Billman's coolant bleed
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From: Midlands
I highly recommend getting a Lisle funnel for this. They work great. The last time I had to bleed mine I just used the funnel. Still do the first steps as Billman explains, but then you just fill up the funnel, keep it running, check the heat like he says, but the funnel is a great assistant for this and will help you get it bled.
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On every bleed I do, I have never needed to wait for the fans, nor have they even come on.
When you remove the radiator cap in the morning/cold, how full is it? When opening the bleeder, is the car off?
When you remove the radiator cap in the morning/cold, how full is it? When opening the bleeder, is the car off?
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From: Madison, WI
Yes a lot of people have tried this method and swear by it - but I presume most of them won't have had their car on ramps for 18 months with all coolant drained with radiators off. Also I have AC fitted which I presume has no impact on bleeding the coolant / heater temps -
1. Did you possibly install the thermostat backwards? I did this once and the car would never heat up.
2. Is the engine getting warm? What does the temp gauge on the dash say?
3. Is it possible your heater core is clogged, and not letting coolant flow through it? Was the old coolant super old and nasty?
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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.
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.
Thank you for the excellent write-up. Just to be clear in step 4, opening the radiator cap after warming up the car causes the coolant to burst from the pressure and spill all over. Am doing something wrong, or should I wait a few minutes?
thanks
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From: Madison, WI
If you start with a cold engine, the coolant doesn't get hot enough to spray out the cap using Billman's method. You're only running the engine for a couple minutes at a time.
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From: Long Island, New York
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From: Fort Myers, FL
Yes a lot of people have tried this method and swear by it - but I presume most of them won't have had their car on ramps for 18 months with all coolant drained with radiators off. Also I have AC fitted which I presume has no impact on bleeding the coolant / heater temps - all the gas is empty at the moment in the AC system.
The AC system has no relation to the cooling system of the car in this case so dont worry about that.
As someone else said, you might have to check and see that the thermostat is installed correctly, or it could be bad too.
I have personally used this coolant bleeding method multiple times, twice with the radiator completely drained, once with the radiator drained and a fresh engine, once with a brand new radiator and fresh engine, and probably some more times that I don't remember.
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Joined: Oct 2022
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I have followed the steps now correctly however no hissing was there, only coolant overflowing (no air pockets?).
What made me do the bleeding is that I had a weird slow leak in the cabin below passenger dahsborad after changing to a new koyo radiator, cap and upper/lower hoses. I didnt think my mechanic did a proper job. Now that i know that there isn't air pockets(heater working fine and is very hot)in the system, what could be the source for this leak?
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Joined: Jan 2020
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From: Midlands
Whatever is going on with the A/C system shouldn't matter. I used the Billman method on (almost) level ground, no funnel, and it worked perfectly. I probably did it 3-4 times more than I needed to, trying to get every tiny bit of air out. That might've been overkill but whatever.
1. Did you possibly install the thermostat backwards? I did this once and the car would never heat up.
2. Is the engine getting warm? What does the temp gauge on the dash say?
3. Is it possible your heater core is clogged, and not letting coolant flow through it? Was the old coolant super old and nasty?
1. Did you possibly install the thermostat backwards? I did this once and the car would never heat up.
2. Is the engine getting warm? What does the temp gauge on the dash say?
3. Is it possible your heater core is clogged, and not letting coolant flow through it? Was the old coolant super old and nasty?
At the initial warm up phase, did you wait for the cooling fans to kick in to know that the engine was up to temperature or did you just wait for the 3 bars on the temp guage (AP1) to show ? The reason I ask is that I noticed that my temp guage seems to have one bar showing even before I start it from cold - so not sure it's 100%. Another thing that is bugging me now is that VTEC did not engage when I was out driving earlier today - I always ensure 10-15 minutes of driving before gunning it. I checked coolant temperature when I got back home with my foxwell OBD2 code reader and it was saying 187' F, which should be warm enough for VTEC to engage i think - read somewhere 140' F is the minimum temp.
1. Like you say, I too suspect I might have fitted the thermostat wrong - the little hole is supposed to be at the top not the bottom to allow air to be bled out easily I believe - but I think the thermostat can only 'face' one way to be seated properly - is that what you are thinking too ?
This is the old thermostat and housing - nasty looking
This is what it looked like when i removed it
and after a good clean - unfortunately I didn't take any pictures of the new thermostat in situ to know if it was the right way up
2. The engine is getting hot alright, 3 bars on temp guage consistently, as are the top and bottom hoses and the hose that has the temperature control valve fitted to it and goes into the firewall - and into the heater matrix I guess.
3. The old coolant was pretty strange looking, so I did flush the system well before putting fresh coolant in and got some residue left over too.
Residue left after the 'rad flush'
strange looking old coolant
Would a thorough radiator flush have cleared out the heater matrix or is there a different procedure for that ? Part of me says go back to the thermostat and start again.
Cheers.