Thermostats replaced but still over heating.

[flatland]

Hi,

Thermostats has been replaced.
I put the arrow on thermostats a bit differently than previous one. I placed it to head the sky.

I didn't fulsh the coolant, I just used the bucket to catch all the coming out coolant from the hose. (It came about half liter or more).

After replacing thermostats and getting everything back to the place, I filled as much coolant as lost while I was replacing the thermostats.

But somehow coolant level is not not going lower. Car was ok for 10 minutes or something, and then started to over heat again.

I checked the coolant level and it was the at the same level.

Can it be that there is some air that barriers circulation of coolant?
Or waterpump failure?

What can it be?

Thanks in advance.

[jamesdc4]

You need to bleed the system.

[02Pilot]

Could be a lot of things: air bubble in the system, water pump failure, blocked radiator, or collapsed hose. Air bubble is the most likely. If you don't have access to a vacuum fill device, elevate the nose of the car, turn on the heat full blast, and fill the system slowly, then bleed normally. You may need to repeat this process several times before all the air is pushed out.

[NNY528I]

you need to follow a proper bleeding procedure and that should fix your problem. What are you doing now to bleed the system?

[flatland]

I left a cap off and ran the engine. It burped quite a bit. I topped up the reservoir as the level of coolant went down. After 15m I turned the engine off and closed the cap. I will see tomorrow what happens with the car and level of coolant. I am not sure if it was right thing to top up the reservoir while engine is hot and cap was off for letting air out.

[bmwdave37]

^ that sounds like a wrong bleeding procedure.

[flatland]

^ that sounds like a wrong bleeding procedure.

heh perhaps. i am researching now.

[NNY528I]

I left a cap off and ran the engine. It burped quite a bit. I topped up the reservoir as the level of coolant went down. After 15m I turned the engine off and closed the cap. I will see tomorrow what happens with the car and level of coolant. I am not sure if it was right thing to top up the reservoir while engine is hot and cap was off for letting air out.

Yesir this is your problem, this is without question not the correct way to bleed the system. Find the right procedure there was a recent thread about it and your problems will be gone. Perhaps James can help you find it as I am horrible at traking down old threads.

[bmw chris]

May not be the one you are referring to but there is one here.

[NNY528I]

May not be the one you are referring to but there is one here.

That is not the correct procedure to follow, the car should not be started at any time in the bleed process with the cap open or any of the bleeder screws open.

[bmw chris]

Hmm, I must have missed that thread then. I bled mine using that procedure and it worked out. But it does make a bit of a mess.

[Mulepick]

The bleed screw on my 530 is right next to the fill point on the expansion tank. Open this, turn heat to hottest setting, fan to lowest. Turn ignition "on" (not "start) and add coolant/distilled water mix until flowing out bleed screw w/no bubbles. Close bleed screw, cap expansion tank, start engine, drive to normal op temp. Allow to cool, recheck, top off if needed.

[bmw chris]

The bleed screw on my 530 is right next to the fill point on the expansion tank. Open this, turn heat to hottest setting, fan to lowest. Turn ignition "on" (not "start) and add coolant/distilled water mix until flowing out bleed screw w/no bubbles. Close bleed screw, cap expansion tank, start engine, drive to normal op temp. Allow to cool, recheck, top off if needed.

There is also one next to the thermostat housing.

[jamesdc4]

Yesir this is your problem, this is without question not the correct way to bleed the system. Find the right procedure there was a recent thread about it and your problems will be gone. Perhaps James can help you find it as I am horrible at traking down old threads.

I'm trying to find your post or the one by Qsilver7 while writing recommendations for my students and installing a new antivirus program on one of my computers!!!

[Mulepick]

There is also one next to the thermostat housing.

Perhaps, but neither the Bentley manual nor myself are aware of one. At any rate, it is not involved in conducting a proper coolant system bleed.

B

[jamesdc4]

The only bleed procedure I've found so far is the one I'm familiar with that Chris already posted a link to above.

