Coolant System Overhaul

[Gee-Lanty]

Hi all,

So I’ve decided to fix my coolant leak myself.

As the car is nearing 20 years old, the majority of parts are still original. I’ve yet to discover if the leaks are confined to the expansion tank and thermostat housing (where I’m certain I have a leak), however Ive bought a new radiator, expansion tank, thermostat housing and water pump.

My car is an automatic, the one part I cannot seem to source here is the additional thermostat at the bottom of the expansion tank which I understand is prone to breaking when removing the old tank.

Should I be worried? I can order this from the U.K. however I will not receive it for a number of weeks.

What is the worst case scenario if the old one breaks?! Any steps I could take to lessen the chances, or somehow fixing if it happens to break?

Also wondering if it’s essential to replace the o-rings to all the hoses?

Any suggestions would be greatly appreciated.

[bigwinn]

If you are careful and know when to catch it, you can stop it doing the ‘ping’ that puts it all over the garage

But for the £10 or so quid they cost plus the time to ship its well worth having one on standby

[Gee-Lanty]

Ok thanks. I have found it cheaper for the E46…item number 17111437362.

What appears to be the same thermostat for the Z4 is listed as part number 17112249366 which is also compatible with the E46 so I’m assuming it’s the same thing sold at a higher price to Z4 owners?

[Gee-Lanty]

Sorry just a quick question…

As the previous owner had used some form of stop leak liquid to seal the cooling system, I was planning on flushing the system with distilled water before commencing the job.

Just wondered if it was even necessary, given that I’m replacing almost all the components of the cooling system. Will any old coolant remain anywhere in such an undertaking?!

Please advise!

[Gee-Lanty]

Ok well I done it! It took me almost 7 hours (and lots of breaks) to change the radiator, thermostat and the expansion tank. It was intense! The water pump wasn’t leaking so I decided to leave it be for now.

Anyway I managed, bled the system and topped up the coolant, no bubbles coming out of the bleed screw. I drove with the heat on and the fan on low, the temp gauge remained stable in the middle on my 45 minute journey home, however the lower radiator hose was only luke warm when I arrived. Should it not have been as hot as the upper hose?