92 525i "PROPER" bleeding procedure.

Ok so Ive been searching up diferent forums and I cant seem to find answer.

Im trying to look for a proper procedure of bleeding the cooling sytem for a 525i. I tried youtube and only found one for a 528, which he too out two bolts and a radiator cap. Im not sure if there is two bleeder screw on a 525i or not because ive been trying to look for it te whole day.

On the video i watced about 528, he took off te radiator cap, the bleeder screw right next to the radiator cap, and a screw from the thermostat housing. Im not sure if its the same procedure for a 525i because I cant find the thermostat on my 525i.

My question is do i have to take 2 bleeder screw on a 525i or there is only bleeder screw on a 525i and that is the one that is right next to radiator cap. And where can i find the thermostat on a 525i?


Additional question. When i switch my blower fan to low, it doesnt wor. But when i turn it all the way to the max, it works. Any possible solution to this? Because i know i have to turn my fn to low when bleeding but my fan only turns ON when i put it on max.


Thanks bimmer forum member

its simple. just a little monotonous.

As outlined in Bentley (you REALLY need to get one if you dont already have it*) page 170-5.

1. Add colant in expansion tank up to "COLD" mark
2. If your expansion tank is on the radiator, loosen bleed screw (right next to rad cap), fill until coolant comes out of the bleed screw and re-tighten.
3. If your expansion tank is separate, do the same as #2 except bleed scre is on T-Stat housing.
4. Put temp controls at full heat; full blast
5. Fire up the car
6. With motor idling at op temp, losen bleed screw until coolant is free of air bubbles.
7. After it has cooled, check fluid level and refill as necessary.

Some things to help.

• Raise front of the car a couple inches to help the air make it to the bleed screw.
• loosen, quickly and close quickly repeatedly. Should be like a "PSST! PSST! PSST!" (keeps more coolant in and air out.)

M50


M20


*If you have a bentley manual and you made me write this I will be upset.

welcome to the 'fest

First I would like to thank you being the first peron to help me

No i dont hve the bentley manual but i woud be glad to get one of those for my further self study. Can you link me to where i cn get a bentley manua?


Ok so im confused with the expansion tank part. Do you mean the coolant container when you say expansion tank? I dont think neither of the picture is the same as my engine. Im driving a 92 525iA/usa if tht helps. My engine looks closely as the first picture but my radiator cap is on the driver seat side. I can take a picture if necessary. Do i have to change the coolant before i bleed the system? Cos i just changed my coolant. Does the fans have to be ON BUT ON LOW before i start bleeding?

Originally Posted by athan12

First I would like to thank you being the first peron to help me

You got it dude, thats what I'm here for...

Originally Posted by athan12

No i dont hve the bentley manual but i woud be glad to get one of those for my further self study. Can you link me to where i cn get a bentley manual?

Bentley Download

Originally Posted by athan12

Ok so im confused with the expansion tank part. Do you mean the coolant container when you say expansion tank?

yes. the coolant tank/ reservoir.

Originally Posted by athan12

I dont think neither of the picture is the same as my engine. Im driving a 92 525iA/usa if tht helps. My engine looks closely as the first picture but my radiator cap is on the driver seat side.

Apologies, thats an M52. you have an M50. it is the style of th efirst one. You are correct. I will update first picture.

Originally Posted by athan12

I can take a picture if necessary.

Unecessary

Originally Posted by athan12

Do i have to change the coolant before i bleed the system? Cause i just changed my coolant.

You do not have to change coolant to bleed th esystem. Especialy not if you have just put new coolant in.

Originally Posted by athan12

Does the fans have to be ON BUT ON LOW before i start bleeding?

Blower fan should be on HIGH with heat on HIGH

Hey I'm back!

With a few more problems.

So I went to work this morning. Warmed up the car for 15 mins, drove it to work for like 10-15mins, and got to work with the temp gauge staying in the middle.

Now, when I get off work. I started the engine, warmed up for like 2 mins(i know I shouldve warmed up a bit more). When I was driving on my way home, the temp gauge started going from the middle to next bar but never goes on the red line. I noticed the temp goes down whenever I drive and accelerate, I'm guessing the wind force is helping cooldown the engine.

When I get home. I took a nap for like 3 hours. Got ready to the bleeding procedure and here's what happened.

