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MG MGF Technical - Which First: Engine or Radiator Fan?

I've been reading a lot about the HGF problems.

Can someone just clarify which fan should come on first.

I have no overheading problems, but very often when I switch off, the engine bay fan (behind the seats)is on. I never hear the radiator fan (at the front of the car) cut in.

I just want to make sure everything is working correctly, as there are three other users, and I'm sure the needle could go into the red with them and they would never notice.

Thanks

Alan
Alan

Alan

Sounds right to me and if you have the 1.8i that engine bay fan comes on more often.

Ted
Ted Newman

Cheers Ted,

My car is the 1.8i. Reading all the HGF info on this BBS I am now more suspicious of what the cooling.

Also owning a 1967 Land Rover, I know how much damage heat can do to an engine, due to lack of simple maintenance.

Alan
Alan

Alan

The 1.8i comes on more for the simple reason that the thermostat switches in at a lower temperature - don't ask me why!

Regarding the HGF - there is without a doubt a higher than normal number of failures on the *F* but there is also campaign by a couple of 'hotheads' to make it seem worse than it is.

The general concensus is that HGF is due to overheating caused by the complicated plumbing and the position of the engine. So my advise is to keep an eye on the coolant - especially if the car has had a 'drain-down' for any reason as the refilling and bleeding is a very finicky process that must be done absolutely right.

Ted
Ted Newman

Ted,

I've been considering an F for a while but the ghost of HGF tends to haunt me.

I get the impression that "a lack of mechanical sympathy" from the owners probably causes a good few HGF failures.

Do you think you've not had an HGF because you don't constantly cane the engine.

I'm thinking along the lines of mga twin cam owners detonating their engines in the early days because they were using the performance to the full.

Andy
Andy

Andy

Obviously constant 'caning' of an engine does not help, however I don't exactly give my engine an easy life.

But I think sympathy or empathy are more important than being docile in keeping an engine running plus of course good and regular maintenance.

Perhaps one of the 'faults' of the K series engine is its 'eagerness' to please, it is a very sweet and free revving engine, particularly once it has got about 10,000 miles under its belt, and as a consequence it gets worked very hard and like you said with the old MGA Twin Cam kept riding on its upper limits so in time something gives way.

Perhaps I am (as Dirk would say) just lucky, or perhaps I don't push the car and perhaps I am (again as Dirk would say) just a boring old fart.

I dont know the reasons or the true statistics of the HGF it is a pity that there are no reliable figures to look at. But I would just add that the K series engine is used by many cars and not just Rover cars so if it was as bad as some would have it these other car makers would not use the K series engine.

Ted
Ted Newman

I hope you're right because I've decided to liquidise some of my assets and get an F.

I did a V8 conversion some time ago with a badly but expensively, rebuilt motor. Eventually, the engine rebuilder went bust. Although there was some satisfaction in that it has left my wife somewhat sceptical about me and MGs.

Just to complicate matters we went to the local Rover dealers at the weekend. He showed us two cars he had collected from the scenery that day. Both were caught out by Derv dumped on the same wet roundabout. Good job he collected the first one promptly, otherwise it could have been bent at both ends. Anyway the sight of mangled bumpers and rear wheels torn off did wonders for my wifes confidence in matters MG.
Andy

Re the original question. If you have never heard your radiator fans running test them just by leaving the car ticking over outside home after a run and everything being nice and hot. Probably within a minute or two you will get the engine bay fan coming on but if you wait a little more you should also get the radiator fans starting.
If they don't watch the temp gauge closely. If it starts to move up to or over halfway, and the rad fan is still not working, turn it off and book a session at the doctors. If the rad fans are not working you are just inviting trouble. Verify them asap.

Alan
Alan

Hi,
Never heard it at mine 1.8i coming up at constant speed, but only in lowest speed (stop and go) in traffic jams and also when the car stands.

My guess and 'heard of' regarding the engine bay fan is still that its not important for the engine cooling but to prevent from airbubbles in the fuel pipes.

I still mean that the only good idea to get the engines temperature down is a coolant thermostat which works at lower temperature (suggestion of Carl) or a addon oilcooler.

But all this is a theory. Who can approve that HGFs occure cause of constant high engine temperature ?
Nobody !!!

At first gets IMO the coolant lost cause of several other well known reasons (leaks, blown hoses, coolant cap, intake sealing etc...) and airbubbles occur in the coolant system. Then the HGF goes off like a security valve for overpressure.

Regards
Dieter
Dieter

I am in the midst of a complex series of temperature readings taken from a number of places within the MGF/Rover 218iS engine bay both static and moving, and on a number of cars. One of the most clear things to date is the very limited alteration of the coolant temp readings compared to the engine bay temp readings which have significant peaks and troughs.

Clearly the engine bay fan is always the one to respond faster and this is normal. However I have for many, many years always included a check of the engine coolant cooling fans (radiator fan) operation both in switching on at an appropriate time, reduce coolant temp and then switch off as part of a routine check/service. (At least every 6 months.)

One fact that is in the cars favour is that the fan is mounted behind the radiator, and so benefits from the rad being a barrier to water and dirt that used to claim many a motor. (The rad fan is so rarely needed.)
The hot airflow also quickly warms it so driving out any condensation/water that may have entered during periods of standing. This means the reliability of the fan is good.

Rog
Roger Parker

I'm not sure how useful the engine bay oooling fan is. The radiator cooling fan is obviously essential whenever the car is a standstill with the engine running. Mine didn't come on because of some fault in the central ECU - and the engine would systematically heat up after a prolonged time at standstill (4 mintutes with a warm motor). Thing is, you don't HEAR the radiator fan - it's silent. So if it's not woking, you won't realize, whereas the engine bay fan is clearly audible. But the important one is the RADIATOR fan... Guys, watch your water temp gauge, and tell anyone to whom you lend your MGF to to beware...!
Tony

P.S.My remark is valid for all cars. I have a friend who blew his Golf Mk II's head gasket because his engine overheated due to a failure of the water pump, and he didn't notice the water temp rising aboce normal.
Tony

This thread was discussed on 06/09/2000

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