Cooling System

Hey I'm here its just been christmas and all .Mine jumps to 107c after idling 30sec or so not 20min.But other wise same operation .Could bypass tstat all together with an inline type and see what happens?

Originally Posted by dolfan13

Hey I'm here its just been christmas and all .Mine jumps to 107c after idling 30sec or so not 20min.But other wise same operation .Could bypass tstat all together with an inline type and see what happens?

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..

Originally Posted by dolfan13

Hey I'm here its just been christmas and all .Mine jumps to 107c after idling 30sec or so not 20min.But other wise same operation .Could bypass tstat all together with an inline type and see what happens?

Air in the system... You've got a leak somewhere or everywhere lol

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!

Originally Posted by SFbay

Nice. Finally ppl started paying attention!! It's number one problem to discuss!

Sure is, so I just got my lazy arse out there and plugged in INPA.. I am getting a tstat error of 279c, but I don't know how to figure out what these mean, any ideas? Thanks!

Originally Posted by cmpcpro

Sure is, so I just got my lazy arse out there and plugged in INPA.. I am getting a tstat error of 279c, but I don't know how to figure out what these mean, any ideas? Thanks!

Tstat error bc you disconnected it lots of times. It's okay just erase errors...
It shows that it cannot see the boiler

Ah I see, well I have some other codes I'd love to figure out, any ideas on a code list for INPA?

Originally Posted by cmpcpro

Ah I see, well I have some other codes I'd love to figure out, any ideas on a code list for INPA?

Inpa usually explains all errors pretty good. What version are you running?

Originally Posted by SFbay

Inpa usually explains all errors pretty good. What version are you running?

Not sure, came with my cable, ncs expert and a whole bunch of other programs, was from the ebay guy everyone on here uses, I probably just don't know how to use it right.. Anyway,

I went and spent $160 on two hoses, two sensors and a bottle of coolant, that's wholesale by the way.. I started thinking, that one line on the top back of the expansion tank, it has a little needle in it, and it goes to the engine.. I bet if that was messed up the system wouldn't bleed or operate correctly.. I called my guy at the dealer, and my cost is $58.. probably double that regularly but I am going to replace that one too.. if no luck, I will replace the water pump with the metal one and do the heater hose linse.. I wanted to do them now but they have to order them.

The hose with the must be a check valve.Probably wont let coolant out of expansion tank back to heads.I had a leak on that hose at the plastic tee or y it had fell apart lol.I replaced it about six months ago.

So these systems have a temp sensor on both sides of the tstat?If so if one was reading wrong the DME would know by comparing the 2?

After searching the temp sensor in the lower radiator hose it's called the fan switch?My fan never seems to run even at 107c.What temp should fan run seems like 107c to keep down climbing temps.

I bought all new sensors with hoses, will let you know progress tonight.

Originally Posted by cmpcpro

I bought all new sensors with hoses, will let you know progress tonight.

Guess what? Checked my car and its not going down at 105. Month ago it worked like a champ!!
Now imagine how many ppl run their cars at 108-110C this will explain coolant pipe issues etc.

Originally Posted by dolfan13

After searching the temp sensor in the lower radiator hose it's called the fan switch?My fan never seems to run even at 107c.What temp should fan run seems like 107c to keep down climbing temps.

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

Originally Posted by 745iguy

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

It's more about what temp it shows.
Fan won't cool it down if radiator is cold. And it's cold that's why there is no sense spinning the aux fan wasting power.
Fan will kick in at 66-70 lower hose.
Simple test: shut down your car, wait 5 mins and start it- the fan will be spinning for some seconds until lower hose cools down

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..

Originally Posted by SFbay

It's more about what temp it shows.
Fan won't cool it down if radiator is cold. And it's cold that's why there is no sense spinning the aux fan wasting power.
Fan will kick in at 66-70 lower hose.
Simple test: shut down your car, wait 5 mins and start it- the fan will be spinning for some seconds until lower hose cools down

So either way that means we need a cooler tstat also? Is the metal impeller wp more efficient other than not having a plastic impeller? Just trying to think of all of what i would need to come up with,and if its worth the time and effort figuring it out for a car that is almost destined to fail by its manufacturer.
Edit added: Dont get me wrong i love the car even as old as it is. But still i definitely want to keep the car but also want to have an idea of what to do before it happens to my car.

