Car is running hot in traffic

Radiator was flush and clean two times there is nothing like something blocked the airflow. I even changed the temperature sensor. One thing more I noticed but as per my mechanic he said me it normal but I do not believe him. The thing is that I have 87c thermostat the suction fan should start spinning at when thermostat open but in my car it start spin at 95c and stop at 93c and the speed is slow I feel that. Second when I use air conditioner the fan do increase speed but it should be more faster I think and the last when I use full blast heater then the fan start spinning full speed very noisy like this in traffic temperature goes down to normal. Now is it a fan problem I have doubt?

Hi yes this is the same suction fan above in photo,
I bought a temperature gun and what I figure out is while driving on highway high speed I stop onside of the road and check upper hose is 87c and lower is 82c this is good and now I tired idle the car for long time and checked the hose temperature upper is 90c and lower is also 90c suction fan is spinning and upper and lower hose are in pressure and because of too much pressure coolant not circulating properly at idle while opening heater temperature goes down to normal quickly is now radiator not doing his job to cool the coolant?

I figure out the problem already it’s the suction fan not spinning on time and when it spin speed is slow need to be fast too to control increasing temperature. In my climate control there is secret menu in that option 10no blower control speed, in that I can see my suction fan speed running at 25% at idle but when I accelerate the speed increase but not much and then when I change the speed manually from there to 60% temperature goes down to normal at idle so maybe it kind of some sensor issue or it’s fan like fan need to be reprogrammed through computer?

Hi KHLOW,

I bought this car last month from used car showroom here it’s a mecerdes e500 2004 Japanese spec, my friend have the same car and same model in his car temperature stay in middle which is 85degree it’s not moving up and down either ac is on or off and that the GCC Specs in United Arab Emirates. My car temperature stay on 80c which is 100c while I’m traffic but once I’m in highway temperature goes down to 85c.

HI KHLOW

Forget to mention before at cold start thermostat open at 87c and then the fan start spinning at 95c and stop at 93c, it’s starting winter now here the car is acting this way then what will happened in summer when it’s 50c hot this car can’t servive and one thing more as I know something is wrong with the car when the car temperature is at 98c I switch off the car and after 2mins switch on and see the temperature is at 103c so this is not good and normal

Alright so that means in ur region or Japanese spec cars in Japan there temperature gauge is always quarter to 12? And can I know what is the boiling point of antifreeze 50 mixed with water? Before I gave the car in one garage they put all water in radiator air bubbles stuck in heater core and because of bubbles when my car is cold after 12hrs system is still under pressure

Yes the coolant was added, one of the bad thing about this car cooling system is closed system means no cap on radiator the cap is on revioser bottle and due to this I can’t check if the radiator is fully top up and the second thing about cooling capacity I read it’s 11.5quart but while refilling after draining all it was top up with two 4L gallons only.

Hi ken,

I was expecting it might be head gasket, the last 3 different garage I went they didn’t find any sign of head gasket failure. Oil was ok, not losing coolant neither engine oil, three time I flash the radiator and bleed properly with 50 50 mix coolant. And today I was in MB workshop they checked the fan operation and said me the fan should start spinning at 85c and stop at 83c but mine start spinning at 95c and stop at 93c something is wrong as per them so they did computer diagnose no fault except one (Can system fault). As per them fan is ok and it’s speed also as per outside temperature fan will not speed up depend on outside temperature fan speed is increased, vechile speed sensor is also ok and as per refrigerant pressure when using aircon speed of fan is ok at idle. They suspect also head gasket but no sign of it then they suspect exhaust gas in cooling system which they can’t check And I try to find in auto spare parts shop they don’t have exhaust gas check in coolant device.

So is it possible when exhaust gas leaking in coolant it will delay fan operation by giving false ohms to cooling fan. Or maybe weak engine head?

And also for an example When driving temperature is at 85c normal and as soon I park the car ignition off and check after 15seconds I ignition swtich on and the temperature is at 88c overheat

Hi KHLOW2008,

Just yesterday I got my delivery (heat temperature gun) I examined it on two hoses after driving for 30mins, first the upper inlet hose 85dec and then strange to see lower outlet hose going to water pump is 88dec now what is this meant? I’m sure water pump is ok as checked by mechanics before I think it’s flow problem in block coolant jackets is blocked somewhere and that’s why at idle temperature jumps up slow slow up and once on highway speed circulation of coolant is ok but not on idle or traffic. Can coolant vapor block the flow in block or in head and is it a sign of head gasket or bad block or head?