Coolant questions

Christopher

Christopher

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I need to replace my leaking radiator.

Can anyone tell me the coolant capacity, and best mix for coolant / water, along with the best way to bleed the system ?
 
Hi Christopher, from memory it is 12 litres. I would use 50/50 - less water the better for corrosion but less heat transfer. To bleed it make sure the heating is on inside the car, i tend to fill it litre by litre so i have an idea how much 'space' is left. I try and have the car nose high so the air bleeds to the top of the thermostat housing where the bleed nipple is. then run the car and make sure the heater is blowing hot. I would then occasionally undo the bleed valve again to make sure the air is all gone.
 
Thanks - so am i right in thinking that the resevoir cap is left off, and then top up as necessary, and then open the bleed screw when the car is at normal temperature ?
 
yes leave the bleed screw open and start filling. Then close the screw when fluid is coming out consistently with no bubbles. Then run car with a airly fullreservoir/header tank for a bit with heater on. Let it cool and top up and open the bleed again. She prob wont take 12 litres as there will be some left in the block heater etc but should get close.
 
30csl said:
yes leave the bleed screw open and start filling. Then close the screw when fluid is coming out consistently with no bubbles. Then run car with a airly fullreservoir/header tank for a bit with heater on. Let it cool and top up and open the bleed again. She prob wont take 12 litres as there will be some left in the block heater etc but should get close.
Click to expand...

this last point is crucial, please remove the old coolant from the block, it only takes a second to remove the hexagonal plug (passenger side - rear part of the block)
it is 12 liters yes
use 50/50
 
Drilling a hole in the thermostat at 12:00 position works well. Also you can remove the small hose at the coolant reservoir and attach another in it's place. Hold the hose from the radiator up in the air and gently blow into the attached hose until coolant comes up and just out of the radiator hose, put your finger over it when it does and then reattach, this gets all the air out.
 
Thanks DQ - is the plug LH or RHS on the block (my passenger side is the other to yours ...)

Steve - does the drilled hole in the thermostat dispense with the need to bleed (i guess any air could pass though it) ?
 
Hey Christopher - on our RHS cars the drain in the block is on driver's side of the bloke which faces the ground - bolt is pretty obvious once under the car - jacking front end up will help with bleeding. Im not sure about the hole - i thought that was to aid with cooling but guess it would help with the initial bleeding? You still want to bleed it the normal way though i imagine and i personally have never drilled a hole in a thermostat.
 
Yes it basically self bleeds, I did it on mine and have never had an air bubble/overheat issue, and I live in a very hot climate.

Christopher said:
Steve - does the drilled hole in the thermostat dispense with the need to bleed (i guess any air could pass though it) ?
Click to expand...
 
I'll chime in with a couple additional things.

You should drain the block by taking the bleeder bolt out of the right side of the block. That's as above.

Someone should have said if it's 17mm or 19mm but if you've got one wrench you've got the other.

When the bolt comes out you will be showered with coolant if you're under the car. It is possible (on my LHD) to take the bolt out from above once you know where it is. Therefore don't do it when the engine is hot or you may be scalded from above or below.

AND... once the bolt comes out it's not unusual for nothing to come out... WTF... it's because the bolt is pretty much at the low point of the cooling jacket and can get sealed up with "gunk" (technical term). If that happens, stick a coat hanger wire in there and wobble it around to dislodge as much of the gunk as you can. This will leave you thinking that the rest of the block may be likewise gunked up, but there's little to do short of a fairly extensive disassembly. There are products which profess to be able to dissolve the gunk... but you'll never know and I don't bother with them. A new radiator and new coolant, drilled tstat, worked wonders on my '73 but the old rad had a hole in it.

Original copper radiators can be patched, usually. If a later aluminum core/plastic tanks version leaks, throw it away.
 
I regularly use Steve's two hose procedure to bleed my system.

As to the drain plug not yielding drainage, I had this problem and worked from the outside to bust through the blockage. I tried the coat hanger, a small screw driver, and several other items in the hopes of making a small hole. I was concerned about getting to rough with it, however, because I didn't want the crap blocking the drain hole to become dislodged inside my engine. I ultimately succeeded using small engraving bit on a dremel to carve a hole in the crap in my engine, and left it to drain slowly. Then filled with water and drained a few more times. I did not attempt to use anything that I might have to pour inside the system.
 
I heard of putting a dishwashing machine tablet in the system for a couple days. The tablets are designed to break up mineral deposits. I've never done it. Just read about.
 
bfeng said:
I heard of putting a dishwashing machine tablet in the system for a couple days. The tablets are designed to break up mineral deposits. I've never done it. Just read about.
Click to expand...

I have heard the same thing. For that matter, there are plenty of corrosion removers available from lemon juice, vinegar, lime away, coffee maker cleaner , denture cleanser and naval jelly. That said, several caveats come to mind.

Unless you are a chemist, using an aftermarket coolant flush product probably makes more sense than using a dish washing formulation. Different brands probably use different formulations and even the same brand may be blended for different regions, where water is known to be particularly hard or soft. Consider also the amount of surfactants and sudsing that could occur. Water pumps generally do not take kindly to cavitation. A related concern might be the concentration of the "unknown" formula. How harsh is too harsh?

