Member
Hello epmedia,
You said " I also have the low temp "aux fan switch", which turns on just over 1/2 on the gauge" I did not know that there is a low temp aux fan switch made can you please give me the info on where/what website you got it at and manufacture thanks. As for the Tstat I already replaced it with the lower temp T-stat which should have improved my situation which it did not. The original T-stat did the same thing but the only difference was with the original T-stat it took a little big longer for the temp gauge to get to the 3/4 mark. When you say 3/8 I don't know where that is on the dial is that near the 3/4 mark? When I say 3/4 I mean the 75% mark. Thanks for your help not sure what to do next or from here. I think I will drive the car and as it gets hotter out I will drive it more and monitor what happens. Unless you guys think I should do something else thanks for your help.
Dave
Originally Posted by epmedia
Hi Dave. Paper clip test = good, great.
This quote from you:
"I let the car sit and sit until the gauge finally got right near the 3/4 mark on temp gauge. At that point Exactly 3/4 mark on temp Gauge the thermostat opens up fully (at 180F to be exact). When that happens you can watch/see the temp gauge drop way down from 3/4 to below the half way 12 o'clock position".
If you are just sitting there idling when that occurs, and all wires are clean to the guage; that suggests to me that the t-stat is NOT moving "smoothely" (like JRCook mentioned). I believe the t-stat should hold the guage within about 1/8 of guage travel - from "start to open", to "full open". And of course the guage will continually creep up if "full open" is not enough, which is when the aux fan will turn on at the temp of the fan switch rating (like GDAus mentioned).
Just so you know, I have the low temp t-stat as well, and it hoovers between 3/8, and 1/2 on the guage. I believe (not verified) I also have the low temp "aux fan switch", whick turns on just over 1/2 on the guage.
Essentially - I believe your guage should hoover between 3/8 and 1/2 with the cooler t-stat, not 3/8 and 3/4. And we still don't know if your aux fan switch on the radiator is good - that would require testing that has not been deemed necessary yet. Or - you could just get a new "mid" switch like JRCook mentioned.
I hope I said that right, somebody correct me if I'm wrong.
Member
Hi Dave. I have the 170F thermostat and my temp guage hoovers between 3/8 and 1/2. I'm not certain about my aux fan switch, it was already installed when I bought the car, yet turns the aux fan on when the temp guage climbs just beyond 1/2.
rockauto.com has 91C switches for 7 bucks (mid temp). I would just get one if I were you. They also have a 170 t-stat for 23 bucks, incase you think the new one installed might be sticking. I would not go colder than mid range, since your are in a cooler part of the world.
I think all the confusion about different opinions of: "where the guage normally reads", is because there are so many different combinations of t-stats and switches to choose from (twice as many as I thought)!
FYI: according to bavauto.com (which does not seem to calculate with your, nor my t-stat Farenheit specs).
stock t-stat = 80C, stock switch = 99C
mid t-stat = 75C, mid switch = 91C
low t-stat = 71C, low switch = 82C
Tbd
Member
Hello Epmedia,
Thanks so much for showing me where the 3/8 position is that helped a lot. Also for the info I decided to go with this combo... low t-stat = 71C, low switch = 82C I already have the 71c t-stat and I ordered the 82c aux. fan switch as I am having trouble getting the fan to come on so this should help the fan to come on sooner. In addition I will change out coolant AGAINand let you know my findings on mon or tuesday when it gets nice here again. I hope this will help can't hurt to try and make a change on it. Here is some info on 82c switch...
We recommend using the 82 degree switch for the low speed and the 91 degree switch for the high speed (instead of the 91 deg. & 99 deg.). This will allow the fan to start at a lower coolant temperature, which will help prevent over temperature conditions in hot weather.
Minor modifications are required - The female spade terminals on the wiring harness for the high temp. switch are smaller than the male terminals on the 91 degree switch. Just clip off the smaller terminals and crimp on two standard female spade terminals. Please note: - modifications required
Thanks for your help
Dave
Hi Dave. I have the 170F thermostat and my temp guage hoovers between 3/8 and 1/2. I'm not certain about my aux fan switch, it was already installed when I bought the car, yet turns the aux fan on when the temp guage climbs just beyond 1/2.
rockauto.com has 91C switches for 7 bucks (mid temp). I would just get one if I were you. They also have a 170 t-stat for 23 bucks, incase you think the new one installed might be sticking. I would not go colder than mid range, since your are in a cooler part of the world.
