dj_efk
A2OC Donor
There's been a lot of talk around failing / sub-optimal thermostats recently and I thought it would be helpful if I create this post in a new thread ahead of a long journey in Audrey - with a known-good OE thermostat - and measure the warm-up temp at 3 minute intervals so that those of you experiencing a slow warm-up time and wondering if this is normal can compare your temperatures to mine using CDIS or VCDS to check.
Test Conditions:
Ambient temp: 12°C (according to the outside temp measurement on the dash)
Route Description: 8.5 miles of flat B roads at up to 40mph, then undulating motorway (including the steep uphill section of M40E after High Wycombe), M25N (again some fairly undulating steep terrain for a motorway) at 60mph or so.
Relevant car notes: Deleted EGR (so slightly slower than standard warm-up), six speed gearbox, 60mph is ~1750 RPM. Car is lightly loaded with just myself driving. Oil level is full (relevant as the oil and coolant temps impact on each other). The climate unit is set to 21°C and on auto.
Measured Coolant Temperatures:
Start: 15°C
3 mins: 38°C
6 mins: 49°C
9 mins: 62°C
12 mins: 74°C
15 mins: 78°C (this is when I joined the M40)
18 mins: 84°C
21 mins: 88°C
Notes:
As can be seen, as the temp got to mid-70s degrees then the rate of increase slowed down and stayed slow while the oil gradually started to catch up and as the thermostat began to open as it should somewhere in the 80s.
The needle was pointing to 90°C around the 16/17 minute mark (dash reading was 81 or perhaps max 82 °C); as has been well documented elsewhere it stays at 90 even when the true temp is ~8/9°C below - and presumably above - this.
I also had to wait at some lights for over a minute between 3 & 6 minutes, otherwise warm-up would have been a little faster.
I can do another one of these if the temp drops again as I’m told it might. Meanwhile I hope this helps someone.
Test Conditions:
Ambient temp: 12°C (according to the outside temp measurement on the dash)
Route Description: 8.5 miles of flat B roads at up to 40mph, then undulating motorway (including the steep uphill section of M40E after High Wycombe), M25N (again some fairly undulating steep terrain for a motorway) at 60mph or so.
Relevant car notes: Deleted EGR (so slightly slower than standard warm-up), six speed gearbox, 60mph is ~1750 RPM. Car is lightly loaded with just myself driving. Oil level is full (relevant as the oil and coolant temps impact on each other). The climate unit is set to 21°C and on auto.
Measured Coolant Temperatures:
Start: 15°C
3 mins: 38°C
6 mins: 49°C
9 mins: 62°C
12 mins: 74°C
15 mins: 78°C (this is when I joined the M40)
18 mins: 84°C
21 mins: 88°C
Notes:
As can be seen, as the temp got to mid-70s degrees then the rate of increase slowed down and stayed slow while the oil gradually started to catch up and as the thermostat began to open as it should somewhere in the 80s.
The needle was pointing to 90°C around the 16/17 minute mark (dash reading was 81 or perhaps max 82 °C); as has been well documented elsewhere it stays at 90 even when the true temp is ~8/9°C below - and presumably above - this.
I also had to wait at some lights for over a minute between 3 & 6 minutes, otherwise warm-up would have been a little faster.
I can do another one of these if the temp drops again as I’m told it might. Meanwhile I hope this helps someone.
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