No hot air longer than 15 sec in passat b5 2000. 1.9 TDI and no light inside working.

edzha90

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Jul 5, 2014
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Hi there,

I bought a car but didn't checked this things...so I am a bit stuck and would need some help.

1. After I turn button to red one (hot air) there is hot air coming in cabin only for 15 sec afterwards it's just cold air.. also after 30 min I do the same thing, just hot air for 15 sec..
2. Most of the time on motorways in evenings or night time engine temperature drops below 90C , I would say to 70C sometimes even to middle 50C..
3. There is no lights working inside.. what could be a problem ? Is there separate fuse for inside lights ?

I scanned car with 'VCDS-Lite' and found this error:


1 Fault Found:
17664 - Engine Coolant Temp Sensor (G62): Open or Short to Plus
P1256 - 35-10 - - - Intermittent

My question is: is this error somehow related to temperature droppings and no hot air in cabin longer than 15 sec ? what could be problem for no hot air coming in ?

As I live in Europe I have an EU VW car.

Also I found something on ebay the engine sensors...

Looks like they are two different sizes, which one do I need ?

http://www.ebay.co.uk/itm/Cambiare-...del:Passat|Cars+Year:2000&hash=item19ebbc31aa

or

http://www.ebay.co.uk/itm/VW-Passat...del:Passat|Cars+Year:2000&hash=item43c8aa03ff

when I will replace do I need to be aware of something ? like oil pressure?
 
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edzha90

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1854sailor - so you think if I replace the thermostat that error might disappear ?

peiphil - that's the last thing what I want to do.. I have seen that's such a headache to replace.
 

edzha90

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I have read a bit of CLR but I'm a bit of a newbie at this. Can I just try flushing the system with water? Like flush the heater core with water from my garden pipe ? If some of you have the information I would appreciate to hear that. Thanks
 

peiphil

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I use a pump sitting in a pail of clr hooked up with hoses forcing it through in reverse flow first.
The return hose to the pail flows into a screen or sieve to catch the pieces of junk from the core
Rinse the core out with the garden hose when your done!
 

1854sailor

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1854sailor - so you think if I replace the thermostat that error might disappear ?...
Since you said that your temp gauge sometimes drops to as low as 50, yes, that is what I would do first. I remember reading somewhere on these forums that the ECU will throw a temperature sensor code if the engine does not warm up within some set time. I'm pretty sure that it was in a post by one of the gurus here.
 

Windex

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Cambridge
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05 B5V 01E FRF
Symptoms like you describe are caused by:

Coolant which is not hot enough (bad thermostat)
plugged heater core
insufficient flow through heater core
hot/cold blend doors not sealing or moving on their own

Does your car have auto-climate control or just manual knobs?

Check the hoses leading to the heater core to make sure that they are not pinched. Also, if there is some sort of shutoff valve on the heater core line (not equipped here, but EU - who knows?), make sure that it is not restricting flow.

You can check the thermostat with a non-contact thermometer on the upper rad hose - you are looking for 90 deg c fully warmed up (or close).

If the upper rad hose stays cold, then replace the t-stat. If the upper rad hose stays hot, then turn on the heater and touch the heater hoses. If they stay hot but the heat in the cabin goes cold again, then you have a blocked core, or insufficeint flow.

Heater core replacement requires removal of the dash - not fun. I have squeaked them out on b5's by pulling the dash rearward 6-8" instead of full removal, still not fun, but a little less work.
 

edzha90

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1854sailor - I thought that if the thermostat is bad the engine would overheat.. but mine doesn't overheat...


Windex - It has manual knobs. I will check all cooling system pipes once engine temperature hits 90C

Today I will change sensor then I will see how it goes.

I don't have a non-contact thermometer but I have a multimeter with temperature measurement option, but if that will help at all ?

The engine temperature is 90C (I believe it's 194F ? ) while I am on motorway driving fast like 120km/h (75mph) or more but if the outside temperature drops like in evenings or nights the engine temperature drops slightly even if I drive 75mph. I just wondered what will happen if the winter will be outside?

