Club 80-90 Forums

Hi all, have recently signed up to the ranks of T25 owners! Have a 1981 2 litre air cooled, its obviously been through the mill a bit as there are some parts missing and I'm currently trying to work out what I need to get. However, it runs well (now!) and was cheap.
Working my way round with the Haynes tonight, I discovered the existence of the air flaps to stop air entering the fan housing until the engine's warm. Worked by a little thermostat and cable according to the manual. Except there is no thermostat or cable or bracket!

At present, the lever on top of the rod that links the flaps is as far back as it will go, almost vertical. This looks as if the flap is open in this position, i.e. allowing cool air in. Am I right? The lever can be moved forwards (towards the front of the van) to an almost horizontal position which I'm guessing closes the flap for cold weather starting.

Obviously I don't want to overheat the van by denying the engine air, but also wonder if I'm going to have trouble starting once the weather gets colder if they are indeed open all the time.

if the thermostat does not work the flaps, then they should be kept open

sleepyrider wrote:Hi all, have recently signed up to the ranks of T25 owners! Have a 1981 2 litre air cooled, its obviously been through the mill a bit as there are some parts missing and I'm currently trying to work out what I need to get. However, it runs well (now!) and was cheap.
Working my way round with the Haynes tonight, I discovered the existence of the air flaps to stop air entering the fan housing until the engine's warm. Worked by a little thermostat and cable according to the manual. Except there is no thermostat or cable or bracket!

At present, the lever on top of the rod that links the flaps is as far back as it will go, almost vertical. This looks as if the flap is open in this position, i.e. allowing cool air in. Am I right? The lever can be moved forwards (towards the front of the van) to an almost horizontal position which I'm guessing closes the flap for cold weather starting.

Obviously I don't want to overheat the van by denying the engine air, but also wonder if I'm going to have trouble starting once the weather gets colder if they are indeed open all the time.

If the lever on top of rod is as you...as far back as it will go, then it should be ok

My vans has never had the cable or thermostat fitted and happily started in the snow last year. I'm pretty sure mine is held open by a spring on the rod?

Sounds Ok then - thanks!

VW designed these flaps so that in the event of thermostat failure, air would still make its way into the areas most needed. Its not uncommon to find the flap thermostat (particularly in bug engines) removed altogether, and often because the rebuilder forgot it, wasn't sure how to fit it correctly or believed it was fine without one. They do run better with this thermostat from cold, requiring slightly less fuel to get the engine warm so there is an economy side to this as well as a practical application. In any event if no thermostat exists, the flaps should be in an open state at all times.

Hello,

As you havn't got a thermostat, you join the cool cruising philosophy club

As has been stated, the VW engine by default is designed to pass as much air as possible, restricted only by the flaps and thermostat for cold starting.

Cool cruising came in in the 70's, where you removed everything that could restrict air flow, and adopt the following starting procedure: Start the beast let it run till it gets lumpy, (45 secs). Switch off. Roll a cigarette , then restart. Cruise cool.

The science behind this is that the inlet manifold cools down rapidly when air first passes through it (thermodynamics). You stop the process, and let the heat of the engine warm things through, before restarting.

This was ok then when petrol was 6 shillings and eight pence a gallon (I'll let you work that out).

Beetle and t2 campers often had a little electrical heater pad fitted to help things along

The T25 plenum chamber (ask your mother) is better designed and will not overcool and thus waste fuel,(sadly no longer 6/8d gall .

In short, dont worry, cruise cool, enjoy,

Cordialement,

took my flaps out of mine - it's pointless having them in on a CT engine as you have to hold them open as it relies on the thermostat/cable to open the flap; if it fails then the flap fall closed and starves then engine of air and forces it all through the oil cooler - nice design there VW!