snowathlete, 

i read your OP, is this the School Run in the UK that you are so cold on are you in some other country.

 

Would wearing hats coats and gloves not be a solution for warmer school runs.

2 hours ago, AwaoffSki said:

snowathlete, 

i read your OP, is this the School Run in the UK that you are so cold on are you in some other country.

 

Would wearing hats coats and gloves not be a solution for warmer school runs.

 

Unless they've moved Wiltshire to foreign parts, it seems likely that she is at a minimum 15 miles down the road from me.  (Mind you Wiltshire is a large, odd shaped county)

 

I thought I'd check this out on my way to work this a.m. at 07.30 the temperature was  -1.5 C

Driving to the depot in stop / start town traffic  it only took 2.1 miles until the system started blowing hot air - seems about normal as it usually kicks in about there or thereabouts, I've just never clocked the mileage before.

Yep, in Wiltshire and the school run is the main problem. Do do other driving too but obviously the school run is five days a week. It's about 2 miles away so I only get a little heat when I'm on the way back. Obviously it's not like I live in northern Scandinavian but that's why I don't live there, I don't like being cold! Don't think wrapping up warm is a great solution really, why not put a more comfortable and convenient solution in place if it's possible and economical? Also as the topic has developed it's clear there are mechanical benefits to auxiliary heating of the engine so it seems a good idea to go down that road if possible.

Sounds fair. 

Would the 2 mile walk or cycle there with the children and the 2 miles back get a bit of a sweat on easily enough even on the coldest mornings?

 

These polluting diesels & petrols on short school runs are the cause of so much pollution and health issues which should be a worry to those with children..

Edited 30 January, 20188 yr by AwaoffSki

are you for real?

No joking obviously.

In an overall sense thought you are right about vehicle pollution being a massive health issue for all of us. The bulk of the solution is around the corner though with electric cars due to become mainstream. Less pollution, less noise, better acceleration, better reliability, what's not to like?

19 minutes ago, snowathlete said:

In an overall sense thought you are right about vehicle pollution being a massive health issue for all of us. The bulk of the solution is around the corner though with electric cars due to become mainstream. Less pollution, less noise, better acceleration, better reliability, what's not to like?

 

A battery you don't own which costs 60% of the vehicle decreasing in capacity/efficiency year on year and charging when I need the car most.

35 minutes ago, voxmagna said:

 

A battery you don't own which costs 60% of the vehicle decreasing in capacity/efficiency year on year and charging when I need the car most.

 

Don't own?

The charging and mileage capacity issues will be solved with better technology over the coming decade.

The manufacturers aren't going to trust you messing around with those big batteries and throwing them away just anywhere. You effectively lease their batteries. Read the purchase contract to buy a Nissan Leaf, Hyundai, or Tesla if you can afford it. I think I'll let the early adopters try them out first to see if the battery efficiency stays up for 5 years. If it doesn't, they won't have much re sale value.

Electric vehicles are only as clean as the source of that electricity. In this country any incremental demand will almost certainly be met by gas or even coal. The big advantage is that the pollution is moved from the major conurbations out to the power plants.

It is also worth noting that, bar a few hot spots in major cities, air quality across the country has improved dramatically over the past few decades. The government's own data show how all of the significant pollutants - CO, NOX. hydrocarbons, SO2, particulates - are down by 60 - 80% with the odd exception of ammonia (thought to be linked to agricultural practices). The info is here: https://www.gov.uk/government/statistics/emissions-of-air-pollutants  

Voxmagna; the market is already making that point. Look at the second-hand values of Leafs, etc, as Quentin Wilson pointed out.

Early adopters always pay more for worse technology, like you voxmagna I'm happy to let others do that, but electric vehicles are going to become the norm and the technical issues will get ironed out, the cost will come down, the resale values will normalize. I didn't know that about leasing the batteries though, I hope that model changes.