I have noticed that when engine temperature is about 20-50C (60-120F) the cabin heat is longer than 15 sec but when the car hits 90C the cabin heat is only for about 15 sec... What do you think if the heater core would be broken/ bad or anything else that thing would't give any heat at all ? I would believe it's the pipes.. what do you think ?
 

1854sailor

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1854sailor - I thought that if the thermostat is bad the engine would overheat.. but mine doesn't overheat…
These thermostats usually fail open, so the engine will not heat up.

The engine temperature is 90C (I believe it's 194F ? )
You can not believe the temperature gauge on the instrument cluster. You need VCDS to read the actual temp. The cluster gauge has so much hysteresis the it will read 90 at much lower temperatures. Our ALH Golf was reading 90 when VCDS showed <70.
 

edzha90

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I will scan today. Where exactly in VCDS I can measure temperature ? I have VCDS-Lite release 1.2 (the free version) . I would believe I have to go on 'Select control module' then engine ?
 

1854sailor

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Yes, Engine Control - Measuring Blocks - Group 001. Coolant Temp is the second block from the left.
 

edzha90

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I changed the engine coolant sensor, it was easy to take out but replace with the new one it was something awful and I am still not sure if I done correctly because the new sensor I can move a bit, comparing to the old one which didn't move at all.

I turned car on so there is no leaking.. in picture you can see that there is no clip, after I took picture I installed the clip I tried to push backwards and it didn't come out with clip so I hope that's how it has to be ?

I tried to push as hard as I can to put it back, but as you can see in picture that's how it looks like. I am not 100% sure if it's fully inside.. how do I know that ?

pic - http://postimg.org/image/6l1hbckd5/full/
 
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edzha90

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Right I have done test drive in city 30 mph speed was it as I didn't wanted to risk drive on motorway right now. I didn't reach the 90C even in VCDS you can see that the temperature wasn't 90C. I have added some pictures so maybe someone can check for me ?

Also the cooling system, the houses to heater core is colder (not even close to engine temperature) than the houses which are connected with engine coolant sensor.. so I believe in cooling system there is lots of rust/dirt etc. same for heater core ? because again the heater core gives some heat for 10-15 sec then it stops..

or it could be a thermostat or antifreeze ? Even though the antifreeze changed in same time when timing belt, water pump, oil filter etc. 1500 miles ago.

I attached pictures with temperature etc. information - http://postimg.org/image/xodp820id/
http://postimg.org/image/4u1qg5ddn/
http://postimg.org/image/m5s01685b/
http://postimg.org/image/vb8i33jm1/
 
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Windex

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If you have a new sensor, and the highest temp you can reach is 64-65 deg c, then the thermostat is stuck open.

A little movement on the sensor is normal when first installed. If you are able to install the horseshoe clip and the sensor will not pull out (and doesn't leak) then you are OK.
 

edzha90

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I've done proper drive. If the sensor won't be correctly installed then it wouldn't show correctly in VCDS temperature ?
Here is picture after 25 miles drive with 70 mph ( 110km/h) the dashboard temperature is 90C but in VCDS is 81.9 is that correct or thermostat still needs to be changed ?

pic - http://postimg.org/image/6ue2zpyap/
pic - http://postimg.org/image/eqmc5crot/

Also I touched the houses in engine, close to heater core houses I felt that inside the housing I can feel some rust or smth like that you squeeze something, like bending so I managed to do around them, so afterwards my cabin heat was hotter and longer..
 
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peiphil

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reread posts #3 #5 #7
Your thermostat is working but a bit low and should be changed sometime before winter however I don't believe that is the root cause of your heater problem!
 

Windex

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At 81 degrees, the T-stat is hanging open or opening prematurely.

By your descriptions, it sounds like there is debris in the hose which is obstructing the heater core. If it were my car, I would replace the stat, and flush the core, rad, block and all hoses and refill with proper G12 at the same time.
 

