D.FYLAKTOS

The hose beneath the aluminium heat tape is this https://www.skoda-parts.com/data/items/56/50741382eef1c.jpg The long hose is factory (is for A/C) and the hose attached to the oil cap is reinforced and can stand temperatures up to 120 'C (it's for the after gas, the factory sends them back to the throttle for lubrication but i didn't like the idea).

In the past i used the MoCool of Motul, the idea was to help my car in hard city traffic conditions to don't get overheated. In the past years i had used similar products as W.Wetter, Royal Purple and i had no problems. Turning back the time i remember that i had a problem with my water pump gasket (this means change of coolant) plus few months latter a thermostat problem (change of coolant also) so i ended-up with 2 brands of G11 Antifreeze in my car because when the 2nd incident happened i was travelling so i could find the same. Those 2 coolant changes made the analogy to be very wrong, maybe i was 60-70% Antifreeze and the rest distilled water and i added the MoCool without taking proper measurements before, if i had done this i could see that my coolant was more thick (more ''strong" s we say it here in Greece). I extract some of this ''coolant mix" (blue colour both) and i added MoCool (blue colour) according to the label on the bottle, after few days on city traffic everything looked good (1-2 'C lower temperature) but soon this stopped and when i opened the cap to make a volatilization i was shocked! The expansion reservoir has full of black ''sludge" and the coolant was black, it was some kind of chemical reaction and i was terrified because i thought that this sludge would be stuck in my water pump blades, my thermostat, it's sensor, in the wall of the hoses etc. I said ''OK, this is the End of my whole coolant circuit" and i had to remove and clean everything which means time and lot of money.

Here is the new air filter box while is installed. The flap is closed, it will open when the temperature (of the air through the hose from the manifold) rises. Now it's ready, i use a heat resistance hose (as the factory had) plus in the connection i use adhesive tape which can hold till 150 'C. For heat insulation i wrapped the upper hose with aluminium tape which can stand till 200 'C

I changed the gear box oil few years back, i used Motul Motylgear 75W-90, i have to check back home my notes for the next change. ''Hey mechanic, i hear some noises when i turn the steering wheel from lock to lock, especially inside the parking'' ''What noise?'' ''It's like gggggnnnk, do i have a problem with hydraulics?'' ''Don't worry, that is an old car, they do it often, no problem you will use to it'' I didn't believe him, i checked the oil level at the reservoir, one click BELOW the Min (!) and i was continiouing to use the car i will had major problem which also could cost me a fortune to fix it.

Yes, many times this is a problem trying to ''marry'' this to the real engine parts when it's time to order an item in an e-shop. Last night i had the chance to go to a boulevard, enough distance to put the 4th gear and reach the speed of 80Km, i was happy when i returned home and the TC-6 showed 10,48 ltr/ 100Km (that's 24,650 mpg) which is my record so far for City fuel consumption. Today home to work, normal traffic and i have 10,58 ltr/ 100Km (which is 24,885 mpg) so generally speaking things are getting better. For sure the new spark plugs were a ''savior'' and i am waiting to see the contribution of the stock air filter design, keep in mind that for 20 years i was not using it so now i must apreciate some things from the beginning.

Here is the mechanism from another view. The code of this part is VW 9A 419 133129826 and i haven't manage to find it in the web to buy it separately. Here is inside the air filter box, the hot air from the exhaust manifold hits this thinner spring which after few minutes due to heat triggers the mechanism.

Modifying the entrance of the fresh air from the grill makes a tiny difference in sound and performance, i have made in the past many modifications and when there is an exaggeration you hear a ''roarrrr" sound especially at high rpm but that does not mean more Hp (as some young driver believe). What looks like a small round hole actually is a big oval hole The part No15 is hard plastic tube S style, if you remove that part then every time you press the pedal far more air comes inside the filter, the sound is more rough but the raising of performance is controversial. One drawback of that modification is when the engine bay is getting hot (city traffic) the air filter gets hot air only and that is not good. The factory paper filter (with the stock entrance) if far the most quiet combination especially in city (idle-acceleration).

