Simon's new Xantia V6 and Leaf blog

[Mandrake]

Something like this ?

https://www.halfords.com/tools/garage-e ... 99738.html

[white exec]

No, silicone is too soft/detachable.
This is good - polyurethane, not silicone...
Put "Pattex 1536070 PU 198 Sealant Polyurethane 310 ml Grey" into Amazon.uk.

Pattex is Henkel. Builder's merchants will stock it/similar.

Caps: 15kV 1000pF ?
There's this from Vishay
https://www.mouser.co.uk/ProductDetail/ ... PlTUKBY%3D
https://www.mouser.co.uk/datasheet/2/42 ... 762659.pdf
Found on the Mouser/Farnell site.

[Mandrake]

No, silicone is too soft/detachable.
This is good - polyurethane, not silicone...
Put "Pattex 1536070 PU 198 Sealant Polyurethane 310 ml Grey" into Amazon.uk.

Pattex is Henkel. Builder's merchants will stock it/similar.

I'm not sure that a sealant that sets really hard is necessary and may actually be a hindrance if I need to open it up again. It's really just there as a gasket on a flat flange which is bolted all the way around. It just needs to be stable and water proof but isn't under the same stresses as say an engine sump.

Also found this: https://www.hunker.com/13414953/polyure ... s-silicone

Caps: 15kV 1000pF ?
There's this from Vishay
https://www.mouser.co.uk/ProductDetail/ ... PlTUKBY%3D
https://www.mouser.co.uk/datasheet/2/42 ... 762659.pdf
Found on the Mouser/Farnell site.

The caps I ordered have actually just arrived as I type this:

https://uk.rs-online.com/web/p/ceramic- ... /?sra=pmpn

The original caps are only rated to 2kV so the 6kV ones I'm using are already providing a big extra safety margin. They're across the 360V high voltage system so the high voltage rating is there for any spikes that may occur.

[white exec]

Polyurethane adhesive does not set hard, but air-cures (using moisture in the air) to form a "rubber" (pretty much like a supple O-ring), which can easily be sliced open. Used to install car windscreens, for example. Sticks to almost any clean surface.
You can even use it to mould your own "rubber bushes". Once you've used it, you'll wonder why you never did before. Sales pitch over. I rest my case, m'lud.

[lexi]

No nonsense roof and gutter sealant from Screwfix or B&Q will do that. Cheap and non setting butyl, so easily removed. If you use polyurethane and there is any recess in joint, then you will have to cut the beggar out if you want in there again.

[RichardW]

RTV silicone will be fine - if it can keep oil in the sump at 100+C it will keep a bit of dust out of that box- and it's plenty strong enough - removing a sump and then the remains is hard going....

[xantia_v6]

Note that it needs to be a non-acidic silicone (instant gasket is OK), not bathroom silicone which does not play well with some metals.

If the theory of the fuse blowing causing a spike is correct (it is plausible), then higher voltage capacitors might be the last thing you want to fit, as the capacitors shorting may be protecting lots of other more expensive components which will fry if the fuse goes again. It sounds like a surge arrestor (or flywheel diode) would be a good addition.

[white exec]

Flywheel diode no bad idea, but usually needs to be rated at at least the current which would normally be pulled by the device involved, and at least 10x the voltage involved. E.g. for a 12v 3A solenoid, the reverse diode should be at least 3A 120V. In practice, throwing in a 6A 400V/1000V would be so cheap, it would likely be done.
Appreciate that the circuit involved here is not a simple inductive one, so some other standards may apply.

[Mandrake]

Note that it needs to be a non-acidic silicone (instant gasket is OK), not bathroom silicone which does not play well with some metals.

Does the Locktite 5660 I linked to at Halfords look like it would be suitable ? As I'd forgotten to order any sealant online I'm hoping to find something I can grab locally on the weekend.

