Problem burping coolant!

[old mechanic]

What I used to do was open up the rad drain plug and the block drain plugs then put a hose in the rad and run the engine with the water going through it for a while.
I have also used the tee on the heater hose too when I thought the air was just in the h-core.

 

[rafteye]

This is incredible! Just in the last 2 weeks I have done almost the same things with the same results. I changed everything at first. It was overheating, so last weekend I re-replaced the thermostat with one with the weep-hole. No change AND I get the thump. Really, the only thing I haven't changed is the temp sending unit and the heater core itself, whic I don't suspect to be an issue. I have burped it twice now. Last time I tried it, I didn't see any visible air escaping. I am almost at my wits end!I will be watching this thread closely and will post any progress I seem to make.

 

[Lt.Jim]

Rafteye good luck. I have'nt had time to work on it this week. Hopefully over the weekend I'll figure it out. Will keep you and everyone else up to date.

 

[rafteye]

Well, I burped 2 more times and took it on a 300 mile road trip this weekend. I think I'm making progress. It seems to be settling down little by little. Apparently, I just have one of those "difficult to burp" Exploders. I did find that parking on an incline helped more than anything. I had never heard that before. Thanks to all for all the suggestions!

 

[410Fortune]

hot water (250+) down the upper hose to the thermostat I am telling you right now will release any air trapped behind that SOB

 

[levishake]

i do know there is a 4way valve on your heater hoses right before they go into your firewall, It's a heater control valve wich is vacuum operated and when you turn the heat off it closes the valves and stops coolant from intering the heater coor, maybe if the valves are malfunctioning there arent letting your heater core purge all the air out? just a geuss

 

[rafteye]

I think I might have found part of the problem. When we put everything back together, one of the heater hoses got routed wrong. It goes up and over the upper radiator hose and creates an "arch" in the hose. It's approximately in the same place as the thumping sounds I am hearing. I'm thinking that there is probably an air bubble in that arch. As soon as I get another gallon of anti-freeze, I'm going to re-route the heater hose the way it's supposed to be! Wish me luck. This is getting a little old!!!

 

[cstmcomps]

I have been having very similar issues. After a ton of research I found a small crack in the block just below the thermostat.

With the engine hot (try to get it to overheat if you can) take a flashlight and look for any escaping steam.

I put in some block sealant and burped it again and the problem is temporarily solved. I will have to replace the engine soon though as I don't like cracks in my block.

I hope you don't have a crack, but look for one anyways.

 

[Bill94]

Subscribed!

 

[Lt.Jim]

Update!

Sorry I have not been back to this thread for a while. So being short of free time lately I have not been able to tinker with this problem. I have just not used the heater for a while to avoid the dancing guage. So Friday I had to use my defroster to keep the window from fogging up with all the rain and cold air in the area. The guage never went past 190 So I tried different combinations with the heat selector and the temp stayed where it should be all weekend. Maybe it was as snoborder42 said and just took some time to work all the air out

I still have the pinging/knocking sound once up to temp. My guess with that is the head gasket(s) or intake gasket(s)

 

[coreweave]

Any updates yet? I'm going through this same problem and it is very frustrating! I will have to try out the hot water trick.

 

[ranger7ltr]

Trapped air in the cooling system...

FWIW, I have run into this problem before and tried hot water, inclined running with the engine running[real popular on 5.0 liter Mustangs], different thermostats, etc.. The relatively painless fix was to heat cycle the engine with the coolant overflow bottle almost full... Run the engine with the heater on until it got to 190-200 F then shut it down and let it cool for 20-30 minutes..

Especially after changing the coolant and thermostat, I would do this and then pick up tools or clean the engine.. Something to pass the time.. From what I can remember the engine would burp itself and the coolant level in the overflow bottle would drop some and I never worried about it again..

If the coolant level didn't drop, I would heat the engine again and then let it cool down.. I never had to do this more than twice on a properly functioning engine...And I think that is what the engine would do itself over time with a working overflow bottle and closed cooling system...

Now if the head gasket or cylinder head was cracked this story had a different ending....

 

[radman]

Bleeding cooling system

Ranger is on the mark.

Operating the engine untill you see the temp. gauge just start to move to normal reading then shut the engine down and allow it to cool off. After cooling down, top off the recovery tank and open the radiator cap and replentish the coolant to full. This proceedure may have to be repeated several times. If the problem is still there you must loosen both heater hoses (while cool) and start the engine. Each hose in turn will be slide back enough to allow some coolant and air to escape from the heater core. Usually the heater core or hoses are the highest point in the cooling system, that is why the air is caught there. The cylinder heads are the hottest place in the system and they also trap air. Should you not purge the coolant properly a cracked head or blow head gasket is a very real possiblity. Engines wit aluminum heads are the most prone to this failer. Never let your engine sit and idle after a flush and fill without this precaution.

