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Coolant flush and thermostat replacement

31K views 28 replies 20 participants last post by  alwaysbored786 
#1 ·
Alright so tomorrow i am going to flush my coolant out change my thermostat and put in new coolant. I've got the 1 gal. of bmw coolant and a thermostat that has a gasket already it looks like. What else do i need and any tips for the job?? my car has about 110,000 miles on it should i flush the system with something else before putting in the new coolant just for preventative measures. Any tips or tricks to make the job go as smooth as possible would be great. Also dispossing of the coolant should i take it to auto zone or something.

thanks,
Seth
 
#4 · (Edited)
When I did my coolant change, not a drop spilled. Here's how: Get a piece of 1 1/2 inch corrugated plastic tubing, about 18~24 inches long should do. For a comparison, its the same black flexible tubing used for sump pumps. Run it up behind the steering rack boot and push until its against the engine block. It will stay in place because the area behind the steering rack boot is rather tight and holds the hose in place. Make sure you break the drain plug loose beforehand. Now reach up with one hand and slide the hose back slightly, just enough to get a thumb and finger in there to turn the drain bolt. Keep the tubing "over" the drainplug while turning. Once the drain bolt falls out, it travels down the tube and into your drainpan along with the coolant. When coolant stops draining, remove the tube, and replace the drainplug. Sure beats a mouth/face/eye/ear/nose full of coolant :) .

And yes, be kind to Ma Earth and dispose of it at an auto parts store that takes used coolant.
 
#5 ·
the #'s on my old thermo and new thermo dont match even though it isnt the bmw part number. They both look the same and are the same sizes. The spring and all that on the old one look just as new as my new one which seems good my engine is dirty.
 
#10 ·
aloha

Alright so tomorrow i am going to flush my coolant out change my thermostat and put in new coolant. I've got the 1 gal. of bmw coolant and a thermostat that has a gasket already it looks like. What else do i need and any tips for the job?? my car has about 110,000 miles on it should i flush the system with something else before putting in the new coolant just for preventative measures. Any tips or tricks to make the job go as smooth as possible would be great. Also dispossing of the coolant should i take it to auto zone or something.




thanks,
Seth
DO u know iof there is a DIY photo page for a thermostat change.
 
#11 ·
ok I did everything ok and things went smooth!!! Changed the thermostat and coolant with all bmw parts. The engine service soon light is still on...how do I get rid of it?

I ran the car through the computer and the code was to replace the thermostat. That's it...I heard soemthing like run the car for a few miles, ture or false? Thanks

I appreciate your help in advance!
 
#16 ·
I just changed my coolant today. When I was draining the radiator, I first tried turning the black plastic "nut" that the blue drain plug sits inside of. I turned it about half a turn before I realized that all I had to do was remove the blue plug. I turned the black platic nut back to the built-in stops, but does anyone know what that thing is, or if what I did will hurt anything or create leaks? Thanks.
 
#17 ·
Not to hijack but, it's such a coincidence that I was going to flush my coolant this afternoon. Put the car on a ramp, take the shield off and 1. I couldn't unscrew the blue drain plug using regular screwdriver as my screwdriver wasn't big enough :(. Do I have to use a special screwdriver? and 2. My drain plug looked different, it was definitely not a 13mm plug. I have a picture of it but don't know how to attach a picture. I got the car used so the PO must have changed it. In the middle of the plug looked like some sort of star. Is it a hex screw? :confused: Any help will be apreciated, I really want to flush my coolant and since it's getting cold outside my window of opportunity is shrinking. Thanks in advance.
 
#18 ·
You might need a bigger philips screwdriver... if you're not sure about the engine block, you can perform multiple drains of the radiator only. It'll take a lot longer, but it can be done. You'll want to drain the radiator, put the plug back in, put in a 50% mix, drive the car with the heater full on until the engine reaches normal temp. Wait for the car to cool down, drain the radiator and repeat process a couple more times. This isn't the best method, but again, if you're not sure about the engine drain block, this will allow you to get the coolant changed. Just make sure that you wait until the radiator is cool before you drain it.
 
#19 ·
in order to call it a real flush youll need to actually buy 2 gallons....

flush...
put new coolant....
drive for a week
and flush again
and add new coolant...

thats how i did it...if you flush only once you wont really flush all the old coolant..some old coolant will stay...at that mileage i would go with my method.
 
#20 ·
Is this DIY almost the same for M3's?
 
#21 ·
if you've drained the engine block and radiator, doing a coolant flush twice is just a waste of money/coolant and a hazard to the environment.

the 325i DIY is pretty good. it mentions to raise the front up, but doesn't really state why. by elevating the radiator a little higher than the engine block, it helps get air out of the system, provided your bleeder valve is next to the radiator. cars with separate expansion tanks are self bleeding as the expansion tank is located higher than the engine and radiator.

the absolute most important thing here is make sure you bleed air out of the cooling system. if you don't, air won't conduct heat well, and you can overheat your engine which could lead to blown head gaskets or other things you don't want. common symptoms of air pockets in your cooling system are:

1. heater blows cold
2. temp gauge fluctuates from middle to hot and back or just stays hot (red)
3. drastic drop in coolant level after driving

after a coolant flush, always pay extra attention to your temp gauge. immediately turn off your engine and let it cool off if you see it climb towards the red. never open the coolant cap while it is hot and under pressure. coolant is poisonous to humans and particularly animals. try to keep your pets away during this task in case they come by and try to lick up spilled coolant.

just want to pass along those safety tips for you and your car to the 1st time DIYers...

using the tubing to direct the flow of draining coolant is a brilliant idea! another possibility is to use a drain valve to replace the plug on the engine block. these drain valve plugs are sold for engine oil pans, but can be used for this application as long as the thread is the same. this allows you to screw on a hose attachment and as it screws on, opens a valve so the coolant starts to drain through the hose. just direct the hose to a collection bucket and you should be able to do this spill free.
 
#24 ·
I've never seen a DIY guide for M54 thermostat. But basically the thermostat housing and thermostat are one piece. It's electrically heated/controlled(?) so you have to disconnect the wire harness, remove hose clamps, remove hoses, then proceed to remove the thermostat housing. Of course, you want to drain coolant before all that.

See any of the E36 thermostat replacement DIYs:

http://www.bimmerdiy.com/diy/e36coolingsystem
http://www.pelicanparts.com/BMW/techarticles/E36-Thermostat/E36-Thermostat.htm
http://logun.org/thermostat.htm

But then just remember that the thermostat housing and thermostat are one piece.
 
#27 ·
on a 2002 bmw e46 the automatic transmition fluid thermostat is located under the radiator expansion tank and like a couple of other d.i.y.fers on e46 fanatics upon pulling it out [expansion tank] the top portion of the thermastat houseing popt out and snapt or broke off has any one taken the tank out without brakeing the thermastat houseing witch cost $55-$70 with tax
 
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