Fluctuations in temperature gauge
03-10-2017, 01:49 AM
#1
Fluctuations in temperature gauge
I'm hoping some can hel me out here... am I chasing a ghost or do I have a real problem.
I have a 2006 S350 and my temp guage fluctuates in certain situation. On the open road and when the guage has seller it sits between about 87 and 92. I am happiness enough with that.
But if I drive around in traffic. It wil sit around 92 to 95 and then when I head out on the open road it drop to 80 and fluctuate between 80 and 90 for about 5 to 10 mins and then settle down agai.
I can't seem to get a solid answer on what it should do. I have repacked the thermostat. No difference. I replaced the collateral temp sensor and that seems to sort of fix it for about 10 days but now it started again. But it only started after I was driving down a fairly steep hill for about 1.5 miles....the engine was doing little or no work at that time. But it has now done it again as described above.
I wondering do I have a real problem. Might I have a small bit of trapped air somewhere..about 50% to 60% of the time I am open road driving at about 60 mph....if I might be air what is the best way to bleed one of these engines. I tried a couple of standard ways...but is there a trick. This startING to annoy me know but I don't want to spend hundreds and hundreds of euro doing swap tonics and guessing what it might be.
Any help would be greatly appreciated
I have a 2006 S350 and my temp guage fluctuates in certain situation. On the open road and when the guage has seller it sits between about 87 and 92. I am happiness enough with that.
But if I drive around in traffic. It wil sit around 92 to 95 and then when I head out on the open road it drop to 80 and fluctuate between 80 and 90 for about 5 to 10 mins and then settle down agai.
I can't seem to get a solid answer on what it should do. I have repacked the thermostat. No difference. I replaced the collateral temp sensor and that seems to sort of fix it for about 10 days but now it started again. But it only started after I was driving down a fairly steep hill for about 1.5 miles....the engine was doing little or no work at that time. But it has now done it again as described above.
I wondering do I have a real problem. Might I have a small bit of trapped air somewhere..about 50% to 60% of the time I am open road driving at about 60 mph....if I might be air what is the best way to bleed one of these engines. I tried a couple of standard ways...but is there a trick. This startING to annoy me know but I don't want to spend hundreds and hundreds of euro doing swap tonics and guessing what it might be.
Any help would be greatly appreciated
03-10-2017, 01:58 PM
#3
Hi
Yeah I understand all that and to some degree that is the same logic I have been trying to apply.
But I can punch a few holes in that...what after fitting a new collateral temp sensor did the temp guage say pretty solid at around 90 C for 10 days when I was driving the same route work and back. Any why did this problem only restart after i came down asteep hill goe a diatan e of about 1.5 miles. During that time the temp droppwd to 80 form about 90. So this evening on my home from work came through town traffic. Temp guage was cycling between 80 and 90 all the while is was dr8nv in town which was about 30 mins. I then hit the open road and the temp keeps cycling between 80 and 90...it took 3 cycles and a distance of about 8 miles before the car settled down and again became pretty rock solid at about 90....
could I still uave a small air lock...but if I did I would possibly expect it to cycle all the time.... does yhe system need a minimum distance to monitor the averages of temp before it settles down....is it as still as theses temp gauges are very sensitive.
I have had may cars over the years...BMW SAAB other Merc and none of these have had such a twitchy temp gauge and to add insult to injury I believe these electronic thermostats are supposed to be more steady than the old mechanical ones.
Does anyone know what signals feed the coolant temp gauge.
many thanks guys....
Yeah I understand all that and to some degree that is the same logic I have been trying to apply.
But I can punch a few holes in that...what after fitting a new collateral temp sensor did the temp guage say pretty solid at around 90 C for 10 days when I was driving the same route work and back. Any why did this problem only restart after i came down asteep hill goe a diatan e of about 1.5 miles. During that time the temp droppwd to 80 form about 90. So this evening on my home from work came through town traffic. Temp guage was cycling between 80 and 90 all the while is was dr8nv in town which was about 30 mins. I then hit the open road and the temp keeps cycling between 80 and 90...it took 3 cycles and a distance of about 8 miles before the car settled down and again became pretty rock solid at about 90....
could I still uave a small air lock...but if I did I would possibly expect it to cycle all the time.... does yhe system need a minimum distance to monitor the averages of temp before it settles down....is it as still as theses temp gauges are very sensitive.
I have had may cars over the years...BMW SAAB other Merc and none of these have had such a twitchy temp gauge and to add insult to injury I believe these electronic thermostats are supposed to be more steady than the old mechanical ones.
Does anyone know what signals feed the coolant temp gauge.
many thanks guys....
