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Discussion Starter #1
ok so just recently bought a 99 323i . first bmw ever owned. i know cars in general pretty well but by no means a mechanic. used to own a auto body shop. so general knowledge i have.





replaced so far:


expansion tank (AM)
auto thermostat (AM)
thermostat housing and thermostat (whaler)
lower rad hose (OEM)
water pump (OEM)
radiator (used) also original i dont believe there was anything wrong with and still have
pulley (AM)
Tensioner (AM)
both belts
BMW Coolant blue
hose orings (OEM)
coolant temp sensor in lower hose (AM)


i have removed machanical fan. and aux fan. replaced with electric fan which at this stage wont shut off when plugged in

original problem was over heating. which it has a few times but never long at all.

theres NO signs of oil in coolant what so ever.

oil level seems fine and had just changed 2 weeks before al problems started.


so now for what my problem is that i can tfor the life of me figured out. top hose gets hot lower stone cold. i have taken a digital point and shoot temp gauge and lower never gets any warmer than the outside temp which is around 40F as its getting cold here in NH right now.

Bleed the system. yea read that is what to do at least 100 tmes on all the forums trying to figure this thing out.

so i did this instead to insure proper bleeding. had my friend (old BMW) tech bring a 2 way valve bleeder over hooked up to compressor and blead system. so problem presisted. so thats when i got water pump. still same problem.

now i have removed thhermostat hook up 12V to the heater element and ensured myself it will open and does.

bleed the system i know.

before i type much more possible useless info any ideas. i keep reading these phrases. keep reading and reading till your eyes bleed. keeping reading till you throw up. well i am there.



My MAIN problem right now is thermostat will NOT electronicly open up. Seems there is no circulation which then in turn leads to pressure relief vavle spitting out coolant and then overheats
 

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Discussion Starter #3
Is (AM) for after market? If so I'd probably start by replacing any cheap after market parts with original or known quality parts.
I do agree with that however its forsure not going to help my case of the thermostat not opening up. Afteramarket yes. Cheap. I did my research and based off other reviews of each part went with it. I still have a account with bmw from my previous auto body shop so parts are much cheaper than list but not wverything in my eyes is always needed to be oem. Personally oem is the way to only go with certain parts tho and i think i got all parts from appropriate places. Except for thermostat but i did go with one that is made by the same manufacturer that bmw puts there name on.
 

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Never put aftermarket cooling system parts in an E46. The cooling system is this car's Achilles heel.

Your not getting flow through the radiator. Are you sure the radiator isn't blocked internally? Pull the AM thermostat and see if it opens when immersed in boiling water. If it doesn't open the thermostat is bad. If it does open the radiator is likely bad.

The electric fan has power at all times. The engine computer (ECU) manages the operation of the fan. Read this: https://drive.google.com/file/d/0B59e0P388oUjMDNkWDk5SkwxVlE/view?pli=1
 

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Discussion Starter #5
Ok so this is what i have done so far. When i first got the thermostat I applied 12 volts to it not installed in the vehicle and confirmed it open then after that I plugged the thermostat into the vehicle put the key on keep in mind was not warmed up and I've been waited a while to see if it would open them and did not not sure if that's even valid diagnose. So what you're saying is boiling water would give a different effect of the thermostat opening other than electronically.?

Going to go ahead and guess that yes you're saying to do that separately as well so I'm going to go do that right now and I'll report back shortly and let you know what happens.


As far as the radiator goes I mean I have taking a garden hose and ran water through both of them that I have and both seem to have decent flow through them.


And here's another thing I also did which is the digital thermometer the left side of the thermostat and left hose lower never really reach much higher than the outside temperature ever the right side goes above a hundred in my eyes I really don't see the thermostat opening and with the amount of bleeding I've done with the bleeder and without up on ramps read all the forms and techniques and tried all with no success I'm no BMW expert by any means trying to learn though I'll let you know what happens after putting in boiling water. Now you say not to cheap out on BMW cooling system parts is it okay to get a brand new aftermarket radiator or is that bad too and should I really invest in getting coolant temperature sensor replaced with OEM vs. The three or four aftermarket that I've tried?
 

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Discussion Starter #6
Never put aftermarket cooling system parts in an E46. The cooling system is this car's Achilles heel.

Your not getting flow through the radiator. Are you sure the radiator isn't blocked internally? Pull the AM thermostat and see if it opens when immersed in boiling water. If it doesn't open the thermostat is bad. If it does open the radiator is likely bad.

