Engine Coolant plug

[jetjockey]

I'm new to doing work on these engines (E46). I've got a 2001 and I'm probably certain....that the engine coolant drain plug on the engine block has never been removed. Maranello did a coolant flush about 3.5 years ago and I had a water pump go about 2 years ago. When I did the water pump I drained the coolant, but did not drain the block as it looked pretty blue and no rust. My question is .... do you guys normally recomend to remove the block plug when doing a flush? I'm about to do another flush this spring, but I'm a little worried about that plug. Is there any chance that the threads will strip out when I try and get it out if it hasn't been removed for years?

PS. When the pump went I talked to maranello service guys about the drain plug and they said just drain the rad and refill. is there anything wrong with only draining the rad if the coolant has no rust?

[SiR]

Yes you should drain the block. the threads will be fine.
If you really want to flush it, many folks will fill/bleed"burp"/flush the whole system with distilled water a few times before the final coolant fill up. Its up to you how far you want to go.

If you dont drain the whole thing than the coolant life will be less than its rated for since its mixing with old fluid.
Im surprised they dont do a full flush.

It doesnt take much longer...

[new member]

When I had my old E46 I was certain that not a single person had ever opened that plug in the cars life. When I did it, it just turned with no problems.

Easiest way to do a flush is a garden hose trick, but it'll require you to remove your thermostat. IF you wish to do so, you need to drain the rad, then remove thermostat and stick a garden hose in the opening and wait for all the blue water to come out. Its the easiest way to do a flush, but its not really suggested as you need to remove the thermo to do so.

If you do coolant flushes on a regular basis, you can attach a water line to the block as showed on the pictures below. That way engine flushes are easy, quick and you dont get water spills all over the place.

[jetjockey]

Thanks for the pointer. I like what you've done it will make thinkgs much easier in the future. I think I will need a thermostat again anyway so I'll do it that way. When my water pump went it was the bearings which litterally blew apart. There was so much play that the metal impeller ended up rubbing on the aluminum and thew up some metal filings...I should have done a full flush back them but the recommendation from the dealer service (not Maranello this time) was that the metal filings in there didn't matter since there are no parts that it would affect. Looking back I feel stupid about not doing the full flush. I flushed out the rad as best I could. But now I'm thinking that the heater core is likely partially plugged as I'm not getting the heat that I used to. So that may be another job to consider at the same time as the flush....but will likely take me at least a couple of days in the spring when the weather is warmer. Might as well do the full system rad and all since it's all (excpet water pump) coming up on 11 years old and I've had the car since 2004...Yikes!!! guess I've been lucky so far.

[new member]

Just for reference, the pictures posted are not of my engine. I just posted them up for visual reference.