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Cooling System

77K views 990 replies 33 participants last post by  bmoneyg 
#1 ·
Hey all, if anyone read my 5 page saga on cooling, sorry for the long read! Anyway, I have a new tstat and coolant and it's working fine. Thermostat is now opening at 105 every single time, even after running for 30min.. all is well, however if I sit in traffic for an extra ordinary long time, like let it idle for 15 min, it will start to climb to 107, but will drop back to 105 when moving, and then drop back down to 102/103.. then driving and stop and go it will run to 105, back to 102/103 and so on, so I know the tstat is opening correctly, but it seems something is not working 100% if it's getting a little too hot idling for a long time, keep in mind this is after driving for 30-40min and then idling for about 15min.. good thing is it's not going to 108 like before.. I know my aux pump is going out, I read other reports on here of others having the same noise mine is making and replacing it resolved it, so I bought one from the dealer and will redrain and replace, but that should have nothing to do with idling..

Also when I drain the coolant and start my car after refilling the water pump makes a really bad loud noise for about 30sec until it evidently gets water inside. I noticed it did that this morning after sitting over night.. I am wondering if my pump could be going, it's got 50k on it, but I don't want to replace stuff thats not bad, and I am wondering if there is something else or another reason that would happen..

Any ideas would be great, thanks!
 
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#2 · (Edited)
Not that easy dude;) saga is not over;) and believe me you're not the only one:
Lots of ppl don't bother looking at their temp sensor until too late.
107 and 108 is not a big difference;)
In summer you'll see 110-112C
Bubbles are getting when idling from somewhere the question is from where?
If you remove tstat element from housing your car will run bubbles free, try it.

Look what I found:

My friends dad had his 2007 750iL added with Evans. He would show me that after hard driving when the car is a full operating temp, he opened the pressure cap and there was no pressure.

It was pretty amazing, I was wanting to add this to my car, but in China, it cost about 4000RMB to have it done to his 750. I would guess the idiot will charge me around 2500rmb the least if I wanted it done to my 530. Therefore, I will be sticking with my annual coolant change plus a bottle of redline Water Wetter.

A lot of drivers of newer premium cars have added Evans product in my area, and all feedback was positive.
 
#3 · (Edited)
Well new data:

I replaced the aux water pump, sound is completely gone.. can't even here this pump run.. the old one if shook could hear the pump in side going from side to side.. I added coolant/distilled watter and a little more water wetter, and well same thing.. almost even quicker this time, though may not.. If I drive without stopping alot the car will run at 102 whole time.. when I start coming to start and stop car runs at 105c, back down to 103, but if I sit for a while it will climb to 106/107 and if I move it goes back down to 105, then while driving I get 105 to 102/3 again.. If I turn on the heater I get the same thing.. temp drops to about 99 for a minute, then back up to 105, and 103 etc, if stopped for a while, 106/107.. drive again, 105, to 103.. I really think my fan isn't coming on right.. also I haven't checked lately but when my tstat opens at 105 the lower hose was only at 40 something, though I havent checked since new tstat..

Even newer data:

Okay, well since replacing the aux pump and the coolant I lost while doing it, the car has gotten worse. It's heating up quicker, though it's def. letting the tstat open at 105, as it drops to 103 everytime, and will do it how ever long you drive, until you stop. When stopping it will start to climb. Also, new pump is alot quieter but I turned the motor off and pump on and it is making the same noise, so there must be air in the system.. Now, I just filled it, so it may need time to work it's way out, it may be mad because I didn't drain entire system but just whatever came out when dissconnecting line to aux water pump, though I did fill, turn aux pump on and fill again.. I am thinking one of the lines are sucking in air, but not leaking, possibly the upper hose as it's the only one I have moved since doing this change.. I wish people on this board had more technical information rather than stereo knoledge, but for now it seems like it's just me and you SFBay..

When it was running very good today, before I replaced the aux pump, the only time I was able to get it to go past 105 was when I turned the heater off, it jumped up, then went back to 105, and then worked correctly, so maybe it is the upper radiator hose, maybe it got messed up being half on for too long..
 
#4 · (Edited)
That's nice you have your own point of view and keep repeating my mistakes. How much money wasted already???
Once again when it's idling your tstat isn't opening, that's why it climbs to 107C++, it was my saga and nobody gave a s#%t here. I'm trying to help you not to waste time and money. I also replaced aux water pump 150$!!!
All f useless!!!!
What I recommend you is to:
Bc it's self bleeding it should bleed the air out automatically.
Since it can suck air only from higher points its upper hoses and heater return hose under intake.
Replace all hoses first!!! If no help
bypass the heater core,
if no help then screw it....
Or go to the dealer and ask them to diagnose cooling system, who knows they might find smth if there is smth.

