Draining cooling system on M635 Euro

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Anfa
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Draining cooling system on M635 Euro

Post by Anfa »

Trying to figure out how to drain the cooling system on my M635-85 (Euro). Just want to replace the coolant so do not want to take out radiator.
I can't find any drain plug on the radiator (or did I miss it?). The other idea would be to pull off a hose but that is actually far from the bottom of the radiator so would not drain properly.

Have read about a drain plug on the block but not sure the M88 has the same as M30? Could possibly see a plug at the end of the block but it is not very easy to get to using a wrench.

How do I do this in the easiest way? What did I miss?
/Anders
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Da_Hose
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Re: Draining cooling system on M635 Euro

Post by Da_Hose »

Hey there,

The M88 and S38 don't have a drain at the radiator. You have to look under the exhaust manifold, on the side of the block. There is a drain plug there. Yes, it's a pain in the butt to get at, ESPECIALLY with euro headers. Yes it will make a mess.

I suggest you start by siphoning out the fluid from the overflow tank. You can feed a hose down through the lower pipe, and get everything out of the crossover. Then unplug the hose at the radiator and siphon out everything from the pipe above the exhaust manifold. Get the siphon hose all the way to the back of that pipe. Then get a nice big catch pan, on top of plastic, with towels thrown around and pull the drain plug.

Or ... just take it to a shop and have them drain/flush if everything above sounds like too much hassle. :wink:

Jose
1987 M6 - My dream car
Anfa
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Re: Draining cooling system on M635 Euro

Post by Anfa »

Thanks, that definitely sounds like it is going to get messy...
I was really hoping I had missed something but seems to confirm what I was suspecting. That bolt is not very well positioned :-)

Does the system require bleeding after refilling? Or is it a self-bleeding system?

Just need to figure out if it is worth getting the floor in the garage all messy or if I should find someone else to do it.

Anders
wattsmonkey
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Re: Draining cooling system on M635 Euro

Post by wattsmonkey »

Hey Anfa,

It is self-bleeding, but I found that I had a big airlock when I did this job.

Do the obvious stuff on refilling: turn rad top hose round and fill the rad first.

Cheers,

Rob
"Most of it necessary; all of it enjoyable." LJKS
'84 635CSi, dogleg...itbs and supercharger????? Eaton Mess
Anfa
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Re: Draining cooling system on M635 Euro

Post by Anfa »

Thank you, then refilling should not be an issue.
Just need to make up my mind if I want to mess with this myself, or spend the efforts on making sure someone else does it properly :D
Anders
tadhg635
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Re: Draining cooling system on M635 Euro

Post by tadhg635 »

just wondering if the same procedure applies to drainage of series 1 635? nice messy job by the sound.

also I've looked through the forum for opinions on evans waterless coulant?
I've heard mixed review with many saying it is not worthwhile but i feel that as long as there are no negative effects of using it then it can only be a good thing. any views?
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MVX11V
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Re: Draining cooling system on M635 Euro

Post by MVX11V »

Apparently it's flammable at extreme temperatures which puts me off, there's enough of that finding an excuse to leak out, in the car already. Here's a test report:
http://www.norosion.com/evanstest.htm
'HAUNTED :evil: ' and playworn 1986 635 Daily.
wattsmonkey
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Re: Draining cooling system on M635 Euro

Post by wattsmonkey »

Flammable coolant that can get too hot? Is the "waterless" element petrol based????
"Most of it necessary; all of it enjoyable." LJKS
'84 635CSi, dogleg...itbs and supercharger????? Eaton Mess
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MVX11V
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Re: Draining cooling system on M635 Euro

Post by MVX11V »

'Evans offers several different iterations of their waterless coolant products. Each is 100% glycol. Some are 100% propylene glycol, and others are a mix of propylene glycol and ethylene glycol'.

Dunno, but as it's not water, it'll probably combust at some point.
'HAUNTED :evil: ' and playworn 1986 635 Daily.
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