urgent : Ford fiesta broken again

Oops, I took the urgent back off that again, I figure that most car problems are urgent.

OK, Firstly, the fan has a temperature controlled switch to turn it on which is not connected to the temperature guage.

Secondly, at that temperature, I'd be expecting to see steam coming out of the car.

Thirdly, a flapping fanbelt is not good. Also its most likely to be the source of the problem as the fanbelt also drives the waterpump. Sounds like you need a new one rather than trying to tighten the old one.

Thanks! I took the car for a test drive (less than a mile) and the needle shot way up again, pulling over to the side of the road and opening the bonnet, I noticed steam coming from the radiator. I *may* be prepared to accept that the steam was from water that had settled on the radiator while I was washing it.

I'll try and look for the wiring that connects the fan to the controller, thats what they said they'd replaced so I'm wondering whether they've made a balls up.

Regarding the fanbelt, is it a job that I could do myself? It looks like a new one should just slip over the cogs onto where the old one is, is that right? And I could pick up one of these fanbelt things from halfords or motorworld?

Thanks for your swift reply!

Just a bit! I'd certainly have expected a hose or pressure cap to have blown! It's not a correct reading I'm sure.

That's definitly the water and alternator drivebelt. It looks to be tensioned OK AFAIC but that's tricky of course. Surely though the OP would hear it squeal if the belt was slipping on the water pump, and if it wasn't running at all then the battery light would be on?

My rover also kept showing a sky-high temperature, and it was traced to a poor earth that served the temperature sender from the head. The fan wasn't kicking in (and never needed to) as there was a different earth for the separate fan sensor which is mounted in the radiator just like the Fiesta

If the temperature guage was normal or below and you onyl ran a mile then it shot way up then your headgasket has probably gone and it needs to go to a garage to get sorted.

I think from the pictures that you have a problem with the temperature gauge on the vehicle. Is the air coming out of the interior heater a lot hotter than normal, or is it about right? The engine would expire a long time before the temperature got as high as it does, and you would really know it was overheating (engine smelling very hot, steam coming from under bonnet, engine very sluggish and even seizing-up), and the air from the heater would be a lot hotter than normal.

It would seem that either the gauge itself is faulty, or more likely, the wiring between the sender unit (which is small brass part with a hexagon shaped body 13mm across and terminal coming out of the back - usually covered with a rubber boot) is touching on the car body or engine block somewhere.

The fan belt should have approx 10mm of up and down movement at the mid-point between the pulleys, on the longest run (between water pump (top) pulley and alternator in your case).

HTH

Anthony Remove eight from email to reply.

I dont hear much of the engine under normal use, to be honest, because I have the radio fairly loud to drown it out. Apparently my tappets need 'sorting', because the car sounds like a diesel. I use the radio to mask that. Maybe I should just get the tappets fixed?

Right! I'll have a look, see if I can find the temperature sender. I'm guessing a multimeter across the meter would tell me whether its working or not? Anything less that infinite resistance has gotta be good, right?

The thing that concerns me is the fact that the fan isnt kickin in, so if the car begins to overheat, then theres nothing to cool it down. Is there a way I can force it to be constantly on, to get me home should the problem occur when I'm at work?

Yes before you burn a valve or jam a follower or something. It'll stop it being so noisy and probably make it go a little better too.

No idea since I have no idea if it's a PTC/NTC and what the final values should be. I'd guess you want a few hundred to few thousand ohms, but that's a guess.

The fan doesn't care about engine temperature, it's far more concerned with radiator temperature and has it's own sensor as Conor said somewhere in the rad. Since your fan isn't kicking in, I suspect that this sensor is fine, the engine is fine and your engine sensor is stuffed.

The sensors cost a few pounds. Go fit another one if there is no obvious wiring defect.

In my opinion the guage is shorted to earth , it should never read that hot, if it really was that hot it would be boiling like mad , making funny noises and steam everywhere . Steve the grease

That needle looks almost as if there is a grounding fault with the sensor and instead of the current actually being transmitted thru the sensor innards, it is going straight to ground, causing a high voltage reading at the guage hence such the almost impossible reading.

Just a guess.

G.

Yep, that's almost certainly a faulty gauge/sender/wiring. If the engine really was that hot, they you would know about it!

Ok after spending much of the day tracing around the electrics of the car, I think I've solved the problem! Not quite sure *what* the problem was, but wherever I've found an electrical contact, I've recrimped and reshielded (high temperature cable shielding) everything. Yes, it is probably the long route, but I've learned a lot about a fiesta's electrical layout!!

I'm happy to report that the car is now running absolutely fine, and the car is booked on the 24th November to have its tappets fixed. The garage reckon that this work will cost about £45.

Im also considering a new car, a Toyota RAV4 or a Ford Focus. Anyone got any comments on either of these models? Or recommendations on other cars: big/small car, diesel/petrol, decent response, decent handling, less than £7000 preferred (not a requirement). Preferably with decent security gear built in, but not a necessity.

Oh, and why dont cars have lights built in under the bonnet? It would help in case you ever break down at night.

Ok, I've opened a few new threads in this. I'll move this post to a new thread.