G31 - preparing to tow caravan

[bennygsr]

Good to see the forum back up and running. Shame a lot of the old topics and "history" are harder to find, but good it's back nonetheless.

I'm preparing my g31 for towing a 1500kg caravan.  Over here in Aus, it's a somewhat unique vehicle with which to do this.

Are there any thing's I can do to maintain vehicle reliability  when towing the heavier load?   People frequently upgrade or install transmission coolers on other vehicles to prevent premature wear and tear?. I've tested the rear suspension by loading a slightly heavier van on the towball and the air suspensions seems to level off quite nicely, but are there any upgrades that may benefit here?

lastly, I'm looking to have an electric brake controller fitted by an auto elec. Specifically this model, which is considered one of the better units over here:  https://www.redarc.com.au/tow-pro-v3-2

 I've seen in some X5's there is some wiring pre installed almost ready for this?  Does this exist with the g31 also?  

Any other tips you might give before towing would be greatly appreciated.  

[BobA]

Is a larger fan recommended? There was a thread on the last site where someone found in addition BMW instructions for a heavier battery lead the whole length of the car but later discovered that the one they had was the same specification from standard. I wouldn’t say that the nose weight of a 1500kg van should give the G31 any bother as standard with the self-levelling. I’ve not towed with mine but I’ve had several hundred kg of sand and cement in the back without a problem.

[Procion]

One thing I would defo' do before towing is change the oil from a 0w-30 to a 5w-40, (Like Shell Helix Ultra 5W-40) much superior high temp' protection.

Don't know how concerned you are about cooling or how far you want to take this but as the ultimate solution  (probably at very great expense) is to install part of the cooling system from the Alpina B5. Same body shell & bits around the engine bay/ grills etc as it's just a G31 with a V8 shoe horned in. I'm guessing something similar is done with the M5.

You'll note from the image it has 3 radiators lumped together to form a "module". The B5 also uses a monster fan, which subject to being able to draw adequate current might just drop straight in.

I believe all 5ers sold in the middle east use a similar additional radiator package.

Sure someone will pop along shortly to offer definitive advice. 

 

 

[bennygsr]

Thanks.

I’ve towed with a 700kg trailer and car has gone well. I suppose I wasn’t  sure about the doubling of weight.

the oil makes sense and I can look into the larger fan however that radiator setup will likely be the same cost as buying a separate tow car ! 

 

[bennygsr]

For a while I’ve been looking into a uni scan and bimmer code. Do these connectors/ apps also give temperature readouts so I can monitor?

[Matthew]

1 hour ago, bennygsr said:

Thanks.

I’ve towed with a 700kg trailer and car has gone well. I suppose I wasn’t  sure about the doubling of weight.

the oil makes sense and I can look into the larger fan however that radiator setup will likely be the same cost as buying a separate tow car ! 

 

Is the towbar retrofitted or a factory option? If it is a factory option, then the car will already have the uprated fan of 600w (the highest rated specification for your car). If not factory fitted then you'll have the standard 400w fan and you will need to upgrade to the 600w fan for towing - it's a straight swap. Don't try fit one of the 800w or 1000w fans as these require a different fuse box in the rear of the car along with a different fan relay with a different wiring harness. The 600w fan will be fine with no need to upgrade the cooling system - that would be crazy expensive for no real benefit on a 530i. The person Boba was referring to did a DIY towbar installation and upgraded the fan to the 600w one and towed a trailer with a race car so probably a similar weight to your 'van.  The self-levelling rear suspension is more than up to the job as the nose weight shouldn't be exceeding the 75kg limit on the towbar anyway. 
 

This is a link for the replacement 600w fan (not sure where you source parts in Aus). https://www.autodoc.co.uk/spares-search?keyword=17427953400 This is the OE manufacturer for the fans in these cars and it’s likely an identical part but with the BMW logo ground off.

Edited March 15, 2023 by Matthew

[bennygsr]

THanks Matthew.  That is super helpful.

As for my towbar - here's where it gets a bit weird in Australia.

I have an aftermarket westfalia (which according to the distributors is OEM) with removable gooseneck. https://australiatowbars.com.au/bmw-5-g30-g31-detachable-towbar-oem-genuine-westfalia-303412600001.html

 Due to different towing regs over here and a tendency to follow the US market with heavier ball or nose weights, the distributor here have said and confirmed in writing, the towbar is rated for different nose weight to in EUrope.  The towbar is rated for 200kg nose weight here in Australia even though the you folks ave 90kg over there?

Another example  is the x5 with genuine tow kit in Australia has 3.5t towing with 280kg on the ball, compared to 140 on the ball in the UK.
Given my car is rare in Australia and rarer still towing a van with little knowledge or support - I'm sort of flying solo, but  I'm going to be super mindful of the rear axle load limit to make sure I'm not doing anything too stupid.

I will see how I go sourcing the bigger fan and getting one to Australia. 

Thanks again

 

[bennygsr]

I've just done a search on the fan and the size of the fan appears the same in physical size with a slightly different design.  Is it possible to just change the fan motor?  https://www.ebay.com/itm/334456435747

[Matthew]

 

The fan mounting, shroud and fan blades look very similar between the 400w and 600w so just the motor piece may be enough for the upgrade. See the 400w/600w markings on the centre plastic ring.