Activa V6 - ES9J4 Coolant Temperature

[Mandrake]

According to the original post, it is wrong much of the time, albeit in a steady state.

I am proposing an approach that would make it more right when in that steady state as it apparently spends much of its time.

The degree of wrongness in the reading on David's gauge is going to be a fault though - it's reading about 60 on the gauge for an ECU reading of 90 when it should be reading about 80 judging by other V6's.

So no point modifying something when there is clearly a fault that needs fixing, either that or the TCT gauge calibration is not compatible with the V6 sensor.

One way to determine the latter would be to look up the part numbers for the gauge temperature sender for the TCT and V6 and see if they are the same part number...if not all bets are off.

[DHallworth]

This V6 engine used to read very cool in the original V6 breaker as well so it probably is going to be a fault in the sender. I'll swap it and try it.

David.

[Stickyfinger]

Do we ALL have the same fault then ?

[CitroJim]

Did you swap the thermostat as part of the conversion work David?

Wonder if it's stuck open.. How long does warm-up take?

[Mandrake]

Do we ALL have the same fault then ?

Did you look at David's dashboard photo ? His reads 60 degrees when the engine is warmed up. Mine sure doesn't - it reads about 80. So no, they don't all have this fault.

[DHallworth]

There's one place I know that has more ES9J4's in residence then FCF... The 406 Coupe owners club.

It turns out there are a lot of guys over there who have suffered from dashboard reading the wrong temperatures and have posted temperatures exactly like mine. They've worked out over there that the temperature sensor that feeds the gauge is a common failure. Over there it's almost regarded as a service item!

I've got a spare one on the V6 engine I've got up here so I went to have a look at it. I've taken it off so at some point I'll whip the one off the Activa and warm them in a pan of hot water and check the resistances. Annoyingly though, the sensor is NFP from Citroen!! Argh! When it was last available it was less then £20, so not really an expensive fix either! I wish I'd have thought about it when the engine was on the stand last year though

Last week when I went to the Activa the low coolant alarm light was on, upon checking it, the level was low but the bottle wasn't empty. I've since done about 30 miles in it and again tonight the level was low. I was pretty annoyed about it so ended up not looking at it last week. Tonight when I went looking for that sensor I saw a blue puddle on the top of the gearbox and a jubilee clip that was covered in white furry stuff. I managed to get a couple of turns on the jubilee clip so will keep an eye on it for level. Last week was the first time since the engine swap I've had to put any coolant in it so it must have just been working itself loose.

When the winter is here I might take the inlet off it and check the cam boxes have stayed sealed properly and do the sensor and check that pipe again.

David.

[Stickyfinger]

Where would the ideal position be for the sensor ?

[Mandrake]

David,

I wouldn't waste time fitting an old second hand sensor - it's probably just as bad. Check eBay and Amazon for the coolant temperature sensors - I got a green ECU one for the old V6 from eBay and it was under £10 from memory. Just make sure you get the right one of the three (Green, Blue, Brown) as the listings are not very clear sometimes which one it is and they are all different.

Re the coolant - did you fit a new coolant expansion chamber when you did the conversion ? If not it will be leaking at the seam, but only when hot and under pressure.

Both my V6 's have needed this replacing and according to the receipts that came with this one it had already been replaced twice before in the 65k the car had done before I bought it! Almost a maintenance item...

Still available from Citroen for about £35.

[Stickyfinger]

Leak : or the Degass chamber.....had to do mine as soon as I got it....this part is not available from Citroen.

Some good metal ones for Ford Cossies are about but not cheep.

[DHallworth]

I did both the gassing bottle and the expansion bottle and cap. It looked like it was a jubilee clip that wasn't tight. I'd had it off when I changed the thermostat so probably just didn't tighten it enough.

I'm not going to fit the old sensor, just wanted to see where it was to compare it to on the engine in situ. I'll warm them in a pan just out of curiosity and watch the readings on a metre, I might even do it with the new one as well if I can be bothered. I'll give Citroen a bell tomorrow and see if any of the dealers have one on the shelf gathering dust somewhere.

David.