 minutes and the thermostat should open up and then you will need to fill the system with another gallon of coolant.

No it doesn't get much hotter then 175F, sometimes a little above it but that's it, even on a hot summer day in the Valley.

I can't remember if the the engine was really hot or just warm. The temperature gauge was going up really fast while driving. When I opened the radiator cap the coolant was pouring out.

I will look at it tomorrow again,
feed some coolant true the hose that go's directly to the engine and see if it takes more of it.

Thanks you guys, everything is fine now, probably the termo didn't open yet yesterday, didn't run it long enough. It runs now between 175F and the next line; 190F(?).

What I do with NEW thermostats is drill a 1/16th hole in the inside edge of them.
Put the thermostat in with the NEW HOLE upwards.
This allows the air to purge out more quickly, does not affect performance.
A heck of a lot better than a overheat to bleed out the air.

The 616 and 617's in the 123's are particularly hard to fill with coolant without getting air bubbles. Park with the front uphill as much as possible and fill the engine from the top radiator hose. Then run it for 20 minutes with the heat on full blast and the radiator cap off. Chances are your temperature will go up very high for the first few minutes, then things will start to flow completely and you will have to add more fluid into the radiator.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13