sell as I know a few of you will go slightly off topic lol, anyway I've got an air on issue, it blows slightly warm on the left icy cold on the right,I changed the valve under the bonnet for a brand new one and issue is still the same. I've tried both normal aircon and tested it on max aircon to bypass the sensors with the same result. Aircon has also been regassed am I looking at hevac flaps/motors or maybe a wiring issue to the valve?
tomcat59alan
Well-Known Member
She may not be wearing any, hence the flap problem, it's been windy today.Tell her to wear some tighter knickers.
tomcat59alan
Well-Known Member
Going to be blend motors then. As i say don't know much about the L322 system but can't see it being a lot different in operation to the P38. But knowing the L322 possibly a thousand times more complex to do the same job. Ant (SaintV8) may know more about this, he has just had his heater unit out and will be more conversant than i am.
Is the warm air the same temp as ambient??
i.e. if it is cold outside, is the air delivered cold and if it is warm outside, the air delivered is warm?? Or is it warm regardless of ambient??
If it is warm regardless of ambient, then the heater valves aren't closing properly - as you have replaced the heater valves with new, you can discount the valve being the issue so must be a wiring to the valve issue causing the valve on the affected side to remain slightly open. IIRC the valves are normally open and the HeVAC powers them closed as necessary.
The valves have been known to stick, or a spot of crap can gather under the valve seat causing it not to close fully....but if yours are new, this also may not be the issue.
The air movement within the heater box flows through the heater matrix regardless of set temperature, the heater valves allow coolant into the matrix to warm it if necessary, the matrix is split in two halves for the passenger and drivers side.....so the only way to get warm air out of the heater is for coolant to be getting into it......the two halves do share a common return line piped into the manifold on the back of the engine.
It is a longshot, but if you have a hole in the matrix the flow can come back through the return into the affected side of the matrix - this happens because on a 100% working system the valve is closed, the coolant can't flow back into the matrix as it would need to displace the cold coolant already in there......but if the matrix has a hole in it, this then allows the hot coolant from the return to displace the cold coolant through the hole in the matrix making it warm and thus warm the air.
I am in the process of changing my matrix as I had issues with one side being a different temp to the other by a marginal few degrees....and then I was getting air locks in the matrix that were difficult to bleed out. Then came the losing coolant and I couldn't figure out where from.....
I then static pressure tested the system and the pressure would drop over a few minutes but could not for the life of me find out under the bonnet where it was coming from......until I saw a dribble of water under the car.
Fearing this was the rear manifold (common item to crack and leak coolant) I crawled under and the dribble was from the passenger side A/C drain......The car hadn't been driven or started for 2 days so it was not condense, tasted it.....bugger coolant. The only way for coolant to be coming from the A/C drains is if the matrix has a hole in it!
I disconnected the pipes to the matrix and tee'd them together to complete the circuit and have been running the car for the last 2 weeks or so while I figure out how to get the Matrix out....the official procedure is to strip the interior and remove the whole HeVAC unit.....but I feel it *may* be possible to just remove the matrix with the unit in place (see my threads) - this I will be attempting over the Bank Holiday weekend shortly!
I would advocate doing a pressure test on the system and see if you have a leak....hope you don't, but your symptoms are scarily like mine were!
i.e. if it is cold outside, is the air delivered cold and if it is warm outside, the air delivered is warm?? Or is it warm regardless of ambient??
If it is warm regardless of ambient, then the heater valves aren't closing properly - as you have replaced the heater valves with new, you can discount the valve being the issue so must be a wiring to the valve issue causing the valve on the affected side to remain slightly open. IIRC the valves are normally open and the HeVAC powers them closed as necessary.
The valves have been known to stick, or a spot of crap can gather under the valve seat causing it not to close fully....but if yours are new, this also may not be the issue.
The air movement within the heater box flows through the heater matrix regardless of set temperature, the heater valves allow coolant into the matrix to warm it if necessary, the matrix is split in two halves for the passenger and drivers side.....so the only way to get warm air out of the heater is for coolant to be getting into it......the two halves do share a common return line piped into the manifold on the back of the engine.
It is a longshot, but if you have a hole in the matrix the flow can come back through the return into the affected side of the matrix - this happens because on a 100% working system the valve is closed, the coolant can't flow back into the matrix as it would need to displace the cold coolant already in there......but if the matrix has a hole in it, this then allows the hot coolant from the return to displace the cold coolant through the hole in the matrix making it warm and thus warm the air.
I am in the process of changing my matrix as I had issues with one side being a different temp to the other by a marginal few degrees....and then I was getting air locks in the matrix that were difficult to bleed out. Then came the losing coolant and I couldn't figure out where from.....
I then static pressure tested the system and the pressure would drop over a few minutes but could not for the life of me find out under the bonnet where it was coming from......until I saw a dribble of water under the car.
Fearing this was the rear manifold (common item to crack and leak coolant) I crawled under and the dribble was from the passenger side A/C drain......The car hadn't been driven or started for 2 days so it was not condense, tasted it.....bugger coolant. The only way for coolant to be coming from the A/C drains is if the matrix has a hole in it!
I disconnected the pipes to the matrix and tee'd them together to complete the circuit and have been running the car for the last 2 weeks or so while I figure out how to get the Matrix out....the official procedure is to strip the interior and remove the whole HeVAC unit.....but I feel it *may* be possible to just remove the matrix with the unit in place (see my threads) - this I will be attempting over the Bank Holiday weekend shortly!
I would advocate doing a pressure test on the system and see if you have a leak....hope you don't, but your symptoms are scarily like mine were!
hi saint yes it is warm air coming from the passenger side, regardless of outside temperature one thing i haven't done is checked the pipes from the valve to the matrix after the car has had a run, i may do that today or over the weekend.i don't use a lot of water but i do lose about 250ml every month or so but i put that down to being normal, i would have thought i would have used slightly more if it was the matrix, when i refill with coolant i does take a little more effort to bleed the matrix (even with heater on) i usually have to give the car a run to get the water circulated but i don't think my aux pump works so thats a job for another day. i did change the coolant a couple of weeks back when my top hose broke and i did give the system a flush but all the water came out clear with no rust residue.
when i leave the car parked up for any length there are no drips underneath, obviously i do get condensate if air con has been running. so fingers crossed it's a wiring issue and not a matrix issue. i'll update once i've checked the pipes going from the valve to the matrix.
when i leave the car parked up for any length there are no drips underneath, obviously i do get condensate if air con has been running. so fingers crossed it's a wiring issue and not a matrix issue. i'll update once i've checked the pipes going from the valve to the matrix.
ok things have got weird just been out in the car first part of the trip with all heating off and both heater pipes from the vales were very slightly warm same as the return pipe from the matrix which i guess is residual heat from under the bonnet, 2nd part of the journey i had the aircon on, as before slightly warm on passenger side, cold on drivers side, now this is where it got strange again checked all the heater hoses and they are only slightly warm as before, so i guess valve & matrix are ruled out, anyway all the time i've had this problem i've only ever gone on what the centre vent is doing, i checked the outer passenger side vent and it turns out that one is blowing cold so it's only one side of the centre vent blowing warm which is most likely ambient temp any further ideas?
There is a 'stratification dial' in the centre vents, this allows the face vents to be a smidge warmer or cooler than the foot vents if needed.
It is cable operated, mine is disconnected as there is no resistance when you rotate the dial.
I wonder if yours is not functioning correctly and is stuck to a warmer setting!
It is cable operated, mine is disconnected as there is no resistance when you rotate the dial.
I wonder if yours is not functioning correctly and is stuck to a warmer setting!