Ppl here except Keif, Wilson and some few others know only about wheels and CPO warranties and don't really contribute anything... Look nobody else here cares about your saga;)
you think creating more threads will attract more professionals, will not bc there are no pros here;))
 
#6 · (Edited)
Yeah, it's really a shame, because the E46 people are super technical, and that was the first BMW I owned, so I thought great, these BMW guys really do know their cars.. then I went to the S class MB and they were technical, but not like the E46 and I figure they much be rich and just bring to the dealer.. then I came here lol.. I don't know what to think.. under a handful of people know alot, the rest know nothing..

Seeing how I replaced the aux pump and it actually got worse I think I am going to need to buy the upper hose first.. that will be my first try.. to be honest SFBay, you have been great, and I thank you, but I am dumping hundreds in this car, nobody knows anything about it, just that it runs super hot and kills itself, it's dropping in value.. I think now that we know it's not head gasket I may just dump it.. I mean, it's not overheating, so if I fix it and keep it, for what, just to let the 105c kill it? I will probably take a 3k or so loss.. but I don't know what else to do.. not sure it's worth fixing with this horrible hot running engine.. and you can tell this engine doesn't even want to run this hot naturally because it cools down to 95c in 5 minutes or less of being off..

Also, when I turned the heater on the aux pump started ok and then started making that noise, even before the enigne was on, so it may be the upper hose..
 
#5 ·
Why dont you start with the basics. Pressure test the system for leaks. The testers are not that expensive, but you will have to buy the correct adaptor for the cap. This will eliminate any doubt about any leaks. Secondly take the belt off of the water pump and wiggle the pulley on the pump for any play. There shouldn't be any and if there is your pump is going up.
 
#7 ·
Try hoses and heater bypass!!
its not expensive, and honestly I also wanna know the result, really curious if I made a mistake selling it that cheap just bc of bloody hoses.
One more thing: one 760i guy here replaced all his hoses bc all of them were sipping. It's possible bc old hoses have old orings in it, you can actually just replace those orings to save some $$$.
I kinda got tired and sold my car:(
I did leak pressure test and it all came out good....
 
#8 ·
Yeah, I will have to do hoses.. If I let the car sit for a while and bubbles go away the new aux pump sounds good.. but whatever is causing the tstat not to open at idle only is obviously air from somewhere when the engine is on, as if I run pump a long time after car has sit without engine on it's fine, with engine on it starts to suck air..
 
#10 ·
I think you can turn on the aux water pump using inpa with engine off and ignition on also
 
#11 ·
The tstat opens just fine until I am driving for a while and then stop.. so I believe one of the hoses is sucking in air when engine is running.. like SFBay said, top rad hose and heater hose behind engine are the highest, so I am going to try replacing the upper hose.. I may even replace the expansion tank just for maint. while I do it..
 
#14 ·
Well speaking of bleeding, lastnight I took the car on the freeway and really ran her, harder than I ever have, not only did I completely get rid of the tapping lifter noise I was having but I heated car up this morning, ran and cooled down and finally coolant was much lower, so obviously got some air out.. I topped off and will continue
 
#15 · (Edited)
It's impossible to ruin waterpump this way;) I think your waterpump is on one leg!

Interesting: a guy who bought my car called me and said he replaced the heater core and problem with bubbles is gone now! He said the heater core was really bad- though I didn't smell anything that bad, but may be a little but I thought it was dust smth. And honestly I almost removed the dashboard but could not finish -too much work.
So....
Leaky heater core or any leak lowers the coolant pressure- therefore it starts boiling inside at 105C causing tstat not to open!!!
Problem solved!
Don't even think driving bmw with a coolant leak!! It's not just a leak its a pressure loss in the system which is almost equal to half open coolant cap.
Imagine 200psi oem spec and 100 with the leak! Other cars have 85-90C tstats and its okay to have a leak bc it won't ruin the system that much. Thanks again to 105C tstat;)
 
#17 ·
It's impossible to ruin waterpump this way;) I think your waterpump is on one leg!

Interesting: a guy who bought my car called me and said he replaced the heater core and problem with bubbles is gone now! He said the heater core was really bad- though I didn't smell anything that bad, but may be a little but I thought it was dust smth. And honestly I almost removed the dashboard but could not finish -too much work.
So....
Leaky heater core or any leak lowers the coolant pressure- therefore it starts boiling inside at 105C causing tstat not to open!!!
Problem solved!
Don't even think driving bmw with a coolant leak!! It's not just a leak its a pressure loss in the system which is almost equal to half open coolant cap.
Imagine 200psi oem spec and 100 with the leak! Other cars have 85-90C tstats and its okay to have a leak bc it won't ruin the system that much. Thanks again to 105C tstat;)
Makes sense but why would it only happen at idle? That I can't figure.. maybe I should switch over to that Evans NPG stuff and have no pressure.. I bet that would solve the issue, but seriously, there has to be some serious air in this engine or soemthing because everytime it cools the water pump makes a bad noise for 30sec then goes away instantly.. I am thinking about letting it cool a little and taking off the sensor on top of the water pump and see if any air comes out or if it's empty then I'll fill..
 
