Coolant preferences

[Noct]

Now put back in all of the drain plugs***, open the Bleeder Valve on the T-Stat housing and pour in 1.5 gals (6 Qts.) of the BMW or Zerex G-05 anti-freeze to mix with whatever is already in the block and top off the system with whatever is needed from the gal. of pure distilled water (closing the Bleeder Screw when bubbles stop). Since the system is about 3 gals and you have 1.5 gal of anti-freeze in it, topping it off with the pure distilled should give about the proper 50/50 mix.

Now with the Bleeder Screw closed, turn the heater temp to full and warm the engine to normal operating temp. Reopen the Bleeder Screw with the engine idling until any bubbles stop coming out. It may take several tries to get fully bled. It helps to have the front raised, or take it out and drive it (don't let it over heat) or let it sit overnight.

Top up the remaining half gal. of coolant with distilled water and you have a gal. of 50/50 mix for the shelf for topping up the system.
________

So after what I've tried so far, it seems like you close everything up under the car, open up the bleeder screw and the start the car... with the car off it seems like you really can't add anything even if the system is open below. I wonder how much coolant you lose through the bleeder valve as your refilling the system.

Really not sure how much Zerex to put also because of the mention of 1 gallon left in the block. I guess I should just pre-mix it all and fill-up because of that. Pisses me off, since I've gone through all this trouble and bought the good coolant I would really have liked to have drained the block. I'll pick up that wrench from Harbor Freight before I do the other car.

[Noct]

*** Torque = Radiator drain plug - 18 to 27 In/lbs , Engine block drain plug - 32 to 40 ft/lbs

Is the radiator drain plug similar looking to the block plug? I don't remember exactly what I did yesterday too well right now... but I know I undid a large hose from the bottom right side of the radiator, I think that led to the thermostat. So probably I've not done this right, and maybe I bypassed the radiator? I think I just wasn't seeing anything else on the radiator to undo.

[slofut]

*** Torque = Radiator drain plug - 18 to 27 In/lbs , Engine block drain plug - 32 to 40 ft/lbs

Is the radiator drain plug similar looking to the block plug? I don't remember exactly what I did yesterday too well right now... but I know I undid a large hose from the bottom right side of the radiator, I think that led to the thermostat. So probably I've not done this right, and maybe I bypassed the radiator? I think I just wasn't seeing anything else on the radiator to undo.

If you pulled the lower radiator hose loose to drain it, that is as good as using the radiator drain plug, so no worries there. (That hose goes to the waterpump)
if you park the car slightly nose down, you could probably get some coolant out of the block thru the lower hose again.
If it were me after spending the bucks on the zerex, I'd probably run the car a couple minutes with the lower hose off and heater set to "on" to purge a bit more water out, keep a running waterhose in the coolant reservoir to keep clean water running thru until the thermostat opens and lets go the rest of the water.
Shut the car off and let it finish draining, reattach the lower hose and pour in 1.5 gal zerex, top off with distilled water, position the car nose high, restart car and run 'til warm with cap off, coolant level will drop a bit when thermostat opens, top up again when needed, replace cap.
Run a few more minutes while warm to get to running pressure and open bleed screw a turn or so until you get spurts, when you get coolant spurting out with no air tighten the bleed screw. Done, rinse everything off with water.
Bill

[Noct]

reattach the lower hose and pour in 1.5 gal zerex, top off with distilled water

Is this done with the bleed screw open and car on?


Thanks guys. Will try this tomorrow if I can get the garden hose to reach.

[hornhospital]

Yes, but open or shut it will still work. Just works better/faster with the bleed screw open.

[BMWtyro]

Noct,

It is a 19mm hex plug located near the top of the right-side engine block directly below #6 exhaust runner (I'm guessing 6+ inches below). You have to crawl 'waaay under the car to see it and to reach it.

