smallredlupo Posted June 12, 2007 Report Share Posted June 12, 2007 (edited) Hi Guys,I got a 1999 T reg lupo, which has just done 38k miles.I wonder whether the situations below have any connections.First, the thermometer on the dash isn't working properly. Most of the time it stays at 0.Even when I'm traveling on a 60mph road for a couple of hours, it stays at 0.But when I slow down the car when reaching a roundabout or something like that, it jumps straight up to about 90~100 C.Once I pass the roundabout and drive on, the temperature gauge drops back to 0 again.Second, my lupo uses about 1 litre of motor oil per 200 miles when running on a 60 mph road.The motor oil consumption is less noticeable when drive in urban areas.For details of my sitaution of insane motor oil consumption can be found in this post.I know a fauty coolant temperature sensor will cause poor fuel consumption.But does a broken temp sensor have anything to do with crazy motor oil consumption?lupogirl Edited July 30, 2007 by smallredlupo Quote Link to comment Share on other sites More sharing options...
db Posted June 12, 2007 Report Share Posted June 12, 2007 It's just a broken thermostat, you should get it replaced, it's only a cheap job and therefore worth doing to see if it makes a difference to your oil consumption. Although i can't see it making that much difference. Quote Link to comment Share on other sites More sharing options...
ID modds Posted June 12, 2007 Report Share Posted June 12, 2007 Surely it will be a coolant temp sensor fault not a thermostat and it will have no real bearing on the oil consumption. Quote Link to comment Share on other sites More sharing options...
smallredlupo Posted June 13, 2007 Author Report Share Posted June 13, 2007 (edited) Surely it will be a coolant temp sensor fault not a thermostat and it will have no real bearing on the oil consumption.How do you tell the difference between a faulty coolant temp sensor and a faulty thermostat?Do they have different consequences?Thanks,lupogirl Edited June 13, 2007 by smallredlupo Quote Link to comment Share on other sites More sharing options...
sciroccotune Posted June 13, 2007 Report Share Posted June 13, 2007 How do you tell the difference between a faulty coolant temp sensor and a faulty thermostat?Do they have different consequences?Thanks,lupogirlif the fan comes on as normal then its 'likely' to be the dash temp sensor, cheap to replace.if the engine runs cool or hot and the fan does not act normal then 'likely' to be a thermostat stuck open (= cold) or closed (=hot). Then again the dash temp gauge would read some temp after a while of running if it was just the thermostat. Quote Link to comment Share on other sites More sharing options...
db Posted June 13, 2007 Report Share Posted June 13, 2007 (edited) How do you tell the difference between a faulty coolant temp sensor and a faulty thermostat?Do they have different consequences?Thanks,lupogirlDon't be misled, they are the same thing, the gauge on the dash indicates coolant temperature, if it's not reading then the sensor/thermostat is misreading, which in turn will be sending the ecu incoherent readings - which could cause under/over fueling because it wont know when to use the choke and therefore could use more oil. Although it is very unlikely. Edited June 13, 2007 by db Quote Link to comment Share on other sites More sharing options...
Gavs_arosa16v Posted June 13, 2007 Report Share Posted June 13, 2007 (edited) Definition of coolant temperature sensor: A variable resistance thermistor that changes resistance as the engine's coolant temperature changes. The sensor's output is monitored by the engine computer to regulate various ignition, fuel and emission control functions, and to turn the radiator-cooling fan on and off as needed. In the PTC (Positive Temperature Coefficient) type of sensor, ohms go up with temperature. In the more common NTC (Negative Temperature Coefficient) type, resistance goes down as heat goes up. I dont know how much of this relates to the one on the vw, but its definatly a sensor problem you have described. When it is broken you get very irregular readings, that go up and down. If it does not cure the excessive oil consumtion, at least it will allow you to be warned if your engine is going to overheat. Just swap it its an easy job.Clicky.If your thermostat goes your car will overheat (they are just a metal diaphragm/valve), that lets the water to the radiator.If I was you I would get the sensor replaced, new oil and filter, and see what happens after that. It wont cost much. Good luck style="vertical-align:middle" emoid=":)" border="0" alt="smile.gif" /> Edited June 13, 2007 by Gavs_arosa16v Quote Link to comment Share on other sites More sharing options...
