air keeps returning in coolant v8

[THE ELK]

tried many times to burp (vent) my efi in a viper, i know when air is in there cos the automatic choke is still on, burped and it ticks over nice, let it cool down a hey presto, choke won't shut down, no sight of leaking no water losed, bleed it again and it's fine, thinking of finding a little separator, but there has to be a cure ,????????????

[steamyrotter]

A few little questions.

What is the Engine? Rover?
Where are you venting? Obviously you will need to vent the highest pipe, and on mine i need to vent the heater lines as well.

not ideal solution but you might need to do some fiddling with it running so it removes all the air from the system.

Good luck

:thumb:

[THE ELK]

venting my 3.9 from the bleeder on the themersat housing , i let the fan cut in and place a tube on the opening and while running let the air out, she then drops to 1000 rpm, let it cool and it returns to at lease 1600rpm if not more,
i'm thinking that i must have the smallest of leaks, when cool, which collects air, if you see what i mean,

[TINKA]

What sort of setup have you got up on your cooling system, is it a sealed system and is there any possibility that there is not enough water in the system so that as it cools down is sucks water back into the system. One other point if you are running carbs on your engine and it is the auto choke that is causing you problems just get rid of the choke all together these cars do not require a choke a couple of seconds to hold the revs on first start up and after that she should be fine. If you did a survey on here you would probably find 90% plus have no choke on their car.

[tonym]

Originally Posted by TINKA

What sort of setup have you got up on your cooling system, is it a sealed system and is there any possibility that there is not enough water in the system so that as it cools down is sucks water back into the system. One other point if you are running carbs on your engine and it is the auto choke that is causing you problems just get rid of the choke all together these cars do not require a choke a couple of seconds to hold the revs on first start up and after that she should be fine. If you did a survey on here you would probably find 90% plus have no choke on their car.

He already mentioned it was an efi in his first post Martin. If it is a rover, what automatic choke are you using? the standard efi doesn't have an auto choke; if it's a flapper (unlikely on a 3.9) then it has an extra injector for cold starts and if its hotwire then more fueling and stepper motor controlled by ecu. I normally bleed mine by cutting the bottom off a large plastic bottle, putting that neck first into the rad filler with anti freeze solution in and undoing the small hose that goes to the plenum heating area until water comes out, then it's bled. Hope this helps a little :thumb:

[THE ELK]

hi thanks for you input,
lump came from a 1990 range rover, was running fine till she boiled over last week, bleed with a hose attached and running squeezing evething possible,shuts down to 1000rpm but creeps up to 1500rpm,is there a way of disconnecting the choke?

[Purple AK]

Elk. Sorry to be negative But have you considered that as it boiled over, MAYBE it has blown a head gasket? And the returning air you are getting is in fact not trapped air, but compression pumping into the cooling system

[THE ELK]

doom and gloom !!!
not that serious, the expansion tank dosn't get hot either,think i'll look at changing the carbs,would be nice just disconnect what i've got,(some how)

[THE ELK]

hi, traced it to the stepper motor not shuting off, faulty maybe or not being told to shut,
if i drain coolant off while running it seems to shut it down, other wise 1500rpm minium,if i pinch the tube from the stepper motor tick is over fine,and runs fine!
any easy test ???????