Your post and help is very much appreciated, however, you only post a partial bleed of the cooling system.
_________________________________________
http://www.bmwtips.com/tipsntricks/JC/Overheating.htm
Over Heating Check List
by Jim Cash on 2002-11-04
I would suggest checking the coolant, and making sure it is bled properly - which can be a rather involved process to do it correctly.
The basics
Cold engine
- check that coolant level is correct
- Ignition on but engine not running
- set heater temp settings to max
- set fan manual to one of the lower speeds
- start engine and within 30 seconds rev it 3-4 times up to 3000rpm
- shut off engine before end of 30 seconds (before it starts to heat)
- reset climate to normal settings
- recheck coolant and top up if necessary.
Hot engine
- take car for a run to get up to operating temp
- using caution - slowly open the bleed valve (steam and bubbles may come out)
- close as soon as you see liquid coolant without excessive bubbles.
- do not overtighten this as they are plastic threads. Just snug till it seals fully.
- after engine cools check the coolant level again and top up if necessary.
Check coolant level every few days for a few weeks and top up again if required
- repeat the Hot engine bleed process again.
If coolant keeps droping after 2-3 top ups have the system pressure tested.
If you are still getting over temps have it analysed by a dealer. The temp is controlled by the engine computer so there may be another fault.
Cheers
Jim Cash
_____________________________________
Parking on an incline or raising the front of the car, as mentioned in an earlier post, is also helpful when trying to bleed the cooling system.
Once again, I highly recommend reading through the cooling system thread I posted in post #6 above. There are lessons to be learned from other member's experience.

[NNY528I]

The only bleed procedure I've found so far is the one I'm familiar with that Chris already posted a link to above.

Thats definately not the right one, I will try to find it.


Ah how quickly we forget, just over a month ago now.

Here is the thread, including the details on proper bleeding of the cooling system.

http://forums.bimmerforums.com/forum...light=Bleeding


There doesnt seem to be an entry for bleeding in the DIY quick links but you mention updating the FAQ in the post.

[bmw chris]

Perhaps, but neither the Bentley manual nor myself are aware of one. At any rate, it is not involved in conducting a proper coolant system bleed.

B

Upper hose right next to the thermostat housing. But you are correct, its not that difficult. And when I did mine I didnt warm the engine up at all. Just burped it until was full then ran the car opening the bleeder screws alternately til no more air escaped. After that drove around the block to warm it up then let it cool off and did it again.

[flatland]

Thank so much for all the replies. OK in the morning, when the engine was cold (with outer temp around -5), I checked and filled the coolant till cold-kart level.

Now I have been trying to bleed in MY OWN WAYS and failed. I am now gonna run the engine to warm it up for sometimes, keeping the engine running, carefully loosen the bleed bolt (not the one on thermostats housing hose), let the steam go (in fact there comes a lot of air but never awaited until unter comes out), close the bleed bolt when water comes off.

I will do this now.

Wish me the luck guys, if my process will be wrong, please correct me again!

I let the engine run, temperature guage indicating 12o clock, opened the bleed bolt next to reservoir cap, after 1 minute it started to let the steam go. And again and again. It would spread the steam for ever. I closed it came back to read more thread.

NNY528I mentioned that bleeding should be done only when engine is cold.

I am totally lost. Because jamesdc4 said in the same thread this below. It says that engine should be warmed and should be running. Then I can loosen the bleed bolt? ahhhhhh iam lost lost lost. Who is right? NNY528I or JamesDC4????

-----------------------------------
This stage bleeds air from the engine, rad and fill tank.
- now warm up the engine (drive a bit if you wish)
- with engine running CAREFULLY / SLOWLY open the bleed screw. Hold a rag around the area to prevent any excess splashing. Keep the screwdriver in the slot of the bleed screw so you can close it quickly.
- you should have some air/steam escape - progressing to some bubbles of coolant.
- as soon as it progresses to the stage where you are seeing liquid coolant come out then close the bleed screw. Do not over tighten - it is all plastic threads and you can easily turn too far at which point the screw jumps back a thread and you have to re-tighten. Just make it snug with all coolant stopped.
- when the car is cold again re-check the coolant level and top up again if necessary.

Says NNY528I in here: http://forums.bimmerforums.com/forum...light=Bleeding

DO NOT OPEN THE RADIATOR CAP OR THE BLEEDER SCREWS IF THE ENGINE IS EVEN A LITTLE BIT HOT! you will ruin all your work and have to start over from the beginning of the instructions I provided above.

