General Panda 1.1 2005 Temperature Gauge Readings Advice

[RobCa]

Hi,
I have a 55 reg 1.1 8v Panda and I'm not sure the Temperature Gauge is reading correctly, your advice on how yours operates would be appreciated.
The History: I bought the car with the head gasket blown (some say I'm nuts!). Anyway, the head was skimmed, valves ground, new valve seals, new cambelt, gaskets, temp sensor assy, replacement radiator etc. Several oil/gasket changes and its been back on the road running well.
The old radiator was leaking which may have contributed to the original problem but I also suspect that the temperature gauge is not indicating correctly when it's warm/hot and hence other overheating signs may have been ignored by the previous owner because the gauge showed ok! I want to be sure that it doesn't overheat again without a temperature gauge warning.

If I plug in an OBD scanner, I can see the temperature being reported as expected. The fan kicks in at 97 deg, cools it down to about 93 deg, etc. It's the dashboard gauge I'm not sure about. In normal operation it rises quite quickly to the quarter mark (about 65 deg on OBD). It then continues to rise to the half mark (level with thermometer symbol) and stays there. It gets there at 80 deg plus and stays there during the fan kicking in and out. It only moves a maximum of a needle width from the halfway mark! I would have expected to see the needle move up and down a bit as the temperature changes from 85 to 97 deg.
Can others advise how their temp gauges behaves please.
I did fit a new temp sensor when I did the work as a precaution but the old one showed the same on the gauge.

Many Thanks
Rob

 

[koalar]

Fans should kick in at slow speed at around 95C

This is still within the dead zone in the middle of the gauge

 

[mjc506]

Yup, normal. The temp gauges on most modern vehicles have a significant dead zone around 'half' that covers the normal operating temp range - mainly so the driver sees the temperature as 'normal' and doesn't worry about the small fluctuations.

Mine (although I'm assuming most are the same) hits the middle at 80°C and stays there at least until 97°C when the fan kicks in (didn't bother trying to get it any hotter during testing). https://www.fiatforum.com/threads/169-1-2-thermostat-bypass.492006/ for some gory/boring details...

 

[DaveMcT]

ar instrument gauges are heavily damped and do not attempt to show accurate numeric values. What matters most is the thermostat opens and closes correctly. Yours is doing the job so really no worries.

I say this, because these engines carry very little coolant in the block and head. Any loss of coolant may well weaken the head gasket before the ECU puts on the warning light or move the gauge enough to read red.

 

[koalar]

Hi,
I want to be sure that it doesn't overheat again without a temperature gauge warning.

The temperature sender is high towards the top of the coolant system

If there is a coolant leak you will hear the engine banging and smell burning oil before seeing much on the gauge

Without enough coolant for it to touch the sensor it’s only reads the conducted heat and it will never go much above 1/2 way.
I put the heaters on hot if the needle goes about one needle width above half way this does two things. First it checks the coolant level. If it’s blowing cold pull over as soon as it safe and top up. Second if it’s blowing hot it adds another fan to a radiator, it’s surprising just how quickly it brings it down

 

[RobCa]

Thanks all for your feedback, most useful. Its good to get confirmation that it's normal for this car. I guess I'm being a bit finicky due to the head gasket going once already!
Thanks

 

[DaveMcT]

The head gaskets are tough, but they can't handle over heating. The first warning you get is a gurgling noise as steam goes through the heater. The engine stops soon after.

 

[koalar]

The head gaskets are tough, but they can't handle over heating. The first warning you get is a gurgling noise as steam goes through the heater. The engine stops soon after.

The coolant system on these engines self bleed very well

If you loose enough coolant the heaters stop blowing hot first. Followed by knocking under load a smell of oil

If you hear gurgling behind the dash on start up or shut down its more likely combustion gases are already entering the coolant system and the head has already failed between the cylinders (there is a water passage just the other side the fire ring which will now have a small gap). A compression test will confirm.

That’s on a UK 1.1 and 1.2 cars which I have owned, but cars with a separate expansion tank may behave differently as I haven’t owned. But I doubt it

There lots of horror stories about. You look at them wrongly and the head gasket goes.


