No heater/recent repair sounds like air pocket...

 

Im betting its air in the line... goota bleed the system properly otherwise you dont get proper heat dissipation.

Take the radiator cap off and run engine to vent it all out. Radiator reservoir will drop so keep filling it.

Squeeze all lines gently in order to push them air pockets out. Please dont stick ur hand it places it shouldnt go though. YOU LOOSE ANYTHING ITS ON YOU NOT ME.

Hope this helps

 

i think air is not an option, its been checked multiple times. I made vcds log yesterday when this problem occurred again in highway speeds. If anyone wants to analyse it, i'm more than happy to share this with you.

 

Co2 from coolant reservoir is checked and fine.

 

-13 ! what strength antifreeze/ coolant, do you have ?, if not sufficient, maybe some ice/slush causing blockage until everything gets hot and blockage melts, not so easy in heater matrix, until cabin gets hot, which it wouldn't!

 

Coolant is ok , nothing to freeze there.

 

Some dross floating around then?, how about draining system disconnecting hoses back flushing and flushing everything through and re- filling with fresh coolant.

 

Please check these logs made yesterday.

 

https://drive.google.com/open?id=0B2fLR8K6EXOyQWlORTQtUGxSbGc

 

Heater core issue possibly? If its cracked or there is a clog it will leak out coolant and you wont get any heat in the cabin. Also helps to cool the engine slightly so if you have a slight overheat condition it could be a contributing factor.

 

Does it hold pressure at operating temp?

 

How many drive cycles (drive, warm up to operating temp, stop, let it cool down) have you done since the repair?

X2 on there being an air pocket somewhere. It can take a few drive cycles to work itself out. As the air is working itself out, it would be normal to have to add coolant to the pressure reserve tank in order to replace the "air" that was lost.

 

Xeno555-Waht do you mean?
FSJ Guy-countless cycles.

Coolant loss is because it boils out from coolant reservoir. Sometimes i have to add coolant after 1000km, sometimes overnight. Yesterday it boiled out some coolant when i left the engine running and visited shop for 10min. Engine temp was 90C.

 

If worried about a possible blockage, you could flush the system.

The tests would then start by putting pressure on the empty cooling system. You then wait several hours to test for pressure loss.

Then you pull a vacuum and wait several hours to see if you lose vacuum.

Fix the above if needed.

If that passes without needing repairs, I wold change out thermostat and water pump.

PS: You can not work on a modern engine without something like this. Anyone who thinks they can will end up in a world of frustration. Engineers assume that you use such a tool to replace coolant so they don't make any allowances for modern engines to burp or release air pockets anymore.

https://www.ecstuning.com/News/Univ...999_2000_2001_2002_2003_2004_2005_2006_2007_2008_2009_2010_2011_2012_2013_2014/

 

This tool was used, when they replaced thermostat.

 

When cold, you can easily squeeze the top rad hose. When at operation temp it should be pressurized.

 

Yes, there was some pressure in when cold, and vacuum valves made noise when i squeezed it. At operation temp it was pressurized. everything else(warm air in cabin) worked fine too. I check it again, when overheating problem occurs.

 

It started blowing cold air to cabin but no overheting. Upper radiator hose was pressurized.

 

The fact that cool air comes out of your vents means 1 of three things: 1) Air in your cooling system 2) partial blockage in the cooling system or 3) the valve that permits coolant to flow through your heater core is failing/failed. Given that you also have intermittent overheating issues it is 1 or 2. More than likely, I really think it is air in your cooling system. You are aware that I just had a similar issue with my 2012 3.6 Touareg and I am almost certain it was a failed thermostat followed by an air bubble in the system due to the thermostat replacement. I recommend pulling the lower radiator hose and the oil cooler hose to drain the radiator and engine block and then use a tool like the one linked below to evacuate the cooling system and let it suck in the coolant. I am not confident these Touareg's can self bleed the entire system. Also make sure you have your key on with heat set to MAX and the fan on to circulate cabin air when you evacuate and refill the system.


One thing I did do that may have helped bleed the air (WHICH I DO NOT RECOMMEND ANYONE DOING) was to get to operating temperature and then (WITH GLOVES AND FACE PROTECTION) unscrew the overflow cap to let the system rapidly bleed off some pressure. There will be a rush of coolant into the overflow tank (especially if there is air in the system) and will probably overflow. Screw the lid back on when it starts to overflow and let the system cool then re-top the coolant to the Max level. Also squeezing the upper and lower radiator hoses can help move coolant/air around.

Coolant evacuation and fill tool
can't post links since I don't have enough posts... Seach for a schwaben Coolant Refill/Air Purge Tool. I got mine from ECS tuning.

 

I will also add that normally, your system should not boil off coolant. This is a sealed system. Coolant only leaves the system if the system needs to bleed off pressure and/or there is too much coolant in your overflow tank.. or there is a leak.

 

It certainly sound like air in the system, you should use a bleed system which will do a much better job than just running the engine with the cap off. It is a funnel with different fitting to suit a variety of vehicles.
GraLis

 

Ok, i'll bleed the system and let you know!

 

Hi put the funnel in the coolant bottle and run the engine till it gets warm and keep topping up the water until all the bubbles have finished coming to the top of the funnel, also make sure the heater is on full so the coolant can circulate. If this does not fix your problem check to see if the radiator is evenly hot (top and bottom) otherwise you may have a blockage also double chech the correct thermostat is installed.

 

I Don't think that funnel technic will work. You have use the tool that pulls a vacuum and let the it stuck the coolant in. There was a link in a previous post for the tool.

 

done everything what you recommended and swapped water pump. Nothing changed . There are no new ideas at this moment.

 

done everything what you recommended.

Including back flushing ?