Jeff

[Noct]

if you park the car slightly nose down, you could probably get some coolant out of the block thru the lower hose again.
If it were me after spending the bucks on the zerex, I'd probably run the car a couple minutes with the lower hose off and heater set to "on" to purge a bit more water out, keep a running waterhose in the coolant reservoir to keep clean water running thru until the thermostat opens and lets go the rest of the water.
Shut the car off and let it finish draining, reattach the lower hose and pour in 1.5 gal zerex, top off with distilled water, position the car nose high, restart car and run 'til warm with cap off, coolant level will drop a bit when thermostat opens, top up again when needed, replace cap.
Run a few more minutes while warm to get to running pressure and open bleed screw a turn or so until you get spurts, when you get coolant spurting out with no air tighten the bleed screw. Done, rinse everything off with water.
Bill

I think I like this procedure better than getting that wrench from Harbor Freight and trying to open the block plug. May do this with my other car too. Tell me if this sounds okay though...

Say I close up the radiator hose, add just 2 gallons of distilled water and drive it around to get it up to temp. Then, get it nose down and put the hose in the reservoir (after opening the drain). This way I won't have as much water and whatever else running down my street when flushing.

[Noct]

Goddamn, it's raining here again (I have to be a little bit selfish sometimes). Will have to put this off again.

[slofut]

if you park the car slightly nose down, you could probably get some coolant out of the block thru the lower hose again.
If it were me after spending the bucks on the zerex, I'd probably run the car a couple minutes with the lower hose off and heater set to "on" to purge a bit more water out, keep a running waterhose in the coolant reservoir to keep clean water running thru until the thermostat opens and lets go the rest of the water.
Shut the car off and let it finish draining, reattach the lower hose and pour in 1.5 gal zerex, top off with distilled water, position the car nose high, restart car and run 'til warm with cap off, coolant level will drop a bit when thermostat opens, top up again when needed, replace cap.
Run a few more minutes while warm to get to running pressure and open bleed screw a turn or so until you get spurts, when you get coolant spurting out with no air tighten the bleed screw. Done, rinse everything off with water.
Bill

I think I like this procedure better than getting that wrench from Harbor Freight and trying to open the block plug. May do this with my other car too. Tell me if this sounds okay though...

Say I close up the radiator hose, add just 2 gallons of distilled water and drive it around to get it up to temp. Then, get it nose down and put the hose in the reservoir (after opening the drain). This way I won't have as much water and whatever else running down my street when flushing.

That will work fine, be careful with the hot water. Get the car up to temp with the cap off the coolant bottle so you wont have pressure to deal with, when the motor gets warm enough to open the thermostat and the gauge needle is vertical, turn the heater on full warm, nose the car down and open the drain or better yet, if you can deal with the hot water and volume, pull the bottom hose again. That should get most of the water out. And this way you wouldn't really need to run a hose in the coolant tank unless the stuff coming out is pretty cruddy. Just drain it. Although if you had the bottom hose off, you could even run a water hose in the bottom radiator neck and flush it somewhat.

[sansouci]

Hi All,
One more tip from the peanut gallery. Buy a cheapo antifreeze tester and before you totally top off the coolant tank, test what little there is. If you don't have enough for -30 degree protection (generally 50/50) add pure anti-freeze. If you are too concentrated, add more distilled water. Test again and you should be good to go.
Ken
84 6 with 125,000 miles

[Da_Hose]

No, pulling the lower hose is not as good as pulling the drain plug.

I just did this procedure and there is a good 1/2 gallon or more in the block after you pull the hoses. The entire block is still full up to at least the level of the water pump. The only other good alternative is to take your car to a shop that has a recycling machine that extracts your coolant, filters it and resets it to the correct specific gravity with fresh concentrate.

If you really want to flush the system, you need to pull the drain plug. If you consider waterless coolant, you MUST pull the drain plug and blow out everything, including the heater core.

Jose

[slofut]

No, pulling the lower hose is not as good as pulling the drain plug.

I just did this procedure and there is a good 1/2 gallon or more in the block after you pull the hoses. The entire block is still full up to at least the level of the water pump. The only other good alternative is to take your car to a shop that has a recycling machine that extracts your coolant, filters it and resets it to the correct specific gravity with fresh concentrate.

