T4 odd heater fan behaviour

[farmsyncro]

Hi all,
In chasing down a mysterious whistle that eventually was narrowed down to being present when the heater fan is on, I discovered a couple of odd things:

1. When the heater fan is on the engine fan is on as well. I can understand this when the a/c is on as there is a need for air flow over the a/c condensor in front of the radiator but, I cannot see an advantage at all when the heater is used.

2. When the a/c was fitted (I believe all were fitted in Australia) the original pipe to the left demister vent is cut and left half open (I'd like to insert a pic here but I do not have permission?). This means a big leak of air bypasses the a/c evaporator & heater core. This is so slack of the a/c fitters - I've never seen anything like it.
Has anyone else noticed this?
I suggest checking the a/c behind the glove box and blocking the remains of the old demister vent to improve fan efficiency (for free!)

Does anyone have an appropriate fix for the engine fan wiring? I assume that it was easier to wire both fans together like this rather than wire the engine fan to the a/c only (as well as the temp switch).

By the way, removing cleaning and lubricating the heater fan has not fixed the whistle - it must be in the engine fan.....all I have done so far is make more work!

Regards,
FarmSyncro

[Transporter]

Try PM jets

[rob64981]

I'd like to insert a pic here but I do not have permission?
Regards,
FarmSyncro

If you upload your pictures to Image hosting, free photo sharing & video sharing at Photobucket you can then copy the [IMG] code and paste it onto ant web site.

We will then be able to see your pictures.(make sure the album is set to public not private!)

Hope it helps Rob

[Sunny43.5]

My own personal experience with T4,s is that the engine cooling fans only operate when the engine reaches a certain temperature , normal operation is that after driving and you shut the engine down the fans sometimes will operate for a short time to lower the engine temp . You could aslo check for something stuck in the fan itself the internal ones can sometimes get leaf debris stuck which will cause an unusual noise . Howard

[Cousin]

I assume that it was easier to wire both fans together like this rather than wire the engine fan to the a/c only (as well as the temp switch).

Hi farm, you're right the a/c were fitted here in Aus, by Delco? I think
And the thermo fans were wired up to it, something about having the system running for a bit after shut down to stop piping bursting
But it wasn't normal to have the heater fan included

Sounds like a botched job, or someones had a fiddle since and got things wrong

I don't have a solution for you, but best of luck with it


M

[jets]

1. When the heater fan is on the engine fan is on as well.

I will check what mine does next time I am out in it.

[Seano]

Sounds like a bodge job to me. My A/C is independant of the heater in operation so when the cabin fan is on.....the A/C is not unless I've pressed the A/C button. Ergo the radiator fan doesn't come on when the cabin fan does.

As for the whistle......I'll wager there is either a) something in the ducting between the pollen filter and the cabin fan or b) a small gap in the pipework after the cabin fan through which the wind whistles....the latter is more likely.

In mine, the cabin fan is behind the glovebox and can be removed simply by removing the glovebox and undoing the screws that hold the pollen filter to the firewall (they also hold the fan unit!) - the fan unit then virtually drops out to the floor. This leaves the heater core in situ beside(?) it. The A/C exchanger is behind the centre stack. I don't recall any OE ducting had been altered to fit the A/C....

[skehanpj]

My 97 t4 has a squeek ...i think it a loose screw on the mounts of the fan body. Ps at least your heater works...01 tdi...heater... no go!

[Seano]

Your 01 probably has the same problem as mine. Fan works but heater control is broken. I just adjust the inline valve in the engine bay (behind and below coolant reservoir) if I want heat...

[jets]

I will check what mine does next time I am out in it.

Checked mine today, when the heater fan is turned on, both rad. fans start running. I was wondering why the engine took much longer to warm up. Looks like the same guy who installed your AC did mine as well.Let us know if you investigate the wiring & can fix the problem.