Hi folks,

Any answers to a problem I'm currently having would be great. i have 1999 1.3 mpi Felicia and I've replaced the engine. I had problems with pipes leaking etc, the usual problems with an engine change. No leaks now, coolant at constant level, just below Max

however the new thermistor switch on the radiator core doesn't appear to be operatign the fan. I've tested the fan and it's fine. I also replaced the gauge sender, but that's a different circuit anyway. I didn't flush the engine before I put in coolant and there is some rust in the coolant. So I have holts speed flush in it now and I'm going to change the coolant. is the rust in the water perhaps "confusing" the thermistor switch? it takes a while to get hot enough to worry me, and I then put on the heater fan to cool the engine.

Help! It's really p*****g me off!:(

Temporarily link the 2 wires to the fan sensor with the ignition on. The fan should run, if it doesn't check the fuse. If it does, the new sensor is faulty....that's assuming the engine is getting hot enough for the fan to need to cut in.

Yes, I'm beginning to think that the new thermistor is pants! I might put my old one back in and see what happens. otherwise I'll visit my local scrappy and find another one from a similar car. It's a real pain as I've just put new coolant in and it's going really well otherwise.

I agree with Dave. The first thing to do is make sure that the fan actually should be cutting in. Most of the cars I've owned with leccy fans they were more like ballast than essential cooling devices (even in traffic).

After reviewing the thermistor situation, I remembered that when I put in the new thermistor unit, I rather "cleverly" put ptf tape on it to help it seal. Now that I think of it, the bloody ptf tape is probably insulating the sensor and as a result it's not getting hot enough. Doh!! I shall remove the unit and the ptf tape and replace and see how I get on. Will keep you posted.

I'm not saying you're right or wrong, but it sounds plausible, if only cos I've never heard of anyone using PTFE tape on a automotive cooling system before!

i used it so seal a leak on the drain bolt - threadlock kept dissolving!

I took off the PTF tape and it's made no difference at all. Damn! So plan B then, either put in the old thermistor or put in one off a scrap car with similar engine. I'm hoping that the new gauge sensor I fitted isn't telling me porky pies, or worse still is affecting the voltage to the thermistor? Is this possible? As far as I know they are two different circuits and the thermister is basically live permanently.

if the fan switch has been leaking some water may have run up the loom or corroded the terminals causing funny readings

:iagree: - the terminals will probably look either grey or green rather than silver or coppery (depending on base material) if this is the case.

iirc the terminals are nickel plated so they should be silvery

iirc it's only the knock sensor(if fitted) that has gold plated contacts

I was thinking in terms of nickel or zinc (silvery) or copper/bronze rather than gold for coppery.

:rofl: that makes perfect sense:rolleyes:

Hi folks, I fitted the old thermistor and I don't think it's working either grrrrr. I get the correct voltage when I test it and when I bridge the terminals the fan starts. Should I be looking for something else, like the amps or watts instead. A local scrappie reckons I've a broken wire in the loom somewhere, but that doesn't wash, if that was the case I wouldn't have any power....would I. My wifes cinquecento (I know a fiat...sorry) has an override switch fitted to run the cooling fan, I don't want to go this far, especially as I'm trying to sell it.

How hot is it getting? Do the top and bottom hoses feel warm? Is it boiling up?

It's getting to the red after a while. Now that you mention it, I must feel the hoses, to my recollection, the top one is definitely getting hot, must feel the bottom one too. Watch this space.

Well the problem has resolved itself. I decided my "new"OE temperature gauge sender must be telling lies. Went to a VW/Skoda dealership for advice. Had a look at the sender, took off the plug to tell him over the phone what it looked like. Was told they couldn't look at it today.Fine, maybe I'll buy a new one and be done with it.Drove off and forgot i hadn't plugged it back in. Stopped and plugged it back in. Driving in town and surprise ditto, the fan cut in.The temp gauge is over reading but shag it the fan works.

Sounds like it could have been an air lock. Did you pour the water/coolant mixture in slowly and run with the cap off until the engine had heated up?

Well the problem has resolved itself. I decided my "new"OE temperature gauge sender must be telling lies. Went to a VW/Skoda dealership for advice. Had a look at the sender, took off the plug to tell him over the phone what it looked like. Was told they couldn't look at it today.Fine, maybe I'll buy a new one and be done with it.Drove off and forgot i hadn't plugged it back in. Stopped and plugged it back in. Driving in town and surprise ditto, the fan cut in.The temp gauge is over reading but shag it the fan works.

dont forget these engines are designed to run quite hot, in fact about the hottest of any car i've driven. guage should read not that far below the red at optimum temp.

my 1300's sat bang on the middle of the temp guage

I have a new thermostat ready for mine for when I can fit it, it seems to run cooler than everyone elses nearer the bottom mark. Hopefully I'll get more MPG if it runs hotter.

my 1300's sat bang on the middle of the temp guage

Mine runs bang in the middle too and never goes above 3/4 as the fan kicks in. With the engine being all alloy i would presume that due to its better heat disipation the engine will run cooler than your typical Cast Iron pushrod (eg Fords in the KA)

A new thermostat complete with new sensor sorted mine out from running on the bottom of the gauge and being slow.

Does the temp sensor on the thermostat housing change only the gauge on the dash, or does it also send info to the ECU?

I think I'll boil test my old thermostat anyway when I take it out to check it is that opening a bit soon.

Does the temp sensor on the thermostat housing change only the gauge on the dash, or does it also send info to the ECU?

It sends a signal to the ECU as well. I think it is slightly different on the SPi Felicia