Aux heater (webasto) questions

[workingonit]

If you were to replace your OEM viscous fan with a thermostatically switched electric fan, then you could have the fan come on where you wanted it to, allowing sufficient time for engine warm-up.

I switched to a 3000 cfm Flexalite 238 fan (it has more cfm than needed, but I do live in Texas), and installed it with a Hayden 3653 adjustable thermostat. I set the starting temperature to 175F (raised it to 185F for winter), and it maintains the temperature on my M54 at 194F, either with the A/C running (with aux. fan helping) or not, with the HVAC system off.

[Clavurion]

Originally Posted by workingonit

If you were to replace your OEM viscous fan with a thermostatically switched electric fan, then you could have the fan come on where you wanted it to, allowing sufficient time for engine warm-up.

I switched to a 3000 cfm Flexalite 238 fan (it has more cfm than needed, but I do live in Texas), and installed it with a Hayden 3653 adjustable thermostat. I set the starting temperature to 175F (raised it to 185F for winter), and it maintains the temperature on my M54 at 194F, either with the A/C running (with aux. fan helping) or not, with the HVAC system off.

For diesel engine the radiator on E53 is so large that not much need for fan. I've run mine without viscous fan (and fan cowl) for several years. No problems even on summer time while towing. Just make sure the electric pusher fan is working if needed.

[workingonit]

Originally Posted by Clavurion

.... Just make sure the electric pusher fan is working if needed.

My electric main fan is a puller; the auxiliary fan is a pusher.

I added a manual override switch under the dash, just for a back-up to the automatic switch. If my temperature display (a smartphone using the Torque Pro app) indicates the temperature rising too fast, or going past 194F (many static tests and actual drives have shown that to be the normal upper limit), then I can reach under the dash and flick on the fan. Actually, I'd probably pull to the side of the road, and inspect underhood as well.

[Clavurion]

Originally Posted by workingonit

My electric main fan is a puller; the auxiliary fan is a pusher.

Yes, I understood that you replaced the viscous fan with electric one. I was referring to front pusher (aux) fan if the viscous fan is left out. The front pusher fan is mainly for AC but is also activated if engine temp rises too much.

[workingonit]

Originally Posted by Clavurion

Yes, I understood that you replaced the viscous fan with electric one. I was referring to front pusher (aux) fan if the viscous fan is left out. The front pusher fan is mainly for AC but is also activated if engine temp rises too much.

Did not know that, thanks!

[Clavurion]

Originally Posted by workingonit

Did not know that, thanks!

On petrol engines there is coolant outlet temp sensor on lower coolant hose from radiator to water pump. Its sole purpose is to control the need for electric pusher fan (in addition to AC system pressure). On diesel engines there is no separate coolant outlet sensor and electric pusher fan is activated if engine coolant temp rises too high. Diesels have lower running temp (thermostat 88 C) and hence lower coolant system pressure (1,4 bar expansion cap vs. 2,0 bar on petrol).

[grounch]

Bringing back this topic for summer.
There should be 2 modes with the remote heating system, heating & ventilation. But on my remote it doesn't switch.
What if i disconnect the webasto, will it do the same result meaning just blowing non heated air into the cabin?
The temp won't fall under 25°c for few month so i'm not really in need of aux heating, even for the engine.

[Clavurion]

Originally Posted by grounch

Bringing back this topic for summer.
There should be 2 modes with the remote heating system, heating & ventilation. But on my remote it doesn't switch.
What if i disconnect the webasto, will it do the same result meaning just blowing non heated air into the cabin?
The temp won't fall under 25°c for few month so i'm not really in need of aux heating, even for the engine.

You can't activate ventilation with remote. The remote signal is just voltage activation directly on Webasto. On nav screen or MID you can activate ventilation.