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Level Switch for Coolant Reservoir / Degassing Tank

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gmerry   
Mon Apr 22 2013, 09:18am
Joined: Dec 11 2009
Member No: #21
Location: Scotland
Hi, thought best to start a new thread on this.

Following Chevron's misfortune with blown head gasket and previous problems with thermostat tank failures and corrosion potential for heater return pipe (above left hand wheel arch), a warning on low level in the coolant reservoir/degassing tank might be a "good thing"

To integrate this into the car's BSI, is a software and wiring job well beyond my capabilities: a reasonable workaround is to wire a coolant level switch in parallel with the oil pressure warning light.

As it happens, the oil pressure warning switch for the 2.7HDi is mounted right on top of the engine. From the harness going to the front injectors, there is a wire going off to the oil pressure switch with a single green/yellow stripped wire. A bit of a give away that the oil pressure switch just switches to earth is the single wire and the colour. From here across to the coolant reservoir is a very short route so easy peasy to connect the two.

The coolant level switch being considered is a reed switch operated by a float. When the coolant level falls, the switch closes and the completes the circuit to earth. A suitable switch in high temperature PPS has been purchased from DEETER Electronics.

On test, the dashboard flashes up STOP and a "oil pressure low" mesasage comes up on the Navidrive display and all in all this should be hard to ignore. To test the operation of the float switch and circuit, it is just a matter of opening the coolant reservoir (cold) and pushing down the float switch.

Regards
G

PS, over the years I have had two Citroen engine problems with coolant loss. In both cases the engine temperature warnings were way too late to save the engine.

PPS, the handbook for 2008 actually shows a level sensor on the coolant tank but no such thing fitted to my car. Some of you may already have it - let us know if you do
e3steve   
Mon Apr 22 2013, 11:44am
Joined: Jan 21 2013
Member No: #1163
Location: Warsash, Hants & Palma de Mallorca, Spain
I have the sensor in the 'header tank', G, but nothing connected to it....

Mine overheated this morning. The first I knew of it was a 'low oil pressure' warning, along with the STOP icon. I was behind a bus when the engine stopped and wouldn't restart until the oil temp returned to normal, at which time I moved the car across the road, out of the way of the traffic and into a parking bay.

There's a Y-split plastic device on the top of the r/h/s of the engine, between the cylinder banks, beneath the butterfly housing and above the services' belt pulleys. Each of the Y's legs is attached to a 20mm-or-so coolant hose, one to each bank. Said device has a vertical joint which is wide open ('stat housing?). I've yet to delve in as I'm trying to help a friend on a yacht this week .

I'll upload an image later.....
gmerry   
Mon Apr 22 2013, 12:07pm
Joined: Dec 11 2009
Member No: #21
Location: Scotland
Steve, really sorry to hear this.

Sounds as though the oil pressure switch connection as a warning rather than as a product of the failure might be a very good thing.

That thermostat tank sounds to be very frail indeed.

Thanks again to Phil for flagging this up.

Regards
G
C6Dave   
Mon Apr 22 2013, 12:57pm

Joined: Oct 01 2009
Member No: #1
Location: Northumberland
Parts documentation only shows a bare expansion/de gassing tank as standard fit on the C6 2.2, 2.7 and 3.0 HDi's so anything else that's there has been retro fit by a previous owner.



Here is a picture of the setup on my 3.0 where you can see the feed hoses coming back to the header, but no level float


Website
gmerry   
Mon Apr 22 2013, 01:12pm
Joined: Dec 11 2009
Member No: #21
Location: Scotland
Page 137 from the 2008 UK Owners manual clearly shows the top mounted level sensor (not float switch). See attached.

Maybe they meant to fit?

Regards
G




Page 121 in the 2009/2010 owners manual also shows the coolant level sensor. Note three wire connection clearly visible.
e3steve   
Mon Apr 22 2013, 05:24pm
Joined: Jan 21 2013
Member No: #1163
Location: Warsash, Hants & Palma de Mallorca, Spain
Here's what I have:






and here's where I'm losing coolant from:






gmerry   
Mon Apr 22 2013, 06:37pm
Joined: Dec 11 2009
Member No: #21
Location: Scotland
Photo of Float switch

cruiserphil   
Mon Apr 22 2013, 07:13pm

Joined: Jan 24 2010
Member No: #38
Location: Celbridge
E3Steve,

If it's under the butterfly housing it's the coolant (thermostat) tank!!!

Regards,

Phil C.
smihaialex   
Mon Apr 22 2013, 07:53pm
Joined: Sep 18 2012
Member No: #1031
Location: Bucharest
1. A float switch is useless, because, unlike let's say the brake fluid, the coolant level fluctuates due to the rise in temperature that leads to pressures regularly reaching 2 bar, which makes the level in the tank go down significantly (hence the term: expansion tank)...

