Technical Fuel Consumption seems rather high

[DemonPandaOwner]

Hello all, and Happy New Year!
I'm after a little advice regards the fuel consumption of my 2004 1.2 Dynamic. The last few times I've filled up, I seem to have gotten through the fuel quicker than before.
1. There isn't a fuel leak.
2. I know it is cold in the UK at the moment, but I've had the car for 12 years, and it's been ok before now in previous winters.
3. I do only do short(ish) trips, but again, my driving habits haven't changed dramatically over the years.

The thermostat appears to be on the blink, as the car isn't getting up to temperature, even on a 30 min + drive. (The best we get is about 1/4 of the way up the scale). Could this be the sole reason for the poor fuel economy? When I topped up yesterday I'd managed 170 miles on 20 litres, which is 6.5 miles per litre, or 38.65 MPG. I may be wrong but this just seems a bit low to me. I now the car is 20 years old, but it's regularly serviced, gets a dose of redex every 5 top ups or so and had the timing chain done about a year or so ago.

Is there anything else I should be looking at? The car does have an issue with "stuttering" in 3rd gear around 1500 revs sometimes, which I have been told might be the MAP sensor, which is on the list to be looked at / replaced, but I've got to wait for the warmer weather as I don;t have a garage to work in, just the cold concrete of the front garden! If there's anything else I should be looking at or checking, I;d rather get it all done in one go.

Thanks for taking the time to read this, and (hopefully) being able to guide me in the right direction. I'm a novice with cars, but my aim in 2025 is to get the spanners out and learn!
DP

 

[koalar]

Plugs need looking at as well

Get a cheap scantool and look at the long term fuel trims

MAP one bolt and thermostat can be done on the road

common problem with thermostate | FIAT Panda (Mk3)

when the weather get cold we get loads of cooling issues heaters only blowing warm P0115 error radiator fans coming on fast. gauge dropping down occationly. gauge only going up 1/4 way 90% are down to a missing rubber gasket inside the thermostat. Because the thermostat is opening and...

www.fiatforum.com

Having a faulty thermostat is the same as burning money, assuming it's faulty, you might as well fix it

 

[jrkitching]

The thermostat appears to be on the blink, as the car isn't getting up to temperature, even on a 30 min + drive. (The best we get is about 1/4 of the way up the scale). Could this be the sole reason for the poor fuel economy?

Yes, it's by far the most likely cause.

What usually happens is that an internal seal in the thermostat fails and allows coolant to flow when the thermostat is closed. The engine can't get up to operating temperature and this trashes the fuel economy.

Replace the thermostat and all should be well again.

 

[eddyweird]

Every car will suffer reduced mpg during the winter months due to air temp and density. Whats the difference between it now and the summer?

 

[jrkitching]

Every car will suffer reduced mpg during the winter months due to air temp and density. Whats the difference between it now and the summer?

This is true, but if the engine isn't reaching operating temperature because the thermostat is faulty, it'll suffer reduced economy whatever the season.

What the OP is posting about is a well-known issue with Panda thermostats, and it isn't about the difference between summer and winter.

I've experienced this exact same issue with my own Panda. Fitting a new thermostat restored normal operation of the temperature gauge and brought the economy back to where it was before. But it will be noticeably worse in winter, even with a properly working 'stat.

 

[eddyweird]

Short journeys and our recent cold weather might never get the temp gauge up to half way especially with heaters on.

 

[jrkitching]

Short journeys and our recent cold weather might never get the temp gauge up to half way especially with heaters on.

It's not considered good practice to put the heater on until the car has reached normal operating temperature; doing so will indeed slow down the warmup, reducing economy and increasing engine wear.

Even with snow on the ground, and gentle driving. with the heater off you should be seeing normal operating temperature within 2 miles if the thermostat is working correctly. But the radiator is very efficient, especially in winter, and it's essential there's no leakage past the thermostat when it's supposed to be closed.

 

[koalar]

Short journeys and our recent cold weather might never get the temp gauge up to half way especially with heaters on.

Post 1

The thermostat appears to be on the blink, as the car isn't getting up to temperature, even on a 30 min + drive. (The best we get is about 1/4 of the way up the scal

Should be up to temperature in 5 minutes, even in winter
Should be half way

cold-start fuel enrichment contributes a 2% reduction in fuel efficiency

 

[jrkitching]

cold-start fuel enrichment contributes a 2% reduction in fuel efficiency

It's a lot more than that!

