Rs 220 Trophy Coolant temperature drops with higher revs?

[oli2833]

Hi I'm new here.

Had my 220 Trophy for a couple of years now, but as of yesterday the coolant temperature seems to be dropping quickly with higher revs. As soon as I back off and drive with lower revs it goes back to normal. No high spikes of temp just completely drops when the revs are higher ( not ridiculous). Wondering if anybody would know what this could be?

 

[VXR killer]

Sounds like dodgey thermostat

 

[Martin_172]

id start at the thermostat, you would expect the opposite with a stuck open thermostat where the coolant temp would go to normal under load and then drop off again under low load, but on a modern car with radiator airflow flaps etc that can open and close you never know!

where are you taking the coolant temperature reading from? obd/rsmonitor?

 

[oli2833]

id start at the thermostat, you would expect the opposite with a stuck open thermostat where the coolant temp would go to normal under load and then drop off again under low load, but on a modern car with radiator airflow flaps etc that can open and close you never know!

where are you taking the coolant temperature reading from? obd/rsmonitor?

Off the RS monitor, it's weird the temp drops rapidly with high revs, but when driving slow and low revs it fluctuates when driving fast the temp goes up and when driving slow it drops and then rises again, but always settles at around 83-85 degrees. No issue in warm up and take around the normal time to warm up.

 

[Racky]

Isn't that supposed to mean that you got air in the system ? Or did I watch to many Matt Armstrong videos ?

 

[Rich-D]

Isn't that supposed to mean that you got air in the system ? Or did I watch to many Matt Armstrong videos ?

Yes, I'd say air in the system as well

 

[VXR killer]

On my megane, temp used the build upto normal when slowed and in traffic, and dropped below when moving. Was the stat, tiny gap in the opening seal.

 

[Adey.]

what temperatures are you actually seeing? temp does regulate and fluctuate. id say anything between 80-95 are normal. From what i remember the thermostat is an 82 degree item, water systems dont hold solid temp they change and react to everything going on.

 

[oli2833]

what temperatures are you actually seeing? temp does regulate and fluctuate. id say anything between 80-95 are normal. From what i remember the thermostat is an 82 degree item, water systems dont hold solid temp they change and react to everything going on.

On a 30 min drive to work between 75-86. But its constant up and down depending on power delivery, revs and speed. I was driving the other day and the temp was up to about 80 and revved over 3500 and the temp went lower than 70 ( <70 on the RS monitor) so unsure how low it went, but then came back up to 85 ISH after about 15 seconds. Never seen it up and down all the time, previously it's got to about 86 then stayed within a few degrees of that even under heavy right foot.

 

[oli2833]

On my megane, temp used the build upto normal when slowed and in traffic, and dropped below when moving. Was the stat, tiny gap in the opening seal.

Definitely normally it would fluctuate a little, but this is dropping faster than I've ever seen before, then creeping back up

 

[Clio_fool]

I doubt the actual coolant temp could vary that quickly. Sounds like a dodgy sensor to me.

 

[oli2833]

Isn't that supposed to mean that you got air in the system ? Or did I watch to many Matt Armstrong videos ?

Problem is I'm not seeing a drop in coolant level or coolant leakage, there's no overheating within that 25-30 min drive, heater in the car is working fine, and no reduced power 🤔

 

[Brigsy]

Sounds like thermostat is weak.

 

[Ricardos]

My Scangauge shows temps always around the low 83-86, never below 80 once it's up to that temp, fan kicks in on 99 degrees in prolonged stop-start traffic.

 

[npt]

Thermostat could be stuck open, its a serviceable item so I would have it changed and flush the system,

 

[Robbie Corbett]

My mates scooby used to drop oil pressure with revs, turned out to be a dodgy earth.

Later on it used to drop oil pressure with revs which turned out to be broken ring lands scoring the oil pump up good.

 

[Martin_172]

On a 30 min drive to work between 75-86. But its constant up and down depending on power delivery, revs and speed. I was driving the other day and the temp was up to about 80 and revved over 3500 and the temp went lower than 70 ( <70 on the RS monitor) so unsure how low it went, but then came back up to 85 ISH after about 15 seconds. Never seen it up and down all the time, previously it's got to about 86 then stayed within a few degrees of that even under heavy right foot.

That sounds fairly normal for this time of year, remember if you have the heaters on the thermostat is probably staying closed so the coolant in the rad will be much cooler, get the revs up, stat will open and cool coolant starts entering the engine so the temp sensor will detect that fairly quickly! where in the warmer weather the stat will be constantly fluctuating between open and closed so the difference in coolant temp between rad and engine block is much closer.