Thread: 300TDi coolant issue - airlock in radiator - help needed

Return valve? You mean the little plastic doofy with 3 hoses? It's a jet pump for extracting bubbles from the top of the rad.

if beutey's suggestion of the 3 way doover replacement doesn't fix the issue....

then if there is the correct amount of coolant in place it's possibly a sensor continuity problem ....

a cleaning of the pickup and the block may be in order



.....Davy Jones always seems happy to chat (if it is one of his that you have installed)

Where exactly is your sensor located ? In the rubber hose via an in-line adaptor or into the header tank via the plug ?

I thought that the brass plug on the thermostat housing was the highest point in the system so if there was any air, it would most likely be there. I have a temp probe at this point connected to an EMS2 and when I have had an airlock in the past, this is where I notice it. I have replaced the 3-way ejector harness in the past as a preventative measure, but it sounds like you have already done that.

As a poor-man's method of bleeding the thermostat housing, I take the vehicle for a short run to get it up to temp, then gently/carefully crack the brass plug open to let any air escape, using the built up pressure in the header tank to force the air/coolant out. If you continue to get air after 1-2 attempts, I'd think you have a problem, but not sure to help you any more.

yah...the plastic doofy with 3 hoses soming off it....that is what I replaced when this issue first started about two weeks ago.

I will replace the thermostat and bleed the system again and see if it happens again.

Cheers
Andrew

I have the low coolant sensor in the expansion tank[Range Rover cap]but despite no trace of leaks,air appears in the system, infrequently but evidenced by gurgling behind the dash.I found these bleed valves on ebay http://www.aulro.com/afvb/attachment...1&d=1349667707 loosen the screw and instant bleed with minimum loss of coolant ie a spoonful.As suggested you could just bleed it and hope eventually the leak will appear,at least the coolant alarm will keep you aware of a potential problem.Is it possible to relocate the sensor to the expansion tank,where it will not be so sensitive to a small amount of air in the system?

relocating it to the expansion tank isnt easy, putting it in the radiator is.

try the coke bottle method for getting it full.