1854sailor

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...Also I touched the houses in engine, close to heater core houses I felt that inside the housing I can feel some rust or smth like that you squeeze something, like bending so I managed to do around them, so afterwards my cabin heat was hotter and longer..
What is the color of the coolant? If it is not pink, you've got a corrosion problem and there is scale in the system clogging the hoses. Like Windex said, have the cooling system flushed, including a back-flush of the heater core, refill with G12/G13, AND you might want to try a new thermostat, too. :rolleyes:
 
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Vince Waldon

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If it were my car, I would replace the stat, and flush the core, rad, block and all hoses and refill with proper G12 at the same time.
2X. :):) Always a good idea to eliminate all the obvious suspects right off the bat, and 99% of the time the simple answer was the right answer.
 

edzha90

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What is the color of the coolant? If it is not pink, you've got a corrosion problem and there is scale in the system clogging the hoses. Like Windex said, have the cooling system flushed, including a back-flush of the heater core, refill with G12/G13, AND you might want to try a new thermostat, too. :rolleyes:
If I do replace the heater core you think I will have proper heat back ?

The color of antifreeze is green I believe ? I took a picture where you can see it's a bit left from the time when I changed temperature sensor. http://s27.postimg.org/p9fpou5hf/20140710_203500.jpg
 

1854sailor

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That is the wrong coolant. You need G12, G12+, G12++, or G13 all PINK and all good for your VW.
 

edzha90

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So I just don't understand why then in garage they use that one. Will that make things worse if I will drive like 500 miles with that coolant ? Because I have move to another city, so then I think to change to the heater core and antifreeze. Or perhaps there is no heat due the bad antifreeze ? So I have to buy any of these G12, G12+, G12++, or G13 but which one would be good, as I think G13 is the newest version ?

also what's the ratio, for example I have to top up 5 liters of antifreeze and the rest with distilled water ? or just water ?
 

Windex

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keep feeding.

The issue with driving the car is that the radiator id just like the heater core - just larger. There are a lot of tiny little passages which may also get plugged like your heater.

Think about it - your heater core is not able to radiate heat because there is not sufficient hot coolant flow through it.

What do you think is going on in the radiator - it radiates heat just like the heater core, just to the outside.

As above:

dump the green coolant
flush everything forward and backward
change thermostat
refill with the proper G12

Stop asking other questions - you know what to do. :D
 

1854sailor

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So I just don't understand why then in garage they use that one.
Because they obviously do not know what they are doing. VW has been using the G-12 and up coolant for at least the last 15 years. G-11 is not compatible.

Will that make things worse if I will drive like 500 miles with that coolant ?
The heater core is already clogged, but since your car is not coming up to operating temp because of the open thermostat, another 500 miles shouldn't make that big of a difference in the radiator. Just have it flushed as soon as you can and you may be able to save the core and the radiator. Like Windex said, flush it in both directions.

...as I think G13 is the newest version? ...also what's the ratio,
Yes G13 is the latest and the greatest. The mix ratio will depend on the lowest temperatures in your region. There's a chart on the side of the jug.

...distilled water ? or just water ?
Distilled water only. Now just do it!!
 
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edzha90

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There is problems to find G12 antifreeze at all.. as I am in UK right know. In their shops (even the most expensive ones) they suggested me G30 which is in pink color and it's is 5 liters and it's about 48$.

I will order antifreeze from internet, because in their shops people are not really educated as far as I know, because all their information they get from their shop manual.

Well guys which one do I need - additive, coolant or antifreeze or all of them are the same it's just depends where in the world you live and you call it ?

I have found on ebay.co.uk G12 and G13 , this is G13 1,5L each - http://www.ebay.co.uk/itm/GENUINE-V...le_Oils_Lubricants_Fluids&hash=item5af74db4f2 so how many liters do I need so I can mix with water ? As my car takes 7 liters (manual)

I've checked the pipes again. The right side pipe from firewall to heater core is hotter than the left side pipe so I assume like you said there is plugged heater core. When I move I will take down to garage and if that is the case I will order a new radiator, antifreeze, thermostat and hopefully that will sort out the problem.
 
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