Peugeot 307CC - Water in the wiring?

Honest John Back Room » Technical matters
What is life like with your car? Let us know and win £500 in John Lewis vouchers | No thanks
View Threaded
Tue 25 Oct 2011 18:27
Peugeot 307CC - Water in the wiring? - Jim Heaton

My wife’s Peugeot 307CC developed a cooling problem. After returning from 30+ miles of motorway driving the engine was running cool, water and oil temp gauges both low and the radiator fan was on continuously. The cooling system header tank showed a water level between min and max so not much water had leaked out. The fault may have existed for a day or two without detection as only short journeys had been undertaken on the previous day. Two days later we took it the main dealer for diagnosis and repair. The car was not used in the interim.

Diagnosis showed a faulty and leaky temp sensor. The dealership wanted us to have a wiring loom replaced as well as the sensor as water may have got into the loom and could get as far as the ECU. Before authorising the repair (£585 including the loom with a parts cost of £270+vat for the loom) we went to the workshop to inspect the bits. Sure enough the sensor was wet but the loom was dry. The explanation given about the loom was that water can creep up (capillary action) between the conductors and the insulation and get to the ECU. My understanding of capillary action needs one end of the capillary to be kept wet. Surely with the source of water removed and a hot engine bay environment any further capillary action (if indeed there had been any at all) would stop and parts would dry out. Needless to say we only had the sensor replaced (£115 including £79 for diagnosis). The car is now running at correct temperature.

Our feeling is that the dealership was trying hard to upsell a simple repair to a lady driver. Has anybody had experience of water damage to the ECU through capillary action in a wiring loom?

Reply | Report as offensive | Link
Tue 25 Oct 2011 21:51
Peugeot 307CC - Water in the wiring? - Avant

Moved to Technical.

Reply | Report as offensive | Link
Tue 25 Oct 2011 23:47
Peugeot 307CC - Water in the wiring? - 1litregolfeater

"upsell" sounds a trifle generous

Think I'd be more inclined to describe it as a bare-faced thieving rip-off.

Reply | Report as offensive | Link
Wed 26 Oct 2011 17:47
Peugeot 307CC - Water in the wiring? - fastjet6

Glad to see you had sense to inspect the parts pre approving the repair, as a fighter jet electrician for the past ten years i can confirm the garage is talking utter tripe. Looms are designed for just such an event before being commisioned for production and will contain drainage loops, allowing any water tracking down the loom to 'drip off' into a suitable area away from sensative electronics. Also, any plug/connecter that is in a region that could expose it to moisture ingress and is therefore deemed to be at risk would at minimum be enviromentally sealed to protect it, producing looms to an inferior standard would leave the company exposed to a potentially crippling recall or law suit.

Ian

Reply | Report as offensive | Link
Wed 26 Oct 2011 19:01
Peugeot 307CC - Water in the wiring? - madf

Fastjet.

You appear to be ignorant of the VW/Audi water leaking into footwelll problem leading to failing ECUs...Your last statement about plug sealing is therfore commendable but totally wrong...See also Land Rover diesel oil leakage into ECU from injector wiring immersed in oil.

In my experience Peugeot electrics are of dubious quality compared to the Japanese. I speak from personal experience of both..

Jim Heaton

See the above and google Land Rover diesel wiring loom.. Capillary actions works with oil.

Well done. If my experieince of PSA dealers is anything to go by, many are ignorant technically... solve problems by changing bits.. and screw the customer at same time.

Edited by madf on 26/10/2011 at 19:04

Reply | Report as offensive | Link
Wed 26 Oct 2011 19:41
Peugeot 307CC - Water in the wiring? - Peter.N.

Water ingress in cables by capilliary action is quite a valid problem, I have seen it many times in antena cables where the waterproof cover has failed, it can travel right down the central conductor in coaxial cables, I have even seen it dripping out of the end, but as already mentioned if the water source is removed the creepage will stop.

Reply | Report as offensive | Link
Wed 26 Oct 2011 20:13
Peugeot 307CC - Water in the wiring? - piggy

<

In my experience Peugeot electrics are of dubious quality compared to the Japanese. I speak from personal experience of both.>>>>

Quite correct! One of the first "mods" I make to any car of mine (usually Italian),is to spray all connectors,fuse boxes etc.with water-proofing laquer. My wife`s Corolla, however,has no need for such treatment. The quality of connectors are a lesson to French/Italian manufacturers on how to do things properly.

