chino101

I wouldn't say that it will get ALL of the air out, but will remove most of it.Enough to get heat from the AC vents, as required per Billman250's instruction. It took me about 25 minutes of idling the car to get most of the air out. Once you've gotten that far, fill the coolant reserve tank to the full mark, and drive it around a bit to ensure that the temperature gauge stays in the normal range and hot air is still exiting the AC vents. As you drive around over the course of several days, small amounts of air will bleed from the system and the coolant reserve level will drop; fill it back up as you observe this.

Here's a video of this funnel in use on a Honda Accord, which is know as a equally difficult cooling system to bleed: http://youtu.be/zUpXgAJ1gjU

Billman250

I have bleed many accords and they are nothing like the S2000. You will get heat in an accord right away.

Run the fan on high. Running it on low will under cool it and make it appear it is getting hot when it is not.

jkelley

Thank you Billman for the thorough write-up

I have 2 questions:

1. What is the overall purpose behind 'bleeding' a coolant system vs. just dropping the coolant from the radiator bottom drain, closing it and replacing the fluid? Am I correct in that it's usually necessary when swapping out a parts (A/C comp, water pump, tstat, etc?) or having to disconnect any coolant lines for some reason, but otherwise usually one could get away with just swapping the bulk of the coolant how I mentioned?

2. I use torque pro from an obd2 BT device which is telling me that my coolant temp is usually around 170°F while driving, generally around 177-181°F while idle for an extended period of time (1+ minutes), and the highest I have seen it was 190°F - are these acceptable temperature range for a completely stock motor under normal (commuting) driving? I searched on these boards but only found temperatures for people with a lot of engine mods, EMS's, etc and didn't know if a stock motor should have different numbers indicating normal operating conditions. (edit: ambient temperatures around around 50-60°F for these numbers, if that means anything)

Thanks!

GSteg

The cooling system will have air every single time you replace the coolant. You need to bleed out the air. It's not as simple as filling up a bottle. There are nooks and crannies in the system that WILL have air.

GSteg

What's the issue with running the fan low. The only thing I'm concerned about is getting the system hot enough for the thermostat to open and all the air to get out. Once the coolant reaches peak temperature, I don't think it matters whether the fan is blow low or high at that point. I've done it with low and high fan speed and both ways get me by without air in the system.

darcyw

i'll reference my post on coolant changes as well for those who need pictures and are visual learners.

https://www.s2ki.com/s2000/topic/998...#entry22616147

My method was based on Billman's expertise and his post. My method worked for me and over the year since, no problems.

darcy

Billman250

An air bound engine gets hot real fast. Blowing air through a 80 percent empty core has little if no affect on warm up speed.

By running the fan on high, it is very easy to feel the change in temp because it over cools the trickle of coolant in the line and air temp stays cold.

Once all the air is out, the high fan will not overcome it and it turns hot very fast.

Fan on high does not effect the outcome per say, but it makes a big difference when conveying a diy.

With the fan on low, the trickle of coolant will be enough to get hot and provide a false sense of hot heat.

Heat on high is the safest way to feel the heat go from lukewarm to red hot.

GSteg

Fortunately, I've never had an air pocket large enough for it to make a difference.

Bleeding air is one of those thing that is simple to do, but many overlook it and end up with erratic idle, coolant temperature that shoots up to the sky, etc. I find the S2000 not too hard to bleed. Had an Acura Legend that was much worse. It was a car notorious for blown headgaskets. A little bit of air in the system and you're almost guaranteed to have a blown headgasket.

s2000maniac

I have done 2 s2k's using this method including mines with zero issues. Didn't mess with not of the bleeders. Plus it saves you from accidentally stripping the bleeder plug.

http://m.youtube.com/watch?v=zUpXgAJ1gjU

Reckon

Question - is this different from a coolant flush? I know my S is coming up on 100k miles and I plan on doing a coolant flush in a few weeks (as well as changing out the rotors and brake pads and the other usual maintenance). Is there a DIY for a coolant flush that differs from this?

Sorry, I know that question sounds somewhat ignorant.