 

You're right of course MikeHig. But as it's going to be more centrally produced, and will take place away from conurbations (great word) that's a good thing, there will be efficiency of scale and it's easier to capture pollutants than it is on lots of moving objects like we attempt now. As you point out though we'll have to meet the initial rising demand with fossil fuels largely. Over time though we'll use more renewable energies, and eventually, nuclear fusion.

 

It's good that pollutant gases have come down, and will continue to, because many are horrifically harmful to health.

Here we go then. 

Instead of talking Green time to do something about it.  Get cars off the roads, and do more towards healthy children. 

http://walkingschoolbus.org 

Not a realistic solution on a large scale for lots of reasons. It's no good thinking idealistically about things, the solution needs to work around people's lifes, which is why electric cars as direct replacement for internal combustion is a much better solution, albeit it with some things to iron out before it becomes the norm.

back on topic, Defa got back to me and very helpful explained the following:

 

"On cars with DSG gearbox there are an oil cooler on the top of this. In the hose who’s go into the cooler there are a thermostat, this will not open before the water is hotter than we can make in the system. Therefor you can’t use a hose heater"

 

Does anyone know what the temp rating on the DSG thermostat is? Anyone got a diagram of where it is?

3 hours ago, snowathlete said:

 

Does anyone know what the temp rating on the DSG thermostat is? Anyone got a diagram of where it is?

Underneath beside the battery another common failure on these I am sure the opening temp is 75 as stated on the box
When it fails the indicated temp on your mdf stays about 75 instead of 90 
 

Edited 31 January, 20188 yr by DEL80Y

With all this talk about fast cabin heating warm up, I don't know why all the masses of heat from the exhaust hasn't been utilized? In its crudest form it's some fins on the exhaust down pipe to create an air to air heat exchanger after the dpf/cat and fan air circulation? Otherwise a fluid based design with over heat protection.

4 hours ago, DEL80Y said:

Underneath beside the battery another common failure on these I am sure the opening temp is 75 as stated on the box
When it fails the indicated temp on your mdf stays about 75 instead of 90 
 

Thanks DEL80Y that's super helpful. 75C is a pain because most of these preheaters can reach a peak of 65 or even 70 but I haven't seen one that achieves 75+

I found a VW workshop manual for a golf that has instructions for installing a coolant pre-heater but the 2.0TDI isn't listed and this will be why. Doesn't look likely that this is possible then. So it'll be a contact heater, webasto or PTC.

 

11 hours ago, voxmagna said:

With all this talk about fast cabin heating warm up, I don't know why all the masses of heat from the exhaust hasn't been utilized? In its crudest form it's some fins on the exhaust down pipe to create an air to air heat exchanger after the dpf/cat and fan air circulation? Otherwise a fluid based design with over heat protection.

Especially as VW has such expertise (re beetle) with exhaust heating. 

An afterthought occurred to me:  How is the EGR cooler plumbed into the coolant system? They went to a lot of trouble and expense to put it in. Is it in the main cooling loop after the thermostat, or before it where it would help get the block and heater bypass up to temperature faster?? Does it take heat from the exhaust gases all the time or only under certain operations? Is there a stat on the coolant side and what temperature does it open?

1 hour ago, voxmagna said:

An afterthought occurred to me:  How is the EGR cooler plumbed into the coolant system? They went to a lot of trouble and expense to put it in. Is it in the main cooling loop after the thermostat, or before it where it would help get the block and heater bypass up to temperature faster?? Does it take heat from the exhaust gases all the time or only under certain operations? Is there a stat on the coolant side and what temperature does it open?