If you really want to flush the system, you need to pull the drain plug. If you consider waterless coolant, you MUST pull the drain plug and blow out everything, including the heater core.

Jose

The question I think was, is pulling the bottom hose as good as using the drain petcock. Or maybe I read it wrong, but that was the reason for my answer. I think he wasn't going to attempt the block plug either way.
Bill

[Chris Wright]

Radiator Drain Plug:

FWYI, the radiator drain plug is a large plastic (usually blue) Phillips head screw right behind the lower radiator hose. Be Careful, the plastic screw can get brittle over time. Pulling the lower radiator hose to drain the radiator instead of the drain screw is Ok, but the radiator spigot that the hose slides onto is also plastic and can be just as brittle. Remember, as Da_Hose says, pulling the lower radiator hose only drains the radiator, not the block.
______

Block Drain Plug:

You don't need any special tools from Harbor Freight, Da_Hose has an M6 and needed it for his M6. You don't.

I believe the first time I took mine out, I had a long breaker-bar to get some leverage because it was such a long reach under the car to get to it. IIRC, it is a 19mm bolt. I can't remember if I had to block up the passengers side of the car to get some room to get under or not?

Here is a photo of the block drain plug looking from under the car. The piece across the lower right corner is part of the subframe and the you can see one of the exhaust pipes at the top of the photo. The plug is in the block right below the exhaust in the center of the photo. I believe the orange thing may be an aftermarket replacement of the center drag link in the steering?

If the image does not open, here is the source: viewtopic.php?t=10590&



Here is another view more from the side with everything removed. You can see its position relative to the freeze plugs and the square casting in the side of the block:

If the image does not open, here is the source: viewtopic.php?t=6836&

[Noct]

A little nervous about having maybe broken something. When I pulled the hose, a little blue screw and washer had come loose and I didn't see where it came from. I also remember another little blue screw or some type of bolt kind of in the way when I pulled the hose.

Bill, you were correct. Nice stable by the way. I'm not attempting the block plug again with this car. I have a med size wratchet from the tool library. It wasn't going to work and I went to the store to get an extension socket. I got the reach but couldn't get it loose. And if I had I would have been nervous about getting it closed tight enough. Chris, it is good to have the other shematics on this thread anyway. Thanks.

The hose flush from the top seems a great idea to me. If the system holds 3 gal, no prob getting it all properly flushed with the car running right? I haven't looked at the schematic of the heater core yet and people keep referencing "blowing it out with air", so I guess there still might be something left to do after this. My car has major amounts of crud, lots of old leaks (and not unlikely new ones) on the underside. I suppose the way I have my wheels turned all the way when I jack the car up may also put some components in the way of the block drainplug. Off to it now guys, thanks.

[Chris Wright]

The hose flush from the top seems a great idea to me. If the system holds 3 gal, no prob getting it all properly flushed with the car running right?

If you are going to fiddle with a garden hose and try to flush the system, get a can of radiator/block flush and a Prestone "Flush 'N Fill" kit and do it right by back-flushing it. The black "Tee" installs in the middle of the heater hose that runs from the back of the cylinder head over to the heater valve. If you don't like the look of the "tee" in the hose you can use scrap hoses to instal it temporary and then replace the original hose:

http://www.prestone.com/products/print/461?popup=1

<img src="http://www.prestone.com/sites/default/p ... 1386861578">

[Noct]

This is from that link...

Back Flush

Make sure engine is cool, remove radiator cap and Flushing TEE Cap. Attach Back-Flow Preventer Coupler to Flushing TEE and water supply line (black end to tee, Yellow end to garden hose). If vehicle has no cap on the radiator, it is possible to back flush by disconnecting the upper radiator hose at the radiator.

Now it sounds like what I've seen reference to in several places, the "radiator cap" is not in fact the reservoir cap which the Autozone guy told me is what they are referring to on the coolant bottles.

As far as the details of that kit, I'll see when I get under the car again if I want to do that but it doesn't seem worth it at this point. When I was down there before I did not identify the heater core nor the tube that you've said goes to it from the block.

[hornhospital]

(1) The reservoir cap IS the radiator cap

(2) You don't "get under" the car to find the heater hose you need to tap into.