It’s simply not the case. I drove from Crewe to Rhyl and back with a massive hole in the side of the radiator. It was running out almost as fast as I could pour it in. I took a watering can and topped it up every 20 miles or so. That head gasket was fine for years afterwards. They do fail. But then again there are millions that don’t.

It’s easy to run with low coolant without knowing. It’s not easy to see the expansion tank level on cars where it’s built into the radiator. A torch at night is the easiest I have found. Extended running with low coolant will shorten its life as will not changing the coolant often enough. The passages in the block will clog and the radiator steel sides corrode.

 

[RobCa]

Thanks for the additional info.
I think the head gasket blew with the previous owner because he ignored the other warning signs. He knew the radiator had a leak and the fan was coming on more. I think he just ignored things because the gauge showed normal!

I agree about checking the fluid level, I have been checking it regularly with a bright torch. It is difficult to see otherwise. So far so good.

It does seem that the temperature gauge may be a bit useless! I was wondering about fitting an additional gauge. The problem is where to fit the additional screw-in sensor. I have seen some aluminum things that will fit in-line to a hose. I guess this could be fitted to the bottom hose so is less likely to run dry if there is a fluid loss. As someone else said, the standard temp sensor can run dry with fluid loss and hence you don't get a temp warning then!
The problem is, Ive been used to a car where the gauge was marked in degree's and the OBD scanner confirmed it was quite accurate. I'll maybe just have to get used to looking under the bonnet a lot more!

 

[koalar]

There are a few third party options

You can add a third party coolant level alarm.

Those that work by a float would be very hard to fit due to space

Those that work via two pins would fit in the space quite easily, but fitting the nut on the inside would be very challenging

Far simpler would be to add a very cheap Bluetooth OBDII module (be careful which one you buy if you have an iPhone) and use a smart phone as a standard temperature gauge

I have one permanently fitted. Accidentally left it plugged in while reading codes. The cheapo one I have does not drain the battery and the body computer goes to sleep as normal. You can add a temperature gauge that reads degrees very simply to your phones screen. I haven’t tried but no doubt you could set an audible alarm

 

[DaveMcT]

A switch like this should be easy enough to fit to the integral radiator coolant tank**. Obviously, measure the available space but it looks likely.
The magnetic float triggers a hall effect transistor.

Stainless Steel Right Angle Water Level Sensor Float Switch Quality Free Post | eBay

Right Angle Stainless Steel Float Switch. A float switch is a device used to sense the level of liquid within a tank. It can be easily converted from normally open to normally close by inverting the float.

www.ebay.co.uk

**It would be more hassle on the spherical tank but at least that's easier to check the level.

 

[DaveMcT]

It’s easy to run with low coolant without knowing. It’s not easy to see the expansion tank level on cars where it’s built into the radiator. A torch at night is the easiest I have found. Extended running with low coolant will shorten its life as will not changing the coolant often enough. The passages in the block will clog and the radiator steel sides corrode.

I have just changed the steel suction pipe on the front of the engine that carries coolant to the pump. The outside was very rusty so time to go. The coolant has always been changed on schedule, yet the inside of the pipe has some rusty lumps. Nothing huge, but I was surprised to see any corrosion on the inside.

 

[Cinq999]

As mentioned above, its quite a large "dead range" on the temperature gauge.

I was driving through Spain in 45+ degree heat, on a motorway doing 80ish up a mountain.

Had Torque running the whole journey to keep an eye off everything.

It moved off the halfway mark at 103 degrees, was at the 3/4 mark at 108. It then cut the engine power to help keep the engine from overheating. Basically limp mode where it wouldn't go any faster than 50.

Fortunately reached the top by then, and it rapidly went back down to low 90's on the way down.

 

[Pugglt Auld Jock]

We should all be very glad we actually have a temperature gauge. The modern trend for "runabout" type cars seems to be to just give you a warning light! Insanity in my view.

 

[Yolanda]

Not just runabout cars. My wife has a 1200 Corsa SE and that doesn't have one either.

 

[Pugglt Auld Jock]

Not just runabout cars. My wife has a 1200 Corsa SE and that doesn't have one either.

come to think of it I don't remember seeing a coolant temp gauge in my daughter in law's Jazz?