Help: Temperature Gauge Above 80? | Engine (2024)

Recently noticed my temperature gauge going about 80 but never above the next marker after 80, but the gauge goes up and down while driving it never stays on the 80 mark, most of the time it does but it goes up and down, its been like this since i brought the car....its a clk a208 2.3 Kompressor 02 plate....

just wondering is this normal? im planning to change the thermostat to see if this helps but ive been told it should just sit on 80 the whole time.

the car does fairly warm up quickly....

Thanks in advance for any advice.....

bobby dazzler said:

sounds like your thermostat is ready for replacement.

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+ 1.

This is such a coincidence, yesterday I got stuck in traffic on the motorway, cuing after an accident and just happened to glance at my temperature gauge and it was way up at 80C! I've never seen it get that hot before and eventually bottled it and turned the heater on full blast to help with the cooling.

Once traffic go moving the temperature dropped back down to 50C (about a third of the way up the gauge) and was there for the rest of the journey. I'll be keeping an eye on mine. Thought it might be the cooling fan not engaging properly?

markmifsud said:

I thought most petrol MB ran at circa 90c ?

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I would have thought so too, but mine normally reads about a third of the way up the scale, which corresponds with 50C. The scale is probably there just for a rough guide as 90C is almost in the red

Hawkwind said:

I would have thought so too, but mine normally reads about a third of the way up the scale, which corresponds with 50C. The scale is probably there just for a rough guide as 90C is almost in the red

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For my car, (320 M112) WIS states that the start of opening for the thermostat is 85c to 89c

Hawkwind said:

I would have thought so too, but mine normally reads about a third of the way up the scale, which corresponds with 50C. The scale is probably there just for a rough guide as 90C is almost in the red

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I think you need a new stat too.
It will transform the car - better running, faster warm up, better heating and improved fuel consumption.

My ML270 regulates at around 83degC, goes up a tad in hot weather or standing traffic, and a tad lower on long constant runs but around the 80 mark, so a little movement I wouldnt be too woried. It was stuck low at 55 to 60 before I changed my stat, low temp would indicate a stuck open stat to me- not sure if your model of car is different but every car I have owned over the past 28 years has been around the 80 to 90degC mark as standard- My Leon cupra TDI sits at 90 and doesn't budge.

As much as a cool reading might give you a warm fuzzy feeling of not pushing things too hard, it is not great news as engines are designed to run at those hotter temps and need to to maximise efficiency- cold engine can have all sorts of implications (thicker oil - it thins as it heats so less lubrication if cold) it can also effect fuel economy.

My feeling would be 80 ish is OK, 70 or below needs new stat.

Regards.

MOZ

Yes I agree that 50C is too low, I just assumed the scale was not particularly relevant as the gauge stayed at about 1/3 of the way up. 85 - 90C would be a far more efficient temperature, though having said that, gentle motorway driving will return up to 36 mpg and even at a constant 90mph I averaged 29.6 mpg.

Might get even more after a thermostat change

+ 1

50º is way too low. 93º is the optimum running temperature, so 90º is about right. Difficult to judge with MB gauges though.

razy85 said:

Recently noticed my temperature gauge going about 80 but never above the next marker after 80, but the gauge goes up and down while driving it never stays on the 80 mark, most of the time it does but it goes up and down, its been like this since i brought the car....its a clk a208 2.3 Kompressor 02 plate....

just wondering is this normal? im planning to change the thermostat to see if this helps but ive been told it should just sit on 80 the whole time.

the car does fairly warm up quickly....

Thanks in advance for any advice.....

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I have a clk a208 but the 320 v6

temp guage should be at 80 once warm and will go slightly over but not above the next marker as you have said. that sounds perfectly normal to me. I had an issue with my fan control relay (turns out it had been replaced but not plugged in correctly) and the temp shot up to just below the 120 mark in traffic because the cooling fan was not coming on.

Now its fixed (plugged in again) it varies between the 80 mark and the one above. once it climbs over the 80 mark the cooling fan should kick in and bring it back to 80 then it will rise again till the fan comes in again.

in short between 80 and the next mark = perfectly normal.

Ed

I did alot of looking into temp issues on this car and the fan control relay burried in the front bumper area below the passenger head light seems to be the only major issue for over heating that i could find.

Beeing a merc nothing is simple and the relay basically varies the cooling fan speed depending on water temp i.e its not just on or off but gets faster the hotter the car gets.

I did do a cooling water flush and change just to be on the safe side.

As long as your fan comes on at 80 ish and it climbs no higher than the next mark even is standing traffic on a hot day, all will be fine.

I believe thermostats fail to safe mode in general meaning you would end up with the cooling on all the time rather than off. if that makes sense lol.

Ed

My e220 estate engine temperature guage never goes above the 60% mark and never below the 50% line.....

Is that OK or too low please??