Avocet

I then put an air line down the hole where the solenoid valve lives. What seems to happen, is that when the solenoid valve opens, it disturbs the balance of pressure between the big chamber formed by the shield and its "lid", and a smaller chamber further down, almost inside the pulley. I have no idea why it's been done like that, but I guess it's to save power. The solenoid will only pull a tiny current, and the actual propelling of the sleeve is done by somehow creating a pressure differential between the large and the small chambers? Seems a million times more complicated than it needs to be! And I can't be sure, but the failure looks like it MIGHT be a slightly leaky diaphragm on the edge of the smaller chamber. (Although I might have killed it by poking the airline down there at 100 PSI...)! 20221101_213047.mp4

Now, I assumed that the little solenoid on the side, pulled on some kind of link rod and mechanically moves the shield, but no! It's a solenoid valve, which allows water to pass through an orifice (or not). The impeller is moulded on to the shaft, so I cut it off and underneath, it's monumentally complicated!

Well, that's not at all what I expected! Here's the water pump with its shield retracted (i.e. full cooling) And here it is with the shield extended (minimal cooling)

That's a result! We had the cam belt and water pump done the other week and I asked for the old water pump back. The shield in there does seem to be stuck! I've tried putting a battery across the contacts for the little solenoid and the shield won't move. I'll post up some photos when I get a minute.

People who race in classes that specify "road" tyres (rather than slicks) will sometimes pay someone to buff the tyres down to somewhere close to minimum tread depth. The cars handle (and grip) better without the tread blocks distorting as much. Obviously, you need to be quite rich to buy a new set of tyres and then pay extra to have them buffed down to almost worn-out, but they wouldn't do it if there wasn't a competitive advantage. Getting back to the Kodiaq, they're so heavy that I wouldn't hesitate to run our "summer" tyres down to the legal limit. The danger of aquaplaning isn't so bad as the vehicle gets heavier. I can remember driving TVRs in the early 1990s in the wet, very timidly on the motorway, if the tyres were getting a bit thin, with Citroen 2CVs overtaking me on their skinny little "bike tyres" without a care in the world! At present, we're on Toyo Proxes Sport SUVs in the summer and Vredestein Wintrac Pro in the winter. Originally it was on Pirelli Scorpion Verdes, and had just had the two front tyres replaced with the Toyos when we bought it, so it looks like under the previous owner, the front Pirellis lasted 22,000 miles. Too early to say how the Toyos or the Vredesteins are lasting on our, but it doesn't get driven hard at all.

No, none whatsoever! OK, the rear brakes don't do that much, but I was genuinely surprised. There's a very small amount of judder, but that's from the front brakes - which I've also just replaced.

I have indeed, thanks. However, in case anyone on here runs into the same problem, it was my phone! It's a hand-me-down from one of the kids, a "Blackview" (Chinese). Although it had worked fine for reading fault codes and live data, it seems this operation was beyond it. I downloaded the app to a Samsung Galaxy S7 and it all worked fine. Also, if anyone is wondering, OBDeleven charge 10 "credits" for winding back the calipers, but it's another 10 credits to close them afterwards! I don't mind the cost, it's only a couple of Euros for each, but when it's 1.00 in the morning and your hands are filthy, the very LAST thing you want to be doing is pi55ing about trying to top up the credits on your phone! The other irritation (though I can't really blame a Chinese mobile phone company for that), was that three of the four rear pads had a good 10,000 miles left on them. They were about 5mm thick. However, the inner pad on the driver's side, was down to about 1.5mm. Originally, I thought I might have had seized caliper slides, but they were fine. The inside surface of the disc was truly appalling! Not only ridges (which I can live with), but lumps missing out of the surface, which were just "milling" the pad material away! 5 years and just 36,000 miles, and it looks like this!

Unfortunately, I seem to have fallen flat on my face at my first attempt! I've connected the (basic) device, bought 10 credits, gone to "workshop", selected "brake pads replacement" and I just get a message saying "not supported"! Help!!!! What am I doing wrong?

