Thermostat ?????

joderest

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Ok, i have a question.
ML270, been fine all summer, temp gets to just over 80 in about 5 miles.
This morning a bit colder, and it took a while, about 8 miles to warm up and reach just over 80 on temp gauge.
Normal ?
I have been to a Mercedes dealership, was shown a thermostat out of a Mercedes marked box, but it had Behr/Mahle stamped on it, is this OEM ?
I can get same on flea bay for half the dealer cost.

Just some advice if poss, car runs, starts and stops fine, has heat from heater almost instantly.
 

Oldspanners

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I think you're being a bit premature there. If the temperature wasn't getting above 80 after 20 miles or never above 80 I would be time to change.
On my C class the noticeable difference was in the MPG and it never got above 65C.
 
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joderest

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ok, thanks old spanners. ( i have old sockets !!!!!)

Cheers
 

Jim2

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On another forum, one poster believed that in most cases where the temp is not rising fast enough, or behaving in a "Jumpy" fashion, 1st thing to do is a coolant flush and change, and see if that changes anything. He maintained that 1st thing people will do is change the thermostat, ( and as well, the coolant of course ) So the problem is solved, but it may have been just the coolant, and not the thermostat.
I have recently flushed and changed the coolant in mine ( W212, OM651) and there was an immediate improvement.....seemed to heat up much quicker, and stay at 90c. But in the last few days, it seems to be taking a bit longer again to reach the 90c, ( falling temperatures may be affecting it) but once there, it stays dead on the 90. So I cannot rule out a thermostat just yet. Let us know how it works out for you, Joderast, if you would?
 

LostKiwi

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As the air gets colder diesels in particular will take longer to warm up.
Every time the piston draws air in with a diesel it's a full cylinder worth and at low throttle openings with small amounts of fuel injected that has a significant cooling effect leading to longer warm up times.
 
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joderest

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Thanks all.
I think the thing to do here is buy a stat and keep it on the shelf until the temp does not reach 80 Odd, i think, but not sure its the original stat, as does not appear any work done in that area, although only 43,000 miles, its over 15 years old !!!!
 

thebiglad

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It's getting much colder during the night, so your engines are having to warm up from a lower start temperature - so it takes longer.
 
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joderest

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there are lots of different thoughts here, so i suspect the best thing to do is change it, it does not look that hard, just being careful of the fuel pipes seems to be only warning.
 

Yugguy

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Stat is so simple to change it is worth doing, and yes, get the OEM part number and buy off ebay.
 
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joderest

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hmm, always the same, consider doing something on this car and it throws up something else.
Last night the BAS/ESP light came on, it seemed to happen as i switched to dip beams, anyway, stopped, restarted, light gone, did not show this morning.
and yes, will order up and change stat soon.
i will update any improvement, but may be a few weeks.
 

daibevan

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My coolant is due to be changed after 15 years. I might change my stat at the same time to save having to replace the coolant for another 15 years.:):)
 

Jim2

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I did mine 2 weeks ago, so now I know exactly what kind of Anti-Freeze is in it ( Comma Xtream G 48, MB 325.0 spec ) It's leaking a tiny amount, and I can't seem to find the leak...….seems to be a slight water mark stain around the water pump, but now with the new blue coloured antifreeze, that might change as it may be easier to spot the leak.( I hope so anyhow. :) But meanwhile, I can now top it up when ever it needs it, without worrying about mixing two non-compatible anti freeze's together. Anyone have any suggestions about coolant leaks in the OM651? All suggestions are welcome...… LOL :)
 

LostKiwi

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Put in some UV dye. Kits are available on eBay...
 

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