General couple of questions about 750 FIRE

[panda_owner]

Now the winter has come and my panda seems to spend 10 l/100km of fuel instead of 6-7 l/100km because of couple of things I have noticed that seems wrong. This is the first time I experience this. So, if someone knows something about this, I would be happy to get some answers to this problem:

1. in the air filter housing there is a 'switch' (not an eletrical, but mechanical, depending of temperature of intake air) that decides to take air directly from outside or from very hot exhaust pipes that comes from the engine. The termoelement that looks like spring around some cylinder object is set to take air from cold outside of car when everything is cold (I mean the engine and the rest of the car). To me, this seems to be wrong, since the purpose of this would be to get hot air when the engine is not warmed up. But I would like to know for sure.

2. Seems to me that coolant thermostat is broken and the cooling water always runs even if the engine is cold. I came to that conclusion because the water hose that runs into radiator is slowly becoming warmer. If the thermostatic switch would be in order, the hose would be cold, and then in a very short time it should get very warm, right? I'm not 100% shure about this, so tell me if I'm wrong. And another thing is that I cannot find that thermostat (his location), so please tell me where it is.

Thanks

 

[alexGS]

Hi,

Sounds like you're spot-on with both points.

The thermostatic air intake is probably operated by a wax capsule in a small brass housing. It's probably faulty. This is not a major concern however, unless you live in a particularly cold climate. You would probably be best to arrange it so that you can manually operate the flap (i.e. take out the 'switch' with thermoelement and figure out some way to jam the flap in either position). Older FIATs had a manual setting - only needs one adjustment and you know it's right for the rest of the season.

A much more likely problem is your second point. Your thermostat needs replacing so that the engine reaches its proper temperature - this should have a noticeable effect on economy. The thermostat is held to the end of the cylinder head by two bolts. It will have a radiator hose connected to it, and also a heater hose. The thermostats frequently fail in the stuck-open position, which gives the symptoms as you describe.

I presume you don't have a temperature gauge... so the next best way I can think of to check for correct temp. is to drive the car for about 5-10km then let it idle for a minute. I would expect the radiator fan to cut in, provided your ambient temp is above, say, 15 degrees.

Probably the easier (and more specific!) way to know for sure is to simply remove the thermostat and inspect it. The plate should be fully closed, until it's heated to 85-90 degrees.

A new thermostat should only be a moderate price (somewhere between the cost of one and two new tyres!) Sorry I can't be more specific but that was just a quick currency conversion...

-Alex

 

[panda_owner]

thanx for your reply, alex. You mean the cylinder head - under the plastic cover with the timing belt?

 

[Enzo]

The thermostat is bolted on the head, spare wheel side(two 10mm bolts)!Then the upper pipe coming from the radiator is clamped on it...

 

[alexGS]

Yeah - as Enzo says... not under the timing belt cover, that's the water pump

-Alex