Matty104 0 Report post Posted August 20, 2009 (edited) Quick ( i HOPE) Question guys, E30 1989 m20b25 Recently my cars temperature gauge has been reading higher and higher, I had it scanned and all he could tell me was that its taking quite a while to heat up, and may need a new thermostat, . But i had replaced the thermostat the week before , The gauge is sitting at about 3/4 now, but got quite high in the bk drive thru untill i switched the heater on full . I just checked the radiator hoses and the top one is hot and the bottom is luke warm,thermo to radiator is hot, bottom of radiator to the metal pipe to thermo hosing is cold and hard to tell weather there is water in there, and the other hose from the water pump to the thermo housing has no water in it, water pump was changed at the same time as the thermostat, ( about a month ago) , i changed the viscious fan today and symptoms are still the same, could the new thermostat be faulty? could it be a faulty sensor somewhere? the reason it is asap is because im supposed to be driving it to the mountian tomorrow Edit: it wasnt untill after i changed the viscious fan that i realised about the hoses being hot and cold etc Matt Edited August 20, 2009 by Matty104 Quote Share this post Link to post Share on other sites
bmw_guy 0 Report post Posted August 20, 2009 As much as i no sh*t all about cars lol Myn was water pump when this happened on new years eve on the way to the mount? Not sure tho bro Quote Share this post Link to post Share on other sites
323e30 0 Report post Posted August 20, 2009 take your old thermostat, destroy it so all thats left is the seal so it lets water flow through without any restriction. try it and see if your issue goes away. just eliminates the new thermostat from being the issue. which it sort of sounds like the problem is. Quote Share this post Link to post Share on other sites
Matty104 0 Report post Posted August 20, 2009 (edited) that was replaced a month ago bro, you probly came and watched us do it haha edit, in reply to brook Edited August 20, 2009 by Matty104 Quote Share this post Link to post Share on other sites
mark247 38 Report post Posted August 20, 2009 If the thermostat is faulty / stuffed they are designed for stuff out to make the car run cold, not hot. Someone correct me if I'm wrong. Replace the temp sensor for the gauge maybe? Or just swap one off that wreck you have out front.... Quote Share this post Link to post Share on other sites
Matty104 0 Report post Posted August 20, 2009 If the thermostat is faulty / stuffed they are designed for stuff out to make the car run cold, not hot. Someone correct me if I'm wrong. Replace the temp sensor for the gauge maybe? Or just swap one off that wreck you have out front.... But if its not opening it will not allow the cold coolent ( from the radiator) to flow back through thus making it hotter and hotter ? i don't know though Quote Share this post Link to post Share on other sites
Guest MAxx Report post Posted August 20, 2009 Does the electric fan come on at all? Is the viscous fan working correctly? Is it bled properly (with heater on etc). Quote Share this post Link to post Share on other sites
mark247 38 Report post Posted August 20, 2009 But if its not opening it will not allow the cold coolent ( from the radiator) to flow back through thus making it hotter and hotter ? i don't know though Yea but they are designed ( i think ) so if they brake the spring pushes the thermostat fully open, causing them to flow all the time. Quote Share this post Link to post Share on other sites
mitchE30 0 Report post Posted August 20, 2009 head gasket. Quote Share this post Link to post Share on other sites
323e30 0 Report post Posted August 20, 2009 even a one month old thermostat can jam. they have a bi metal in them that allow them to open when the water temp goes up. They are there just to help the car get up to the correct temperature faster when the car is first on. if they jam the car water will just keep getting hotter. if its partially jammed then you may get a slightly higher temp constantly and it will warm up slower from cold Quote Share this post Link to post Share on other sites
Guest MAxx Report post Posted August 20, 2009 (edited) But if its not opening it will not allow the cold coolent ( from the radiator) to flow back through thus making it hotter and hotter ? i don't know though Yep thats correct. They usually fail in the open posistion. But you could of possibly even got a faulty one. Edited August 20, 2009 by MAxx Quote Share this post Link to post Share on other sites
