Hi All

My Felicia diesel has always read a bit low on the temperature gauge and lately seems to be getting lower still. It reads somewhere halfway between the bottom and the normal mark and almost never goes higher so I decided to replace the thermostat and sender today. (Who's idea was it to put the thermostat underneath?)

Anyway, the temperature now comes up to normal much quicker and my low revs stutter seems all but gone.

Now the bad bit - if I stop and let the car idle the temperature keeps climbing well past the 110 mark with no sign of the fan kicking in. I chickened out before hitting the red and put the heater on full blast. Does it sound like I need a new fan sensor too? I've never heard it run in all the years I've had it. I don't know whether it's hotter with the new thermostat or maybe it's always been like this but the gauge just wasn't showing it.:confused:

Thanks

Mitch

The heat on mine climbs pretty quick (stuck in traffic usually), but my fan kicks in normally before it gets into the red (about 3 / 4 the way up the dial seems about right)... then again my temp sensor is ooold and it could be hotter than I think

My 1.6 Felicia decided not to turn on the radiator fan as well - the same symptons as you have. I replaced the fan switch and it now works as it should. You can hear the gan kick in beofe the temp needle reaches the upper end of the normal temperature range and it doesn't go out of that range.

I think I may have fitted a duff thermostat too. Over the last couple of days I've been monitoring it and it just seems to climb steadily, even when moving.

The symptoms before this were that it was cool all the time on the gauge so I thought I'd find the thermostat stuck open (which it wasn't). I thought I'd save myself some hassle by doing the sender and stat at the same time but I think I replaced a perfectly good thermostat.

I think the thermostat's going to have to come back out again and see about the fan circuit then.

Could be the water pump ?

Could be the water pump ?

I didn't have this trouble before the sender and thermostat went in so hopefully not. Would there be any other signs if it was the pump?

I can bring the temperature back down by putting the heater on full and opening the sunroof and windows so I don't think it would be the pump...

A silly question maybe, particularly since I can no longer remember the exact details when I changed the thermostat on my I.9 D since it was so long ago, but I'll ask it anyway. Are you sure you put the thermostat in the right way round? I realise that it may only go in one way, but I've heard of other cars where that was the problem. Just a thought.

That's a good point, it wasn't genuine Skoda so looked considerably different but I think I got it the same way round. I'm going to put the old one back in this weekend, it definitely wasn't stuck open as I'd thought and I had none of this trouble with it.

I've had the heater on to keep things on normal this week and that keeps it bang on centre but could get a bit uncomfortable as summer arrives.

Replaced the replacement thermostat and had the wiring to the fan switch and the switch itself replaced and now I at least get a steady temperature although this is half way between the "normal" mark and 110 degrees. At least it doesn't just keep climbing now.

I've had the fan running today after leaving the engine idling for a while and I'd swear I've never heard it run ever before so it's probably been broken since I've had the car, luckily I don't usually get caught in jams. It ran for a while after switching off, briefly went to a faster speed,then shut down and there's no way I could have missed this before.

Looks like the first thermostat I put in was duff but at least it uncovered the fault on the fan circuit. I may try the old temp sender again though to see if it reads normal on the gauge then. Or I may leave well alone while I'm ahead.

What colour band do you have on your sensor? If you look at threads relating to problems when starting the 1.9 diesel from warm (not form hot or cold) you'll see that a dodge is to put in the sensor from a petrol engine. I can't remember if it's the 1.3 or the 1.6, but the point is that it forces the glow plugs to come on every time you turn on the ignition, so the warm start problem disappears (although it doesn't address the root cause of this problem which remains a bit of a mystery). I did it, and it worked with a yellow banded sensor, but after that the temperature reading was always higher, more or less where you describe it now. Since I hadn't changed anything else, and since the thermostat is a mechanical, not an electronic, device, it can only have been an incorrect reading due to the incorrect (but functioning) sensor.

So, that's a long winded way of saying you might like to check the sensor, maybe by putting the original back in.

Again, just a thought!

Mr Music

It was green the same as the one that came out. The new one's not Skoda though, it's interpart or somesuch. I'll give the old one a go on the weekend anyway and see what it reads. It has been easier hot starting as it was spinning and spinning sometimes unless that's just a change in the weather.

help... my diesel felly has had new thermostat, rad switch, full flush through all the wiring checks out but the needle for the temp gets soooo close to the red the first time i nearly needed new undies. however when you relese the coolant cap there is a bit of pressure but the water doesn't boil out.i was thinking that it may be the coolant sender giving a false reading. has anyone had the same or similar problem? if so how did you resolve it.

Does the fan kick in at all? Mine had broken wiring at the connector on the switch at the radiator.

Is the temp sender the one with the green band? I read that you could fit others to help with warm starting but I would guess that would muck about with the reading on the dial. (I'd have thought low rather than high though.)

no all the fan wiring is ok new fan sensor fitted last week and the fan kicks in 1-2mm before the red (according to the guage around 120 degrees) the sensor has no banding but has a small green dot.i can find no signs of a short back to the dash and all the earths have been cleaned.

My replacement sensor has a green dot and that reads high too. Do you think the fan would come in sooner if it was really that hot? You could be right about it being the sensor.

it's the only thing that hasn't been replaced. i will check the voltages to and from the sensor later and see if there's an obvious reason.

just had a look at the wiring diagram. pin 2&4 goes to the dash and 1&3 goes to the DECU so the read independantly from each other which might explain the engine running ok even though the guage reads incorrectly. will let you know what i find.

My replacement sensor has a green dot and that reads high too. Do you think the fan would come in sooner if it was really that hot? You could be right about it being the sensor.

The fan is activated my the temp sensor in the fan switch.... which is independant of the ecu/dash temp sensor.

The fan is activated my the temp sensor in the fan switch.... which is independant of the ecu/dash temp sensor.

That's what I was getting at, so long as the fan sensor is working and doesn't think the engine's hot then maybe it's not as hot as the dash sensor thinks it is:)

fan sensor checked out ok as it should (it's new) the problem is the coolant temp sensor there are 2 built into the sensor unit one for DECU and one for the dash checked both and got very different readings from each, so now waiting for the new sensor to turn up.

fan sensor checked out ok as it should (it's new) the problem is the coolant temp sensor there are 2 built into the sensor unit one for DECU and one for the dash checked both and got very different readings from each, so now waiting for the new sensor to turn up.

May explain why mine runs better with the new sender but the dash reading is high. I was thinking of getting another but tempted to leave it as it runs better than it ever has and the fan very rarely kicks in so doesn't appear to be getting that hot.