Underheating & fan has never come on

I'm wondering if someone can help me with this problem, been searching the forums for days looking for posts that help.

I've got a 94 1.7TD and the temp gauge will only just show over 1/4 sometimes a tiny bit higher, but never up to 1/2. Because of this I've never heard the fan running to cool it down.

From other threads, it seems that it could be the thermostat suck open, dodgy fan switch or gauge sender unit / coolent monitor (can't find those on the engine, where are they?).

Any ideas?

Normally an engine running cool is alright, but I hate the idea of the gauge being wrong and the engine getting way too hot (although I've done 200 miles + at a time and it runs fine. . . . but fan will never come on even after such a long drive)

I want to test the fan to see if it works, but have no idea how to power it up.

You've never sat in traffic? Lucky, lol.

Anyways, the Fan switch will be on the rad, should be the only two wires running into it, anyway, remove the plug (going into the rad) and connect a bit of wire over the two terminals in the plug. The fan should then come on. If it does then I would have though all is fine, If not, then start checking fuses

Jon.

Hi mate,

As MEP says, the fan switch is mounted on the rear right hand side of the Rad about half way up.

The 1.7 diesel unit normally does run very cool, and around 1/4 to 1/2 in non traffic situations is ok. You could always leave it running for a while stationary and watch the gauge rise if you want to check it.

Alan

Same place as one the Panda's then, though I probably would be

Generally on FIATs the thermostat is the first thing to fail, of the things you said.

If you feel the radiator top hose shortly after starting the engine, it should be cold. Then when the engine has warmed up (five-ten minutes?) the radiator hose should become suddenly hot. If instead the hose becomes steadily warmer, then I'd suspect the thermostat failed in the slightly-open position. You can of course take it off and inspect it. Ideally, the thermostat is air-tight or very nearly so.

-Alex

Thermostat is mounted on the right hand side of the engine. It has the hose from the right hand side of the radiator going into it. Looks a bit like a funnel where it meets the thermostat unit.
The sending unit for the temp gauge is at the back of the thermostat unit facing the bulkhead.
The fan switch is located on the right hand side of the radiator at the rear. It is about half way up.

All of the above are easily and cheaply replaceable. With a stuck open thermostat, I would expect it to take a long time for the gauge to start moving, is this the case? It wouldn't however prevent the coolant temp from rising over 1/4, it would just take it longer to get there. I dont see it being stuck shut, as that would cause overheating problems, rather than running cool.
The fan switch and the temp sender work independently of eachother, so in theory, your temp sender gauge could be faulty, but the fan will still come on when the fan switch reaches the required temperature.

It is rare to need the cooling fan on the 1.7td if everything is working correctly (especially if you never get caught in traffic or sit stationary for long periods of time). Most diesels, especially the older ones, run cooler than petrol engines anyway.

Hope that helps,
Alan

Alan

A BIG thanks to everyone that's helped.

Alex, I'll have a feel of the top hose and see if it creeps up in temperature or not. Panda, I'm not going to get a shock putting a wire across the plug am I?

Can't thank you all enough


Hi Alan.

The temperature gauge doesn't take long to get to 1/4 but as mentioned, it just never goes above it. What I'll do when I get in from work tomorrow is park in the drive way and just let it idle for 10(+?)mins and see what happens.

* crosses fingers and hopes something doesn't go POP! *

Lol, no. I done it in the Panda in a service station outside Tamworth the week before last, and a straded lady still asked me to look at her Auto Avensis even though I looked like I hadn't a clue what I was doing (I did really, roughly, though).

Jon.

I did the first test today (the easy one)

Drove home from work and left it ticking over on the drive, it took around 5 - 10mins to get to 1/2 and the fan kicked in right away. So the fan works

Next thing I'll test is starting from cold to see how the top pipe warms up. Fingers crossed because I got a quote for £54 for the thermostat (because it's built into the housing)

Did the oil the other day as well, so figured I'd to the belts soon. . . . got quoted £74 for a timing pack (the 2 belts, tensioner and idler) . . . does that sound about right?

Good Good. Sounds like your getting it sorted. Have you bled the system? You'll find out if you need to when you check the top pipe like you say your going to.

Keep us all updated