I think all the confusion about different opinions of: "where the guage normally reads", is because there are so many different combinations of t-stats and switches to choose from (twice as many as I thought)!
FYI: according to bavauto.com (which does not seem to calculate with your, nor my t-stat Farenheit specs).
stock t-stat = 80C, stock switch = 99C
mid t-stat = 75C, mid switch = 91C
low t-stat = 71C, low switch = 82C
Member
Hi Dave, hope all works out good for you, atleast the parts are inexpensive enough for trial and error, and especially since it's related to the cooling system
Robert
Last edited by epmedia; 03-10-2010 at 02:18 AM.
Tbd
Member
Hello Robert,
Yes our fans are 1 speed you are correct there. Okay I though of another ? for you as I want to do this job correctly. If possible I want to leave the upper radiator hose attached and just disconnect the bottom radiator hose only. Is that okay if I do that or will that cause air to be in the system by not disconnecting the upper hose? The other question is if I just remove the lower hose should I remove the radiator cap before I disconnect the lower hose or after? I am asking this because I think you remove the radiator cap before you get started that way it lets the air out. Also I believe you are supposed to squeeze the hoses after you disconnect them to let the air out is that correct? I am asking so I when I do the job I don't get any extra air inside the cooling system. Thanks for your help with these ?'s.
Hi Dave, hope all works out good for you, atleast the parts are inexpensive enough for trial and error, and especially since it's related to the cooling system
Robert
Member
I wouldn't worry about the air getting in, it seems to me that you will have to let air in to get the coolant out, right? Anyways, this is what I did to get the air out. Made sure my heat switch was on. I filled up the radiator and squeezed all the hoses. The antifreeze level went down a little so I added more and squeezed the hoses again. I did this a couple of times until I couldn't hear antifreeze squish around and the level stayed the same in the radiator. Then I put the radiator cap on and ran the car to operating temperature. After the car was warm I shut it off then opened the radiator cap to the first notch to release the air. Lastly, I opened up the cap all the way and had to add a little more antifreeze. The next time I started up the temp went up to where it was supposed to be. Hope you get this thing sorted out!
Member
Hi Dave, for just replacing the switch - I would leave the hoses and cap on.
Make a rubber plug for the radiator, based on the size of the new switch threads. If you did not get a new "seal washer", you can use the old one if it looks good.
WITH ENGINE COLD - Remove the old switch, pop in the rubber plug and compare switches (threads). Put the gasket on the new switch (be aware - the old gasket may stick on the radiator when you take the old switch out)... and you know the rest. Just do not over tighten it, dont want to mess up the radiator - only tighten super snug!
Fyi: If you remove the cap or hose - fluid would come out very fast and make a big mess. Clean up spills too, so no outdoor animals drink the coolant
Be sure to run your heater full hot when you are topping off the coolant, and check the coolant level atleast twice: before and after a test drive.
And like eerienine says: there's no way around "not" getting air in the system.
Welcome eerienine
Last edited by epmedia; 03-10-2010 at 05:34 PM.
Tbd
Member
Thanks epmedia!
Member
Thanks for answering back so I will do it the hard way which is disconnecting the lower radiator hose ONLY and let out the coolant. I want to do it this way so I can also add new coolant and make sure I get the mix correct incase I messed up the last time. However my ? to you is do I need to remove the radiator cap before I disconect the lower radiator hose? I ask because I want to do the job the correct way and I think the cap should be open to let the pressure and air out/in which will make the coolant come out quicker. I am not sure which is the correct way to do it though please advise thanks.
Dave
Hi Dave, for just replacing the switch - I would leave the hoses and cap on.
Make a rubber plug for the radiator, based on the size of the new switch threads. If you did not get a new "seal washer", you can use the old one if it looks good.