Hi guys,

Found this from another thread on this forum. I am now gonna try this.. I think I didn't wait long enough until coolant comes out off the screw loosened. I think that 's been the problem.

i will do this below and post you if it has workedout.

crdiscoverer
We're not an island!
Join Date: Jul 2007
Location: Costa Rica
Cars: 97 Euro 528, 78 KE30
Posts: 1,528
iTrader: (0)


My method (it works 100% of the time):

- Engine should be cold or warm (not hot). Don't start it yet.
- Put the front of the car higher than the rear (ramp, jack, hill). This will force bubbles/air up front.
- Turn on heater to max temp, and any fan speed you like (it doesn't matter).
- Open the hood, remove expansion tank cap and loosen the bleeder screw.
- Start the engine.
- Start filling the tank with coolant up to the very top, you will see that as soon as it reaches almost the neck of the tank, it will go down a bit. Add more, and repeat. Because the car is circulating the coolant around the system, you'll have to keep adding and it will keep going down for a while, be patient.
- While you're adding coolant, keep an eye on the bleeder screw (remember it should be already opened). Coolant and bubbles will start flowing out of it.
- Keep adding coolant to the tank until you only see a continuous stream of coolant coming out of the bleeder screw. It will happen at some point, don't close it before.
- When you're sure no more bubbles show up, quickly close the bleed, put the radiator cap on, check if hot air is coming out of the interior vents, unlock your OBC and check the temp (shouldn't be over 115 C on an I6, mine stays at 94 C).
- If at some point a fountain of coolant comes out from the reservoir, it means you let the engine get too hot and you need to wait for it to cool down and repeat the process.
- If you can't feel the heater working, there's still air in the system.

That's it. Do it step-by-step and you'll have a fully bled cooling system. After a few days the coolant level may go down a bit, just add to the mark in the morning when the engine is cold. An additional note: My 528i has two bleeder screws, one on top of the water pump and another just next to the reservoir. I only use the former, the other is not really necessary, keep it closed the whole time. AFAIK V8s only have one.

[cnn]

Hi,

Thermostats has been replaced.
I put the arrow on thermostats a bit differently than previous one. I placed it to head the sky.

I didn't fulsh the coolant, I just used the bucket to catch all the coming out coolant from the hose. (It came about half liter or more).

After replacing thermostats and getting everything back to the place, I filled as much coolant as lost while I was replacing the thermostats...

I wrote a cooling overhaul for my 1998 528i, very similar to your 6-cylinder 520i engine:
http://www.bimmerboard.com/forums/posts/199986

NOTE that:
- Thermostat arrow pointing to the sky is correct, that is where air is bled out.
However, I drilled a small hole in the thermostat (see the DIY). Drilling hole is an old trick, so it works very well.

- By the time your thermostat is bad, the Water Pump, Fan Clutch, Rservoir+Cap are not far behind.
Troubles are waiting for you in the near future ---> therefore do a cooling overhaul as in the DIY.

- And YES, to bleed: raise the front up about 6 inches (a sloped driveway is fine), be patient and repeat the process. And keep the HVAC setting at HOT.

HTH.

Report back what your outcome is.

[NNY528I]

Thank so much for all the replies. OK in the morning, when the engine was cold (with outer temp around -5), I checked and filled the coolant till cold-kart level.

Now I have been trying to bleed in MY OWN WAYS and failed. I am now gonna run the engine to warm it up for sometimes, keeping the engine running, carefully loosen the bleed bolt (not the one on thermostats housing hose), let the steam go (in fact there comes a lot of air but never awaited until unter comes out), close the bleed bolt when water comes off.

I will do this now.

Wish me the luck guys, if my process will be wrong, please correct me again!

I let the engine run, temperature guage indicating 12o clock, opened the bleed bolt next to reservoir cap, after 1 minute it started to let the steam go. And again and again. It would spread the steam for ever. I closed it came back to read more thread.

NNY528I mentioned that bleeding should be done only when engine is cold.

I am totally lost. Because jamesdc4 said in the same thread this below. It says that engine should be warmed and should be running. Then I can loosen the bleed bolt? ahhhhhh iam lost lost lost. Who is right? NNY528I or JamesDC4????