2. Some cars have the thing on top of the expansion tank, some don't (in fact most don't), but the ones that I have seen and that do have it, also have cables leading from it (saw this in a Peugeot 407, for instance), which makes me think that, if your car has nothing attached to it, maybe either the tank has been replaced with a second hand spare from a Pug 407, or there was some malfunction with the sensor and the service engineer 'fixed it' with a pair of pliers...

3. Having had both the corroded pipe, as well as the blown thermostat casing, what I can say are these (facts only):
- the car is able to function with less than the full ~5.5 liters of coolant (I wouldn't recommend it, but it can - mine ran for ~3 months with lower than normal levels until I realised I had a problem and had it fixed (it took 3 months to get from full to almost empty and display STOP engine temp too high message);
- the car will show increase in coolant temp if coolant level is not ok, so if you have concerns regarding the cooling, just have the NaviDrive in Trip Mode and have it serviced if displayed temp goes up (I wouldn't bother with fitting a level sensor);

Just my £0.02

Cheerios,
Sam
gmerry   
Mon Apr 22 2013, 09:52pm
Joined: Dec 11 2009
Member No: #21
Location: Scotland
Another shot of the float switch installation.



e3steve   
Tue Apr 23 2013, 07:08am
Joined: Jan 21 2013
Member No: #1163
Location: Warsash, Hants & Palma de Mallorca, Spain
Thanks, all, for your input.

It seems that the 'stat "tank" failure is a known problem, then? I've found many comments, after Googling keywords, and it appears common.

The Jaguar installation of the 2.7 engine has a modification that employs an alloy ass'y but, apparently, the hose arrangement differs enough to make it unusable for us PSA-ers. Bummer....

When I saw the Cartier sensor in the header, I immediately thought that the PO may have had low-coolant issues and had disconnected it. But it didn't concern me, having thought further, as dis'ing a 3-wire sensor would produce a fault indication. Also, I lifted out the header tank and searched for the dis'ed connector; no sign of such, so I gave it no more thought.

Removing the surrounding components doesn't look to be too traumatic a task, so I'll make a start, hopefully, this evening.

Stay tuned, pop-pickers!
Tjensen   
Tue Apr 23 2013, 10:43am
Joined: Jul 17 2012
Member No: #954
Location: Bergen
The Cartier unit with a float and warning ability placed inside the expansion tank saved my XM V6 several times. It warns you if 1. the coolant suddenly drops 2. It has gradually decreased to a dangerous low level. In the case of 1. this is very important because low or non-existing coolant will not circulate and get hot enough to trigger a warning. Then the oil-temperature warning is our only hope before damage in the C6.
cruiserphil   
Tue Apr 23 2013, 02:24pm

Joined: Jan 24 2010
Member No: #38
Location: Celbridge
I have to say lads, I like G's float switch solution. The wiring intrusion is minimal. Unfortunately I believe the Cartier switch will also need a positive supply wire (if it's the same as XM which it looks like!)if you want to retrofit a 407 tank. I believe this is a must have modification.

Regards,

Phil C.
gmerry   
Tue Apr 23 2013, 03:20pm
Joined: Dec 11 2009
Member No: #21
Location: Scotland
On a bit of a tangent to the float switch.

I needed some new coolant to complete the installation so tried to purchase some BASF G33 coolant.

It appears that BASF only supply this to PSA exclusively and it is a OAT silicate free coolant, but with a blue/green dye. BASF also supply direct to the aftermarket (via Comma in the UK) G30 coolant which is "the same thing" but with a purple dye and they recommend this as suitable for Citroen and Peugeot. I guess they should know as it's their coolant.

So we have a choice!!

Regards
G
e3steve   
Wed Apr 24 2013, 10:26am
Joined: Jan 21 2013
Member No: #1163
Location: Warsash, Hants & Palma de Mallorca, Spain
I'm beginning to think that une personne ou deux high up within the Citroën design hierarchy needs tarring & feathering for his/her/their oversight in the omission of a coolant level warning!

I've just followed, from beginning to end, member Chevrons' overheating story. What utterly rotten luck! And I could be in the same bateau, as I had no idea there was a problem with my cooling system until I was warned of 'low oil pressure'. I then flipped screens over to Vehicle Monitoring and observed the oil temp was increasing; then, whilst at a standstill in traffic, the motor died and wouldn't restart, but just cranked slowly and flashed the speedo graphics as though the battery was very low!

Needless to say I'm now pooping my knicks a bit, although I've not yet observed oil in the coolant or vice versa.

I can feel a trip to Citroën's head office brewing. I'll drive the damned car through their front doors as a protest......
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