Note: This is when the engine is cold
-I jacked up the car
-Turned the ignition
-Put the temp setter to HOT
-Put the heater on MAX/BLAST/SUPER/ULTIMATE
-Opened the radiator cap
*I was surprised that my coolant tank is empty. I'm assuming it leaked out when my car was parked at my work. A couple or three days before we found out that the coolant was LEAKING/OVERFLOWING out of the coolant tank. Its not overly filled, we just put it on COLD level. I'm assuming that there's air going to my tank and causing the coolant to OVERFLOW/LEAK from the radiator cap. But anyway, I procede with the bleeding procure.

-Unscrewed the bleeder screw
-Started putting coolant in the reservoir *BUT THERE IS NO AIR OR BUBBLE COMING OUT OF THE BLEEDER HOLE* (isn't there supposed to be bubble or air coming out of it?)
-I filled the reservoir until its overflowing and still no bubbles are coming out the bleeder hole.
-So I put the bleeder screw back
-Put the radiator cap back
-Started the engine
-Waited til the engine is at the middle temp
-Unscrewed the bleeder screw with the "PSST, PSST" motion, but there is only a tiny bit of air thats coming out of it.

Also my heater is not blowing any hot air from it. Any possible reason for this? Am I supposed to take out another bleeding screw from the thermostat? or theres NO bleeding screw on the thermostat housing for my M52?

I think your doing everything right. I had the exact same issue with my heater. I hate to admit this but it took me an hour to get everything working correctly from bleeding all the air out. It was a PIA both times I did it. Just when I thought I had enough coolant in the system I had to add another half gallon etc. and keep track of my mixture. I did mine with the cap off and got coolant everywhere. It would be fine then boom bubbles galore and coolant leaking all over. I ended up using three drain pans to catch what I could after it ran all over the core support. I have never had such a hassle bleeding a cooling system. Your issues with the heater and the gauge rising are identical to mine. I checked mine for about a week after the initial bleed and got air a couple times when opening the cap and had to top off the coolant once.

Originally Posted by athan12

Hey I'm back!

With a few more problems.

So I went to work this morning. Warmed up the car for 15 mins, drove it to work for like 10-15mins, and got to work with the temp gauge staying in the middle.

Now, when I get off work. I started the engine, warmed up for like 2 mins(i know I shouldve warmed up a bit more). When I was driving on my way home, the temp gauge started going from the middle to next bar but never goes on the red line. I noticed the temp goes down whenever I drive and accelerate, I'm guessing the wind force is helping cooldown the engine.

When I get home. I took a nap for like 3 hours. Got ready to the bleeding procedure and here's what happened.

Note: This is when the engine is cold
-I jacked up the car
-Turned the ignition
-Put the temp setter to HOT
-Put the heater on MAX/BLAST/SUPER/ULTIMATE
-Opened the radiator cap
*I was surprised that my coolant tank is empty. I'm assuming it leaked out when my car was parked at my work. A couple or three days before we found out that the coolant was LEAKING/OVERFLOWING out of the coolant tank. Its not overly filled, we just put it on COLD level. I'm assuming that there's air going to my tank and causing the coolant to OVERFLOW/LEAK from the radiator cap. But anyway, I procede with the bleeding procure.

-Unscrewed the bleeder screw
-Started putting coolant in the reservoir *BUT THERE IS NO AIR OR BUBBLE COMING OUT OF THE BLEEDER HOLE* (isn't there supposed to be bubble or air coming out of it?)
-I filled the reservoir until its overflowing and still no bubbles are coming out the bleeder hole.
-So I put the bleeder screw back
-Put the radiator cap back
-Started the engine
-Waited til the engine is at the middle temp
-Unscrewed the bleeder screw with the "PSST, PSST" motion, but there is only a tiny bit of air thats coming out of it.

Also my heater is not blowing any hot air from it. Any possible reason for this? Am I supposed to take out another bleeding screw from the thermostat? or theres NO bleeding screw on the thermostat housing for my M52?

You have an M50, not 52. you only have one bleed screw, the one right next to the rad cap. Top off, bleed. top off, bleed. top off bleed. the PSST PSST PSST will only allow a little air out at a time anyway. This is all normal. its just a giant PIA to keep taking air out so little at a time. If there isnt coolant coming out of the bleeder hole then its all air. wait till coolant comes out. close it.

Athan12, you need to be bleeding the sysetm with the engine running.

Originally Posted by Monsignor

You have an M50, not 52. you only have one bleed screw, the one right next to the rad cap. Top off, bleed. top off, bleed. top off bleed. the PSST PSST PSST will only allow a little air out at a time anyway. This is all normal. its just a giant PIA to keep taking air out so little at a time. If there isnt coolant coming out of the bleeder hole then its all air. wait till coolant comes out. close it.