Says NNY528I in here: http://forums.bimmerforums.com/forum...light=Bleeding


Hi guys,

Found this from another thread on this forum. I am now gonna try this.. I think I didn't wait long enough until coolant comes out off the screw loosened. I think that 's been the problem.

i will do this below and post you if it has workedout.

Did you read the whole thread? Here are the salient points and the correct procedure,




NNY528i wrote:

you are boiling the coolant while trying to bleed (that second rush of bubbles you mention) steam expands 2000 times from liquid water so it pushes coolant out of the system leaving you with low coolant level.

you should only bleed it when it is cold. if it runs for 5 minutes the coolant will start to boil if the system is not presurised. With the car cold and NOT RUNNING, turn the key to the start position, adjuster the heater to highest heat setting then bleed the system at the bleeder screws till no air comes out. then top up the expansion tank and close up the system tight, run the car till it reaches normal operating temperature then shut it off again and let cool to ambient temperature(several hours minimum) now check the level in the expansion tank, if normal, you should be finished, if low then fill to normal level and repeat the heat to normal temp and cool off cycle until the expansion tank stabilizes, then fill the tank to the correct level and you should be good to go.


DO NOT OPEN THE RADIATOR CAP OR THE BLEEDER SCREWS IF THE ENGINE IS EVEN A LITTLE BIT HOT! you will ruin all your work and have to start over from the beginning of the instructions I provided above.

Really?
I have followed this procedure for bleeding my coolant system since I have owned the car (540 - perhaps it is slightly different for the i6s, but I would doubt that). I've never had a problem with air in the system. If you have some evidence that this procedure is incorrect, please post it up so we can get it right.

TIA

Well for starters, the procedure layed out in the bentley manual is as I presented it above, it does not include any hot engine venting. I can scan it in if you would like or you can look it up on page 170-14.

if you open the bleeder or cap when the engine is hot, the coolant at the hottest points in the system(the heads and cylinder jackets) will begin to boil, flashing coolant to steam. Coolant systems require the pressureto raise the boiling point of the coolant mixture.

This is the exact issue the OP is having, the boiling coolant is pushing out excess coolant from the system, even though the system appear to be bled, upon cooling the contracting coolant pulls coolant from the expansion tank to make up the lost coolant from the boilover. This leaves the engine partially fulled with coolant. This is the purpose of the heat and cool cycle I described and as described in the bentley manual, to draw coolant into the engine and displace any air.

I also believe this methodology is essentially the same as the BMW TIS procedure as well that also does not involve opening the screw with the engine hot.


With this response;

Thanks for your response.
I want to be sure I'm not giving out bad info., and the bleeding procedure has worked for me. Apparently I've been lucky.
No need to scan the Bentley (I have a copy).
Your argument is logical and sound, so unless someone else cares to take on the challenge, I'm changing the FAQ to reflect this information.

Thanks NNY528I!

Please follow this procedure, it is the only correct procedure per BMW and Bentley manual and it will solve your problem if you follow it exactly.



1)With the car cold and NOT RUNNING, turn the key to the start position, adjuster the heater to highest heat setting

2)Now bleed the system at the bleeder screws till no air comes out. First at the Thermostat cover then at the expansion tank.

3)Next top up the expansion tank to the cold fill level and close up the system tight.

4)Run the car till it reaches normal operating temperature then shut it off again and let cool to ambient temperature(several hours minimum)

5)Finally with the car completely cold check the level in the expansion tank, if normal, you should be finished, if low then repeat procedure from step 3 and fill to normal cold fill level and repeat the heat to normal temp and cool off cycle until the expansion tank stabilizes, then fill the tank to the correct level and you should be good to go.

DO NOT OPEN THE RADIATOR CAP OR THE BLEEDER SCREWS IF THE ENGINE IS EVEN A LITTLE BIT HOT OR RUNNING(even if cold)! you will ruin all your work and have to start over from the beginning of the instructions I provided above.

Cooling System Bleeding (I6 w/video)

[cnn]

The Bentley bleeding procedure is full of useless stuff. I have done this many times on different cars. It needs to be done with engine running, not engine off.