Covid measures are here in Greece for 2 years. All the previous years i didn't pay attention to my night cold starts, they were brief, 1-2 times per week i was in a boulevard and i could engage even the 4th gear and the fuel consumption was good. Then came the mistake from the mechanic (wrong valve gaps) plus the NGK which didn't worked good and the very thick coolant and the fuel consumption started rising. Additionally he restrictions from the Covid made things in fuel consumption worst as ever. I have some photos to upload from the instalation of the new air filter plus the flap mechanism and for few days i will put the ''hot air'' hose in different positions to find what's best. Today my night cold start wasn't too short but not 3:45 as the old ones, tomorrow i will use the timer to see if there is any improvement in that sector. In the road things are good, one click lower noise at idle (traffic light) from the air filter box and in acceleration. I have also some photos to show from the previous coolant expansion reservoir which had a bad look like dirty with a black and sticky substance on the walls.

I have not that air filter box thermostat since 2002, has been removed and i can not find it in my closed of spare parts. I bought and installed a new at 2022 because i want to solve the problem with my ''second'' cold starts. Turning back the time it was my mistake that i removed that item but as already said i had a ''bad advisor''. ALL the ols cold starts were out in the fresh air and i was traveling 1-2 times per week in a boulevard and sometimes in the highway. I didn't gave any special attention of how many minutes the rpm were at 1100 because i was in a hurry to return home after work. For 2+ years things are different, cold starts in parking garage-hard traffic-not high rpm-mainly 1st and 2nd gear etc, all of these didn't existed in my life so far. The car was clogged and when the TC-6 arrived finally i had a tool to work, i have live indication of what's happening and that socked me. Step by step, making corrections i am lowering the fuel consumption, from the worst of 14,7 ltr/ 100 Km now i am at 10,7 (i have seen 10,6) ltr/ 100 Km and i am optimistic that i will manege to make it better.

Brand new, tested with heat gun and refrigerator and works as it should be. Cold start: allows hot air to come to the air filter helping the starting process. As the time passes and you are not in a boulevard or highway the temperature rises so it closes the hot air hole allowing only fresh air to come from grille. Yes,there was no reason to feed with hot air the filter all the time, this is no good in a trip. I cover the hole and the car had only one (and for some months two) entries of cold air only. My problem is if it stucks on the 1st position while i am in a highway or a mountain route i will have a performance problem plus poor combustion. That flap mechanism is not visible and i have to bent in a very Hot engine to find the solution.

Here is the connection, the flap has an U shape and the rod a Π shape, it clicks and thus controls it. That air filter sensor is very sensitive, a little bit of rubbing by hand and immediately reacts. The crucial point is ''for how long"?

The Mediterranean people when the joking do it obviously and in internet they add a LOL or an emoticon with smile. As @Pete_Ex-Wino said it's not a reliable item, as you can see below there is no ETKA number for this part, it's not something you can buy it separately. So if after a years or two the flap stay in the closed position blocking the cool air and allowing only the hot air HOW how will you find out? Let's say you are in a highway and the car start showing signs of poor performance, the last thing that will come to your mind is that flap. IF that air filter thermostat was reliable there would be no worry by me.

The thermostat with the pin pushes the rod and opens the flap and when withdraws the flap goes back to normal position (which closes the cool air). Hot air->thermostat warm->pushes pin->rod goes front->opens the flap. Since has wax inside soon or later there will be a leak and the rod will not moved (front or back) and will stay in one position and ''game over''. The rod is something like this: In the end has a hook and it grabs the flap so it controls the movement (Front-back). I wonder if i make a simple flap with lighter plastic or with aluminum tape, the incoming cool air after (for example) 40 Km speed could be capable to push it back and close the Hot air hole? Let's say it can, then in city traffic when the flap is back the Hot air from the manifold can push it to open a little bit?

I live in 3rd floor, i can't do this at home. I wonder if i make this flap work as manually, the strength of the incoming air (from the front grille) would be capable to make it close? I mean at 40Km speed could make it go back and ''seal'' the hole of the hot air?

Yes i saw that pin, is flat in one and and pointed at the other end. The Warm position must be blocked 100% ?

After 20 years the original air filter box is in my hands again, take a look of the mechanism. Upper entrance: hot air from the exhaust manifold Right entrance: fresh air from the grille The initial position is with the clapet closed which means the throttle gets air only from the upper entrance (hot air) and later the clapet will removed and the throttle will get fresh air from the right entrance. As you can see from my finger the spring is strong so how the clapet will open? The fresh air would have the capability to do this? The temperature of the hot air from the exhaust will make the mechanism to make the spring get shrink? And every time the car stops (no incoming air) the clapet will close and the throttle will get hot air? Is this good for the engine?

