Billman250

Ok I found my previous procedure and even further revised it. Also added to FAQs above under "engine stuff".

This procedure is the same to follow when doing a coolant flush also.

S2000 coolant bleed:

FIRST THING TO KNOW: Do not drive the car down the road until the interior heat is good and HOT. If you do, you will overheat the engine. This engine can go many miles with air in the cooling system, then suddenly overheat. One good overheat is all it takes to destroy the engine or the head gasket.

On the same token, if your heat is EVER less than hot, you have a leak!

It will help greatly to do this procedure in an extremely quiet area. You will be listening for a small hiss off air from the bleeder and it can be hard to hear if it's not quiet.

Keep the car in a local loop (one block from shop) while working on coolant-air and MONITOR THE HEAT! If the heat suddenly gets less than hot, return to shop immediately and work the air out.

Park car with nose elevated slightly (as long as nose is not going downhill you will be ok)

Fill the radiator slowly with the front bleeder open, don't even bother with the one on the firewall. It does not work as intended.

I highly recommend straight Honda TypeII blue coolant directly from Honda. I have seen this coolant go 12 years and remain 100% spotless.

Replace radiator cap. Close bleeder.

Initial start on cold engine: Turn heat on high..... Temp dial to full hot, mode dial to face vents, fan on high. Start car, idle to operating temp (3 bars on ap1) or hold at 2500 rpm to speed process. After the initial warm up, car will be run in 2 minute intervals until heat is hot. No more.

1: TURN CAR OFF.

2: Open bleeder a very small amount, slowly....just enough to hear the air hissing out.
let it sit until all hissing stops, 5-30 seconds.

3: Once hissing stops, squeeze the upper radiator hose completely flat with your hand covered with a rag, addition hissing/air will come out. Hold it flat until all hissing has stopped. Close bleeder WHILE HOSE IS SQUEEZED. Then release hose.

4: Open radiator cap, fill to top. Replace cap.

Run car another 2 minutes at 2500 rpm while monitoring heat out of the vents.

If you don't have hot heat in 2 minutes, shut it off/repeat steps 1-4 until heat coming out of the vents turns sharply hot...not warm air. You'll know it's hot when the temp changes sharply and is close to burning your fingers.

Once the heat turns hot, repeat steps 1-4 one last time(last radiator top-up). You are now safe to drive the car.

The key here is never open the bleeder with the car running. If you read carefully you will see at no point do you do so. All that will do is waste coolant, and stop you from getting the air out.

Last step:

Fill the overflow tank about 1/2" over the full line. It will make up for the tiny bits of air that will work itself out by morning.

Billman250

Can someone post the exact number of coolant bars at operating temp on an ap2? A CR model? Any other dashes I missed?

08S2000

I believe there are 16 bars total and 8 lights up at the operating temperature. I will confirm later today.

Mine is 08 and the number of bars maybe different from 04 to 07.

Billman250

ap1v1 dash (3 bars for op temp)
ap1v2 dash (3 bars for op temp)
ap2v1 dash, 04-05
ap2v2 dash, 06-07
ap2v3 dash, 08-09
CR dash

I think this is how they lay out.

Allday

Thanks for bumping this back to the top ill try it tomo and let you know how all goes on the other thread. Thanks
-Daniel.

sillyboybmxer

Thanks for the continued revisions of your threads. Helps us all a bunch

When you say if your heat suddenly doesnt blow hot that we may have a leak, do you mean a head gasket leak???

ed-gsxr

Billman250

No... Any leak, external or hg, will drop the coolant level, and once it's low enough the system will go air bound.

zeroptzero

Thanks for posting up this thread Billman250 , I like the updated version even better.

I always knew the bleeder on the firewall was useless, thanks for verifying that I'm not nuts. I could never get fluid to come out of it during a fluid swap.

Great work on this.

Wannabes2k2k11

I followed your procedure a year ago when I replaced the radiator. Now you're saying to not pull coolant out of the aluminum hose on the firewall? Just want to clarify. I have to say I spent quite some time bleeding the cooling system. This car was probably the most obnoxious I've ever done. Took forever!!!

Now I'm taking everything back out I have coolant leaking from a couple places.

One place is some leaking on the lower hose. There's not much the eye can see on the lower hose. It looks good to go. However, I'm assuming the rubber is old enough now that it's getting by.

The second and more visible place is the temperature sensor. Should there be some sort of teflon tape on the threads? I can't remember if there was, and I haven't looked at the sensor yet.

I'd hate to spend money on parts that it doesn't need. However, at least for the lower hose I see no other logical explanation. I mean the OEM hose clamps should never fail.

On another side note, after only 3,000 miles the coolant was very dark from the normal bright green. Now when I did it, I never took the time to use a cleaner. But I did thoroughly flush the system with water. Anyways I've had a suspicion about a leaky head gasket, but the car hasn't over heated. I'm not sure if their could be a relation, or if I should buy some sort of test kit for cheap.