Which thermostat?

[Error404]

Thing is my car will hit 90 at idle, in traffic etc. Only drops when moving 20mph +
The faster the speed the more the temp drops, so thats why i think the thermostat is stuck open or partially open

[Thuppu]

Aah, ok.

[andy10v]

I will be trying out some that they open at 71C on my current builds
Like the idea of water/coolant exchange earlier

Any reason?

I thought you wanted to keep the engine at its optimum operating temperature at all times?

[DNA-S2]

Reason ... To keep it cooler of course.
Try thermostat and log some data at lower temps 75/80C and compare.
Should be better

[UrS4boy]

G62 ECU Coolant Temperature Sensor Info

Reason ... To keep it cooler of course.
Try thermostat and log some data at lower temps 75/80C and compare.
Should be better

Umm...

Q: How do you think the G62 coolant temp sensor info is going to interpreted by the ECU?

A: That the engine is not up to temp and the ECU needs to keep the mixture a bit richer (= less power, more fuel consumption) until the engine gets to design temp (87 to 90 C) (- which it will never do with that lower temp thermostat).

Click on the G62 label:

http://members.shaw.ca/speedtek/UrS%20Engine%20Bay%20Device%20Map.html

[DNA-S2]

I guess I am on different level from you mate as I use Vems hence I am able to do a bit more options on what I need and how is needed [emoji6]

[newsh]

Alex, have you got a boot round the MFTS? If not it can be cooled by the airflow and give a false low reading. If the MFTS is shielded from the airflow then it's almost certainly the Thermostat.

[UrS4boy]

I use Vems

Enough said. (You *might* have mentioned that before - in which case I wouldn't have bothered replying).

But for the Motronic folks, what I said will hold true (ish).

[Error404]

John, yes I have the OEM boot on the MFTS

[Michael S2]

What is considered normal cruising temperature then? Say at 3000rpm 6th gear. I would have thought it normal for temps do drop when air is moving faster.

[S2central.net]

Enough said. (You *might* have mentioned that before - in which case I wouldn't have bothered replying).

But for the Motronic folks, what I said will hold true (ish).

All Danny is saying that with VEMS (or any other aftermarket ECU) - the correction for water temperature can be easily customised to taste... well it can for those with Motronic knowledge too but thats a moot argument.

I personally think the S2s with auxrad removed will all run cooler at highway speeds due to the blast of air directly over the water manifold... I absolutely saw that when I deleted the auxrad - nothing to do with thermostat or MFTS flavour. Mine dropped from 90C to 87C.

If the engine is struggling to get towards 80C then the 'stat must be part stuck open !

All that said - its important to monitor the water temps at the ECU (via G62) as opposed the MFTS which just drives the gauge... That will avoid any confusion about whether MFTS is reading lower because of a cooling affect onto its own body.

[DNA-S2]

All Danny is saying that with VEMS (or any other aftermarket ECU) - the correction for water temperature can be easily customised to taste... well it can for those with Motronic knowledge too but thats a moot argument.



I personally think the S2s with auxrad removed will all run cooler at highway speeds due to the blast of air directly over the water manifold... I absolutely saw that when I deleted the auxrad - nothing to do with thermostat or MFTS flavour. Mine dropped from 90C to 87C.



If the engine is struggling to get towards 80C then the 'stat must be part stuck open !



All that said - its important to monitor the water temps at the ECU (via G62) as opposed the MFTS which just drives the gauge... That will avoid any confusion about whether MFTS is reading lower because of a cooling affect onto its own body.

Thanks for explaining in detail mate [emoji106]
Can't believe I didn't see you at ADI
So wanted to have chat with you mate and talk about Lazarus ...
Gutted [emoji17]

[S2central.net]

Danny - yeah I only realised you were there when I asked someone who was in the white S2/RS2 Avant as it was driving off... D'oh - next time sir... I have to call you !

[Bowie69]

What is considered normal cruising temperature then? Say at 3000rpm 6th gear. I would have thought it normal for temps do drop when air is moving faster.

Thermostat is designed to keep temps up, even at cruise, so your needle shouldn't drop below 87/88C on your gauge when cruising, unless it is icy cold out (like -20C).

As for running a 71C stat, that's about optimum for power, hence DNA-2's fascination with it, for a road car it may be too low, as you would never get the oil up to temperature properly to remove the water from it -for this reason I run an 82C in my Rover V8 on Megasquirt

[gnutz2]

No idea what thermostat I run but it allows me to drive temps down to 70c, I'm sure its not faulty as it's allowed me to do this since it was fitted.

I run the car at around 75c to help with charge temps and my water temp compensation turns off at 55c.