If the theory of the fuse blowing causing a spike is correct (it is plausible), then higher voltage capacitors might be the last thing you want to fit, as the capacitors shorting may be protecting lots of other more expensive components which will fry if the fuse goes again. It sounds like a surge arrestor (or flywheel diode) would be a good addition.

That thought had crossed my mind too...

The fuse going first is the theory of kiev who probably has the most experience diagnosing these problems, however I'm not sure I agree with him and we've debated back and forth about it. He's basing it largely on an x-ray of a single failed fuse that shows a mechanical fracture instead of the melting of the wire you'd normally expect. But I'm not sure that can be extrapolated out to other failures as they do vary a bit.

I'm more of the opinion that the original capacitors were either rated too low (originals are 2kV) or are actually defective and don't even meet their claimed ratings - eg the original 2kV rating is plenty but they didn't live up to that rating. Thus a capacitor failed first during a spike, went shorted, and blew the fuse. The fault codes from my onboard charger indicate "excessive current in the converter" which would be consistent with the capacitor going shorted before the fuse blew, I think, but its certainly not conclusive.

The service bulletin in the USA talks about "insufficient durability of capacitors in the onboard charger", but doesn't mention which capacitors so take that doublespeak however you will. Whether that means the caps should have been better than 2kV or that they were a faulty batch that didn't meet their rating I don't know.

As for them sacrificially saving other components, keep in mind that the HV supply is 360 volts, any semi-conductors on this rail are unlikely to be rated to survive a 2kV surge anyway, so 2kV vs 6kV is moot. I haven't looked at the circuit diagram but I would imagine there must be some sort of surge arrestor in place already, which lends more weight to the cap went shorted first and then blew the fuse theory that I favour.

Unfortunately there are no official schematics of the insides of the charger available, only the external connections to other units - kiev has reverse engineered a significant amount of the power circuitry in the onboard charger (although I can't seem to find the thread he posted them in with a quick look) but there are still big gaps in our knowledge about the circuit.

For those with an electronics background you might find the following thread of interest, which is the main thread covering these failures:

http://myimiev.com/forum/viewtopic.php?f=23&t=4079

Page 3 is where it really starts to get interesting. This is what fixing cars in the future may be like!

The two caps and fuse failure seems to be quite common, but there are variations on this.

[RichardW]

Note that it needs to be a non-acidic silicone (instant gasket is OK), not bathroom silicone which does not play well with some metals.

Does the Locktite 5660 I linked to at Halfords look like it would be suitable ? As I'd forgotten to order any sealant online I'm hoping to find something I can grab locally on the weekend.

Yep, that's fine, it will be neutral cure stuff.

[white exec]

Strong smell of acetic acid (vinegar) is the giveaway for standard silicone sealants.

[Mandrake]

Plowing my way through that 45 page thread to make sure I'm fully up to date on all the troubleshooting other people have done. Some interesting things I've found so far. A reverse engineered section of schematic containing the two capacitors and fuse in this post:

http://myimiev.com/forum/viewtopic.php? ... 170#p37367

The two 1000pF caps are on the far left in parallel and come from the switching output of the inverter in the onboard charger which is (not shown) to the left. The 20A fuse which will be blown is on the far right. Physically it is contained within a different unit, the MCU, and this then goes to the traction battery.

This post has some good pictures of one where one cap has blown clean away, although some only seem to split:

http://myimiev.com/forum/viewtopic.php? ... 190#p37447

Other discussion centres around the black relay next to the two caps and the two white resistors at the opposite end of the potted region. (visible in the second photo of the second post) They are not in the same part of the circuit as the capacitors however in at least one car the relay contacts had failed and the resistor burnt out. The resistor is a precharge resistor which is then supposed to be bypassed by the relay contacts once the electrolytic capacitors charge up, (anti-surge system) however an open circuit relay contact causes the charger to function initially but the resistors to be overloaded once the charge current ramps up until one burns out.