(3) open the hood. look down along the firewall beside the brake master cylinder and booster. There are hoses going to the heater valve (held to the firewall by screws) and the heater core pipes (you can only see the hoses going through the firewall, but that's what they are). ONE of those hoses goes to the block. That's where you'd put the Tee fitting; anywhere on that hose that's convenient.

You're making this a LOT harder than what it is.

[Chris Wright]

This is from that link...

Back Flush

Make sure engine is cool, remove radiator cap and Flushing TEE Cap. Attach Back-Flow Preventer Coupler to Flushing TEE and water supply line (black end to tee, Yellow end to garden hose). If vehicle has no cap on the radiator, it is possible to back flush by disconnecting the upper radiator hose at the radiator.

Now it sounds like what I've seen reference to in several places, the "radiator cap" is not in fact the reservoir cap which the Autozone guy told me is what they are referring to on the coolant bottles.

As far as the details of that kit, I'll see when I get under the car again if I want to do that but it doesn't seem worth it at this point. When I was down there before I did not identify the heater core nor the tube that you've said goes to it from the block.

Under the car? Why? The heater inlet hose is not under the car. It runs from the back of the head, across to the heater valve. It is into this hose that you cut and insert the flushing "Tee" to which you attach the garden hose using the included adapter. You remove the cap on the coolant expansion tank. The water goes into the "Tee" and back-flushes through the back of the head into the block and back through the radiator and out of the expansion tank.

The "tee" goes into the heater hose running horizontal into the heater valve at the top of this photo !! :

[jacko]

I've installed a lot of these over the years with good success. I DID have one of the "T" fittings cracked once at the intersection of the 3 legs. Just something to check from time to time. I carry a heater hose splice in my toolbox now.

[Da_Hose]

Ahhhhh ....

If it is the rad. drain plug we are talking about, then it would be the same as pulling the lower hose.

Jose

[Noct]

Thanks for the pic of the heater hose.
I did end up undoing both the radiator and block plugs. I think the block plug is a little harder to get to in the '88 than the '87 and prior models. The first time I tried it I was under the car much further for some reason. This time I had left the jack in place and did not go back that far.

After removing the block plug I added 3/4 gallon of distilled water to the reservoir and it seemed to run through right away. I wish I had added more water, but whatever. I may be replacing the radiator by the end of the year also.

Refilling seemed slow even with the bleed screw open. For some reason there was never any fluid coming out of the bleed screw. Someone told me that means the system is not full, but I will take it for a spin tomorrow and see what happens. Pretty sure I have close to 50-50 in there now. The bottle also says you can go up to 70% I think that would imply a higher pH, so perhaps that's a good thing instead of having some tap water in the system. Somehow I have to do everything the hard way!

[Chris Wright]

Refilling seemed slow even with the bleed screw open. For some reason there was never any fluid coming out of the bleed screw.

That is normal, it can be slow to refill, but you need the bleeder open and fill until coolant comes out.

Someone told me that means the system is not full,

Correct. You do know that you just open the bleeder screw a few turns and the coolant comes out of a slot in the front of the casting below the bleeder screw. You may need to remove the screw and clean out some sludge to clear the passage?

but I will take it for a spin tomorrow and see what happens.

Make sure you have coolant out of the bleeder first.

[Noct]

Funny, there didn't seem to be any sludge below the bleeder screw and it worked on my last try. So, all straight FINALLY!! Thanks guys!

[slofut]

Funny, there didn't seem to be any sludge below the bleeder screw and it worked on my last try. So, all straight FINALLY!! Thanks guys!

You're a pretty ambitious and persistent fellow to get that block plug out!
Good job!

[Noct]

Funny, there didn't seem to be any sludge below the bleeder screw and it worked on my last try. So, all straight FINALLY!! Thanks guys!

You're a pretty ambitious and persistent fellow to get that block plug out!
Good job!

Yes, thanks. It is also at least a bit of OCD, no doubt! I am pretty good at letting things go too though, as evidenced by the sight of my kitchen.