Think i'v got wind

[clasabro]

The coolant temperature excursions are back. Temperature was steady for about 80 miles then suddenly went into the red. Stopped nothing felt exceptionally hot the system didn't have excessive pressure in it, expansion tank was full swan neck empty. put the swan neck cap on the expansion tank nipped the line back to the swan neck and blew down the overflow pipe. got a gob of air and water out of the swan neck. topped up what i had spilt, put all the caps back on. Temoerature o.k. for about 70/80 miles then off we go again. I guess I must have an air lock somewhere, any ideas how to get rid if that's what it is I cannot see any obvious bleed points.

[chassis 33]

Is the heater on full when you fill/check for air, thats a classic place for air to hide? The cabin heater pipe coming off the inlet manifold is a good place to crack open to bleed air out, front drivers side corner of the inlet manifold, or the middle rear of the manifold depending on the age of the manifold.

Regards
Iain

[Number 7]

clasabro said:

The coolant temperature excursions are back. Temperature was steady for about 80 miles then suddenly went into the red. Stopped nothing felt exceptionally hot the system didn't have excessive pressure in it, expansion tank was full swan neck empty. put the swan neck cap on the expansion tank nipped the line back to the swan neck and blew down the overflow pipe. got a gob of air and water out of the swan neck. topped up what i had spilt, put all the caps back on. Temoerature o.k. for about 70/80 miles then off we go again. I guess I must have an air lock somewhere, any ideas how to get rid if that's what it is I cannot see any obvious bleed points.

do the rad. fan(s) come on and go off at about the right temps. according to the gauge? The gauges can be unreliable. When re-filling the system after draining, it should be done slowly through the swan neck (which is NOT a pressure cap)with the heater circuit open and I find that squeezing the top and or bottom rad hose will help the air out. Once you've got as much coolant in as you can through the swan neck, replace the cap, and put a little coolant into the header tank. Leave the pressure cap off, start the engine and let it warm. When the warm coolant is almost at the top of the header tank (engine still running) replace the cap and let the coolant reach full temp., checking that the stat, opens - you can feel the increase in the water temp in the swan neck, and should see the gauge dip. Check that the fans cut in. When cool, top up the header. In your case I'd say drain some coolant from the header, and go through the routine from there.

7.

[tallbloke]

Head gasket problem? Could one of the cylinders be pressurizing the system and pushing air into the cooling galleries?

[chassis 33]

tallbloke said:

Head gasket problem? Could one of the cylinders be pressurizing the system and pushing air into the cooling galleries?

Roger, don't scare the poor bloke!

[tallbloke]

chassis 33 said:

Roger, don't scare the poor bloke!

Ian you're right. As the man said, no excessive pressure in the system.

[jmorgan]

Probably not much help but I had a slight problem with the swan neck breather going under the AFM causing the odd air lock. Re routed over and cured that little problem.

[leorest]

Number 7 said:

clasabro said: The coolant temperature excursions are back. Temperature was steady for about 80 miles then suddenly went into the red. Stopped nothing felt exceptionally hot the system didn't have excessive pressure in it, expansion tank was full swan neck empty. put the swan neck cap on the expansion tank nipped the line back to the swan neck and blew down the overflow pipe. got a gob of air and water out of the swan neck. topped up what i had spilt, put all the caps back on. Temoerature o.k. for about 70/80 miles then off we go again. I guess I must have an air lock somewhere, any ideas how to get rid if that's what it is I cannot see any obvious bleed points. do the rad. fan(s) come on and go off at about the right temps. according to the gauge? The gauges can be unreliable. When re-filling the system after draining, it should be done slowly through the swan neck (which is NOT a pressure cap)with the heater circuit open and I find that squeezing the top and or bottom rad hose will help the air out. Once you've got as much coolant in as you can through the swan neck, replace the cap, and put a little coolant into the header tank. Leave the pressure cap off, start the engine and let it warm. When the warm coolant is almost at the top of the header tank (engine still running) replace the cap and let the coolant reach full temp., checking that the stat, opens - you can feel the increase in the water temp in the swan neck, and should see the gauge dip. Check that the fans cut in. When cool, top up the header. In your case I'd say drain some coolant from the header, and go through the routine from there. 7.

This is similar to my method except I run the engine watching the air/liquid bubble out of the Swan neck and keep topping up until no more comes out. When the engine is warm, it's on with that cap and the rest is as quoted before. Don't know if its a better way but I haven't had an air lock... Yet.
Leo

[clasabro]

Thanks guy's. I have tried with the heater both on and off usually squeezing the heater pipe pumps some air out, have even tried filling the heater matrix seperately then reconnecting. I have an adjustable otter switch on the fan, that I have set to come on as soon as the temperature starts to rise so cannot relate the temp it starts to a number. Will try every tip this weekend.