If I try doing the "lung method" is it gonna be faster to see coolant coming out of the bleeding hole?

Correct me if I'm wrong. This is what I heard. You blow constant air into the coolant tank with the bleeder screw off?

Originally Posted by BMR_LVR

Athan12, you need to be bleeding the sysetm with the engine running.

Is it supposed to be at normal op temp before I take out the rad cap and bleeder screw? Isn't that gonna cause the coolant to do a "coolant fountain out the radiator cap"?

Originally Posted by S406

I think your doing everything right. I had the exact same issue with my heater. I hate to admit this but it took me an hour to get everything working correctly from bleeding all the air out. It was a PIA both times I did it. Just when I thought I had enough coolant in the system I had to add another half gallon etc. and keep track of my mixture. I did mine with the cap off and got coolant everywhere. It would be fine then boom bubbles galore and coolant leaking all over. I ended up using three drain pans to catch what I could after it ran all over the core support. I have never had such a hassle bleeding a cooling system. Your issues with the heater and the gauge rising are identical to mine. I checked mine for about a week after the initial bleed and got air a couple times when opening the cap and had to top off the coolant once.

Was yours overflowing coolant over the coolant reservoir too?

I think your fan clutch failed thus causing the engine to over heat and loose coolant .The air that replaced the coolant can be difficult to remove. You need to slowly displace it for the closed cooling system to cache prime. Only then will you see flowing air bubbles escaping the air bleeder screw.

Originally Posted by luckydog

I think your fan clucth failed thus causing the engine to over heat and loose coolant

i thought this too especially after cooling off while moving

Is it hard to fix my fan clutch?

replace*

nope.

Originally Posted by athan12

Is it hard to fix my fan clutch?

Not really, be aware that it is reverse threaded on most if not all BMW engines, including this one.

UPDATE:

Heater is now working fine.
It doesn't overheat when on idle anymore.
No sign of coolant leakage underneath.
Coolant started coming out of the bleeder screw and saw bubbles came out. Squeezed the hoses to push bubbles out of the bleeding hole. Kept bleeding until no bubbles are visible.

I just tried bleeding it again, and it's been 30 minutes since its on idle. Temperature remained in the middle.

I'll see after I drive it though. Hopefully everythings gonna be fine

great to hear it was just a decent bleed issue.

do keep an eye on that fan clutch. when the car is running and it doesnt engage, it may overheat again. idling, the open thermostat will keep it cool enough

where can i locate my fan clutch tho

you see that silver, venty, finned almost alternator looking thing in the middle of the fan blades?

Jack Pot.


Remove the fan shroud, a couple pop rivits holding it onto the radiator support. then, using your "special tool" (i didnt, will explain later*) Hold the pully its attached to, and using your 32mm wrench, un screw the fan from the pulley (its your WP pulley btw).

THE 32MM NUT IS REVERSE THREAD. NOT "RIGHTY TIGHTY LEFTY LOOSEY" TURN WRENCH TOWARDS DRIVER SIDE

remove the fan and fan clutch and then subsequently remove the fan blades off of the fan clutch. installation is reverse of rremoval.

*I dont have the special tool. I heldp one of the 4 blts at such an angle with a pair of channel lock pliars to hold the pulley while i broke the nut loose. This is not the recommended way, nor is it usually successful. I do not suggest you use this method.

What are the symptoms of a defective fan clutch? i dont wana take it out if nothings wrong with it

fan not engaging causing over heat.

fan not unengaging

When I observe my engine. I hear a sound that turns on for like 3-5 secs then turns off. Then after an interval it goes on and off again. Is that the fan clutch?

Originally Posted by athan12

What are the symptoms of a defective fan clutch? i dont wana take it out if nothings wrong with it

A fan clutch in good condition will turn with slight resistance when cold (with the engine off of course). Kind of like if it had molasses in it.

If it has failed, it will either turn with little to no resistance or it will not turn at all. Yours likely will turn with little to no resistance. If it were locked up, then you would hear a definite roar when the engine revs go up.

Some recommending rolling up a newspaper and sticking it into the fan with the engine idling. If the fan stops, then the fan clutch is bad. It if tries to chew up the paper, then the fan clutch is good.

DISCLAIMER: I have never used this method and a little leery of it because the 20+ year old fans can become brittle and may break during the testing procedure. Others have done it with no problems.

Hope this helps.

@BMR_LVR I just noticed we have the same Year and engine

UPDATE:

I just checked my coolant level after letting it cool down(really cold), and it's at normal level.