Hi All

I am new here so please forgive any stupid questions and if I ask the blooming obvious. My daughter runs a Skoda Felica 1.3 MPi R Reg with approx 23K on the clock, it’s her first car having just passed her test. We seem to be getting really poor MPG each thankful only lasts approx 320 miles; also if it stalls it is difficult to start. I need to change the exhaust as the back box is a blowing a bit. We dropped it into a local Skoda dealer and they narrowed the poor consumption down to ‘2 sensors’ - £50ish and £150ish each’ but they said replacing them may not fix the consumption. I have not had a look at the spark plugs.

I have had a quick scan through the posts here and some suggest that the poor consumption is due to a ‘faulty stat’, I take this to mean the thermostat.

What does the great collective think is causing the poor consumption?

Does anyone know where I can get a new thermostat?

Many thanks

Mark

I recently bought 1998 Felicia, I'd also like to know if there's a way to increase fuel efficiency, I'm only getting 25-30MPG.

I recently bought 1998 Felicia, I'd also like to know if there's a way to increase fuel efficiency, I'm only getting 25-30MPG.

New thermostat is available from Jorily, either direct or via eBay. Less than £20, 10 minutes to fit. It will be the improved version as the old original type is renowned for breaking.

I replaced mine as the guage didn't register at all unless stuck in traffic. It has not improved the mpg though. Replace it anyway, as it forms part of the ECU's information gathering and will eliminate any problems associated with coolant temp.

I am currently trying to find out why my mpg is so poor, considering I keep reading on this forum about 40mpg. I wish :'(

If you hear in the engine the chain (the noise will seem to come from below) there's your problem

if you hear in the engine the valves or you dont at all (It feel like a type writer but loud from above) then the valves are to loose or to tight

if the car runs fine but feels heavy is a rich mix (exhaust will be chacoal black)

if the car runs fine but feels light is a lean mix (exhaust will have water coming out)

do check plugs heat range and spark color, if it has a canister coil check wires and spark (should be loud, crisp and bright)

do a complete maintenances on the engine (filters, fluids, valve gap, timing, cleaning, etc..) it can give you back the wasted F.E.

correct me if i'm wrong but I thought 320 miles from a tank is pretty good.

I work that out to be about 35mpg, which is good if you're getting that from driving around towns. I usually only manage 320 miles if I am driving long distances along the motorway

ditto, the Fellys tank is only about 9.5 gallons (imp).

Another possibility is the engine needs a good, long, high speed run to clear the cr@p out, only 23k at that age means a LOT of short distance usage at a guess.

Yeah, my sons 98 Gli estate was getting above 40mpg average (after he passed his test), and while we were using it to give him driving lessons our combined average was 48mpg (mostly cross county with some dual carriageway).

I dont know what daily mileage your daughter is doing, but my son does about 200-250 miles a week, mostly longish trips to a college 25 miles from home.

That was the car he crashed, I dont have any figures for the replacement (punishment) Lxi "P" plater.

I too had experienced poor mpg (around 29mpg mixed driving) until I replaced the thermostat which had definitely broken (Plastic lugs snapped off). I have just worked out my last tank full and have averaged 46.4mpg which is based on predominantly A road driving and trying to keep the revs in the green whilst building up speed. I am surprised and very happy with this for an 11 year old car that cost me £700 a couple of months ago!

I also recently travelled a full tank doing motorway speeds and not really paying attention to the revs whilst getting up to speed and averaged 39.5mpg. My conclusion is that the thermostat has made a big difference, I have to admit that the ambient temperature has increased a few degrees but clearly the car is much happier operating at optimum temperature.

All I have to do now is touch up the key scratch which decorates the car along the entire length and I will have a relaible and not too shabby looking car, the felicia is a winner as far as i am concerned!

Andy

I've just ordered a new thermostat sensor and the MK2 housing piece, are they both easy to fit?

I've just ordered a new thermostat sensor and the MK2 housing piece, are they both easy to fit?

Very easy to fit, the housing is held on by three bolts if i remember correctly. The sensor is simply held in by a plastic clip, which you pull off. It can be a bit flimsy though so be careful when pulling it off just to ensure it doesnt break as you will need it again (unless you have a replacement). The sensor can then just be pulled out. You will probably lose a bit of coolant but no probs there as long as you refill

Ok, thanks. When I checked the sensor before there was just a rubbery/plastic? thing on the end and not the metal piece on all the photos, does this generally mean a new one is needed?

Ok, thanks. When I checked the sensor before there was just a rubbery/plastic? thing on the end and not the metal piece on all the photos, does this generally mean a new one is needed?

The sensor will come with the metal part on the end as this is the part that actually 'senses' the temperature. The clip that holds the sensor in the housing should look a bit like a horsehoe.

What I meant was there was no metal bit on the sensor I took out today, so this means I need a new one? :p Here's a photo:

Also the coolant is a brown murky colour, should I flush it out and put new coolant in when I change the housing piece? Thanks.

What I meant was there was no metal bit on the sensor I took out today, so this means I need a new one? :p Here's a photo:

Also the coolant is a brown murky colour, should I flush it out and put new coolant in when I change the housing piece? Thanks.

Yeah it definitely looks like you need a new sensor, the metal part is acutally part of the sensor (as you may have seen in other pictures of the sensor) so once you receive it, just plug it straight in. Probably worth flushing the system and putting new coolant in. Haynes manual says your supposed to do it every three years but when it looks murky, its worth changing. When you take the thermostat apart, check to see if the metal part (and any of other parts of the thermostat) of the sensor has fallen into the housing as it might damage/block other parts if its left in.

There's nothing "missing" from that sensor. There are various types of them around, and that's just one of them. Some are metal, some have the plastic "blade" construction.

However, whether it's the "right" one seems to be a topic of discussion - I've seen some say that the blue-ringed sensor is the wrong one for a petrol MPi car, but I've got one in one of mine, and it behaves fine - no different when it has an orange one in there (I've tried both).

I've replaced the thermostat piece and a new sensor arrived today, which I've fitted and it's now on the 90C level. Thanks for your help! I will go for a long drive later today to see my MPG.

Edited 12 April, 201016 yr by ONW