ID modds Posted June 14, 2007 Report Share Posted June 14, 2007 Spot on Gav right on the money. style="vertical-align:middle" emoid=":shades:" border="0" alt="shades.gif" /> Quote Link to comment Share on other sites More sharing options...
Rosse Posted June 17, 2007 Report Share Posted June 17, 2007 (edited) I also think it is the thermostat and not the sensor. If it is stuck in the open position, all coolant will always travel through the radiator. Resulting in massive cooling (lots of air) on the motorway, and a low reading in the dash. When you stop at a traffic light, no more air through the radiator, so no cooling -> temps go up. It is the thermostat's job to compensate for this and to keep the engine's temperature at the same level.Specially on the 1.0l AHT engine, it happens a lot that the thermostat breaks off in the plastic housing, resulting in this exact behaviour. Edited June 17, 2007 by Rosse Quote Link to comment Share on other sites More sharing options...
lupogtiboy Posted June 17, 2007 Report Share Posted June 17, 2007 (edited) you'll need sensor 059 919 501 a and seal n 903 168 02 both working out around £27 inc vati don't think it'll be the thermostat because surely if the thermostat didn't open, the car would overheat? was certainly the case on my old 6n polo when the thermostat housing fell apart! Edited June 17, 2007 by lupogtiboy Quote Link to comment Share on other sites More sharing options...
smallredlupo Posted June 18, 2007 Author Report Share Posted June 18, 2007 Thanks for the part numbers, lupogitboy.Where can I buy them from? Halfords? style="vertical-align:middle" emoid=":P" border="0" alt="tongue.gif" /> lupogirlyou'll need sensor 059 919 501 a and seal n 903 168 02 both working out around £27 inc vati don't think it'll be the thermostat because surely if the thermostat didn't open, the car would overheat? was certainly the case on my old 6n polo when the thermostat housing fell apart! Quote Link to comment Share on other sites More sharing options...
Gavs_arosa16v Posted June 18, 2007 Report Share Posted June 18, 2007 Your local VW Quote Link to comment Share on other sites More sharing options...
lupogtiboy Posted June 18, 2007 Report Share Posted June 18, 2007 vw or possibly eurocarparts Quote Link to comment Share on other sites More sharing options...
smallredlupo Posted July 30, 2007 Author Report Share Posted July 30, 2007 (edited) I had the temp sensor replaced, engine oil and filter changed a couple of days ago.Now the temp gauge on the dash is reading some temperature!!Haven't seen the needle move in so long that I wonder whether it's reading normally... haha...Just after driving for 3 mins, it's reading about 90C and then it stays there all the time until I switch off the engine. Sorry to ask such a dumb question, but was 90C normal?And, also having had the radiator fan switch replaced (cus the mechanic said that's reason why the fan wasn't working), my radiator fan is still not spinning...Is it supposed to be on when the engine is running or when temp gauge/engine reaches certain temperature?(because I haven't seen my fan moving either in so long... )Having driven 65mph for 20 minutes, no signs of moving fan...Then I lightly touched the grids on the radiator and it was hot but not scorching. Which indicated that hot coolant was nicely flowing to the radiator, did it?BTW, could overheating the engine result in the engine using excessive engine oil?Many thanks~lupogirl xx Edited July 30, 2007 by smallredlupo Quote Link to comment Share on other sites More sharing options...
lunalupi Posted July 31, 2007 Report Share Posted July 31, 2007 (edited) From what I remember...90o sounds about right - the needle should be pointing straight upwards style="vertical-align:middle" emoid="" border="0" alt="smile.gif" />As for the fan, I've never actually heard mine on once the car is stopped...you may just not be hearing it Edited July 31, 2007 by lunalupi Quote Link to comment Share on other sites More sharing options...
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