Pop up Lights when hot

[wparslow]

Happy New Year everyone. Well, I', 1,500 miles into using my +2 as an everyday car and I wanted to throw this one out to see if anyone has a similar experience.

Basically if my car gets hot (80 degrees or more) the headlights pop up within half an hour of the car being switched off. If I drive the car a couple of mkiles without allowing it to get hotter than 70 degrees the headlights will stay down indefinately.

This is getting a bit irritating as my car is progressively getting hotter the more miles I put on it - it will be going to Matty's to be checked out for that soon, but in the meantime any ideas on the pop up phenominon?

Thanks in advance - Wayne

[tdafforn]

Is the system a failsafe system?
ie. the lights come up if the vacuum system is disconected?
if it is, then it could be that the non-return valve on the intake manifold is a bit knackered, and is failing at higher temperatures.
Cheers
Tim

[wparslow]

Yes, it's a +2 130/5 so the lights pop up if the vacuum fails. If the car runs without gettihg hot though the lights will stay down for well over a week.

[tdafforn]

Does sound like a leak that is temperature sensitive.
Could well be the non-return valve, as it is in contact with the inlet manfold and would be effected by changes in car temperature..
Cheers
Tim

[rgh0]

I agree that it is most likely the leak is in the non return valve but could be in many other locations in the vacuum system ( eg the solenoid valve, the tubing, the tube connections or the actuator diaphram). It you get it all right your head lights should stay down indefinitely.

My record maximum is more than 6 months without the headlights coming up when my plus 2 was waiting for a new second hand rear screen and I did not drive it or start it in that period.

Rohan