coolant change on 540i need a little help

[dbals]

I have a 95 540i and was going to change out the coolant. I know where the drain plug for the radiator is but isnt there one for the block? Can someone (maybe with bently manual) steer me in the right direction.
Thanks
-Drew

[MBXB]

Here's the thread from a few weeks back:

http://www.bimmer.info/forum/showthread.php?t=7853&highlight=M60+drain+plug

[Kalevera]

Ramon dumped a good link, but for what it's worth:

The block has two drain bolts. You'll need extensions and a swivel or swivel sockets to reach them. They're tucked up by the headers, by the block casting numbers. There are usually heat shields in the way (unless they were previously removed), so have a set of nut drivers or small sockets available to remove them.

Also, it's a messy job. Get a good catch pan under there and be ready to duck out once each bolt comes out.

best, whit

[dbals]

Thanks guys.....Ill give it a shot.

[MBXB]

whit

Think it would damage anything to wet vac the coolant out thru the lower radiator hose; leaving the reservoir cap off? Just wondered.

[Kalevera]

Nope, one of the guys I used to work with did just that/with pressure vs. vacuum. But on the engines that I've done, I've always just opened the bolts.

One thing to remember is that like engine oil, all of the coolant won't come out of the block unless it's taken apart. Case in point: drained an M52 from a 528 last week to scavenge a few parts from the block; head and oil pan were already removed. I turned the block on its side to remove the oil pickup and dumped coolant all over the place via the water jacket. The heater core also stays full of coolant unless it's blown out.

So, Jeff's process of flushing the block might actually be a better solution in the long run -- water is more efficient at cooling than any coolant (edit: uh, rather, typical automotive coolant), so adding water to the system (to dilute whatever's left in the block, partially drained or not) then emptying it as much as possible before refilling with a 50/50 water/cool blue mix might be copacetic.

best, whit

[tim s]

reservoir tank is not blocked. when i flushed my car it was blocked & was keeping the system from draining, i had to blow it out with the air compressor.
it drove me nuts trying to flush it until i found the blockage.
tim s.

[632 Regal]

Even with a couple drain pans it still gets a bit messy under there, I srarted the engine between flushes to get all the passages to flow between rinces...not to bad concidering you only do it every couple years.

[uscharalph]

reservoir tank is not blocked. when i flushed my car it was blocked & was keeping the system from draining, i had to blow it out with the air compressor.
it drove me nuts trying to flush it until i found the blockage.
tim s.
That's an infamous place for blockage.

[GS535i]

If the block drains do not cooperate, on most cars one can remove the thermostat after draining the rad - and then use a rag to seal and stuff a garden hose into the pump suction. Open the hose to flush residual out the other large rad hose: this way, the entire block is flushed. When doing this, the engine can be safely run for a few minutes, using the pump to assist. Which opening the hose goes in depends on the coolant flow path - quite obvious when the hoses are off and the starter is hit. Reverse the procedure to flush the rad.

When everything flows clear, reconnect everything - and add 50% of the coolant systems stated capacity as PURE antifreeze/coolant. ( eg two 4l jugs in a 16l system). This is important as the block remains ~ 1/2 full of water, and you need to arrive at the correct final concentration .... normally 50%.