Peculiar cooling system problem
Discussion
On a Volvo T5, when at idle or driving slow it reaches normal temperature, but driving 50+ the gauge drops quickly, to rise again once slowing down. I have tried it with the torque app and normal temperature is around 84-92 on a 90 degree thermostat, on motorways it barely reaches 70.
The thermostat is new and tested to work in boiling water, no error codes, car runs fine but doesn't blow hot air inside like it used to, no leaks in the cooling system.
Could it be the temperature sensor, even if it's newly changed too? Or if anyone has any suggestions on something else?
The thermostat is new and tested to work in boiling water, no error codes, car runs fine but doesn't blow hot air inside like it used to, no leaks in the cooling system.
Could it be the temperature sensor, even if it's newly changed too? Or if anyone has any suggestions on something else?
Finlandia said:
Lets hope you're right, but I don't really see how it can be faulty when it opens and closes as it should in a pan of water.
As you bring the pan up to heat from cold, at what temperature does it open; and just as important- at what temperature does it start to close?My money says it may open and close in warm water, but nowhere near the correct temperature.
It doesn't sound particularly odd. To me it sounds like a cluster issue.
Cruising along with a normally low ambient (i.e. ~15C) would see a 70C ECT. I have seen those temps before in testing.
Typical thermostat failure modes are:
1) (if stuck open) the system never warms up unless excessive load
2) (if stuck closed) fine operation at low loads/town work but overheating at higher speed/load
Your heater comment is too subjective to diagnose. What is the time to temperature? Get a thermocouple in there and do a test!
Cruising along with a normally low ambient (i.e. ~15C) would see a 70C ECT. I have seen those temps before in testing.
Typical thermostat failure modes are:
1) (if stuck open) the system never warms up unless excessive load
2) (if stuck closed) fine operation at low loads/town work but overheating at higher speed/load
Your heater comment is too subjective to diagnose. What is the time to temperature? Get a thermocouple in there and do a test!
littleredrooster said:
Finlandia said:
Lets hope you're right, but I don't really see how it can be faulty when it opens and closes as it should in a pan of water.
As you bring the pan up to heat from cold, at what temperature does it open; and just as important- at what temperature does it start to close?My money says it may open and close in warm water, but nowhere near the correct temperature.
GroundEffect said:
It doesn't sound particularly odd. To me it sounds like a cluster issue.
Cruising along with a normally low ambient (i.e. ~15C) would see a 70C ECT. I have seen those temps before in testing.
Typical thermostat failure modes are:
1) (if stuck open) the system never warms up unless excessive load
2) (if stuck closed) fine operation at low loads/town work but overheating at higher speed/load
Your heater comment is too subjective to diagnose. What is the time to temperature? Get a thermocouple in there and do a test!
It doesn't really sound like it would be stuck open or close, maybe just not opening and closing at the right temperatures. Will have to check further.Cruising along with a normally low ambient (i.e. ~15C) would see a 70C ECT. I have seen those temps before in testing.
Typical thermostat failure modes are:
1) (if stuck open) the system never warms up unless excessive load
2) (if stuck closed) fine operation at low loads/town work but overheating at higher speed/load
Your heater comment is too subjective to diagnose. What is the time to temperature? Get a thermocouple in there and do a test!
At what temperature should a 90c thermostat start opening and closing?
DonnyMac said:
I had the exact same problem on an old 5 Series 15-20 years ago just after a major service.
The car eventually seized.
The dealer had put the brand new thermostat in the wrong way around.
BMW gave me a new engine, which was nice.
Mine is the right way in there, but the thought of the engine running cold is a bit worrying and I really don't fancy having it seize on me.The car eventually seized.
The dealer had put the brand new thermostat in the wrong way around.
BMW gave me a new engine, which was nice.
ShayneJ said:
- Your thermostat is buggered
ShayneJ said:
replace it also i don't know if
the T5 has a viscous fan or electric
but maybe check if viscous that the clutch hasn't seized
or leccy check the switch is not failed short making the fan run constantly
It's electric and seems to be working as it should.the T5 has a viscous fan or electric
but maybe check if viscous that the clutch hasn't seized
or leccy check the switch is not failed short making the fan run constantly
Finlandia said:
On a Volvo T5, when at idle or driving slow it reaches normal temperature, but driving 50+ the gauge drops quickly, to rise again once slowing down. I have tried it with the torque app and normal temperature is around 84-92 on a 90 degree thermostat, on motorways it barely reaches 70.
The thermostat is new and tested to work in boiling water, no error codes, car runs fine but doesn't blow hot air inside like it used to, no leaks in the cooling system.
Could it be the temperature sensor, even if it's newly changed too? Or if anyone has any suggestions on something else?
To clarify, it SHOULD be sitting at 84-92, but the dash display and the Torque app are showing it as <70?The thermostat is new and tested to work in boiling water, no error codes, car runs fine but doesn't blow hot air inside like it used to, no leaks in the cooling system.
Could it be the temperature sensor, even if it's newly changed too? Or if anyone has any suggestions on something else?
feef said:
To clarify, it SHOULD be sitting at 84-92, but the dash display and the Torque app are showing it as <70?
On the dash, when the temperature is where it should be at 3 o'clock, the torque app shows the temperature range at between 84 and 92, this is idling or driving slow city traffic, when doing motorway speeds the dash gauge falls to 4 or 5 o'clock or around 70 on the app.Did you get the new one from a Volvo dealership ?
It sounds like it is sticking open, when you are pottering around town etc it will mostly be open. Obviously once you hit ze autobahn the cooling effect of the radiator is greatly increased and it should start to close.
The other possibility is that it is getting stuck on something in the housing, I think they are pretty simple on those (metal job on the top of the engine ?
I take it the heater is nice and hot when idling/around town and it drops off once on the motorway ?
It sounds like it is sticking open, when you are pottering around town etc it will mostly be open. Obviously once you hit ze autobahn the cooling effect of the radiator is greatly increased and it should start to close.
The other possibility is that it is getting stuck on something in the housing, I think they are pretty simple on those (metal job on the top of the engine ?
I take it the heater is nice and hot when idling/around town and it drops off once on the motorway ?
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