Air lock?

DAVID ROBERTS

DAVID ROBERTS

New Member
Ive just replaced the head gasket on my van and having a few little issues , while standing but running all seems fine no over heating etc but when I take her out for a drive there either seems like pressure build up and heat issues , although the temp gauge doesn't go over halfway .... Does anyone have any tips on air locks and bleeding ?
Thanks in advance ..... Keen to be out injoying the summer !
 
Howdy David, I have never bled(or needed to) my Commer coolant, heat issues could be crud in the radiator or engine jacket.
Mine used to boil over at halfway:oops: until I corrected the sender, then it boiled over where it should:rolleyes:.
 
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Hi David. Did you replace the head gasket because it was leaking before? Where you having over heating problems before you did the HG. As dodgeram has already suggested it sounds like a restriction in the cooling system. What's the history of the engine, these engines are prone to silting up if they've been left for a long time without anti-freeze in.
 
Panky said:
Hi David. Did you replace the head gasket because it was leaking before? Where you having over heating problems before you did the HG. As dodgeram has already suggested it sounds like a restriction in the cooling system. What's the history of the engine, these engines are prone to silting up if they've been left for a long time without anti-freeze in.
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Hi Panky , I bought the van form Edinburgh a few months ago , it's featured in a thread on here Dutch commer .... It came back with little issue , the overdrive kept slipping out but a oil top up sorted that.... Wasn't till I was almost home ( Landsend ) that it started to over heat a bit and was losing a little water , a few days later cottage cheese in oil ( not a lot ) so I stripped down , new head gasket,re ground valves , set tap pets etc also fitted height tourque starter and su carb / manifold set up from Tim commer .... So starts up no problem with a little choke and runs standing still doesn't over heat but when I take her out for a little run no more than a mile or two she definitely starts to struggle and seems to get hot although the gauge only reads half , also the top rad hose gets really quit hard ??
 
Ah yes Davy's old van formerly Dutch Courage:)
So it hasn't been laid up for a long time, hmmmm, and the over heating is a new thing since the HG change so it's either the head gasket again or, as you suspect an air lock. I would try attaching a garden hose to the heater outlet on the head and force water back through the engine and back to the open hose you've disconnected - then do a reverse flush and attach the garden hose to the actual heater hose and push the water back through to the open heater tap on the head - if you catch my drift. This should clear all the air out including any that nay be trapped in the heater - I've got to say though that I've never had an airlock issue on a Commer engine either but hopefully this will sort it and it's nothing more sinister.
 
Hi David, have you changed the thermostat? If not try running without one in at all to see if it makes any difference. If it does then obviously a new stat is in order. If not try taking a heater pipe off the engine and then start the van up to check that water is being thrown out by the water pump. Like the others are saying I also had no problems with air locks after draining the system. I did however have a problem with a faulty gauge. The whole story is on the overheating conundrum thread.
 
Test the thermostat in a few cups of boiling water to check it is fully opening. Check the water pump is pumping water round the system. the postbus had the same fault till I put a rad flush in the system. When I drain the water it is always a bit rusty water.:):):)
 
Jimmy van said:
Hi David, have you changed the thermostat? If not try running without one in at all to see if it makes any difference. If it does then obviously a new stat is in order. If not try taking a heater pipe off the engine and then start the van up to check that water is being thrown out by the water pump. Like the others are saying I also had no problems with air locks after draining the system. I did however have a problem with a faulty gauge. The whole story is on the overheating conundrum thread.
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hi Jimmy , ive put a new thermostat in, but didnt check it first , but have now taken it out but it had no change... water pump also work fine .
 
Colin Stewart said:
Test the thermostat in a few cups of boiling water to check it is fully opening. Check the water pump is pumping water round the system. the postbus had the same fault till I put a rad flush in the system. When I drain the water it is always a bit rusty water.:):):)
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im going to check the rad again in a mo and give a good flush .
 
dodgeram said:
Just out of interest, was there a fault/damage to the old head gasket...or is it binned now?
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Hi dodgeram.... it seemed to be between the back and second pot through the middle :/ Ive flushed the rad trough again and tried the hose pipe filling both ways through the heater pipe, water ran freely both ways ..... took it out for a run again but after about a mile she just doesn't like it ..... BOOOO HISSSS
 
Sorry to say it does sound like head gasket again:( Maybe it needs a bit of a skim. But yes do check for bubbles in the rad to confirm.
 
Hi guys , thanks for all your input , I did check for bubbles , there where none , looks like a strip down again on the weekend :( BOOOOOHISSS
 
When I've had similar problems, it has been sediment around the back of cylinder 4 in the block causing local bpiling. You may get lucky and find a way of flushing it out maybe through the block drain tap. Otherwise it's head off again I'm afraid.
 
Sounds like head yes, out of interest some head gaskets aren't stamped 'top' they appear to be symmetrical but aren't and the wrong way up blocks a water way
 
jimberlake said:
Sounds like head yes, out of interest some head gaskets aren't stamped 'top' they appear to be symmetrical but aren't and the wrong way up blocks a water way
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Hi jimberlake,,, yes I did notice that and pretty sure it went on the right way up ..... I think lol
 
colinthefox said:
When I've had similar problems, it has been sediment around the back of cylinder 4 in the block causing local bpiling. You may get lucky and find a way of flushing it out maybe through the block drain tap. Otherwise it's head off again I'm afraid.
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Funny u should say that because 4 was a lot dirtier than the other 3 ????
 
It's odd that it was fine for all those miles then just started playing up, that's why I suspect the head gasket, but a good flushing wont do any harm.
 
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