Just look at my DIY again:
http://www.bimmerboard.com/forums/posts/199986

1. Step #18 shows you to fill coolant through the bleed hole.
Do this with engine OFF, this gets rid of any air pocket in the UPPER Rad hose. Now close the bleeder screw:



2. Now, with FRONT end raised about 6 inches:
- Set heater to Max heat
- Run the engine until it reaches operating temp, any air pocket trapped at behind the thermostat will be expelled out into the UPPER radiator hose.
- At this time, open the bleeder screw a tiny bit: small amount of steam will escape, no worry.
- When liquid (instead of air) comes out, close the bleeder screw.
Here is the pic that shows it bleeds steam with engine RUNNING:



3. Let the car cool down for 1h or so.
You may want to repeat the process one more time and keep an eye on coolant level for one week or so.

I did this about 4 years ago and have never needed to bleed again.

PS: As I mentioned above, drilling a small tiny hole in the thermostat gets rid of the "Air lock" problem.

Hope this helps.

[flatland]

NNY528I! I have read your threads now thoroughly and won't start the engine on while doing bleeding.

Now I am gonna do your way again as the engine should be cold enough.

I have a few things to make sure.

1. Lifting up front of the car.
2. ON mode (not starting the engine)
3. Cabin heater to hottest with low fan speed
Question here: how many minutes should I be awaiting before I can open the bleeding screw? Immediately? If I open it straight up, it won't come nothing.
4. Bleed screw on thermo housing open->Bleed->close it->then bleed screw on reservoir->bleed->close it
Question: Is this right? One by one while another screw is closed??
5.Now opening the reservoir cap while other screws are closed for making coolant level topped up to cold/kalt level.
6.Close everything and start the engine up for warming it up to operating temparature.


Am I gonna do the things right?
To add my car sympthom, it won't over heat when idling, but will over heat when driven for like 5 to 10km.

[cnn]

The bleeder screw on the Reservoir is basically useless.
Trust me, use the bleeder screw on the Thermostat Housing.

[jamesdc4]

Thats definately not the right one, I will try to find it.


Ah how quickly we forget, just over a month ago now.

Here is the thread, including the details on proper bleeding of the cooling system.

http://forums.bimmerforums.com/forum...light=Bleeding


There doesnt seem to be an entry for bleeding in the DIY quick links but you mention updating the FAQ in the post.

Thank you, NNY528I. That's exactly what I was looking for. You're better at finding threads then you give yourself credit for. Also, with four kids and my two ailing parents living with me, the forgetting happens much more quickly than you can imagine.

Thank so much for all the replies. OK in the morning, when the engine was cold (with outer temp around -5), I checked and filled the coolant till cold-kart level.

Now I have been trying to bleed in MY OWN WAYS and failed. I am now gonna run the engine to warm it up for sometimes, keeping the engine running, carefully loosen the bleed bolt (not the one on thermostats housing hose), let the steam go (in fact there comes a lot of air but never awaited until unter comes out), close the bleed bolt when water comes off.

I will do this now.

Wish me the luck guys, if my process will be wrong, please correct me again!

I let the engine run, temperature guage indicating 12o clock, opened the bleed bolt next to reservoir cap, after 1 minute it started to let the steam go. And again and again. It would spread the steam for ever. I closed it came back to read more thread.

NNY528I mentioned that bleeding should be done only when engine is cold.

I am totally lost. Because jamesdc4 said in the same thread this below. It says that engine should be warmed and should be running. Then I can loosen the bleed bolt? ahhhhhh iam lost lost lost. Who is right? NNY528I or JamesDC4????


Says NNY528I in here: http://forums.bimmerforums.com/forum...light=Bleeding


Hi guys,

Found this from another thread on this forum. I am now gonna try this.. I think I didn't wait long enough until coolant comes out off the screw loosened. I think that 's been the problem.

i will do this below and post you if it has workedout.

Sorry about the confusion flatland. I'm going to place the correct bleed procedure in the E39 FAQ once I figure out which one is definitively correct.

Your argument is logical and sound, so unless someone else cares to take on the challenge, I'm changing the FAQ to reflect this information.

I wasn't expecting Cam to pipe in on the Jim Cash side of this debate.
cnn brings up the question of whether to bleed while running the engine and also the debate about bleeding while warm. I too have used Jim Cash's bleed procedure with no problems at all, so I'm on the fence about this.