Berlingo 1.6 hdi temp gauge reading 90° when cold.

[Pete the painter]

Hello. I am looking for some advise/help to figure out what's going on with my van. At the start of the week I noticed my temperature gauge running around 110° and realised I was low on coolant. I topped up the coolant bought from local garage thinking that was the issue. Next morning put the key in ignition one turn and the temperature gauge was reading 90° before I started the engine. There are no warning lights on but worried that it may be doing damage. Not sure if it's a sensor what sensor it is thermostat or something else. Struggling to find anyone to look at it. Grateful for any information folks.

[myglaren]

Welcome Pete.
Your thoughts on it being sensor related are quite probably correct.
Anecdotal only but I had exactly the same symptoms with one of my C5s (2.0 HDi) and it was indeed a failed sensor.

[Pete the painter]

Hi thanks. More information. Next day I drove for a short distance and the gauge was over 100° the front fan came on and stayed on for short while after turning engine off. I took off the wires leading into thermostat which brought the fan on looked at the gauge and it was reading as if the engine was very hot don't think this would be right as it was very cold outside and usually it takes 10-15 mins to warm up. The fan in the cab comes on but after a while cuts out. Thermostat ? Would the thermostat stop the engine for getting coolant ? Hoping I can narrow it down to certain parts before I go to a mechanic and also if I can fix it myself a bonus. Not the best of things to happen few weeks before Christmas when it's needed the most.

[myglaren]

I'm afraid that I discovered it when setting off for work one morning. Car had stood overnight so was clearly not over temperature.
I did assume it was a sensor problem, dropped the car in at the garage I use near work, picked it up on my way home all fixed and as said only a sensor. £19 all told.

[Pete the painter]

Not pleasant I'm sure whole load of unnecessary worries fixed at small cost. I hope my issue isnt anything major afraid to drive it at the moment until I can find someone to look at it. With no warning lights on a lot of garages don't want to know.

[MattBLancs]

1.6 HDi coolant temperature sensor is on a plastic "manifold" that also houses the thermostat. Sensor on its own is about same cost as quoted above (~£20 or so) housing with thermostat and sensor complete isn't much more.

From what you've said, 90°C registered on what's clearly a cold engine, then sensor definitely seems likely candidate.

(I've 206 that is opposite, only seems to run at 70°C indicated, so am changing housing as will rule out "sensor is giving incorrect reading" and "thermostat is opening too soon" in one go. Used to run at 90°C consistently)

I believe, unlikely earlier engines which often had up to three coolant temperature sensors: one for the gauge, one for the ECU and sometimes another sensor or thermal switch for the cooling fan. Think 1.6 HDi is single sensor feeding all three. So if that sensor gives a hot reading = displayed on the gauge, it stands to reason it'll also bring the radiator cooling fan on.

Not sure why cabin fan should work then stop - odd!

[Pete the painter]

Thanks for the reply Matt I'm gearing towards the thermostat and sensor. I spent few hours on YouTube and now wondering if I would need to flush the coolant system when replacing the thermostat in the event of air block. What's your thoughts. I'm not sure why the cab fan switch's off I'm guessing it cuts out when the cooling fan on rad kicks in ??

[MattBLancs]

wondering if I would need to flush the coolant system when replacing the thermostat in the event of air block.

I'd buy a bottle of coolant, pop bottom radiator hose off, drain, flush with hosepipe and refill with new coolant and water after changing thermostat housing.

However, it's not a nice time of year for a job like that!

There are bleed points - not sure on Berlingo specifics, but usually one on cabin heater matrix pipework (about 25mm outside diameter rubber hose. Normally looks like a tyre valve cap. Another on the head / thermostat housing. Quite often one on the radiator too.