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MG MGF Technical Help Me! Water temperature repeated up and down BBS discussion at MG-Cars.info
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MG MGF Technical - Help Me! Water temperature repeated up and down
| My car has a water tank of the factory. When I do not turn on any air/hot conditioner. My water temperature will rise slowly, and normal value is that the water temperature is " below middle line by One blank". But the engine arrive the work temperature, and my car was idle speed . The factory water temperature will rises slowly and value is "above middle line by one blank". Because I have installed extra water temperature. The water temperature happens while rising and I look my extra water temperature which is 102 degrees. The factory water temperature has already come "above middle line by one blank" . But the extra water temperature will also drop 95 degrees, and the factory water temperature will downward " below middle line by 2/3 blank" . But the condition can not keep 30 seconds. The water temperature will repeat to up and down. My water have not decrease in Auxiliary Radiator, and the fan had work. My water pipe and radiator have washed . Why have the condition ? IS the condition normal Or non-normal ? What will I need to do ? |
| KUO yuan-hsin |
| Do both temperature gauges work off the same sensor? If not, where your extra sensor is located? Chris |
| Chris |
| The sensor of extra water temperature has been installed in the radiator bottom hose. And I turn on my air conditioner. The factory water temperature keep normal value is " below middle line by One blank", And the temperature CAN NOT move. The extra water temperature is 85 degrees. My coolant is fresh and thickness to full 60%. |
| KUO yuan-hsin |
| My header tank has not oil ,and my oil level gauge is normal color and has not emulsification. |
| KUO yuan-hsin |
| Is the rising and falling change in temperature always happening? Or does the rise and fall only happen when you have the air conditioning on? |
| Leigh |
| The rising and falling change in temperature that always happen in engine idling speed. Turning on air conditioning will CAN NOT happen. But Other factory MGF in Taiwan HAVE NOT state with my car. their car CAN NOT change any parts , and their car used all factory parts. So I do not know my car is normal or non-normal. I always think Why My car is not the same with other MGF. |
| KUO yuan-hsin |
| I found new state. The factory water temperature was gone up to "above middle line by one block". My extra water temperature was 101 degrees. I directly force the fan opened the biggest with turning on the fan relay. My extra water temperture dropped quickly in 3 mins then. And It had already dropped to 85 degrees. I also sprinkled water on my radiator . And It dropped to 75 degrees. But My factory water temperature stayed on "middle line". I also turned on the hot/air conditioner to the strongest fan speed. But the factory water temperature still stayed on "middle line". Then I moved my car. The factory water temperature was down to "below middle line by one blonk". But I idled speed for 4 mins, My factory water temperature was up to "above middle line by one block". What's happened with my car? |
| KUO yuan-hsin |
| Today My thermostat was removed . It was normal ,after I test the thermostat . But My car idled speed was whitout thermostat, The factory water temperature was up to "below middle line by one blank" . The extra water temperature was 85 degrees. I used infrared thermograph to test water pipe of installing sensor near engine , the temperature was 88-91 degrees. I drove my car that the factory water temperature was down to "above middle line by one blank". The extra water temperature was 70-75 degrees. If the factory water temperature will have problem, the factory water temperature will not increase with idle speed OR descrease with drive the car. So My problem can not solve. What's happened with my car ?? |
| KUO yuan-hsin |
| I am confused. I think we're lost in translation. Can you draw some pictures instead? |
| Leigh |
insert picture...
