I've always seemed to have an issue with my TDV8 it seems like it's recirculating load's of air (more than water) and it seems to spit water out when I'm towing my big trailer which eventually leads to it coughing and filling the header tank with water which then takes the water from the block (no hot air in the cabin) . I've tried bleeding the water system in so many ways and nothing seem's to work?.
I've tried the hydro carbon test and the water stays blue also I've vacuum tested the system and it looses very little ?.
I've replaced the thermostat housing and water pump and various other parts recently (within 12 months)
Just always panic as it seems to loose water when I'm towing and will eventually start to get hot if I was to let it ??...
I have a video but not sure how to upload it ?.

Difficult to diagnose that.

Could be an airlock which moved to the cabin system. Could be dropping when hot due to water moving through the cooler for the gearbox pushIng the air out.

As you say you have pressure tested the system and checked for a leak, and there is none where is the water going? You said it's. it dropping much pressure, it shouldn't really drop any. Is it going anywhere? Or is there just a lot of air in the system and its pushing it out so you see a coolant drop in the header tank.

If it's persistent mate I would get it to a garage, get them to test the system, and properly bleed the coolant. If you have changed parts you can probably rule out issues with those, but there is a lot to the rest of the system which could be trapping air such as the fbh, oil/water cooler, gearbox cooler.

Would have thought that after 12 months that it would have bled itself by now though.

Did you check the small pipe running off he bottom of the tank to the block? That one chafes on the body and can wear through. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

I took a great video of the header tank anyone know how I can upload it ??.

stick it on youtube and place the link on your post.. ... - .- -.




Y. O. L. O.
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Is the pressure cap releasing prematurely or not sealing properly?

Try this ..

its there,

exactly why are you running it with a funnel in? There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

what does it look like when you run it with the pressure cap on? There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

I was running it with the funnel in so I had the water at The highest point to see if it would bleed but it never seems to stop bubbling air out ? . If you put the cap on you just see the air and water going round like you see in that video ??.

Hi did you find out the problem