I don't remember if i mention it before but when i said to the mechanic to remove the reservoir and clean it with a spray and then use compressed air or a clean rag to clean it inside said immediately ''NO''. I was against of use of any chemical way, i asked why and he insisted that there is a possibility to remain something and this will make a chemical reaction with the Hydraulic Oil and soon or later i will have a problem with the seals. He preferred the ''flush with new oil" method.

I can find a new Skoda Original air filter box from a local parts shop so everything would be as the 1st day. It was a mistake from that i believed a guy then ''Hey, you have a ECU chip and free air filter so you don't need that system". Maybe the density of air plays some part, the oxygen is different, no fresh air down there.

I didn't said the car is colder in that case, i said that my worst cold start are in that occasion so except if something ''magic'' is happening then this situation must be the cause. Keep in mind that for 17 years the car was parked outside (not in a garage) in the road so after finishing my shift at night the 2nd cold start of the day was with the car cold (as in the morning/noon when i was starting from home). The last 4years allow me to park my car in the garage to the end of it which is 5 floors below earth, has many benefits and only one drawback that 3:45 minutes of waiting. So it's worth to reinstall that system as it was from the factory?

When the engine starts the exhaust manifold starts getting hot thus some quantity of warmer air from the hose is transferred to the air box, there must be a reason for this isn't it? I suspect that is to help the cold start that's why the clapet closes after a while. After 6-7 hours i don't know how much heat can remain in the engine bay. My best cold starts is when the car was outside in the road for all night and the worst are when the car is parked inside a building.

Above the exhaust manifold there is a cover (yellow arrow) which has a socket where fits the hose which brings hot air inside the air filter box (green arrow) those first minutes. Is this hot air except the better emissions can make the cold start easier? I have removed that hose many years so i can not remember if the ''second" cold starts of 2000-2001 were with a delay of 3:45 as i have the latest years.

My next task is to replace the ''clapet'' on the air filter box , below is the lower part VAG 6U0129607B When you start the car hot air (red arrow) comes from the exhaust manifold and when the temperature rises (if i remember correct at 30 'C) then the clapet opens and allow cool air (blue arrow) to come inside the box while closing the entrance of the hot air. According to theory those first minutes the hot air will make the starting process easier, the fuel-air ratio will be better etc. As a young driver (No internet back then) i follow the advise of a guy and remove it, i can't find it now so i had to buy a new air filter box or the lower part as Used. Few weeks back another Felician mention it, i can't remember if it was @Papez @J.R. @Pete_Ex-Wino

Due to Covid restrictions and 2 times Quarantine period there were no options except home-work-home. Few years back things weren't this way, i could go to a boulevard or make short trips to national roads that's why i was seeing better fuel consumption. I will try to go the highway and later i will make a detour to a quiet mountain road, so far the spark plus turn out to be an excellent choice!

Update: Today noon after finishing work i found a boulevard and finally manage to put the 3rd-4th gear even for few seconds, i reached the U turn and turn back again having the chance to put 3rd-4th gear again but for a little bit. Unfortunately the city traffic ''caught me'' and after one kilometre i returned home because i didn't had enough time. The TC-6 showed fuel consumption 10,68 ltr for that small trip which means: 1) My Trusty as is isn't for hard city traffic 2) the Air Intake Manifold cleaning, the correction on the thermostat Coolant Sensor and the new Iridium spark plugs were worth it. The new plug for the Coolant sensor is coming soon, i can't leave the old cables because after so many years are hardened and i don't trust them.

I use the car for house to work and work to house, steady hours same route and the road conditions are 95% the same. I know when the temperature will start rising, when it will reach the 91 'C when the fan will start spinning for 1st time etc and the weather all these days was the same except a light rain today. The 2nd cold start of the day is from the same spot 5 floors below earth almost the same time and i follow the same rout to exit, one road block, turn right, main road, here is the 1st traffic light etc. I began with 13,1 ltr fuel consumption and now i am on 11,02 (same road conditions) and when i pushed it few days back in the mountain (Champion spark plugs) i was in 10,8 ltr. The car is one click better when i start from the traffic light plus on the acceleration after change from 1st to 2nd gear in the alleys close to home. I want to find a boulevard with minimum traffic to push the car at higher rpm or one evening to go out to the national road to see the difference with the iridium spark plugs.