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MG MGF Technical - Cooling Fan Fuse TF160

Had an interesting on this week. Got caught in slow moving traffic. Slowly the temp crept up to about 3/4 on the guage and the Oil temp went uo to about 'vertical' deg. Engine bay fan cuts in and temp drops to just over a half and the cycle repeats over and over again. Eventually got into m-way services (will never stop on hard shoulder when traffic stationary - always a prat using the hard shoulder to jump the queue). Checked out system and found radiator cooling fan isn't coming on; fuse blown. I didn't replace it and as the traffic was flowing OK I finished the journey.

Spoke to a dealer next day; it's not the first they've had. The fuse goes for no apparant reason, is replaced and is fine thereafter. They've even striped the front of another car and involved the factory all to no avail.

My fuse has been replaced and in a 7hr journey from Oxford - Lancs (avg 31mph - heavy traffic) switched on / off countless times. I'll be keeping an eye on the fuse though....

So anyone else had it blow? And might be worth a fuse check (under bonnet box no2 I think) to make sure your's is OK.
Ian Walker

not that uncommon Ian - been a few cases of this being reported here. Similar problems also occur when the ECU temp sensor connections corrode...

The under bonnet fuse box number system is different in the owner's hand book to that reported in the workshop manual!

I used the workshop manual number system (which makes the 15A rad fan fuse #6 rather than #2, but we're talking about the same one!) - details at http://www.mgf.ultimatemg.com/hgf_pages/related_problems_overheating.htm
Rob Bell

So not that unusual then!

The fuse on a TF is 20A... And yes Rave says it's underbonnet fuse 6, handbook calls it fuse 2 (but the second one in!!!). The box is un-numbered but labelled.

The pass comp. fuse for cooling fan et al is 6.
Ian Walker

>>The pass comp. fuse for cooling fan et al is 6. <<

It's fuse 15 for the radiator fan Ian - fuse 6 is the engine bay cooling fan. :o)

BTW - fuse 6 in the under bonnet fuse box is rated 15A for the Mk1 MGF and the MY2000 MGF - so I am surprised that this has been re-rated for the TF?
Rob Bell

Ooops! My speed reading needs improvement! Yep pass fuse box Fuse 15 is the rad fan (20A). Rave says the underbonnet one is 20A as does the box lid and that's what's fitted to mine.
Ian Walker

Well well, there you go. I wonder why the fuse has been re-rated? A more powerful fan in the TF perhaps?
Rob Bell

Or a larger fuse to cope with the problems they've been getting?

Bruce
Bruce Caldwell

on a similar vane can anyone give me a bit of advice? My MGF overheated, rad fan not working, when the garage took a look they said it had been comming on at too low a temp and had blown a fuse. They sent the EMU away and said everythings great now but the fan still seems to be on a lot. I know it's hot out there but hadn't expected it to come on whilst moving swiftly. Also it goes off as soon as the ignition is switched off, shouldn't it stay on a while. I'll admit to not knowing a lot about such suff but get fed up with their condescending comments so would like a bit of advice before going back again.
Jane

Jane

I had become used to engine fans that stayed on for a while after killing the ignition - previous cars and motorbikes alike.

When I first got my F I asked the question and was told 'no, as there is only the radiator to cool'. And also 'they all do that'.

I can accept this to a point as the rad is at the front and the engine is at the back but a bit of fan would help reduce the sudden heat build up when air stops moving through the rad.

I must admit to not hearing the radiator fan very much but, over the last 2 weeks, have got used to the engine bay fan coming on even when driving. I can force the rad fan to operate by getting the car really hot and then leaving it to tick over for about 15 mins.

Shout at me if I sound condescending (really not intended) but: radiator fan is at the front and cannot normally be heard while driving while the engine bay fan is behind the grill on the right hand rear wing and can be heard as it is just behind your head.

John Ponting

>>I know it's hot out there but hadn't expected it to come on whilst moving swiftly. Also it goes off as soon as the ignition is switched off, shouldn't it stay on a while.<<

Jane, how can you tell that the radiator fan is coming on? It should be inaudible - especially when the car is moving? Or are we talking about th eengine bay fan? (ah - I see that you've asked the same question John...)