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| KUO yuan-hsin |
| I see! Car overheats when stationary and cools when moving Could this be the same problem as the TF160 overheating thread on the BBS? Does your radiator fan come on when the car is stationary? |
| Leigh |
| I don't know if this helps but I would welcome any others comments. I too have been wondering what is 'normal' Under normal circumstances my standard MGF water temperature gauage (which I know is poor and doesn't respond quickly enough) sits as KUO says just one mark below the center. It never seems to move from here, but I take the train each day so most of my driving is short distances or at weekends in empty or fast moving traffic. So car never gets too hot. However, I noticed on my MGF (which I don't have anymore) that in a traffic jam the water temperature guage rises and about halfway from center to red and then I hear the engine bay fan kick in. The guage then rises to the red at which time I usually panic, and switch on the heater blower full blast. In all cases to date, the traffic has cleared and I have been able to move after a few minutes, with air cooling the radiator normally and the temperature falls back to standard setting, ie below the centre. I realise reading the archives that you can't hear the radiator fan, but is this normal operation ? I have since sold the MGF and have a TF and have never been stuck in traffic or brave enough to leave the car idling to see what happens. I never also tried to see what happened in the MGF if I had remained stuck in traffic. (Don't have a lot of heavy traffic in northern ireland) So what do others see ? If in a jam or idling does the standard temperature guage rise and then the radiator fan kicks in ? Should it rise to the red or is the guage so poor a response that you don't get much movement before the Radiator fan kicks in ? What does eveyone else get. Surely you all can't be like me and you must get stuck in jams on the M6 or M1 or M25 we all hear about. Brian |
| Brian |
| Ah! Just read the thread update on overheating 160 ! It would seem that normal operation is one mark under the centre on the standard temperature guage. From reading on the guage will the begin to rise as the water temperature gets hotter and then the radiator fan will kick in. Obviously if fuses and contacts, and sensor etc operate normally. So it would seem I should begin to panic if it gets to red section as the radiator fan should have kicked in by then. So at least I now know it is normal for the guage to rise and then fall back. Where it seems to show on the temperature guage seems to depend on how accuate the reading is as Tim suggests his was under reading Brian |
| Brian |
| Hot in Switzerland last weekend. Temp dial as steady as a rock - 1 notch below half way. I have a remote stat. It should remain steady even if the temp outside is 45C and you are stationery in traffic. I was in a traffic jam for 10 minutes last weekend and no movement whatsoever with temperature dial. Julian |
| Julian |
| Brian, those symptoms suggest a blown radiator fan fuse - the precaution of changing it for a higher value is well worth doing, as the fan motor gets older the initial current surge as it powers up gets bigger. KUO, the contacts on the two factory temperature sensors (gauge & ECU/fan) commonly develop bad connections. Try cleaning them with electrical contact cleaning spray or if they're badly corroded use a corrosion-reversing chemical. |
| bandit |
| I have a TF 135, 2004, which has overheated twice in ultra-slow traffic - namely, stopping, going a few meters, etc. Once the traffic restarts, temperature goes down. I went both times to the repair shop explaining what happened, they told me they tried everything they could to get the car heating, but did not succeed and could not find anything wrong anywhere. But I am afraid it might happen again. Denis 2004 TF 1950 TD |
| Denis L. Baggi |
| Dennis, The consensus seems to be the temperature guage should not go up in slow moving / stationary traffic. bandit and Tim suggest that if in slow moving traffic the radiator fan should kick in and start to cool the radiator water. So anything other than is this not normal. So as bandit suggests check out the fuse. According to the archives the fan can get stuck and so cause the fuse to blow. Everone suggests upgrading the fuse eo 20amp from 15 to gat around any initial high starting current on the motor. As suggested you could try taking off the engine cover and disconnecting the connection to the temperature sensor and this should cause the fan to start. If it doesn't then its either duff fan or fuse. If its ok and does start then Tim suggsts that you clean the contcats as dirty contcat can resulting in a fulty temperature reading and the fan not starting when the temperature starts to rise due to slow traffic Brian |
| Brian |
| Here's the page on Dieter's site I was referring to in the 160 overheating thread: http://www.mgfcar.de/sensor/index.htm It shows that mid-way on the gauge is 100-110 degrees. The rad fan should come on at 102, so if the needle moves AT ALL there is probably something wrong. By the time it gets to the red the coolant will be at 125 degrees! The gauge, oil temperature gauge and ECU's temperature sensors are all separate so that failure of one will show up. The coolant temperature sensor is the one which controls the fan (as well as timing, mixture, etc) and is an aweful design really - it goes low resistance when it's hot, which means that any corrosion on the connectors which cause an increase in resistance results in the sensor under-reading and being impossible to register a high temperature. Hardly fail-safe! Cheers, Tim |
| T Jenner |
I turned on air conditioner and idle speed that the water temperature is normal. The fan can been switch on. The sensor had been change new sensor. In Taiwan many MGF's water temperature is all normal . Why can not My MGF be the same as other MGF ?
