decsnz 0 Report post Posted June 9, 2007 Hi there, I am new to this forum and BMWs. I just got myself a 95 318ti. I have noticed that the temp gauge moves around a bit from 1/4 to 1/2 way. depending on how fast I am going. It goes down when I go faster and back to half way when going up a hill or stopped. What would cause this? The car has only done 52000ks and the engine was checked before I purchased it. Cheers Quote Share this post Link to post Share on other sites
alex 0 Report post Posted June 10, 2007 Hey man welcome! I'm no pro, but it just sounds like a faulty gauge, but dont take my word for it. Quote Share this post Link to post Share on other sites
Katalyst 0 Report post Posted June 10, 2007 Have you checked radiator coolant levels?? will drop when ur going fast cause ur ramming cool air through the engine bay test it by running ur car and let it heat up, watch it, listen to it, too see if ur fan kicks in and cools things down hope tht it helps Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted June 10, 2007 Your thermostat is faulty Quote Share this post Link to post Share on other sites
decsnz 0 Report post Posted June 13, 2007 Your thermostat is faulty Thanks botanymotorworx. I have replaced the thermostat and it has fixed the issue. I am interested though as normally when the thermostat goes it only affects how long the vehicle takes to warm up and does not affect the running temp once the vehicle is warm. Cheers Quote Share this post Link to post Share on other sites
OLLIE 26 Report post Posted June 13, 2007 Thanks botanymotorworx. I have replaced the thermostat and it has fixed the issue. I am interested though as normally when the thermostat goes it only affects how long the vehicle takes to warm up and does not affect the running temp once the vehicle is warm. Cheers the thermostat is still the piece of equipment that reads the temperature and tells the gauge what to show, so if the thermostat is faulty (gives intermittent readings) then the gauge is going to flicker and do funny things. Quote Share this post Link to post Share on other sites
Mike 1 Report post Posted June 13, 2007 the thermostat is still the piece of equipment that reads the temperature and tells the gauge what to show, so if the thermostat is faulty (gives intermittent readings) then the gauge is going to flicker and do funny things. quiet noob the thermostat controls the flow of water to the radiator. your thermostat obviously wasn't closing like it should have, so the engine was being cooled too much at higher speeds Quote Share this post Link to post Share on other sites
Andrew 30 Report post Posted June 14, 2007 quiet noob the thermostat controls the flow of water to the radiator. your thermostat obviously wasn't closing like it should have, so the engine was being cooled too much at higher speeds And to add to ollie's n00bness hah - the flicking of the temp gauge is usually caused by problems with the SI board. Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted June 14, 2007 The thermostat controls engine running temperature by altering flow The temperature sender unit ( different part ) signals the temperature guage in the dash and DME They are both different components Quote Share this post Link to post Share on other sites
OLLIE 26 Report post Posted June 14, 2007 pwned. such old technology - 2 seperate parts to do basically the same thing (measure temperature), if the thermostat measures the temperature to control the flow of water to the radiator why can't it also tell the temperature gauge in the dash what to show thus reducing the number of individual parts/weak points on an engine? Quote Share this post Link to post Share on other sites
Mike 1 Report post Posted June 14, 2007 (edited) the thermostat isn't an electrical device, its a mechanical valve which operates based on the temp of water flowing through it. A temp sender is basically a temperature dependent resistor, its resistance changes based on temp, the uce and gauge simply read this resistance. have any luck with my forum prob btw? Edited June 14, 2007 by Mike Quote Share this post Link to post Share on other sites
OLLIE 26 Report post Posted June 14, 2007 have any luck with my forum prob btw? instructions here Quote Share this post Link to post Share on other sites
Mike 1 Report post Posted June 14, 2007 ah wicked, cheers. mine went bung using search function too Quote Share this post Link to post Share on other sites