WITH ENGINE COLD - Remove the old switch, pop in the rubber plug and compare switches (threads). Put the gasket on the new switch (be aware - the old gasket may stick on the radiator when you take the old switch out)... and you know the rest. Just do not over tighten it, dont want to mess up the radiator - only tighten super snug!
Fyi: If you remove the cap or hose - fluid would come out very fast and make a big mess. Clean up spills too, so no outdoor animals drink the coolant
Be sure to run your heater full hot when you are topping off the coolant, and check the coolant level atleast twice: before and after a test drive.
And like eerienine says: there's no way around "not" getting air in the system.
Welcome eerienine
Member
Hi David, get your drainage positioned, loosen the hose to where it starts peeing (twist it to break the seal), then loosen the cap. If you take the cap off first - it willl be a rage of a drain. Slowly make the hose leak more. Again - there is no way to do it wrong (air in system-wise), just trying to make less mess for you.
Tbd
Member
Hello Robert,
Thanks for answering me back yeah I am pretty good a keeping it clean as last time I did it I spilled no more then the palm of my hand as I have a large bowl/pan to catch all the coolant when it drops. I will try it the way you suggested thanks less coming out more slower is always better
Dave
Member
Hi Dave, remember we mentioned "no matter how you do it" you will be introducing air into the system, there is no wrong, or right way to do it, and there is no way to get around it. Only disconnect hoses needed (assuming you are changing thermostat). There's no sense in making more work for yourself
Tbd
Member
Hello Robert,
The way I do it is disconnect the lower radiator hose only then slowly remove to cap to let out more and more of coolant. When done draining that should allow me to add new coolant to system and will allow me to install and loosen the auxiliary fan switch without worries of coolant pooring out or spilling on me while I am under the car hence why I need to drain the system completely by removing bottom radiator hose. The other way to do the job CORRECT is removing all hoses and draining everthing/all coolant out I think this would only be the way to go if I were replacing/changing the T-stat which I am not doing that again as I already verified it works correctly. So I will go with removing only the 1 lower radiator hose to drain most/all of the coolant out of radiator so I can work under the car and not have to worry about spilling any coolant on me the ground or anywhere. Thanks for you help and if you have any suggestions that would help me further let me know please and thanks.
DAve
Hi Dave, remember we mentioned "no matter how you do it" you will be introducing air into the system, there is no wrong, or right way to do it, and there is no way to get around it. Only disconnect hoses needed (assuming you are changing thermostat). There's no sense in making more work for yourself
Member
Hi Dave, I thought you were going to work with the switch from the top. And yes, if you are going under - definately drain all the coolant
Tbd
Member
Hello Robert,
Yes I did work from the top already however to get the switch off and install the new one you need to go under the car and use a deep socket 22mm and remove the old switch and put in new switch. So I will drain the coolant from the lower radiator hose only. That was my question to you is that okay that I am draining it only from the lower hose and not disconnecting the other hoses i.e. the top hose and t-stat? The other question is when I install the new switch how will I know which wire goes on which spade connector or does it not matter? Thanks for your help Dave.
Hi Dave, I thought you were going to work with the switch from the top. And yes, if you are going under - definately drain all the coolant
Member
Hi Dave, yes - just disconnect the bottom hose, and the 2 wires don't matter where they plug in.
Tbd
Member
Okay thanks very much for your help I will let you know after I do it what happens thanks again.
Dave
Member
Hello Robert,
Okay I think I have invested enough time & Energy into this problem..... I did everything and not much difference it seems a little bit cooler but still goes over the 12 o clock position. The fan did not come on which is good that means the car is not getting that hot and it could be a faulty gauge, mixed parts used on the car from 83 or 84 or I don't know. Well in the end the good news is it is not overheating the bad I still am perplexed and don't know what is causing this problem.
Here are some questions I thought of for you. What color is your engine coolant? What is the correct kind to use? I used (green) prestone I think or peak which I think that is the correct coolant to use. Thanks for your help in this matter.