The electric fan has power at all times. The engine computer (ECU) manages the operation of the fan. Read this: https://drive.google.com/file/d/0B59e0P388oUjMDNkWDk5SkwxVlE/view?pli=1
do you really think it would be best if i got a oem coolant temp sensor? and how about radiator. is that really a must to go oem? and fan? i hate to spend all this money and car not work due to something major in the end and not keep it.
 

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Discussion Starter #7
Never put aftermarket cooling system parts in an E46. The cooling system is this car's Achilles heel.

Your not getting flow through the radiator. Are you sure the radiator isn't blocked internally? Pull the AM thermostat and see if it opens when immersed in boiling water. If it doesn't open the thermostat is bad. If it does open the radiator is likely bad.

The electric fan has power at all times. The engine computer (ECU) manages the operation of the fan. Read this: https://drive.google.com/file/d/0B59e0P388oUjMDNkWDk5SkwxVlE/view?pli=1
boiling a pot of water thermo dropped in and nothing appears to move or open. how long would it take?
 

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Discussion Starter #9
Update

ok so one of many of my problems resolved. the most recent would be the expansion tank wasnt seating properly on the mounting plate. that is the automatic cooling piping. put a different oring on itand now system builds up pressure. however the heat comes and goes. took it on the highway coolant temp got to like 110 and lost heat so i got off the nearest exit and temp went down and heat came back a little. more i reved the lower the temp would go. never went lower than 85. but was up and down dramaticly. now i have consistantly no heat. let car sit for 12 hours. checked coolant leveland it was fine.

my question is. cause i have this gut i will be told to rebleed the system. what is the proper proceder on re bleeding.

and what are the dos and donts

cracking open bleed screen when running or not running.
pressure relief cap when i can and cant open it

basicly not trying to get more air in the system just want to get it out.

next question is i read that the heater control valve could be clogged. is this something i should look into?
 

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Raise you're front end

Remove expansion tank cap and open bleeder screw

Key to position 2, fan on lowest setting, heat all the way up

Add coolant slowly until you see it start coming out of the bleeder screw (if there are a bunch of little bubbles coming out of the bleeder screw with the coolant then keep going until the bubbles stop

I also give every thing a couple gentle taps with a rubber mallet.
 

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As I had problems with this, I thought adding my 2 cents might help.

Raise you're front end

Remove expansion tank cap and open bleeder screw

Key to position 2, fan on lowest setting, heat all the way up to 90, but fan on low, this will open the heater valve.

Do not start the engine

Add coolant slowly until you see it start coming out of the bleeder screw (if there are a bunch of little bubbles coming out of the bleeder screw with the coolant then keep going until the bubbles stop

I also give every thing a couple gentle taps with a rubber mallet.

Replace the bleeder screw (careful, they strip easily)

You will probably have to siphon out or use a turkey baster to get the coolant level down to the correct level

Test drive, then check fluid level again.
This thread is an exhaustive look into our cooling system. http://forum.e46fanatics.com/showthread.php?t=914109
 

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Discussion Starter #12
**update**

unfortunately i have done all of above and then some. i am new to bmws not new to googleing information. and thats all i keep reading is everyone getting the answer of bleed the system.

so i have made progress

oem thermostat
oem waterpump
oem lower coolant hose
new aftermarket cooling fan

so my fan didnt work before. now it does when ac is on.

my main question this moment is to test cooling fan would be to unplug coolant temp sensor in lower hose and if it turns on that would mean temp sensor is bad right?
 

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I have a 1999 323 Automatic sedan, 190k. I have replaced cooling system with OEM parts and have done the fan delete modification to electric. I agree with the comments above, "you need to bleed the system correctly. it took me a while to learn how to bleed the system.
As far as the electric fan it should be plug and play. When the AC is off The fan should automatically turn on at 97C when the car starts to get too hot.. *...... However..... When the AC is on, the fan should automatically stay on. hope that helps. If the fan is not coming on then yes i would replace the temp sensor which is only $16. FCPeuro.com has life time warranty on everything they sell.
 

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put a different oring on itand now system builds up pressure.
Just an FYI, the expansion tank doesn't need an O-ring.

People make bleeding out to be hard to do. I have been doing it on so many E46's, E39's, X3s and many others it isn't even funny. And this is over 10 years time.