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| KUO yuan-hsin |
| Kuo, Are you saying that your car ONLY overheats if the airconditioning is OFF - if you have the airconditioning ON it doesn't overheat? The cooling fans work differently on cars with aircon. This is the section from the workshop manual about it - I'm in a bit of a rush at the moment so can't really digest it but it might help! Cheers, Tim DESCRIPTION AND OPERATION 4.26 MG TF Compressor To operate the compressor, the ECM earths the UB wire between the ECM (C0159) and the coil of the compressor clutch relay in the A/C relay pack (C0173). The energised compressor clutch relay connects the power feed from fuse 5 in the under bonnet fuse box to the R wire between the A/C relay pack (C0172) and the A/C compressor clutch (C0127). The A/C compressor clutch is earthed through the compressor fixings and energises to transmit drive to the compressor. Cooling and condenser fans The ECM operates the two fans together at one of two speeds. Low speed is achieved by connecting the fans in series and high speed is achieved by connecting the fans in parallel. The fans operate at low speed when either the compressor clutch is engaged or the engine coolant temperature is between 92 and 99 °C (198 and 210 °F). The fans operate at high speed when either the engine temperature is in excess of 107 °C (225 °F) or the medium pressure switch in the trinary switch detects a system pressure in excess of 18 bar (261 lbf.in 2 ). When refrigerant system pressure exceeds 18 bar (261 lbf.in 2 ), the medium pressure switch closes and connects the U wire, between the ECM (C0159) and the trinary switch (C0279), to earth on the B wire between the trinary switch (C0279) and the earth point (C0564 on LHD) or earth header (C0017 on RHD). On receipt of an A/C request, the ECM (C0159) earths the US wire from the A/C relay pack (C0173) to energise cooling fan relay 2. The energised cooling fan relay 2 connects the feed from fuse 6 of the under bonnet fuse box to the PS wire between the A/C relay box (C0172) and the cooling fan motor (C0005). The feed passes through the cooling fan motor (C0005) to cooling fan relay 1 in the A/C relay pack (C0172) on the US wire, then from cooling fan relay 1 to the condenser fan relay. The condenser fan relay connects the feed to the SU wire between the A/C relay pack and (C0172) and the condenser fan (C0280). The condenser fan (C0280) is earthed on a B wire connected to an earth header (C0017). With the fans connected in series, they run at slow speed. If the engine temperature or system pressure increases to their respective switching points, the ECM (C0159) earths the UY wire to energise cooling fan relay 1 and the condenser fan relay in the A/C relay pack (C0173). The energised cooling fan relay 1 switches the feed from the cooling fan motor to earth on the B wire between the A/C switch pack (C0172) and the earth point (C0564 on LHD) or earth header (C0017 on RHD). The energised condenser fan relay switches a feed from fuse 5 in the under bonnet fuse box to the SU wire between the A/C relay pack (C0172) and the condenser fan (C0280). With the fans connected in parallel, they run at high speed. |
| T Jenner |
| Brian, that's not it. The fan did kick in yet temperature kept on rising. If it had been that simple, do you think the repair shop would not have found anything? In fact I have not been to reproduce it myself. So that's not the answer. Thanks anyway, Denis |
| Denis L. Baggi |
| -------------------------------------------------------------------------------- Hi,can anyone tell me where to locate the fan thermostat switch and relay on mgf 1.8 vvc,2001,y reg.Car is overheating and water bubbling in expansion tank and fan is not coming on.I thought it would be worth testing these before looking into other possibilities.Any advice would be greatly appreciated.Cheers .Ray |
| ray |
This thread was discussed between 02/05/2008 and 21/05/2008
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