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[shanjon]

ok i have scoured the site and done everything suggested including changing the hbv and checking all the vacuum pipes and backflushing the matrix but still i have no heat in the cabin,
if i refill cooling system let the car get up to temperature everything is great i have loads of heat until i switch it off and leave for half an hour and then no heat and display says coolant level,
however the other day i forced water round the system using the pipe that goes from the expansion cap to the plenum and it was great all day but the next day nothing and displaying coolant level again ,,,,,
im assuming it is sucking in air or leaking from somewhere but i cant find any evidence of a leak..
someone please tell me its something obvious   i have only had the car 4 weeks and love it but am sick of no heater

[PaulW]

Coolant Level warning is usually just a dodgy sensor in the headertank.  They can be got new for around £34 from VX, or sometimes cheaper on eBay.  Unless the level is actually visibly dropping, then its not really worth worrying about the message.

As for the heat issues, someone with more know-how should be along soon

[hotel21]

Have you ensured that all air is removed from the system?

From COLD, fill water to correct level.  Leave header cap OFF.  Start engine, have heater settings at HOT.  Let engine warm up and regularly 'burp' the large radiator hose next to the battery by squeexing it.  You should see water emerge into the header tank from one of the small hoses.  Ensure level remains correct.

Once all hot, replace cap.  There should now be heat in the cabin.

Remember to check water level again next morning when its all cold.  All air should now be out of the system.....

Remember to ensure the correct 50/50 mix of water/coolant...

[Marks DTM Calib]

One question at this stage.......

Are you loosing coolant?

[shanjon]

Have you ensured that all air is removed from the system?

From COLD, fill water to correct level.  Leave header cap OFF.  Start engine, have heater settings at HOT.  Let engine warm up and regularly 'burp' the large radiator hose next to the battery by squeexing it.  You should see water emerge into the header tank from one of the small hoses.  Ensure level remains correct.

Once all hot, replace cap.  There should now be heat in the cabin.

Remember to check water level again next morning when its all cold.  All air should now be out of the system.....

Remember to ensure the correct 50/50 mix of water/coolant...

have done all of that several times but i only get heat for a short period of time each time i do it

[shanjon]

One question at this stage.......

Are you loosing coolant?

i can not see any leaks but im pretty sure i must be as water lev el does appear to drop a little, althoughb the car must be leaking or sucking in air as i have blown 2 pipes the one that goes to rad by battery i have forced water throughb system with hose to the point where all air is out yet i could go to car now and disconnect heater matrix pipes or hbv pipes and no water would leak  (or very very little)

[Marks DTM Calib]

Right

So water is being lost whcih is a key clue in the symptoms.

What you have to consider is that during heat up the coolant expands and will force some water out of any weak points in the system but, the pressure will not increase considerably as it would on a fully sealed setup.

As it cools and contracts, it will effectively drop to less than atmospheric pressure and now draw air in at the point at which it was leaking.

My approach to diag would be to remove the plenum and inlet and plug the two coolant pipes that feed the throttle body and then pressurise the system (I have a coolant bottle cap with a car schrader valve fitted) to about 15psi (not to high as you could risk damaging it!) and look for the leak...

[shanjon]

thanks mate i will try that sound very feasible, i will update as soon as i have tried

[Marks DTM Calib]

thanks mate i will try that sound very feasible, i will update as soon as i have tried

Do watch the pressure though, the safety valve is normaly in the expansion cap (on my modified cap I drilled through the air admittance valve so the safety valve is still present).

And dont forget to carry out the test on a cold engine.

[shanjon]

no leak and water level is staying consistent however car runs at 92.5 to 95 degrees all the time i really dont know how to proceed with this, i have tried sucking on the vac pipe that goes on hbv and still no change, what is the best way to force water round the system to push out air as i have tried through top hose on rad and that just seemed to airlock the matrix and i tried the pipe that goes to intake plenum from expansion tank,

[jonathanh]

Right, as to the HBV if vac is applied then it bypasses the heater so disconnect the vac feed to it and check whether it is bypassing the matrix.  Reach in the drivers footwell to feel the heater pipes through the bulkhead, if they get scolding hot (when engine running) then your HBV is ok and you are getting got feed into the cabin.

If the heater pipes get hot then your problem is within the air distribution unit.  (i.e. you get a hot matrix but the internal flaps do not open to allow heat through).  If you do not get a hot matrix then focus on the hot water feed.

You can do both of these chest in about 5 minutes without taking loads of gubbins off.  let us know how you go

[shanjon]

top hose on matrix hot,,,, and bottom cold and disconnecting vac pipe makes no difference

[jonathanh]

that's odd.  with vac applied the hot feed to the matrix should divert and the top hose to the matrix goes cold. (best way of checking is start up from cold with heater settings on fully cold, pipe should stay cold)  Anyway, seems like you have heat to the matrix but no flow.  Is the HBV connected correctly?  could the matrix be clogged?

[shanjon]

that's odd.  with vac applied the hot feed to the matrix should divert and the top hose to the matrix goes cold. (best way of checking is start up from cold with heater settings on fully cold, pipe should stay cold)  Anyway, seems like you have heat to the matrix but no flow.  Is the HBV connected correctly?  could the matrix be clogged?

as mentioned previous i have replaced the hbv and backflushed the matrix several times, the hbv is fitted correctly and was a new one from the stealers,

[Marks DTM Calib]

that's odd.  with vac applied the hot feed to the matrix should divert and the top hose to the matrix goes cold. (best way of checking is start up from cold with heater settings on fully cold, pipe should stay cold)  Anyway, seems like you have heat to the matrix but no flow.  Is the HBV connected correctly?  could the matrix be clogged?

as mentioned previous i have replaced the hbv and backflushed the matrix several times, the hbv is fitted correctly and was a new one from the stealers,

Seen the bypass valves connected wrongly a few times so do check it...