No Pressure In Radiator Hoses ?

[reeceo21]

as the title says what would cause this. i was thinking thermostat so i will change that tommorow. is there any other factors which could cause this. my water pump has just started noticeably leaking. could this cause it ? also out of curiousty has any one ever had really bad fuel economy and then fixed it. the mechanic thinks everything is fine but only 250ks to a tank

[Mayuri Krab]

Worn out radiator cap not holding pressure?

[89CAL]

+1

Cap creates the pressure in the system. The pump only creates flow. Depending on the size of the leak that may have an affect but it sounds like it's only dribbling out the telltale so shouldn't affect pressure to much. But that said if it's leaking you will have to change it out. May as well do the timing belt etc while your at it unless that has only recently been done

As for fuel economy, depends how you drive and what conditions occur when your driving, e.g traffic, highway driving

If you boost lots you will chew fuel. You could have a faulty O2 sensor, also try resetting your ECU as it's easy to do (that is if you have a standard ECU)

if you have an aftermarket ECU then the tune might be to rich

Edited August 24, 2011 by 89CAL

[tiberis]

A small leak can very easily result in you having no pressure.

The leak is only small because there is no pressure, there is no pressure because there is a leak etc... etc...

I just replaced my radiator because it had a small leak out of a tiny crack, cap was fine but system was never really under pressure.

Thermostat only regulates temperature, does not affect pressure. So only replace it if it is broken.

+1 for O2 sensor on the end of its life could also be combined with temp sensor not having a correct reading (your coolant system isn't 100%) and therefore always keeping it a bit rich (is your idle always high even after car is hot, like over 1k RPM? that could be a sign of temp sensor not reporting correctly).