 

Here's a diagram of the same CFGB engine coolant system on the Golf:

http://workshop-manuals.com/volkswagen/golf-mk5/heating_ventilation_air_conditioning_system/auxiliary_heater/aux._heater/heater_booster/connecting_auxiliary_heater_thermo_top_v_to_coolant_circuit/connection_diagram_for_coolant_hoses_in_vehicles_with_auxiliary_heating_engine_codes_cffa_cffb_cfgb/

 

As you can see in the diagram there is a webasto heater installed as well, so it'll be slightly different on my car's engine without one. Does the Webasto get up to 75+? Even if it does it will only do that if it's on longer enough so it must be possible to fit an electric pre-heater. You're thinking that you might be able to install one and heat up all but the DSG? I don't really know enough about the system to understand how big a difference the DSG thermo makes, but Defa seemed to think it mattered. There's another thread on here where someone installed an aftermarket Webasto and had temp sensor errors come up. That was the Engine Coolant Temp. Sensor (G62) though which I think is the main thermo? Number 10 in the diagram. Anyway, that was fixed with a code change suggested by RossTech, presumably telling the sensor that it had a Webasto fitted so not to go nuts.

 

No diagram I can find for the Superb, but interestingly the Audi A4 only has  a4/2 valve thermostat if the heater is fitted, if not there is a different theremostat shown in a different diagram. I don't have a full understanding of why.

http://workshop-manuals.com/audi/a4_mk3/power_unit/4-cylinder_tdi_engine_(2.0_ltr._4-valve_common_rail)_mechanics/engine_cooling/parts_of_cooling_system_(on_engine)/diagram_of_coolant_hose_connections/

 

Edited 1 February, 20188 yr by snowathlete

Thanks - and aren't these cooling systems complicated even just trying to follow the flow routes? Item 10 the 4/2 way valve with thermostat seems an interesting part to understand? From the diagram alone I couldn't be 100% sure it's working and I'd need more data to confirm what's going on. I have this idea for all those wondering about their heating systems:

 

VCDS is pretty good at monitoring the various temperature sensors. You can start by logging the engine block temperature and coolant temperature as the car warms up. If you don't have vcds you can tack K type probes around the various hoses. Then from cold take the car for a drive at commute speed and distance. The engine block temperature should be rising much faster than the coolant (radiator) temperature, if the system is warming up just on bypass without leakage. Leakage could be deliberate bypass of some coolant past a faulty thermostat or they designed it that way to avoid to fast a temp rise in the engine block?

 

The heater matrix can never be hotter than the engine block. If it's cooler (without the fan running) hotter coolant must be bypassing it? Then external (PTC) heating of the air is the only way. I wonder about electric boosters in the liquid coolant line, because they could be heating other parts of the cooling system? By the time the main coolant stat starts to open and the temperature is rising, the engine block should be still hot yes? But many things can happen. If the main thermostat opens too quickly, stored heat in the block jacket will drop quite quickly? Sometimes with the older systems you can improve things by changing the stat for one that opens 5C higher. Remember those Summer and Winter thermostats? With these modern complicated systems you need to understand whats going on first. As for the EGR heat exchanger, I've not figured out its flow yet, but since it has it's own control thermostat, vcds might monitor its temperature? If not then tape K type probes to the hoses. I picked up a couple of Chinese 4 input K type electronic thermometers which would be just the ticket. Unfortunately I'm too busy looking at dpf regen. at the moment to go another course.

 

I'm reasonably happy with 'MY12 fixed diesel Yeti, but it does take a little longer than MY07 V.W to warm up, so I might do some experiments. VCDS is the quickest way to get data and learn what's going on.

Yes, the diagram is pretty complicated to figure out.

 

I don't have VCDS but will probably get it in a month or two. I'll be able to do the test you suggest then, and I'll let you know.
 

