Idle problem after replacing waterpump

[2002jm]

Ok, my first crazy question for the experts on this forum:)

I am thinking about buying a 318is. The owner replaced the waterpump and has told me he needs to bleed the system.
Is it possible that air in the lines would cause major idle problems?
I was thinking the temp sensor is getting air past it so it is not reading correctly.
I was sent a video clip of the engine 'running' and it will not idle at all. Have to hold the trottle open to keep it running.
What do you think?
jm

Ok, more information, the owner said it was rough before he replaced the pump, but now it seems worse?

[EN318isPDX]

Ok, my first crazy question for the experts on this forum:)

I am thinking about buying a 318is. The owner replaced the waterpump and has told me he needs to bleed the system.
Is it possible that air in the lines would cause major idle problems?
I was thinking the temp sensor is getting air past it so it is not reading correctly.
I was sent a video clip of the engine 'running' and it will not idle at all. Have to hold the trottle open to keep it running.
What do you think?
jm

Ok, more information, the owner said it was rough before he replaced the pump, but now it seems worse?

This is a very common issue on the M42, I doubt that the water pump could cause idle issues (but its worth a try). I'd check into the mess of vacuum hoses and make sure that one has not come disconnected. I had my ICV unplug from the intake and it would run but i had to keep on the gas. Also poor fuel pressure can cause a bad idle since these motors require 91 octane from the factory

[2002jm]

Thanks, will pass the information on and see what happens.
jm