Matty104 0 Report post Posted August 20, 2009 Does the electric fan come on at all? Is the viscous fan working correctly? Is it bled properly (with heater on etc).viscious seems to be working fint and it was bleed properly but now has developed the massive airlockYea but they are designed ( i think ) so if they brake the spring pushes the thermostat fully open, causing them to flow all the time.ahh you could be right there, just remembered it haddend on my 4k a while backhead gasket. No water in oil though? Quote Share this post Link to post Share on other sites
Guest FrantiC Report post Posted August 20, 2009 Just run NO thermostat see if the problem goes away. Quote Share this post Link to post Share on other sites
323e30 0 Report post Posted August 20, 2009 Just run NO thermostat see if the problem goes away. +1 first step. Quote Share this post Link to post Share on other sites
Guest FrantiC Report post Posted August 20, 2009 viscious seems to be working fint and it was bleed properly but now has developed the massive airlock ahh you could be right there, just remembered it haddend on my 4k a while back No water in oil though? Doesn't always happen. Headgasket would have to break between a water and oil channel if they were to mix. It's possible to just blow between the water channels and cylinder .. Or your head is cracked. Quote Share this post Link to post Share on other sites
Matty104 0 Report post Posted August 20, 2009 how will no thermostat work with a big drive? probly just going to be better to get someone else to drive i think, im guessing it will need to be bled again with no thermostat Quote Share this post Link to post Share on other sites
Matty104 0 Report post Posted August 20, 2009 Or your head is cracked. shhhhh Quote Share this post Link to post Share on other sites
323e30 0 Report post Posted August 20, 2009 (edited) thermostats are only needed to get the car to running temperature quicker. once the car is warm they are no longer needed. ive got no thermostat in my race car. takes ages to get warm, but once it is warm it sits solid in the middle on the temp gauge. Edited August 20, 2009 by 323e30 Quote Share this post Link to post Share on other sites
Guest FrantiC Report post Posted August 20, 2009 If it is stuck OPEN, you would take forever for the car to warmp up - Well longer than usual that is. The thermostat opens at a certain temp (81C? forgot what it was).. So when it gets hot enough, it opens and flows water through the radiator to cool it. It pretty much keeps the engine temp above 81C, if it ever drops, the thermostat would close and no water would pass through the radiator and be cooled. If it's open ALL the time, engine never gets to a proper operating temp and will run richer than usual (so be prepared for slightly crappier gas milage). Quote Share this post Link to post Share on other sites
melowpuf 19 Report post Posted August 20, 2009 If it's open ALL the time, engine never gets to a proper operating temp and will run richer than usual (so be prepared for slightly crappier gas milage). And a cold heater.... not fun if you are heading up the mountain.. Quote Share this post Link to post Share on other sites
mark247 38 Report post Posted August 20, 2009 I e30 i just bought has no thermostat. Just gets off the blue. It's getting near the top of my 'to do' list. Quote Share this post Link to post Share on other sites
Guest MAxx Report post Posted August 20, 2009 With no thermostat it will almost never heat up. My car had a failed thermostat and it never went above the blue mark. Going down the kaimais it went below the cold mark and i had no heater at all!!!!!! Quote Share this post Link to post Share on other sites
Matty104 0 Report post Posted August 20, 2009 right , just got the thermostat off, spring side (toward the engine?) had water , dome side (toward housing ?) is bone dry, just about to boil it Quote Share this post Link to post Share on other sites
Guest FrantiC Report post Posted August 20, 2009 Airlock? Sounds like it doesn't have enough water in it then. Try driving it around for a few days without the thermostat. Quote Share this post Link to post Share on other sites
323e30 0 Report post Posted August 20, 2009 right , just got the thermostat off, spring side (toward the engine?) had water , dome side (toward housing ?) is bone dry, just about to boil it should only fit one way from memory. sounds jammed tho. even if its not bleed correct it wont be bone dry. its not ideal to run an engine without a thermostat , but for fault finding purposes to narrow down the issue it is completely fine. Quote Share this post Link to post Share on other sites