1 hour ago, voxmagna said:

The heater matrix can never be hotter than the engine block. If it's cooler (without the fan running) hotter coolant must be bypassing it? Then external (PTC) heating of the air is the only way. I wonder about electric boosters in the liquid coolant line, because they could be heating other parts of the cooling system? By the time the main coolant stat starts to open and the temperature is rising, the engine block should be still hot yes? But many things can happen. If the main thermostat opens too quickly, stored heat in the block jacket will drop quite quickly? Sometimes with the older systems you can improve things by changing the stat for one that opens 5C higher. Remember those Summer and Winter thermostats? With these modern complicated systems you need to understand whats going on first. As for the EGR heat exchanger, I've not figured out its flow yet, but since it has it's own control thermostat, vcds might monitor its temperature? If not then tape K type probes to the hoses. I picked up a couple of Chinese 4 input K type electronic thermometers which would be just the ticket. Unfortunately I'm too busy looking at dpf regen. at the moment to go another course.

I'm not sure I follow you entirely but the stat to the engine will be even higher rated than the DSG one. The thermostat will open just before 90C usually, I think. Pretty standard, but surely this means that no coolant pre-heater on any car would be able to warm the engine block, so I don't really understand.

 

The 4/2 valve stat may not be entirely mechanical? I'm not sure how the flow to the 4 ports is controlled. Maybe someone can enlighten us.

 

I think you do see a brief drop in coolant temp when the stat opens on cars for the reason you point out - suddenly the stat opens and the hot engine is quickly cooled by the cooler coolant that rushes in. I think this brief drop can be seen on the graphs of the Defa tests I linked to. But obviously it stabilizes quite quickly. But with a pre-heater in operation the coolant might reach 65C and sit there until the stat opens once the engine itself is up to temp, in rushes fairly hot coolant so you will get less of a drop.

Not sure why this would upset the engine except it may thing something is wrong because coolant is hot while engine is not, and maybe throw a fault. As Defa have a verified oil contact heater though it obviously doesn't seem to mind the other way round when oil is hot but coolant is cold, presumably because this is considered normal by the engine as engine gets hot first.

 

 

 

 

 

 

 

 

 

There's a lot to learn or discover! With all the Waxstat type thermostats I've tested the thermostat temperature rating is when it is fully open. They usually start opening 5-8 degrees before that. When you test them it's that initial opening phase that's important for good cabin heating. They should open slowly and I usually warm and cool them about the initial opening temperature which is when they can stick. 90C is quite high compared to the 70-80 you could get in older cars. But these days they use similar size radiators and push up the cap pressure for the temperature overhead.

 

I agree a coolant heater isn't likely to get up to that temperature and open the main thermostat. I'm assuming there will be some pumped circulation around the engine block and heater matrix and that large amount of metal outside in a cold engine bay will need some watts? There seems to be 2 arguments. 1. Keep the engine warm or allow it to warm up quicker with a coolant heater to get warm air from the heater, or 2 accept the engine should only take 2-3 miles and warm the air coming from the cold heater matrix?  Wall mounted air conditioners with reverse heating mode usually have up to 1kW heaters fitted to avoid unheated cold air falling on peoples heads. This is one of the little known things about 'efficient' reverse heating. Every time the things cut in and out on their stats, loads of juice is used initially. This is the same problem with car heaters. We always leave the blower at set positions and in auto mode (I think) the system pushes out cold air instead of stopping it until the matrix has warmed up. But then we like to think from all the noise the screen is being demisted when not much is happening at first. That seem to be how the Yeti works. We've also sometimes noticed on a long run that air from the vents can cool down noticeably? That might be a vaguary of their control and response, but it happens. Therefore I'm thinking that if cabin comfort is the objective, then auxiliary heating the air but only with the alternator running is probably the best way.  I've experimented with some of these PTC window defrosters and my main criticisms were cheap high velocity noisy fans and loads of amps needed. 10-15 amps just doesn't do much so I think you'd be looking at 20-30 safely wired in and the blower might need to be run on low speed? A car heater matrix puts out kilowatts of heat, the heated rear screen takes about 30 Amps and doesn't feel that hot by comparison. PTC is nothing magical, it's still a hot element with air blown over it. Truck heaters are often diesel or propane gas powered so they can sleep in their trucks. A propane gas catalytic heater (no flame) will give out a lot of watts!