Originally Posted by 745iguy

So either way that means we need a cooler tstat also? Is the metal impeller wp more efficient other than not having a plastic impeller? Just trying to think of all of what i would need to come up with,and if its worth the time and effort figuring it out for a car that is almost destined to fail by its manufacturer.
Edit added: Dont get me wrong i love the car even as old as it is. But still i definitely want to keep the car but also want to have an idea of what to do before it happens to my car.

I've been working on it for 2 weeks already and I'm almost done with 92C tstat!!!! Will be testing very soon. At least it's working in my boiling pan!!!)
If it works good, it would mean N62 will last for a while without all crazy leaks and air in the system!!
Also I already tested my car without tstat and it actually worked pretty well at 70C and 85 max! No problem with the air or anything, but of course the aux fan was on almost all the time bc lower hose was 70C all the time.
But my car ran great and very quick!
Did you notice that at 105-108 your car becomes slow as a dog??? Also tranny shifts weird??
Wish me good luck with tomorrow installation and testing!!!
You know what I like about N62???
My friend yesterday screwed his coolant pipe seal and his car ran without coolant 10mls!!!!
Guess what? Head gasket is alive and all is good!!! These engines would be the most realiable engines in bmw history if not 105C tstat!

Originally Posted by SFbay

I've been working on it for 2 weeks already and I'm almost done with 92C tstat!!!! Will be testing very soon. At least it's working in my boiling pan!!!)
If it works good, it would mean N62 will last for a while without all crazy leaks and air in the system!!
Also I already tested my car without tstat and it actually worked pretty well at 70C and 85 max! No problem with the air or anything, but of course the aux fan was on almost all the time bc lower hose was 70C all the time.
But my car ran great and very quick!
Did you notice that at 105-108 your car becomes slow as a dog??? Also tranny shifts weird??
Wish me good luck with tomorrow installation and testing!!!
You know what I like about N62???
My friend yesterday screwed his coolant pipe seal and his car ran without coolant 10mls!!!!
Guess what? Head gasket is alive and all is good!!! These engines would be the most realiable engines in bmw history if not 105C tstat!

the reason i replaced my exp tank:
pulled up at wal mart low coolant? ...
look under hook coolant pouring out of the side with some steam....
****.. grab what i went there for, drove me and my wife home about 5mls and ordered one and some bmw coolant got there in a couple days replaced it, then i started replacing all the hoses in the system.
hottest ive noted on the car was 102 so far, and that was after a highway run and idling shortly after.
Interesting about the tstat, makes me wonder if it should just be gutted and left that way.
if your tstat works, you could sign me up for one good luck man

Originally Posted by 745iguy

the reason i replaced my exp tank:
pulled up at wal mart low coolant? ...
look under hook coolant pouring out of the side with some steam....
****.. grab what i went there for, drove me and my wife home about 5mls and ordered one and some bmw coolant got there in a couple days replaced it, then i started replacing all the hoses in the system.
hottest ive noted on the car was 102 so far, and that was after a highway run and idling shortly after.
Interesting about the tstat, makes me wonder if it should just be gutted and left that way.
if your tstat works, you could sign me up for one good luck man

You replaced all hoses?? What about that heater return hose which is under intake!??
So now your aux fan kicks in once higher than 103??

Look at my masterpiece!
You can see magical 95C

Originally Posted by SFbay

Look at my masterpiece!
You can see magical 95C

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?

Originally Posted by cmpcpro

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?

92/98 it's impossible for n62 bc tstat won't even move at 100C only if DME opens it up all the time.
I'm assuming hoses are the culprit, probably not head gasket but even 102 is a lot...
I noticed my car runs 105 all the time, so I vented it and its back to normal 103-105 but it got air from somewhere. Also noticed a little residue on upper hose, so will replace it tomorrow. Bmw recommends new coolant hoses every 3-4 yrs, this is how long it lasts at this high temp!
Lets see how my retrofit will work, but I spent 300$ already for testing 4 different tstats.... Lets see it's almost there, just need some tweaks. If I get 98 the hottest that would be awesome.

Look this is oem tstat
It's 99,6 C did not even move mm!
N62 will run at 92C which means bypassing radiator circuit only in Alaska