Bleeding Engine Coolant
Thread Starter
Joined: Nov 2003
Posts: 25,566
Likes: 2
From: Heart of England
Bleeding Engine Coolant
Discovered today that I have an air lock in the heater system after my radiator change 
I get varying temperatures of air out of the heater. At best it is warm on full heat.
I've tried bleeding it using the bleeder on the right hand side of the head.
Us RHD owners don't get the bleeder designed for the heater matrix
So as the heater tubes are the highest points on the water system any ideas on how to bleed the air out of the heater system
I get varying temperatures of air out of the heater. At best it is warm on full heat.
I've tried bleeding it using the bleeder on the right hand side of the head.
Us RHD owners don't get the bleeder designed for the heater matrix
So as the heater tubes are the highest points on the water system any ideas on how to bleed the air out of the heater system
Joined: Feb 2007
Posts: 9,433
Likes: 312
From: Dunfermline.
Try taking the rad cap off and squeezing the heater hoses to aid the flow, if the level drops you may have shifted the air. It may be possible to run the engine with the cap off without the coolant pissin all over your feet, this may also push the air around and out. raising the front of the car on ramps might help?
I'm going to ask the techs at work tomorrow though.
I'm going to ask the techs at work tomorrow though.
Thread Starter
Joined: Nov 2003
Posts: 25,566
Likes: 2
From: Heart of England
Tried the rad cap off and hose massaging trick
I've read the 08 Honda Workshop manual and that states run the engine with the rad cap off.
Ramps!
Good idea!
I'll try the combination of ramps and hose massaging
I've read the 08 Honda Workshop manual and that states run the engine with the rad cap off.
Ramps!
Good idea!
I'll try the combination of ramps and hose massaging
Joined: Jan 2008
Posts: 378
Likes: 0
Gee, two relevant water system questions in one day.
So...after I had the electric pump replaced I picked up the car from the honda dealer and it overheated as soon as I got onto the motorway. Stuck on the M40 on a cold night has made my solution to this stick in my brain.
The coolant hoses to heater form a natural air-lock on the S. The solution was a manual bleed. Remove the hose that goes to the heater valve, insert a long piece of plastic tube into each end of the split hose. On the heater valve side (suction side) put a funnel and fill with coolant. The water pressure should force water into the heater matrix. If your get a helper to start the engine for a couple of seconds the funnel will be sucked empty really quickly. Turn off engine and you have a full heater matrix. While you have good static pressure bleed at the manifold.
You can take the rad cap off while you do this but you need a put an inverted drink bottle in the rad cap, seal the joint (i used a latex glove), cut the bottom off so you can fill it with coolant if needed, and cable tie it in place. The car will run happily with the drink bottle in the filler and its a good way to see if gas is getting into the coolant system.
A bit of quality bush engineering as they say at home!
Matt
So...after I had the electric pump replaced I picked up the car from the honda dealer and it overheated as soon as I got onto the motorway. Stuck on the M40 on a cold night has made my solution to this stick in my brain.
The coolant hoses to heater form a natural air-lock on the S. The solution was a manual bleed. Remove the hose that goes to the heater valve, insert a long piece of plastic tube into each end of the split hose. On the heater valve side (suction side) put a funnel and fill with coolant. The water pressure should force water into the heater matrix. If your get a helper to start the engine for a couple of seconds the funnel will be sucked empty really quickly. Turn off engine and you have a full heater matrix. While you have good static pressure bleed at the manifold.
You can take the rad cap off while you do this but you need a put an inverted drink bottle in the rad cap, seal the joint (i used a latex glove), cut the bottom off so you can fill it with coolant if needed, and cable tie it in place. The car will run happily with the drink bottle in the filler and its a good way to see if gas is getting into the coolant system.
A bit of quality bush engineering as they say at home!
Matt
Thread Starter
Joined: Nov 2003
Posts: 25,566
Likes: 2
From: Heart of England
Messed about with it this morning.
I think I've solved it!
Tried pouring coolant down the heater hose. PITA as I had to take the battery out to get at the hose clips, even then only managed one!
Disconnected the control arm to the valve so I could get the valve further open.
Jacked the front up in the air.
Ran it up with out the rad cap on.
Kept bleeding air out of the head bleed point every few mins.
Put the cap on and brought it up to pressure.
All seems to work well now!
Off for a blast round the N Wales lakes to test it
I think I've solved it!
Tried pouring coolant down the heater hose. PITA as I had to take the battery out to get at the hose clips, even then only managed one!
Disconnected the control arm to the valve so I could get the valve further open.
Jacked the front up in the air.
Ran it up with out the rad cap on.
Kept bleeding air out of the head bleed point every few mins.
Put the cap on and brought it up to pressure.
All seems to work well now!
Off for a blast round the N Wales lakes to test it
