PipH

It's quite likely the EGR valve is sticking again. If it was replaced at a Skoda dealer, I think you have a 2 year warranty on the part.

I believe the cluster has the immobiliser in it which has to match with the engine ECU, otherwise computer says NO. Changing the cluster may be opening up a whole new can of worms, unless the person changing it knows exactly what he/ she is doing. Getting the old one repaired should be much simpler & probably cheaper.

It wastes a tiny bit of engine power trying to circulate coolant to a closed thermostat. ( Just the same as any previous engine ) Once the thermostat opens the pump sleeve should have operated anyway & the pump circulates as normal. A domestic circulator for your central heating uses about 50w of power, that's less than 1/10 of a HP. It's a bit like Stop/ Start ( unless your in a lot of stop/ start traffic ), the energy saving is miniscule.

The pump has an electrically operated sleeve that STOPS the pump from pumping coolant for a quick engine warm-up. This sleeve sticks & causes the engine to overheat, it usually un-sticks itself after a while & engine temperature returns to normal. If you disconnect the electrical connector behind the pump it just reverts to a normal pump & won't stick again. A cheaper option than new belt, pump & labour.

If all the indicators are their normal brightness & it is just the repeater in the cluster that's dim, I'm sure the problem will be in the cluster. Probably needs a new LED, but as you say, there have been problems with dry solder joints at the interface plug.

As a start I'd check the battery terminals are tight & Halfrauds haven't left one loose. I'd also have a look around the engine fuse box for any sign of overheating.

If you can't find any leak, & with the symptoms of coolant getting into a cylinder ( engine won't turn over ), it sounds like a head gasket leak, or possibly an EGR cooler leak, with coolant getting pushed into the inlet & cylinders. As a check, I would try blanking off the EGR as it comes out at the front of the engine. ( quite easy ) It will put the engine into " limp mode " but you can still take it for a drive. Then leave it overnight & see how it starts the following day.

My Superb is exactly the same. Earlier models had 2 pipes on that sensor that both connected to either end of the DPF. Now it is connected to the DPF by just the 1 pipe, the short stubby pipe senses atmospheric pressure.

I hope you told the garage you had already been in touch with the DVSA. If they'd any sense, you can be sure they won't pass another similarly corroded vehicle in the near future.

Once you get the cooling system to start to cool the engine, replace the thermostat. Otherwise the heater will be very poor & the engine will give poor MPG.

I believe the engine has 3 pumps. A charge cooler pump ( electrical ), a cabin heater pump ( electrical ), & main engine coolant pump ( mechanically driven off the cam belt ) with an electrically controlled sleeve. Disconnect the plug for the N489 valve as shown in the picture link item No 1. Once the sleeve becomes free it won't operate & get stuck again, car can be driven for ever & a day after that or you can get it changed at great expense.

Here is a link to it's location, N1 in the diagram. https://karoqs.ru/forum/threads/154/ The pump will only start to work once the sleeve becomes un-stuck. But at least it won't stick again with the valve disconnected. They usually do seem to unstick themselves once the engine gets overheated. Nothing to loose.

Yes, that pump is notorious for the sleeve getting stuck even on pumps that have been changed. As I said above, disconnect the pump sleeve electrical plug ( N489 ) & hope the sleeve becomes unstuck. This plug is on the timing belt side just above the main belt driven cooling pump.

As it's a MK3 it must be the EA288 engine. This has a separate coolant pump for the cabin heater, which explains why the cabin heater always works ok. This engine also has the troublesome sleeved engine cooling pump ( V488 ), where the electrically operated sleeve that stops coolant circulation has a bad habit of getting stuck, preventing circulation of the main engine coolant, which seems to be your problem now the thermostat has been removed. This troublesome pump has a sleeve control valve ( electrical ) N489, which when operated stops coolant circulation. This is operated by the ECU while the engine is cold. So I would electrically disconnect this valve & hope the sleeve becomes unstuck at some point, which they usually seem to do. If the sleeve comes free, the pump just pumps all the time as older pumps do. If it stays stuck, the only other way of proving it is the problem would be to add an extra electric cooling pump into the main cooling system somehow. But that could be easier said than done.. Otherwise it's timing belt off to get to the pump.

