i need to replace the coolant. on a 2004 "s" ..where do i drain it from? and would PRESTONE brand do? and are there a tricks that i should know of.

 

Do a search.

Here are the basics (the Bentley manual is helpful if you plan on doing much with maintenance):
Take the cap off the expansion tank and unclamp the lower radiator hose from under the radiator (drivers side). That will drain the coolant from the radiator and expansion tank. The engine block has a drain but it's pretty much impossible to get to. Once the coolant stops flowing from the radiator, re-attach the lower hose and fill up the coolant reservoir. If the engine is warm, the coolant will start flowing into the radiator; if not, it'll just sit in the expansion tank (thermostat closed). With the expansion tank full (and cap on), start the car and let it warm up. You can open it up if you need to add coolant but be careful of hot gases. There is a bleed valve on the upper radiator hose infront of the engine. Use a big screwdriver to loosten it and purge the air from the system. Do this until only liquid flows out.

Have someone keep an eye on the coolant temp gauge (I did mine with the cap off the reservoir by accident and the lack of pressure in the system caused the temp to go higher than normal). I followed the Bentley manual but they didn't mention anything about having the car warm so I was expecting the coolant to flow from the expansion tank to the radiator on a cold car...which it didn't. They said something about a 2nd bleed valve that would let the coolent into the radiator that I could not find (all the pics were on a Cooper). I also didn't know if I should have the cap on or not when I started the car. When fluid wasn't flowing and the temp gauge read 2/3, I turned the car off and tried again. With the cap on, everything went fine and I was able to bleed the system.

I used Prestone All Makes All Models. It's silicate free and shouldn't harm anything. I also added some Water Wetter.

This would be a great how-to for any of you who know what your doing. There really isn't any solid info on the right way to flush the coolant. I know Randy is busy so maybe someone else can do it.

 

way to go "kapps" you tha man .. you have friends in sunny south florida,
on my way to the garage,i can smell the grease already :-) yeahbaby.. minisofmiami.com

 

anyreason why u would want to do this?

 

 

Your temp probably went so high because of air in the system, not the cap. The cap with pressure helps increase the coolant's boiling point. Open the bleed valve when filling the system and it should be ok. Also turn the heater to hot on manual systems or front defrost on auto systems to flush out and bleed the heater core.

 

Cooper's have 2 bleeder screws. MCS's have 1

 

Yeah, that's what I was doing. I had the bleed screw open, full heater, and the cap off but I was getting no flow through the upper hose. I actually had the bleed screw comletely off at one point but nothing was flowing. I later assumed the problem was that the engine was cold and the thermostat was closed so no coolant was allowed to flow from the expansion tank into the system. It got a little scarry but after I shut the car off and started it again, everything started to work like I was expecting. Next time, I might just take a funnel and fill the system partially through the bleed screw.

 

Wouldn't the dealership do this for you? I just complain about having "mucky brown" coolant and my dealer flushes out my system for me.

 

Can you mix coolant? That is, can I use prestone to top off the coolant from the factory?

 

Distilled water will be ok for low surge tank levels. Only add to a level between the markers, not to the top of the tank.

 

I've mixed Prestone All Makes All Models with BMW stuff. It's silicate and Phosphate free so it should work fine.

 

See my gallery all sorts of pics of process.Good luck.Ps lifting right rear of car up gets most of coolant out.Just a little trick I learned in the process.

 

And, if you take the radiator support off, tilt the radiator towards the bottom opening all of the remaining coolant in the radiator will come out. Also, grabbing the hose from the thermostat housing forcing it as low as possible will siphon off more coolant, ditto for the water pump hose.

Draining and refilling most of the coolant is not a substitute for radiator cleaner and flush but done at least yearly will clear up the dreaded brown coolant syndrome.

 

They have two. Find the top right corner of the intercooler (closest to the driver) and look directly down. You will see a shiney 10mm head bolt. that is the second bleed screw.

 

Sure enough. Follow the heater hose from the waterpump. It attaches to a pipe with a bleedscrew. Thanks