trapped air

[Rob.S]

Trying to fix a problem of my 16v sometimes idling at about 1200rpm I changed the thermostat + fueling temp sender on it this morning (after draining off some coolant from a hose going to the expansion tank until it was below the stat housing level) After topping it up it now idles at about 1500 - 2000+ rpm and all I can think of is there is air trapped.

I Followed the normal procedure of getting coolant flowing from the radiator bleed screw and then topping up the expansion tank then running it without the cap on until the fan cuts in. Ive also squeezed hoses, ran the heater, revved it, poured more into the expansion tank and drained from the radiator bleed screw etc etc but the revs are still sticking. Any ideas what it is and how I can make sure there is no air trapped? I flushed and changed the coolant only last week and it seemed ok after that apart from the 1200rpm revs problem still being there.

Thanks in advance for any advice!

Rob

 

[cliocup]

Throttle cable problem I should think. The plastic shroud and casings fall apart and the cable sometimes doesnt go slack enough when you release the pedal to allow the throttle to fully close, hence, high tickover.

If you had air in your coolant, the car would run very hot and the water would boil etc.

Have a play about with the cable and check theres no tension when throttle closed.

 

[Rob.S]

Thanks but Ive had that problem before and it doesnt seem to be that although ill double check in a min! The water does seem to be boiling so I guess that confirms air trapped Not sure what else to try though to get it out and whether to risk driving it the 10 miles back home since Im at my girlfriends now.

 

[Rob.S]

Ive just had another play around and found the plug on the throttle (potentiometer i guess) was the problem. Think I must have spilt coolant in it or knocked it lose. Its still running hot but Ive sorted one problem out!

 

[Nick Read]

The high idle problem is often down to a faulty thermostat that basically tells the ECU to choke when the engines already warm and not choke when its cold.

 

[Nick Read]

i know youve just changed the stat but most of the time people will tell you to clean this and that but it often comes down to a thermostat problem.