Reply | Report as offensive | Link
Thu 27 Oct 2011 11:22
Peugeot 307CC - Water in the wiring? - TeeCee

And the reason why aeroplanes don't use cheap, off-the-shelf, French automotive electrical components is............?

Reply | Report as offensive | Link
Thu 27 Oct 2011 16:40
Peugeot 307CC - Water in the wiring? - madf

And the reason why aeroplanes don't use cheap, off-the-shelf, French automotive electrical components is............?

No plane uses cheap connectors . period.

Reply | Report as offensive | Link
Thu 27 Oct 2011 21:33
Peugeot 307CC - Water in the wiring? - fastjet6

You clearly have never seen the quality of plugs and wiring on aircraft, it is scarely shocking, thats why its all quadraplex systems.

I discussed the capillary effect with the lads at work and only one had ever seen it, and that as was previously stated was in an ariel co-axiel cable but i am also aware of how poor the french are at producing anything electrical, seems like every week i am asked to test a collegues peugeot looms and have seen some very confusing syptoms, however, for garage to call a loom change without even carrying out any basic inspection and testing on a phenomina which is rare is a disgrace, too many garages have far too few skilled mechanics and assume the customer has far too much money.

Reply | Report as offensive | Link
Thu 27 Oct 2011 23:09
Peugeot 307CC - Water in the wiring? - nico77

Peugeotlogic have documented this issue about the temperature sensor and 307s with water in the loom / ECU

www.peugeotlogic.com/workshop/base/workshop.htm

If you look on the left under Magneti Marelli and 307 Throttle Malfunction

I guess you caught this in time - they say they just dried the connector

ciao

Reply | Report as offensive | Link
Thu 27 Oct 2011 23:15
Peugeot 307CC - Water in the wiring? - Peter.N.

My experience has been with TV, PMR and amateur radio antenna cables where water ingress by capiliary action is not at all uncommon but of course the water input there is fairly continious.

Reply | Report as offensive | Link
Fri 28 Oct 2011 15:11
Peugeot 307CC - Water in the wiring? - Jim Heaton

Peugeotlogic have documented this issue about the temperature sensor and 307s with water in the loom / ECU

www.peugeotlogic.com/workshop/base/workshop.htm

If you look on the left under Magneti Marelli and 307 Throttle Malfunction

I guess you caught this in time - they say they just dried the connector

ciao

Hi, I checked this link out and it seems that the garage were not spoofing when they said water could creep up the harness by capilliary action. As you say, I hope we caught this issue early, the fitter at the garage had the connectors off the ECU and there was no sign of any water at the ECU end of the wires. Thanks for this response.

Reply | Report as offensive | Link
Sat 29 Oct 2011 13:31
Peugeot 307CC - Water in the wiring? - Jim Heaton

Thanks to all who responded to my question. Here is news of some developments.

The reply from nico77 is "on the money". It looks like the garage were reporting a genuine cause for concern although clearly trying it on to upsell the job.

I have done some experiments with wires and water at home. I used fountain pen ink to stain the water as it was the only dye to hand. I know that ink has surfactants and other additives to make it flow so will not be representative of car coolant ( I intend to repeat the experiment with 50% antifreeze solution ). I used 3 types of flexible wire, two with a translucent polythene like insulator and one with an opaque insulator and more typical of car wire. Each sample is 50 cm long. The arrangement has one of each type of wire laid horizontal and an end immersed in the inky water and a sample of the opaque wire held vertical with an end immersed in the water. The results were astonishing and lead to the conclusion that water can creep along between the conductor and insulator at a rapid rate if the conditions are right.

One of the translucent plastic samples had visible droplets of water between the conductor and the insulation 30 cm along the 50 cm length after 24 hours. After 48 hours, touching the end of the wire to absorbent paper produced a speck of water on the paper.

The other translucent plastic sample from a different wire has shown no signs of water ingress at all after 72 hours.

The horizontal opaque sample gave a result that is very similar to the first clear sample. By touching the end of the wire to absorbent paper after 48 hours I got a speck of water on the paper.

The vertical opaque sample has yet to show a result on absorbent paper after 72 hours.

The capillary action in the horizontal samples must have been aided by a syphon effect; the vertical sample will show only capillary action.

Reply | Report as offensive | Link