Update: The gauge has remained solidly on 90 ever since (but without the trailer). It's done about 100 miles since then. Today, I drove it from cold with my willing co-pilot logging OBDeleven coolant temperature against my gauge readings. Gauge = 55 degrees Coolant temp 55 degrees Gauge = 60 degrees Coolant temp 58 Gauge = 65 degrees Coolant temp 60 Gauge = 70 degrees Coolant temp 63 Gauge = 75 degrees Coolant temp 67 Gauge = 80 degrees Coolant temp 69 Gauge = 85 degrees Coolant temp 73 Gauge = 90 degrees Coolant temp 77 And there it remained. Highest we saw was me thrashing it up a long hill in Sport mode, where the coolant got up to 94 degrees but the gauge was still showing 90. So... forgive my doubting, but it does indeed seem to like to pretend that it's 90 when it isn't! Next question: (though something of a thread drift). When I absolutely mash the throttle pedal into the carpet, the most it will show is 87% accelerator pedal position?!

Thanks all. Carlston, I measured the front discs this afternoon. Closest I could measure was 315mm, so I'm guessing they're the 314 discs, given that they're a bit crispy round the edges. Tier, that does indeed seem to be the case, thanks.

Thanks! And yes, I'd be inclined to agree (although of course, it's a 4-wheeled trailer so there's rolling resistance as well, to consider)! But... "Silikat teabag"...???! What's one of those?! The car has been fine today, by the way (not towing a trailer). Wife has an 80 mile round-trip in it tomorrow too, so we'll see how it does at higher speeds. My OBDeleven dongle arrived today, and I had a quick play with it. I wasn't able to do so for long, but just sat in the car with it plugged-in and the engine idling, it said the coolant was 69 degrees, and the gauge reckoned nearer 80 degrees.

Thanks, yes. I'm just trying to understand what those changes are. If it's just a case of opening out the slots in the radiator grille, then I have a file and a holesaw...😉 What I'm really struggling with, is why it was fine, laden and only overheated when it was unladen! Yes, the engineers will have worked out that a bit more cooling was necessary, but they'd have done this, based on a worst case, situation towing 2 tons, in the middle of Summer in the South of France, up a mountain, I imagine, rather than half a ton up Shap in Autumn! I think the most likely explanations so far are: 1. Water pump shroud starting to fail 2. A windy day with the wind behind us on the way back, so much less airflow through the radiator. The latter would explain why the problem went away when I turned West and although not directly into the wind, at least some of it was on the nose.

Thanks, as you say, cooling fans shouldn't have been part of the equation on the motorway. In fact, slowing down to a stop, and letting the engine idle, would bring the temperature down very quickly. As luck would have it, the car is due for a cam belt, so I'll probably ask them to throw another water pump at it anyway. I was of two minds whether to do so or not, but I think this has convinced me! Just really odd that on the way down, the ambient temperature was higher (18 degrees) and the trailer was laden, but on the way back it was unladen and the ambient temperature was lower, yet that's when it overheated, and it stopped immediately I turned West and headed into the wind.

Thanks JR. I've just ordered an OBDeleven module and I have a willing co-pilot, so I'll try to get some live temperature data when it arrives. So far, the car's temperature gauge, once warm, as stayed rock-solid on the 90 mark, in all weathers, long and short runs, with and without aircon. This is the first time I've towed anything moderately heavy, and the trailer has no frontal area to speak of, Ambient temperature was 18 degrees, at most, but it was only 13 degrees and raining at the top of Shap on the M6, and it was still overheating. Oil temperature got as high as 121 degrees, but was mostly around 110-115. It was just weird, they way it was fine laden, but overheated on the way back in cooler ambient air, and unladen!

2017 diesel 2.0 150 4x4 DSG. Set out today, towing my big trailer that weighs about half a ton empty. After about 50 miles, stopped to pick up a bout a ton of firewood. Towed the trailer with the wood in it, for another 100 miles - no problem at all, but there was a strong headwind and the car was working hard. At 60 on the motorway, the slightest incline would cause it to drop down into 6th. Averaged 30 to the gallon, heading South Southwest. Dropped the wood off, so the trailer was empty again, and headed for home. Within about 10 miles, the temperature gauge was creeping over 90. On the uphill bits it got to about 105 degrees so I slowed down to about 50 and the temperature dropped again. And so it was, most of the way home. Any uphill bit (even with the wind behind me and the trailer empty), the gauge would start reading over 90. Going up Shap, it briefly touched about 112 degrees. However, the engine wasn't working as hard. It stayed in 7th gear and the average fuel consumption went up to 37 to the gallon. However, for the last 40 miles, heading West, it was fine again. This is the first time I've towed any significant load with it. The car does NOT have "towbar prep", and it's an aftermarket towbar. The wind today, was quite strong, and South Westerly. What I THINK is happening, is that with the wind on the nose, even though the engine was working harder, there was enough getting through the radiator to cool it. On the way home, with the wind largely behind us (except the last 40 miles), there wasn't. Does that sound plausible? If so, does anyone know what the necessary cooling system mods for "towbar prep" are, please?