Dave
Member
I have an 81 320i and I had the exact same problem where the gauge was showing that I was overheating, so i replaced the entire cooling system. Head gasket and new head, radiator, water pump, thermostat, cooling relay, electric fan and then i moved on to the electrical side of it. everything i could possibly think of and nothing would bring my temp back down. I decided to unplug the electric sensor and buy a cheap temp gauge to see if the gauge itself was the issue. Now this gauge is showing that im running a solid 180-200 degrees. So it could just be that the gauge itself doesnt work correctly. It was easier to spend the 15 dollars and know what my temp is that seriously start messing with the electrical system and possibly cause other problems. Just some advise cause i spent a lot of money to try and fix something when it ended up just being the gauge the whole time.
Member
I had this problem as well. The aux fan is going to come on no matter what the coolant temp is when you turn the a/c on. My fan did not come on by itself without the a/c on. Relpaced the switch on the radiator and everything is good.
Member
Just to verify...when you turn on the heater, you get blasted with a LOT of heat, correct? If not, the thermostat could be bad (I know you replaced it, but I have had a new one act up on me) or you could have air in your system. If the heat takes a while to get in the car, you can bleed it by putting the nose of the car uphill so the radiator is the highest point.
With the engine cold, turn on the car, take off the cap, and turn the heater on full heat/fan on high. Let it run for 20 minutes, and then carefully rev it a few times. If there is an air bubble in there, this will get rid of it. Hope that helps.
Also, NAPA sells a radiator bleeding kit for about $20. The part number is 77-4000. Works perfectly and is easier to see the air bubbles...
Tim
Member
Funky gauge huh...never thought about that. Where did you plug the 2nd temp sensor in for the secondary water temp gauge?
I put in a 180F aux fan switch last summer which work great (temp always 12 o'clock) if left to idle and it went a hair past 5/8 bang aux fan kicks on and back to 12 o'clock
But now it's fall and alot cooler outside and my temp sometimes passes the 5/8 and the aux fan doesn't come on?
First thing i want to do is test the resistance of the switch....how did you test yours to determine it was working?
Last edited by msiert; 11-01-2012 at 08:42 PM.
Member
Hello there,
I wish I could remember the post and instructions to tell you. Basically they told me to turn the key to the aux position (car not started) then connect a paperclip to each end of the aux wires and that would jump the aux fan. If the fan comes on with the paperclip test it works if not then its your fan. HOpe that helps you.
Dave
Member
Update: Aux Fan Switch
That 180F (82C) Aux fan switch that I bought last Summer and worked so great stop working.
Bought a new one to replace it for this Summer driving season once installed that will confirm if the first one went bad or not. The a/c switch kicks the fan in so that's the only other thing that could be bad
Last edited by msiert; 04-02-2013 at 09:05 AM.
Murray
Member
Incorrect my new friend.... Allow me to shed some light on your problem to help narrow it down for you. I had the same problem as you last year. The problem being the aux fan would not come on when it was hot (the correct temp) outside correct? If that is your problem then read the following very carefully. I was about to change the aux fan switch then I got a idea that worked. My friend who is electrical engineer told me he used to have this car and its the fuse box connections. He said to take a wire brush to the contact points of all fuses that go near/to the aux fan. Now your fuse box says which ones go to the aux fan I can't remember what they call it I think its called temp sensor or heater can't remember sorry. Anyways long story short I wire brushed all contact points (on the fuse ends and where the fuse slips in the hole) for all fuses because I did not know which one was to aux fan and it worked. That was my problem I confirmed it by after doing the wire brush cleaning I let car idle in hot summer sun and BOOM THE FAN CAME ON TO MY SURPREISE..... That is your problem I think b/c it was mine. One thing to keep in mind here..... NONE OF MY CONTACT POINTS IN THE FUSE BOX LOOKED CORDED OR BAD. I still to this day don't understand how/why my contact points can look new/great and still need to be wire brushed to make them work.... If anyone on here chimes in please Answer this question for me as I never go the answer. Hope this helps/solves your problem my new friend.
- - - Updated - - -
One more thing to add here of importance..... Before I did the above mentioned to my car I made sure everything else was fine and in good working order... I changed my radiator, t-stat, engine coolant, and the aux sensor. So before you narrow it down to the fuse box contact points please make sure everything mentioned here & on the car is in good working order. In short my car would not overheat and was in good working order. Hope this helps you to narrow it down some more. When you are done and do find the problem please post back here for me and everyone else to see so we all can learn from and what this problem is......
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