Cooling system refresh hints

[ac427]

I have a coolant leak somewhere and the car has done 187k miles. So i thought a cooling system refresh might be in order.

Has anyone on here done a refresh recently?

Is there anything to look out for or hints?

[Stilt]

I have a coolant leak somewhere and the car has done 187k miles. So i thought a cooling system refresh might be in order.

Has anyone on here done a refresh recently?

Is there anything to look out for or hints?

When you say "look out for or hints," do you mean hints in terms of identifying the leak(s)?

There are only a select number of places or points where you can have a coolant leak:
- Water pump to block gasket
- Thermostat housing to #7
- Between the water pump and the thermostat housing ( #6 )

- 7 to heater core pipe ( #7 on image 2)

-Coolant temp sensor on the heater core pipe
- Seal between #10 and the water pump (14)

[ac427]

Thanks for your reply. I just meant from hints anyone who has replaced all the cooling system parts. Such as fit this part first or watch out for trapped air here.

I do have a leak in the system so i'll have a look at the places you mentioned.

I know when i changed my starter motor a couple of years back, the "F pipe" that connects to the other end of the return pipe would leak a bit if you leant on to get the starter motor bolts out.

[01SG]

If this were an e36 in question, I would implore you to get a power bleeder because that car seems to always be a headache to bleed. Never had any unusual problems with the e46 though. Just be careful with that plasticky expansion tank pipe that runs across the front of the car. I snapped that by accident once.

https://www.fcpeuro.com/products/bmw...53#description <--that one

Also, this is one area to make sure you go Genuine BMW on all of it, except maybe the radiator itself.

[ac427]

If this were an e36 in question, I would implore you to get a power bleeder because that car seems to always be a headache to bleed. Never had any unusual problems with the e46 though. Just be careful with that plasticky expansion tank pipe that runs across the front of the car. I snapped that by accident once.

https://www.fcpeuro.com/products/bmw...53#description <--that one

Also, this is one area to make sure you go Genuine BMW on all of it, except maybe the radiator itself.

Thanks very much. I had fun with that pipe when my expasion tank had a leak. They are not cheap either.

[WOLFN8TR]

Hi-Temp Silicone and Viton Oring Kit.

[WOLFN8TR]

Thanks very much. I had fun with that pipe when my expasion tank had a leak. They are not cheap either.

https://www.rogueengineering.com/Rogue-Engineering-E46-M3-Coolant-Vent-Line_p_83.html

[robgill]

This is a super helpful tool. You can use it to pull a vacuum on the cooling system an hear where your leak is coming from. Also used to refill the system with no air bubbles.

https://www.amazon.com/gp/product/B000IHK1VI/

Also, use OE parts and WOLFN8TR Orings.

[ac427]

This is a super helpful tool. You can use it to pull a vacuum on the cooling system an hear where your leak is coming from. Also used to refill the system with no air bubbles.

https://www.amazon.com/gp/product/B000IHK1VI/

Also, use OE parts and WOLFN8TR Orings.

Funnily enough, i kept the cap off of the original expansion tank with the idea of making something to pump the system up to pressure. Thank you for the link.

[bmrdvr]

I've done this on my car and to each their own on how far to go in but if there are any parts of unknown age, I would do them. All the coolant hoses, all the heater hoses, the radiator, overflow tank, overflow tank cap, sensors and of course the water pump and associated o-rings. I personally would not get an aftermarket water pump (unpopular opinion alert). I am probably the only person that had one of the steel impeller ones fail on earth but after that, I'm done with them on any of my cars and will only put in the OE stuff from BMW.

Also, I find the vacuum filling systems unnecessary on the S54 personally. For the M20? Absolutely, that engine sucks to fill but the S54 you just fill it till it pisses out the vent screw and you're done (make sure fan low, heat all the way up to open the heater loop). I've also had 3 bad Mahle-Behr radiators in a row on my 335 but my M3 does have a Nissins in it the last 50K miles with zero issues (I'll go with an OE one next as all of this shit is going to China now even Mahle and Lemforder stuff).