Sorry, just coming back to this, because a couple of things today, made me question it! 1. When starting from cold, the gauge creeps up, bit-by-bit as the engine warms up. I'd have thought that if it was a "managed" reading that just read 90 for any temperature between 70 and 110, it would jump from 70 to 90 as t warms up - but it doesn't! The gauge just carries on 75, 80, 85, 90 as it warms up. 2. I towed a significant weight for the first time today. About 1.5 tons, on the motorway. At one point (see separate thread, 'cause I'm puzzled about this!), it started overheating. The gauge went past 90, 92, 95, 97 (ish), 100, (ish) and so on. Max temperature was about 112, briefly. Reducing speed brought the temperature back down, but again, the gauge move gradually.

Thanks Carlston, that's really helpful stuff! I had no idea there were three sizes, just a few mm different! I'll pop a wheel off again at the weekend and check. I had a look at Autodoc, as they're my preferred supplier, but post-Brexit, the stuff takes longer to arrive and the prices aren't quite as good as they used to be. Apec front discs from Eurocarparts were just over £50 each, last time I looked, and I can get them next day.

Thanks. So anything with a DSG box has a water-to-oil transmission cooler with a thermostat?

Ah, OK, so it's an oil thermostat? Or is the DSG box water cooled?

Fantastic, thanks! Doesn't look like Mtec do brakes for the Kodiaq though. I'll get a set of those bits, that's perfect, ta. I was wondering about VCDS. That's the one that used to be VAGCOM isn't it? I've had OBDeleven recommended but I'll have a look at VCDS too. The OBDeleven website isn't terribly clear, so I was going to message them tomorrow. I think the freebie (once you've bought the actual reader) version will read fault codes and do the rear caliper actuators, but I'll ask. Credits seem to only be a couple of Euros each.

Hi All, I put our "winter" wheels on this weekend (just another set of wheels with winter tyres on them). While I was at it, I had a quick look at the pads. They're getting fairly thin now. About 4mm on the fronts and a bit less on the rears. There's also a very slight judder through the brakes (which everyone will say is a "warped disc" but I suspect is the disc thickness varying). So, what with one thing and another, I guess I'm going to need new discs and pads all round. Before I start, I have a few questions, please? 1. Does anyone have any recommendations as to brands and suppliers? 2. I was going to purchase an OBD eleven device anyway for other diagnostic work, so I think I can use this to retract the handbrake actuators. Does anyone have experience with this device and can it do that? 3. I've seen various threads / heard rumours about the caliper bolts being some weird head that isn't hex, Torx, Ribe, spline or anything previously known to man. Is this actually true?! If so, can someone tell me what socket / bit type I actually need, please?! 4. Is there anything else weird about the job? Are the fronts pretty conventional? Thanks!

That's interesting! Two thermostats in the DSG?! How does that work, please? (I'm interested because ours is a DSG).

Went out in it this evening. Ambient temperature 11.5 degrees C. Rural area, single track roads with hills, relatively light throttle openings. From startup, it took 6.5 minutes for the gauge to first reach normal, and 3.4 miles (average speed 31 MPH). There was a lot of standing water on the road though.

Same here, just to add to the weight of numbers. Any old screenwash, but NOT washing-up liquid. (Did that many years ago and it doesn't work well - forms little balls after a while and blocks jets). An occasional wipe of the wiper blades with a bit of kitchen roll soaked in vinegar can help if the screen gets a bit streaky or greasy.

Sounds like the shield in your water pump has jammed in the open position. If they jam in the closed position, the engine overheats quite quickly. I wouldn't have thought there would be a fault code associated with it, because the problem is mechanical. Electrically, the actuator that moves the shield will have received a signal from the computer that tells it to do so, and would be a short or open circuit, so the onboard diagnostics would have no reason to suspect anything was wrong.