Cooling system bleeding

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Harry2000

Member
Posts
60
Location
East Yorkshire
Now then , should I have coolant flowing out from the small black pipe at the thermostat housing to the T piece which joins up with the rad and header tank

300tdi 90
 

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If I remember correctly 200 and 300 TDI header tank coolant levels are lower than the coolant level in a cylinder head and thermostat housing
So now you have removed that pipe you have introduces an airlock into the thermostat housing/cylinder head
You will have to follow the correct procedure to refill and bleed the system then roadtest until the stat opens
 
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That plug looks like it has seen better days. I would seriously consider changing it for a brass plug to reduce the likelihood of problems in the future. The plastic ones are notorious for binding and having to be cut out piece by piece and bits falling into the thermostat housing whilst doing it.

I think I have seen a thread somewhere that had a domestic radiator bleed plug used instead of the plastic plug. This was the type you can get from plumbers merchants or screwfix etc. The advantage is it has that little bleed screw and also cheap - plus you can pick them up at screwfix etc do usually off the shelf and local. Please note I have not done this myself so can't give you first hand experience, but perhaps others on here have and can comment?
 
1-2in-radiator-air-vent_min_6918_P_1.jpg


This is a similar thing to what I saw. I think they are 1/2" taper thread so tighten with caution, but cheap with a bleed screw - you just need a radiator bleed key to open the vent.
 
That plug looks like it has seen better days. I would seriously consider changing it for a brass plug to reduce the likelihood of problems in the future. The plastic ones are notorious for binding and having to be cut out piece by piece and bits falling into the thermostat housing whilst doing it.

I think I have seen a thread somewhere that had a domestic radiator bleed plug used instead of the plastic plug. This was the type you can get from plumbers merchants or screwfix etc. The advantage is it has that little bleed screw and also cheap - plus you can pick them up at screwfix etc do usually off the shelf and local. Please note I have not done this myself so can't give you first hand experience, but perhaps others on here have and can comment?
Yes I can’t get it out ☹️
 
If I remember correctly 200 and 300 TDI header tank coolant levels are lower than the coolant level in a cylinder head and thermostat housing
<snip>

@Harry2000
I went and looked at mine after @lynall said that ... when full (as in over full) the water level is above the head, however there is a valve so you need to top up the rad then the thermo housing as this is above the radiator.
So @lynall is right and I was wrong ...

 
When mine was stuck I cut the hexagonal section deeper by cutting away the flange to the same shape as the upper bit. This made a much deeper hex section to get a sparkplug socket on. I used a decent braker bar and just rocked it backwards and forwards to loosen it.

I originally thought I was just going to shear the top off, but it actually came out. I was really pleased as I didn't want to have to pick it out. There was still some residue in the threads but I managed to scrape them out with a scriber.

Good luck with it.
 
Ended up breaking it to get it out , took thermostat housing out and covered the hole into engine with some cardboard and had vacuum into the hole to catch debris, then drilled the bung and drove a chisel in and turned the chisel with stilsens
 
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