 

[koalar]

Yes, it's by far the most likely cause.

What usually happens is that an internal seal in the thermostat fails and allows coolant to flow when the thermostat is closed. The engine can't get up to operating temperature and this trashes the fuel economy.

Replace the thermostat and all should be well again.

Start with the obvious

But I doubt it will fix

The car does have an issue with "stuttering" in 3rd gear around 1500 revs

 

[jrkitching]

The car does have an issue with "stuttering" in 3rd gear around 1500 revs sometimes

I doubt it will fix that either. But neither will it account for the car not reaching operating temperature; these are most likely two separate issues.

Start with the obvious

Yes, change the thermostat first and take it from there. That needs doing whatever.

 

[koalar]

It's a lot more than that!

That's from some tests run awhile ago, unfortunately the links are now dead,.I can't remember what car was used or the exact testing

What ever the real world difference is, you might as well change the stat as you are just throwing money down the drain by not changing it

 

[jrkitching]

What ever the real world difference is, you might as well change the stat as you are just throwing money down the drain by not changing it

Yes, I was losing around 8-10mpg overall just before changing the 'stat.

Can't be good for engine wear either, and emissions will likely be off the scale.

That's from some tests run awhile ago

Back in the early seventies, some motoring journal did some tests; running with the choke fully out got economy below 7mpg. Eek!

 

[varesecrazy]

I've experienced this exact same issue with my own Panda. Fitting a new thermostat restored normal operation of the temperature gauge and brought the economy back to where it was before. But it will be noticeably worse in winter.

My 1.1 also..

In similar cold/ snowy weather to now,

The temp would actually fall away when coasting downhill..

Chances are you don't travel far enough to see this

@£15 thermostat sorted that

 

[eddyweird]

If you do change it soon DPO let us know the the difference. Think 8-10 mpg extra will sway a lot of readers to get theirs done if their engines are not getting to temp.

 

[DemonPandaOwner]

Morning gang! So, I've finally got round to trying to fit the new thermostat for the Demon.
However, taking things apart to get access (as per the YouTube video I found) there seems to be a lot of oily residue. Is this normal? At the last MOT I was.told there was a slight oil.leak but they couldn't see where it was coming from and there was no discernable difference in oil levels.

So can anyone shed any light here?
Thanks.

 

[varesecrazy]

That's a bit of history there..

It WAS the ignition distributor mount, the O-ring is still there to seal oil

For what it is now.. You can just add "instant gasket" type sealant to the ring and mating faces

 

[DaveMcT]

The top cover is leaking. New gasket and O rings should sort it. Give it a blast of water soluble cleaner before opening up too much. Brake cleaner is OK but £costly as you'll need a lot to wash off that much dried grease.

Not using the heater when engine is cold usually means the screen mists up even more than usual. I would rather lose a couple of mpg than crash the car.

The ideal solution is a block heater but good luck trying to find anything that will not cause more trouble than it solves.

 

[DemonPandaOwner]

**UPDATE**
So I've put more fuel.in today after the thermostat was replaced and we've got a figure of 41.32 MPG. Not a.great improvement over before but a tiny bit. TBH most of the driving has been short journeys around town, so hopefully with some.longer journeys coming up things will.improve. Have put new.plugs in today along with a new MAP sensor, so we.will see how things go!
Just wanted to leave a quick update for anyone else who's having similar issues

 

[The Panda Nut]

The top cover is leaking. New gasket and O rings should sort it. Give it a blast of water soluble cleaner before opening up too much. Brake cleaner is OK but £costly as you'll need a lot to wash off that much dried grease.

Not using the heater when engine is cold usually means the screen mists up even more than usual. I would rather lose a couple of mpg than crash the car.

The ideal solution is a block heater but good luck trying to find anything that will not cause more trouble than it solves.

ays of the heater making much difference went with the introduction to the permanent circulation systems and air blending. It will take a little longer the heat up with the heater on but not much. Mine has the climate control and the heat will not work until it has enough warmth in the system to do something. This normally takes half a mile before it piles in to the party, even in freezing conditions.