#16 · (Edited)
Just to prove that n62 is a real time cooling bomb! Yes it's a real disaster which will kill all the gaskets including engine and tranny and front suspension!!!!! Bmw made it to last 3-5 yrs otherwise very soon you need to do this:

http://youtu.be/F_gjFZJbAoE

So this what we are getting from 105C engineering!
In other words every single point of cooling system plus they don't even want us to know if we're running hot!:

Water pump weep holes (all models)
Coolant tank glued joints (all models)
Radiator crimp joints, Between aluminum core and side tanks (all models)
Thermostat covers (most common plastic Thermostat covers)
Coolant temperature switch (replace switch)
Coolant hose quick connects "O" rings (all late models)
Coolant leaking at heater valves and hoses entering the fire wall to the heater core.

Ps. The only thing I must admire is how good the engines and trannies are built so they can sustain all that heat!!!
Seriously if temp was 90-95C it would last really really long time.
Well.. bmw introduced 105C V8 and V12 design in year 2000 and they pumped their profits significantly!!
I'm still working on 95C thermostat retrofit and that's great that nobody cares about it here;)
 
#985 ·
BMW rear engine block coolant passage cover



I recently replaced my valley pan coolant pipe on my 2002 e65, but now I seem to have a leak from the rear of the engine. I suspect it is the rear engine block coolant passage cover. Do you know how many hours I am looking at to remove and replace the transmission? I have read TIS and understand all the work involved. Just trying to get a handle on the hours involved. Thanks in advance!
 
#25 ·
TIS says there is a plug on the block by steering shaft.. I know system is self bleeding, and I know it does, because after about three hot and colds it went down a little, but if I have a big air pocket somewhere, it may not get that.. just trying to figure out why water pump now has no water when car starts, when it obviously did before.. makes me thing, air pocket.. who knows.. going to replace upper hose tomorrow, maybe more, maybe expansion, and going to go completely by the book on filling, and we'll see how it goes.
 
#27 · (Edited)
Then you my friend have the same exact problem, so something is broken on yours too, also killing your aux water pump prematurely.

I just went down to the dealer and spent $160 on a new upper and lower hoses and new sensors and a bottle of coolant. The upper hose was $178 reg.. my cost $71.. don't even want to know what this stuff would cost retail..
 
#29 · (Edited)
Nice. Finally ppl started paying attention!! It's number one problem to discuss!
Once again for everyone here:
1)If your engine goes higher than 105C when idling- you've got air bc of the coolant leak
2) When it's 105C aux fan should be spinning to lower the temp to 103C
3) running higher than 105C will kill your engine gaskets, valve stems, water cooled alternator and tranny prematurely, causing tons of oil leaks etc. will also raise your coolant pressure which will lead to expansion tank explosions etc. also will cause detonation therefore loss of power and horrible mpg!
 
#40 ·
I wonder what the voltage needs to be read at the fan switch to make it come on, and if there is a way to modify it so the fan comes on earlier than it is supposed to. Would be an interesting mod to make these cars run cooler so long as it doesnt trigger emissions MILs
 
#42 ·
SFBay your car is climbing to 108 now too? So you bought another car and its doing the same thing? Obviously we've hit on something here.. I have spent hundreds, in cash on this now.. I went all out today, figured at the very least it needs to be done for maint. I bought a new expansion tank, new sensors, new upper and lower hose, and I bought a new hose for the top back expansion tank fitting, it goes to both heads under the intake.. I have to take off the TB to get to them, so I bought a TB gasket too.. Only hoses that will remain are the one on top of radiator, the one on bottom of expansion going to water pump and heater hoses.. I have brand new tstat, aux water pump, all this I bought in the last couple days.. all from dealer. If after all of this we still have issue, then I am really lost..
 
#48 ·
Looks great man!! What did you use? What throws me, is the guy above, replaces his hose and his car wont run hotter than 102.. Paper and a few others won't run hotter than 92/98.. I don't understand this.. is it just on the little lines running coolant or is their tstat opening early for some reason? How hot does your car get now? 108 and back down?
 
#52 ·
this was right after a highway run and some city driving, taken right after i parked.

no i actually didnt replace heater hoses, nothing after that duo valve, only things i didnt replace
 

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#53 ·
ps wth is that 6 degree thing? that cannot possibly be correct.
 
#55 · (Edited)
If you step on gas dme opens up tstat fully plus your waterpump is on its max, so what's your question??
I removed tstat and it's equal to full open mode almost so my temp never went higher than 66! while driving.
Also tstat will open on its own when you keep high rpms: even with air in the system it will open tstat bc of too much flow.
 
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