Although replacing the relay and resistor is a major job, (as that requires a lot of unsoldering with a proper unsoldering station to get the board out) they can at least be tested from the top with a little bit of ingenuity described in an earlier post.

[Mandrake]

I didn't mention this before but when I brought the Xantia out of several weeks disuse on Sunday to cover for the off the road Ion I was greeted with this:



At the time I took the video on Sunday I wasn't sure what the noise was and whether it might be the bearing on an idler wheel but I've since decided that it's probably the clutch in the air-con compressor dragging, (rusty ?) as when I turn on the aircon the scraping noise stops.

However this is complicated by the fact that the gas pressure in the aircon system is low and overdue for re-gassing, as such the pressure switch doesn't quite trigger when the engine is cold and it's not until the engine has warmed for a few minutes that the clutch will engage.

Also, I can't actually tell whether the aircon is working now - it's efficiency was already down on what it should be due to (presumably) low gas pressure, it will still engage the clutch, however when it does, I can't particularly say that the aircon is working as it still struggles to clear fog off the window and I don't hear the slight "woosh" of pressure that you normally hear through the evaporator when the aircon system starts pumping.

Initially the noise seemed to go away and I thought maybe there was just some rust on the clutch due to sitting a long time in this horrible weather, but the noise has got worse during the week, and while it comes and goes (possibly because the A/C won't stay on continuously due to low pressure) it can be a bit scary sounding sometimes and it's actually starting to sound like the bearing on the clutch pulley may be stuffed as well, and maybe a stuffed bearing is allowing the clutch to wander out of true and start scraping ?

Hard to tell because even when the clutch is engaged (and thus not a source of noise) the A/C compressor itself is pretty noisy and has been noisy for quite a while even when it was working. Not sure if it's noisy because it's faulty or just due to low gas pressure.

So I'm in a bit of a bind now. I have no other car to drive so I'm forced to take the risk and keep driving it until I can fix the Ion or buy a car to replace the Ion. I was already actively looking for a 30kWh Leaf to replace the Ion before its charger went kaput but was assuming I had the option of a part trade available but with that car broken and off the road I don't at the moment so that makes buying a lot harder.

Does anyone know whether the clutch pulley assembly (including clutch bearing) on the A/C compressor can be removed and replaced with the compressor in-situ or indeed at all ? Or is it a permanent part of the compressor in which case I'm looking at a replacement compressor ? Can the actuator mechanism of the clutch be lubricated at all in case it's sticking and not retracting properly ?

If the compressor needs replacing as well that's a job for someone else to do as they'll need to gas the system up again afterwards as well. Are second hand A/C compressors available and usable ? I've never had to change the A/C compressor before in a car so have no practical experience of this.

What a mess...two cars and they both let me down at once...

[RichardW]

Doesn't sound very happy....

A replacement clutch unit used to be available, but now NFP

Mind you, at £385 for the early one, and £454 for the later one, that's no bad thing!!

This time of year, the AC is probably dropping in and out due to the ambient temp. You could wire 12V direct to the clutch so it was always on... other short term alternative is to fit a shorter belt bypassing the compressor - don't know how practical this is on the V6.

My version of the docs shows a procedure for replacing the clutch, but it is with the comp off the car, whether or not you can do it on the car will depend on how much room there is between the pulley and the chassis rail, but you will need special tools anyway.

[Mandrake]

Looks like you can get an entire brand new compressor with clutch for £213!

https://www.autopartspro.co.uk/nissens-7522507

At that price for new I'm not sure it's worth messing around trying to replace only the clutch on an old compressor when there is a question mark over the compressor itself now as well as it doesn't seem to be cooling even when the clutch engages and has been very noisy (engaged) for the last year or two when it was working... maybe replacing just the clutch and re-gassing the system would be enough, maybe not!

Perhaps I should just get a quote from my trusted local indy on fitting a whole new compressor and gassing the system up - I was going to ask them to re-gas the system before this latest clutch problem happened anyway....