Bleeding Coolant-- What am I Doing Wrong?
 

Argh, I hate coolant! :mad:

I'm having trouble figuring out how this is supposed to work-- I've read some threads and Clark's, watched some YouTube, and read the manuals, but things aren't matching with what I'm experiencing.

The methods I've tried:
1) The Haynes way of crack the bleed screw, leave the cap on, run it for a while, and let it get messy.
2) A modified version of something I saw on YouTube, where I put a threaded nipple of the right size in the bleed screw hole, attached a clear hose to it, put the other end of the hose in a little bucket on the ground, and left the cap off. Heat on high, let it run for a while.

Both times the results were about the same-- lots of bubbles in the coolant for a while, then a short period of no bubbles, then lots of bubbles followed shortly by spraying coolant everywhere, and in the second method, total overboil of the coolant tank.

So what gives? Should I stop as soon as the coolant runs clear? :confused:

first, have the car situated so the nose is slightly higher than the tail. then, you have to have the engine fully warmed up. then, you have to have the heater turned on the highest heat setting, with the fan on high

make sure you actually have a bleed screw in there, and not just a regular bolt. i have seem cars where somebody swapped that out.

i have found that leaving the cap off for the first bit can help. also, raising the rpms a bit at the beginning can accelerate the process, but you have to go back to idle once you get things moving.

however, it sounds like you have a stuck thermostat, and not a bleeding problem

Check, check, check, check, and check.

I'm not sure how a stuck tstat would be related to this? I'm pretty sure I just don't know what I'm doing. ;)

if the thermostat is stuck closed, the car will essentially boil over and push the coolant out of any exit above it that is open.

a quick way to see is to check the temperatures of the upper and lower hoses. they should only be about 20 degrees different. if one is cool, and one is hot, either the thermostat is not opening, or the pump is not pushing the coolant

if you go to change the thermostat, check it first for operation before installation. dangle it on a string in a pot of water and bring it to boil (don't let it sit in the bottom of the pot). if it opens at the right temperature, you're fine. my experience is that about 1 out of 10 new thermostats do not open and close like they should, and about 1 in 30 don't work at all.

Get a Vacuum Coolant Refiller and never look back. Hands down the easiest way to bleed the system (and check for any leaks).

i wonder how well that would work on a system that has the reservoir after the thermostat. as it is, on cars with a stock thermostat, i have to run the engine to get coolant down into it. i bypass that problem by drilling my thermostats. but, with the thermostat closed on an OEM system, how would the device get coolant past it?

interested to hear though. could be cool (pardon the pun)

My method is super easy and can be done with the engine dead cold.

1 - Clean off the overflow hose and put it in your mouth (no coolant will come out of it)
2 - loosen the bleed screw and put a wrench on it.
3 - Take off the reservoir cap and put your hand over the neck, this allows you to blow into the overflow into the reservoir.
4 - Blow, open bleed screw, close bleed screw, relax.
5 - Repeat 4 until you only get coolant. Tighten bleed screw properly.
6 - Rinse mouth with beer (or something)
7 - Go drive, heat on high, get car hot,
8 - Park with the nose up a bit, possibly in your driveway or good dip in a parking lot. Engine running, chock the wheel,
9 - Give it one last bleed at the screw (no hose-in-mouth at this point)

Works great, super easy. I do not even get air in the final bleed, I just do that to be certain.

Ah, that makes sense. I'll check that out before I keep going. Thanks!

I was thinking of buying a pressure tester kit for this approximate purpose, but I found that a valve stem will fit in overflow hose. I haven't got it leak free, but it seems like it holds 10 psi well enough. Haven't had a chance to try it yet. I just cut a presta valve off an old bike tube.

again, the problem i see is that the thermostat is like a "dam" in the middle of your "river". it separates the upper half from the lower half. you only have access to the upper half. any air trapped in the water jackets of the engine, heater core, etc, will still be there, until you get the thermostat to open.

besides much more even cooling temperatures, this is a very real benefit of drilling the thermostat. you don't have to wait for the thermostat to open. the holes allow a small amount of coolant to pass at all times. it is not without its potential problems though. in extreme climates, you can have slightly lower limits on temperature control. it will take a bit longer for your engine to warm up in extreme cold, and in very extreme hot, the system can saturate.

I drill a 1mm hole in my thermostats also if I do not get one with a jiggle valve. Jiggly make happy.

How do you seal the reservoir neck? Isn't the overflow only in play if the cooling system cap seal is lifted off it's seat?

So, four and a half months later... :P

The method that finally worked for me was the Clark's Method 1 under Venting the Cooling System: Coolant System Draining, Filling, and Venting

Few notes:
- I did fill the block first using the upper radiator hose (actually bought a cheap one for this purpose since this hose is a pain to deal with).
- I used the device I described above (presta valve from a bike tire zip tied tightly in a short length of hose and a little plastic coupler to attach to the overflow hose, a cheap cap with the lower seal removed to allow air into the reservoir, and a bike pump).
- The tstat dam problem is solved by bleeding cold, then running until the fans come on, then bleeding again (carefully!). Then running again to check that it all works.

Worked pretty good. Simple, almost drama free. There was some overflow while the car was warming up, but once I bled it a second time there were no issues. Drove it around a bit, all good!

Find someone with a Motive bleeder, pressurize the overflow tank to 15psi and bleed the system with the bleeder screw, that's all you need to do and if you have a leak it will quickly appear !

BTW, even though my little thing below my name says Boise, I actually live in a tiny 200 person town an hour from anywhere, so not real likely to find anyone with spiffy coolant bleeding tools (and see previous post)! :)

Meh, you do not need a pressure system. It's easy to just blow the coolant through via the overflow tube (cap off, palm covering opening).

I imagined it taking a lot more time to bleed (given previous failed attempts), otherwise I might have done something similar. Not real keen on putting my mouth anywhere near coolant though, especially after it overflowed through that tube...

Update from above and question to follow! Posting to this thread because it might be relevant.

I drove the car maybe 300 miles since the above successful coolant bleeding, but then it got snowy and I've just been running it once a week until it gets hot.

Yesterday I ran the car for maybe 30 min while I did some outdoor chores. When I came to shut it off, the temp was a little higher than the middle (doesn't usually get there even on a 95 degree F day), and as I was about to turn the key off, as I found out later, the lower radiator hose partly popped off on the engine side with the resulting steamy drama.

It has been subzero temps and was in the 20s when this happened. The hose didn't come all the way off, and the clamp seems a little loose. The hose is in fine condition. I did not remember to check the temp of the upper radiator hose, but seems like the tstat could be stuck closed...

So what gives? Seems mighty coincidental...