Bongo Fury

Has anyone tried installing any generic electric cooling fans? We are still having issues with a burning rubber smell when towing up steep hills and have replaced most likely culprits or eliminated them. The only one left, is Helen's suggestion that the gearbox is getting too hot. It continues to work just fine however that is looking increasingly likely as the cause (although still not sure why it is a rubber smell).

My thought process is instead of an expensive and tricky to install auxillary oil cooler, is to install a relay on my existing TM4 and a couple of 7 inch fans in the lower grill (I have the Aero kit) aimed at the trans cooler.

Then I though why stop there, there wouldn't be any harm installing a 12 or 14" one on the main rad too. (I don't have an issue with overheating but for £15.....)

Any thoughts/experience?

Personally I would find the cause of the burning rubber smell,you don't want to be fanning the flames.

rita wrote:Personally I would find the cause of the burning rubber smell,you don't want to be fanning the flames.

I guess the OP is hoping that improved cooling to the trans cooler will remove the suspected cause and result in disappearance of burning rubber smell. Agree there's a risk extra fans may just blow the smell away before it reaches the nostrils, rather than fixing root cause of it, although you'd think fans in that position wouldn't flush out smells rising up from the engine bay?

I've fitted electric fans to landrover defenders in the past
I've just tie wrapped them to the radiator
They never moved and they took some real off road welly
Switched in the cab so u can switch them on before needed

I don't disagree Rita however I have replaced everything remotely rubbery and as soon as the heavy load is off the engine/gearbox the smell isn't there and not traceable. Where do I go from here?

I've already replaced the crank pulley, as the most likely and the belts. What else rubber is there? I've driven about 8000 miles with the smell and it hasnt got worse and nothing has gone bang!! How do I diagnose it?

If it is just the trans getting hot, the fans are the solution, not just masking it.

roosmith wrote:I don't disagree Rita however I have replaced everything remotely rubbery and as soon as the heavy load is off the engine/gearbox the smell isn't there and not traceable. Where do I go from here?

I've already replaced the crank pulley, as the most likely and the belts. What else rubber is there? I've driven about 8000 miles with the smell and it hasnt got worse and nothing has gone bang!! How do I diagnose it?

If it is just the trans getting hot, the fans are the solution, not just masking it.

I'd go for it. Surely has to be a worthwhile mod anyway regardless. BF autobox specialist Alacrity (Geoff) always recommends extra cooling on auto transmission when doing heavy duty towing, and he knows his stuff.

Put one of the cheap engine temp alarms on your gear box hose ( flow to the cooler )
See what temps it getting to
Have you checked your tyres for temp after towing

This one doesn't have an alarm but there accurate , quick reading I've had one on me hose to rad shows me when me stat opens for 2 years or so now
http://www.ebay.co.uk/itm/221258917210? ... EBIDX%3AIT

That would identify if it's gear box getting hot
I should think it is getting hot I've hit 107c with aircon on , scavenger fan on , heating on but never any smells

roosmith wrote:I don't disagree Rita however I have replaced everything remotely rubbery and as soon as the heavy load is off the engine/gearbox the smell isn't there and not traceable. Where do I go from here?

I've already replaced the crank pulley, as the most likely and the belts. What else rubber is there? I've driven about 8000 miles with the smell and it hasnt got worse and nothing has gone bang!! How do I diagnose it?

If it is just the trans getting hot, the fans are the solution, not just masking it.

I think any Auto Transmission Specialist would advise you to Upgrade the Cooler.

Good Luck.

You also need to make sure that the vehicle is getting a Full flow from the box to the cooler and return.

have you cleaned out the front heater matrix, removed the dead flies. there is a rubber type gasket that seals the heater matrix in to the housing and the air scoop from the heater motor, this deteriorates with age, maybe thats fallen on to the front heater pipes inside the unit.

rita wrote:

roosmith wrote:I don't disagree Rita however I have replaced everything remotely rubbery and as soon as the heavy load is off the engine/gearbox the smell isn't there and not traceable. Where do I go from here?

I've already replaced the crank pulley, as the most likely and the belts. What else rubber is there? I've driven about 8000 miles with the smell and it hasnt got worse and nothing has gone bang!! How do I diagnose it?

If it is just the trans getting hot, the fans are the solution, not just masking it.

I think any Auto Transmission Specialist would advise you to Upgrade the Cooler.

Good Luck.

That's true, but what we'd really like to ask them is if this could work as a cheap alternative, even if not as effectively. In the end, both approaches are ways of increasing the amount of heat that can be conducted away. Has anyone tried googling to see if others have tried it, and how they got on?

Thanks for the feedback, one and all. I'm sure the "proper" way to do it would be upgrade the cooler however my uneducated theory was the fans do exactly the same job ie cool the oil more. The beauty being that it costs a fraction.

The flow of oil between box and cooler is a fair point. Maybe its time for an oil change and flush.

Northern, the heater matrix pointer is most welcome. I will check however the smell is only while towing up steep hills and the water temperature only rises a couple of degrees, in line with heavy load. Hence why I've started to think it is nothing to do with the water/engine cooling.

I have a temp sensor on the side of the auto box.
the only time I've seen a large variance in temp was when after 40mins @65mph (from the passenger seat!) i noticed the hold light was on. this would stress the system enough for any testing without towing.
considering putting a buzzer on hold light. (not that a certain person has done it more than once.)

Just reading over everything again, I've going to have a good poke around at the weekend and carry out some more indepth maintenance over the winter but on the theory these fans can't do any harm for around £40 all in, it's got to be worth a shot. I'll report back.

On the subject of the hold button I found it invaluable when towing up and down mountains in Ireland, as not only does it give engine braking when coming down hills, it runs the engine therefore water pump and helps cooling no end. If I coasted down a hill after climbing the temperature would steadily increase up to 101 on one occasion, put the hold light on and the increased revs kept it to mid 90's.

roosmith wrote:Just reading over everything again, I've going to have a good poke around at the weekend and carry out some more indepth maintenance over the winter but on the theory these fans can't do any harm for around £40 all in, it's got to be worth a shot. I'll report back.

On the subject of the hold button I found it invaluable when towing up and down mountains in Ireland, as not only does it give engine braking when coming down hills, it runs the engine therefore water pump and helps cooling no end. If I coasted down a hill after climbing the temperature would steadily increase up to 101 on one occasion, put the hold light on and the increased revs kept it to mid 90's.

Really interesting to see those figures - I'd always appreciated the theory but wondered how much it helps in practice. Like you, I use combinations of 'S' position and HOLD to make best use of engine braking (which seems excellent on the diesel), but I got in the habit mainly to keep the brakes as cool as possible after an experience in the Yorshire Dales years back when, heavily loaded and after upping and downing several steep hills, I experienced a bit of brake fade. Don't like the engine going much above 2500rpm on the over-run though - not sure why, but maybe its fear of lack of upper cylinder lubrication or somesuch. Probably irrational.

I'll be interested to hear how you get on with those fans - I love a bit of Bongo-experimentation. And from googling, and looking at ebay, fitting fans to transmission coolers seems to be a well established practice:

https://www.google.co.uk/url?sa=t&rct=j ... ghdJA0MEeg

http://www.ebay.co.uk/sch/i.html?poi=10 ... 7754390133