 

[coreweave]

FWIW, I have run into this problem before and tried hot water, inclined running with the engine running[real popular on 5.0 liter Mustangs], different thermostats, etc.. The relatively painless fix was to heat cycle the engine with the coolant overflow bottle almost full... Run the engine with the heater on until it got to 190-200 F then shut it down and let it cool for 20-30 minutes..

Especially after changing the coolant and thermostat, I would do this and then pick up tools or clean the engine.. Something to pass the time.. From what I can remember the engine would burp itself and the coolant level in the overflow bottle would drop some and I never worried about it again..

If the coolant level didn't drop, I would heat the engine again and then let it cool down.. I never had to do this more than twice on a properly functioning engine...And I think that is what the engine would do itself over time with a working overflow bottle and closed cooling system...

Now if the head gasket or cylinder head was cracked this story had a different ending....

Great tip!

I understand the stock temp gauge is just "dummy" gauge that moves based on the resistance values, but if you were to guess, where abouts on the temp gauge would read 190-200 degrees? I would imagine it is smack dab in the middle since that's where the gauge climbs to before it falls to the "C" notch (thermostat opening up).

I bought a thermostat with the jiggle pin in it, and it was taking forever to warm up to operating temp range (barely past "C" notch). I was letting the Explorer only idle for approx. 15 minutes to purge the system because I had thought the temp gauge stopped moving. After having a problem with my garage door opener, I went to investigate why it was not opening and let the truck idle on the inclined driveway for about 30 minutes. After fixing the garage door opener, I went back in the Explorer and noticed my gauge was holding steady in the middle which was the first time since owning this vehicle. I took a look at the reservoir tank, and it had gone down.

So it looks like the system purged itself, but I haven't had a chance to drive it yet to verify it.

If the problem is still there you must loosen both heater hoses (while cool) and start the engine. Each hose in turn will be slide back enough to allow some coolant and air to escape from the heater core

Ok, just so I understand this 100%, loosening the heater hoses allows the air to be pushed out the heater core from the pressure of the system. I'm sure it doesn't make a difference, but do I loosen the hoses at the heater core or heater control valve? How do I know when the air is completely out of the heater core - when I see coolant start leaking out??

 

[radman]

Coreweave,
Keep the inlet side of the control valve open. Loosen the return hose at the core while the systyem is reasonably cooled off. There should not be pressure present. If the system is hot you are in danger of scaulding yourself. Start the engine and wiggle the hose off slightly, DO NOT REMOVE IT, you want to be able to control the amount of coolant lose while you are doing this. If air is present you will see some spray along with the coolant. Repeat until you get only coolant. Reinstall the clamps check radiator coolant level and let engine warm up to full temp. and shut down and allow to cool off again. Repeat if needed.

 

[radman]

Coreweave,
In your reply to Ranger you discribed about allowing your engine to idle for 15 minutes unattended, I would warn that the coolant temp gage should be monitored during this period as this is when an air lock can cause the most engine damage. You were fortunate but this is a risky thing.

 

[35Remmy]

Is the return hose the one on the left or right where the heater core lines come out of the firewall?

 

[radman]

Its the one that runs back to the water pump. The inlet hose comes from near the therostat area on the engine.

 

[BIGHVM]

Guys I hate to say this but I believe this is a headgaskit problem........cant tell what side but it IS just that! Sorry.

 

[coreweave]

Guys I hate to say this but I believe this is a headgaskit problem........cant tell what side but it IS just that! Sorry.

Could you please give reasons why you think this is to be the case? There is no signs of coolant in the oil (or vice versa), no signs of burning coolant, or no exhaust gas in the cooling system. I have not yet done a compression check, but I'm pretty confident I will have pretty even numbers. The engine runs great otherwise.

I did drive the X around today for about 100 miles. I believe I still have air in the system. The temp gauge is doing it's usual thing (fluctuating) but I noticed a couple things. Instead of the gauge dropping fast like before, it slowly creeps down to the "C" notch while driving. And the "gurgling" sound has disappeared. I also noticed the level of the coolant reservoir has gone up. I will try radman's tip of loosening the heater core return hose.

radman, you mentioned to keep the inlet of the heater control valve open. I am assuming this is done by turning the heater on? I really appreciate your patience and help.