On some of your shots of the DPF App, the DPF Output Gas Temp is higher than the Input Gas Temp, the DPF must be burning soot to raise the temperature. I suspect you are correct when you say the EGR is sticking open & causing more soot production. You can get one of these :- https://www.ebay.co.uk/itm/11-EGR-AGR-Emulator-Simulator-Plate-for-VW-Audi-Skoda-Seat-2-0-TDI-CR-II-Euro-5/183869556154?hash=item2acf7ac5ba:g:OaAAAOSw-DRdHK14 which will disable the EGR, but causes engine to emit more NOX.

Does the main radiator get hot right to the bottom. If not, could be the thermostat is stuck shut or only opening a little.

So guess it must me an EA288 engine, where the EGR gas is taken after the DPF ( should be clean ), before being injected back into the inlet before the charge cooler. Soot has blocked the charge cooler, which suggests there may be a problem with the DPF passing soot through, which it shouldn't do. The whole purpose of it is to trap the soot & burn it off at intervals. I would keep a close eye on the cars performance, & at the first sign of any further problem, have another look at the charge cooler in case it is full of soot again.

I'd like to know what the charge air cooler has been blocked with. Is this an EA288 engine that has the water cooled charge air cooler ? What is the engine code ?

The first reply by PetrolDave on Dec 5th was pretty spot-on then. No air getting to the engine through the intercooler.

If the only fault cod.e relates to P0322 ( crank sensor ) would have thought the problem must come from there. It only sends a pulse to the ECU at every revolution of the engine. As you've changed the sensor I'd be checking the wiring back to the ECU. Disconnect both ends & check the wiring for any earths or stray voltages & check the loom for any rubbing/ chafing.

That's the one I used.

I don't think the throttle valve creates a vacuum as such, but just reduces the airflow which it thinks is being replaced by exhaust gas. I keep a log of fuel consumption & noticed no change. I do mainly long journeys interspersed with a few short trips, it currently works out at around 60mpg average.

An EGR emulator is a possible answer to a problem you don't have yet. I don't know your engine code, but there is one for the CFWA 1.2 engine. https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=vw+1.2+egr+emulator&_sacat=0&LH_TitleDesc=0&_oac=1 And with the EGR out of the way, the DPF will have an easy time maintaining itself.

Apologies for hijacking CS45's thread, but In reply to J.R. I fitted an emulator to my Superb II 2l & my son's Tiguan 2l. Both took about 30 mins. Removed the air inlet pipe to the turbo to give access down the back of the engine. Found the EGR plug with the aid of a torch & mirror, it is completely hidden. Reached down & found it by touch & disconnected it. Connected it to the emulator & emulator to MAF. Secured the wiring & job done. As long as the EGR isn't partially stuck open you don't need to blank it, but that is easy too if needed at the front of the engine. Both engines have been trouble free since & regens happen when they need to without any problems. I don't know if access is the same on a Yeti.

An emulator is an electrical device that fools the ECU into thinking the EGR is fully functional, when it is actually disabled. It plugs into the electrical connector that is normally plugged into the EGR valve, & also plugs into the MAF sensor. Takes about half an hour to fit. This will solve your problem if the problem is the EGR sticking or partially stuck open. The hardest part is finding & disconnecting the EGR plug which is down the back of the engine. You will need a mirror & torch to find it. The DPF will still function as normal. This is one on eBay :- https://www.ebay.co.uk/itm/EGR-Valve-Simulator-Repair-1-6-TDI-VW-Audi-Seat-Skoda-CAYA-CAYB-CAYC-CAYD/143326591746?hash=item215eee3b02:g:3UQAAOSwSnRdJzkz You need to check your engine code to see if it the correct one. I have only used Tafmet ones, but they don't list one for the 1.6 engine at the moment, may be out of stock. Your engine will produce more NOX after fitting, but NOX is not tested at the MOT, yet.