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73tiiDavidPA

Radiator Fluid Drain & Block Plug

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With the warm up regulator being replaced, it was of course time to change the radiator fluid.  Scope creep of course lead to replacing all the coolant hoses and now that I have access to lots of stuff, some of the brake vacuum hoses too.  To get at all this the plenums came off last night.  Never have I had the the car disassembled.  A couple of questions arose with regards to the radiator fluid though.  

 

First, how much fluid should actually drain from the car?  The owners manual and repair manual say there's something like 7 liters in the car.  Now I was able to catch most of it, some of it of course when all over the floor.  What I caught was only about 5 quarts though., with perhaps no more than a quart ending up on the cardboard I laid down to catch spillage.  I've removed all the hoses, and drained the block at the plug.  Is this normal?

 

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And on the drain plug.  I ordered some new ones from Bavarian Auto, but they certainly don't match what came off the block.  I put a new crush washer on the old plug and reused it.  I'm assuming mine is an original style that is NLA?  Any reason I should go with the newer style, longer threaded plug?

 

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Also, are there any preferences to radiator fluid?  I bought some remixed Prestone that I have on the shelf from when I started this project.  

 

 

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I've never measured the quantity coming out but 5 quarts sounds fine to me.

If the new plug fits threadwise and shoulderwise with the crush washer, I wouldn't have a problem using it.

Use BMW blue antifreeze mixed 50/50 only.

Edited by yeewiz

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I'd reuse the original plug.  The more parts that stay on the car the better, imho.  New stuff only when necessary.

 

I took the advice I read on here and used BMW BLUE coolant.  I am not sure why it makes a difference though.  Perhaps we will be enlightened in this thread.

 

New hoses makes good sense, but to save a few cents, I reused mine.  They are old, but BMW branded and seem fine.  I reused the hose clamps too, but oiled the screw bits and ran them back and forth with an electric driver to make sure they were moving smoothly.

 

Are you going to flush the block/radiator?  I skipped that step, since there was no rustiness/crud in the coolant that came out and I did not have any overheating problems.

 

Putting antifreeze in Gatorade jugs is almost dangerous!  Keep those away from children ; )

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1 hour ago, 73tiiDavidPA said:

 

Also, are there any preferences to radiator fluid?  I bought some remixed Prestone that I have on the shelf from when I started this project.  

 

I use BMW coolant, but folks will chime in that they've used Prestone for decades with no problems.  Buying pre-mixed is an expensive way to go - just get 100% coolant & add your own cheaper distilled water.

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Yeah, i use what ever coolant is available. I also use 100% and mix my own distilled water. At the end of the day its just Glycol, shouldn't matter too much between brands.

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Looks like a good job catching the old stuff 5 qts is about right with a little spillage I've always figured it's a 6 qt system give or take a bit. The BMW coolant is good stuff but good old Prestone will work fine in our cars also the blue stuff is required in newer BMW's because it's formulated to work with the plastics used in the cooling system of their newer cars, thankfully we don't have that problem.

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All good points above.  I'm still trying to figure out a way NOT to spill coolant when draining the system.   You want project creep?  Maybe someone can send you a picture of a drain cock on the block.  I drain my system at least once a year cuz I'm always taking my engine apart for some reason or other. I wouldn't waste money on BMW brand coolant.  Preston 50/50 for me.

DrainCock_sml.jpg.8dc779b224ba7f311c42808aada99df3.jpg

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Paul, looking at your picture reminded me that theirs a company that make valves for oil pans that you can fit a hose too for draining on cars that have drain plugs that are over the cross member, most oil pans have straight cut threads and use a crush washer just like your block drain if you could fit one of those you could catch  all of your coolant easy-peasy .EZ-106_1500__79741.1510432521.1280.1280.

Edited by Son of Marty

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42 minutes ago, Son of Marty said:

theirs a company that make valves for oil pans that you can fit a hose too

 

Thanks for that.  I only have the rad drain valve.  I haven't done the block valve yet, as others have.  I hate spillage!  Especially when you get it on your head.  :o

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23 hours ago, '76mintgrün'02 said:

I'd reuse the original plug.  The more parts that stay on the car the better, imho.  New stuff only when necessary.

 

Yes, I cleaned the old plug and used a new crush washer.  Agree about keeping it original.  

 

20 hours ago, PaulTWinterton said:

All good points above.  I'm still trying to figure out a way NOT to spill coolant when draining the system.   You want project creep? 

 

Perhaps another day... trying to keep away from creep.  I have two shows to go to this fall and only limited time in the garage.  

 

 

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The block is relatively shallow behind the block drain-

if anyone tries to use it I would test it to be sure

it doesn't bottom on the inside of the cylinder wall...

 

t

L7

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