You don't need to raise the front end (I never have).
Make sure you roll the center vent to three red dots, 91 degrees, and I always do defrost (blowing it at the windshield) on full blast.
Open bleeder screw, pour in about 1/2 gallon of Distilled water (ONLY USE DISTILLED WATER) and check for leaks.
If no leaks add 1 gallon of BMW coolant or Pentefrost BLUE coolant ONLY! (DO NOT USE GREEN or ANY OTHER COLOR OR YOU ARE ASKING FOR PROBLEMS!).
Then top off the rest with more distilled water until it comes out of the bleeder hole.
When you get close to the end fill SLOWLY! Tighten bleeder screw and put the cap on.
Done deal. It really is just that easy.

Perhaps you need a new expansion tank cap?:dunno:
 

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Discussion Starter #15
i appreciate all the helpful comments truly i do.i also dont want to sound like a dink by saying i have done all of above.

i think i am over looking something though. i will be the first to admit that.

So the other day after getting my new cooling fan in i felt confident it wasnt going to over heat.. which it did. i was thinking and i realized why and when all my problems started. the outside temp got cooler i stopped using my ac. that being said. no ac meant my cooling fan wasnt running anymore or atleast due to the ac not on.

what sensor tells the DME to turn the cooling fan on?

is there a relay?

i jsut got a new fan. it does kick on when the a/c is on and only when i unplug the coolant temp sensor located on bottom radiator hose (passenger side)

i got a bluetooth obd2 reader and i watch the temp closly.

also just got a oem coolant temp sensor

what are causes of cooling fan not kicking on due to coolant temp reasons??
 

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I had a similar issue with my 1999 BMW e46 sedan. After I replaced the coolant temp switch the fan started to turn on at low to medium speed when the coolant temp hit 97c. That's without the AC on.

If still not working then might be a bad relay. .....
 

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i appreciate all the helpful comments truly i do.i also dont want to sound like a dink by saying i have done all of above.

i think i am over looking something though. i will be the first to admit that.

So the other day after getting my new cooling fan in i felt confident it wasnt going to over heat.. which it did. i was thinking and i realized why and when all my problems started. the outside temp got cooler i stopped using my ac. that being said. no ac meant my cooling fan wasnt running anymore or atleast due to the ac not on.

what sensor tells the DME to turn the cooling fan on?

is there a relay?

i jsut got a new fan. it does kick on when the a/c is on and only when i unplug the coolant temp sensor located on bottom radiator hose (passenger side)

i got a bluetooth obd2 reader and i watch the temp closly.

also just got a oem coolant temp sensor

what are causes of cooling fan not kicking on due to coolant temp reasons??
Temp sensor in the lower radiator hose controls the fan
 

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Discussion Starter #18
Temp sensor in the lower radiator hose controls the fan
so i just got back inside from installing new temp sensor and filled entire system with new fresh coolant.

bleed it just like everyone says to. but this time tried with defrost on instead.

let car warm up at idle to 103c and fan did not kick on. also there was no heat this time. which says to me needs to cool down for 4 hours or so and be re bled,

now hears a question still haven't gotten answer to. re-bleeding. how to do it?
do i removed bleed screw and expansion cap and fill till bubble free or do i just fill it if its low?


Bleeding procedure i have been following the entire time
engine at least at ambient outside temperature
ignition position 2
heat temp 91
fan low (this time defrost)
bleeder screw out
expansion tank pressure relief valve cap off
poured coolant in the expansion tank filler neck as slow as i possibly could till coolant came out bleeder screw hole bubble free. (took about 2 mins after it started coming out of bleed screw till bubble free)
then took turkey baster and removed approx 5 turkey basters worth till it was between min and max fill level bubbles on float stick.

Some times what i have done is at this point got in the car and started engine and revved to about 4k rpm for 20 secs. then shut car off and then checked coolant level and repeated as necessary which i have read is now added to BMW protocol for bleeding system.

then i will run engine till warmed up

last few times went well but not proper. what i mean by that is either unplugged cooling temp sensor so the fan would run constant. or ran it with ac on. both ways it will drive no problems until i slow down then the over heating begins. revving engine at times will bring the temp down.

AS I STATED WHEN I STARTED THE THREAD WAS "AT A LOSS" "Help!!!!!

Would it help bring it to BMW dealer and paying the $139.00 for diagnostics ran? and if not BMW dealer a BMW specialized shop to run diagnostics?

Just unsure of how in depth there obd2 scanners can go. is there a affordable scanner i can buy for the car that would possibly help with these issue and future problems. For under $300. If so any recommendations
 

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ROLL TIDE!
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Your bleeding procedure is not your problem. Sounds like it is fan related. Put the mechanical fan back on and see if the problem persists.
 
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