Equally important, not all aluminum is considered "dishwasher safe." This may be mostly for cosmetic reasons. The E30 engine cooling system uses substantial amounts of aluminum.

For all of these unknowns, I would be inclined to use something specifically marketed (intended) for the task. Using an original 40+ year-old radiator and heater core makes some of us tread more conservatively than we once were. Radiator flush may tend to unmask any weakness in a compromised cooling system. This could be a good thing or a not-so-good-thing. Depending upon who is asked, flush may also weaken a marginal system, that might otherwise remain functional. It is obviously good to discover a cooling system problem - sooner rather than later. However, by that logic it would always be better to replace radiators (sight unseen) every three decades - as opposed to four or five. Or at least use a sacrificial zinc annode underneath the pressure cap. :eek:



More on the wonderment of flushing? http://www.sancarlosradiator.com/VoltageDrop/flush.htm



Not an endorsement, but one suspects it is probably Wurth considering.
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anodeassortment.jpg
 
Flush is good, side drain plug is good, thermostat drilling is what I would consider critical. In the lives of my previous BMW's (probably because I'm a hack) no matter what I did the temp gauge would rise and fall in traffic (rise when stopped/fall when moving) :-). Since I have drilled my thermostats I have not had that problem, I think it's critical in keeping the head cool.
 
Peter C, you said your temp gage will "rise when stopped/fall when moving" and endorsed drilling the tstat.

The stated symptom is typical of a radiator with insufficient airflow and the usual suspects are the fan clutch or fan itself, maybe a fan shroud can help.

Drilling the tstat is simply to help bleed the cooling system. One hack to another, why do you consider drilling the tstat to be of critical importance?
 
To the best of my limited knowledge, older Whaler and Behr M30 thermostats did not have an integrated bleed hole. Modifying them with a small bleed hole, as Steve mentions, has been done by many since the cars were new. The down side of this modification might be if the hole is too big or if there were too many holes, since this might interfere with the thermostat's efficiency and preventing the engine from reaching operating temperature - as quickly as possible. On the up side, big holes will no doubt prevent air bubbles - and they may also forestall overheating - on a defective thermostat (more on this below).

Some newer thermostats, for newer models (e.g., Ford, Toyota and Mini) have integrated bleed holes. Stant describes use "bleed notches, check valves, and other methods to assist in releasing air from the cooling system."

Toyota has included a "jiggle valve" that evidently permits the passage of air when the system has reduced pressure, but seals the hole to maintain the thermostat's working efficiency. No idea whether Behr or Whaler adopted a similar feature on newer M30 thermostats.



Bubbles flow up or down?
e89abd99-5d3d-4e9e-ab8d-44d2296c42ef_zps4f41a4ef.jpg



Toyota
Jiggle-valve.jpg



Mini
Jiggle_valve_2.jpg




On a related note, some thermostats has also been improved so that, in the event of failure, they remain in the open position, presumably avoiding an overheating situation. To quote Martha Stewart, that seems like a "good thing."
 
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lloyd said:
To the best of my limited knowledge, older Whaler and Behr M30 thermostats did not have an integrated bleed hole. Modifying them with a small bleed hole, as Steve mentions, has been done by many since the cars were new. The down side of this modification might be if the hole were too big or if there were too many holes, since this might interfere with the thermostat from functioning efficiently and allowing the engine to reach operating temperature - as quickly as possible. On the up side, big holes will no doubt prevent air bubbles - and they may also forestall overheating - on a defective thermostat (more on this below).

Some newer thermostats, for newer models (e.g., Ford, Toyota and Mini) have integrated bleed holes. Toyota has included a "jiggle valve" that evidently permits the passage of air when the system has reduced pressure, but seals the hole to maintain the thermostat's working efficiency. I have no idea whether Behr or Whaler have included this feature on any new M30 thermostats.

e89abd99-5d3d-4e9e-ab8d-44d2296c42ef_zps4f41a4ef.jpg



Toyota
Jiggle-valve.jpg



Mini
Jiggle_valve_2.jpg




On a related note, some thermostats has also been improved so that, in the event of failure, they remain in the open position, presumably avoiding an overheating situation. To quote Martha Stewart, that seems like a "good thing."
Click to expand...

good point

funny to see the jiggle valve at 6, instead at 12, i thought air bubbles would be on top of the hose,...

Steve did not mentioned that usually the recommendation is a 2mm diameter hole
 
I wondered about that too. I am unfamiliar with the Toyota system and assume there might be other means of purging air from the cooling system. Or the information is erroneous.

One diagram for an Acura has it the way you seem to favor.
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As do other diagrams.
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This page https://hellafunctional.com/?p=629 provides some relevant information when making your decision on how to proportion water and antifreeze. Very good reference. It's all about balancing the anticorrosion, heat capacity/transfer, boiling point and freezing point. The latter is a distant third for most of us as we don't drive in freezing temperatures.

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I run something around 30-35% antifreeze to gain a bit more (+10 percent) cooling capacity. I change it out every other year and the system stays clean. The boiling point, especially at ~14 PSI, isn't impacted by much. With clean, stock radiators I've never had overheating issues on the E9 or E3, including running AC on both and auto box cooling embedded in the radiator with the E3 on days up to the lower 90's.
 
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