Regarding the question on whether the radiator fan should come on after the ignition is switched off, the answer is "why should it?" and "what good would it do?" Why? Because there is practically no circulation of water between the engine and radiator when the water pump stops; there is too much distance between the rad and engine for a thermosiphon type circulation.

Now if you had an electric water pump which was activated when the ignition was killed, they'd be a completely different answer.... ;o)

Rob Bell

John (not condescending) and Rob (just a little bit)

Thanks for the comments, no really! You're right I can't here the fan when moving but it's definatly the rad fan, I get out and have a listen as soon as I stop, and you can here it in traffic if I turn off the music. I'm now happy that it's normal that it goes off with the ignition. No I hadn't thought why, just that it was different to previous cars. But as a recent example I just drove back from Tesco's, about 3 miles, no traffic and the last mile at about 60mph. As soon as I slowed to pull in the drive I could hear the fan, got out and checked and yup that was it. Also there's no movement on the temp gauge, it sits at one notch below middle fan on or off, should it get warmer than this before the fan engages. If you tell me this seems normal I'll happily leave the chaps at the dealers alone, they think I'm a nuisence anyway, or should I be concerned they've not put it right yet. Oh, and the weather report, warm, not raining at the moment and a bit muggy.

Jane (knowns nothing but willing to learn)
Jane

Jane

It seems that the water temp. guage is not as accurate or responsive as it could be. My TF160 does the same, it gradually raises until a "gnat's" below half way and stays there no matter what the conditions. I'm told that it does move when the car is in danger of overheating but I would prefer that it gave a realistic indication of slowly rising temperature.
Norman

Apologies Jane, no intention of being condescending nor precieved as being as such :o/ One of the difficulties of communication over the internet; impossible to judge the tone of voice!

Norman - two options: 1 - fit a digital water temperature gauge or 2 - install Bruce's temperature warning system (as sumarised on Tony's website): http://www.apttony.co.uk/Servicing/WarningLights.html
Rob Bell

>>Also there's no movement on the temp gauge, it sits at one notch below middle fan on or off, should it get warmer than this before the fan engages.<<
Yes, this really bugs me too; the temp gauge is a poor example of instrumentation - you might just as well have a light to show normal/excess temp.
Other cars show operation of thermostat and cooling fans on the temp gauges so there's no excuse.
Your temp gauge behaviour is normal - for an MG.

One option would be to add a small indicator to show fan operation.

Steve
Steve

Hi all,
anyone with a decent amp-meter that have actually measured the needed feed for the front fan ? As it probably will be above 10 A an ordinary cheap digital meter won´t do. They all seems to stop at 10 A maximum. Removing the tempsensor connector and taking out the fuse while measuring with the meter probes in the fuseholder would give some useful info. IMO doing this at stand-still is worst case = no help for the fan to spin easier with the help of speed. Probably figures very close to the rated fuse will be seen. Upgrading the "F" one´s to 20 A would probably help without fear for burnt cables etc.

BR, Carl.
Carl Blom

I've had my temp guage replaced (paint peeling) and the new one indicates slightly lower on the guage 3/8 vs 7/16. So the guage isn't that accurate.

When the system is working ok the needle doesn't move as the thermostat and rad fan kick in and out and keep the eng temp rock steady whatever the road speed. When my rad fan fuse was blown the following happened:-

1. In moving traffic the needle stayed in the 'right' place. Suggesting the thermostat alone could cope with the help of speed induced air flowing through the rad.

2. In stationary traffic the temp guage rose to about 5/8 - 3/4 and the engine bay fan would cut in and bring the temp down to about 1/2 or so. If engineleft running the cycle would start over again.

In looking at the manual the rad fan comes on at a water temp of 102 (104 in another section of he manual!!!) and off ot 96 (98). The engine bay fan on at 75 and off at 60. The warning light comes on at 110-130.

Air-con cars have two radiator fans.
Ian Walker

This thread was discussed between 18/07/2003 and 25/07/2003

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