Rob4x40

Rob4x40

Active Member
My son & I noticed a strange noise today - not for the first time, but much more prolonged. It sounds like water running down a drain and emanates from the passenger footwell. Despite the fact it was raining and that I had thrown a couple of buckets of water over her to remove petals fallen from the trees, it doesn't appear to be drains of any kind - stop the engine and the sound stops too...

There has been a notable lack of heat on the passenger side since I purchased the car in February, but I put that down to blend motor and have a new one to fit as and when I get time. There is an occasional handbook symbol but I confess I've not invested in diagnostics yet! It does get warm, but driver's side gets much hotter.

There is no moisture inside the vehicle and no loss of coolant so I'm assuming that there is an air lock/blockage or similar in the heater matrix? Question is, how do I prove that or clear without dismantling half the car? The service invoices show a new matrix fitted in 2011. Dare I flush the coolant using a radiator flush solution or is that asking for trouble?

Edit: forgot to say it's a 1997 4.6HSE with LPG
 
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Air lock in the heater matrix gurgling??

LPG vaporiser pipe work???

I would have said sunroof drains, but you say it stops when engine off hmmmmm
 
get car to temp, turn heater to high heat turn it on and open radiator fill cap give it a half hour. How is temp gauge? could be half open/half closed thermostate
 
This is almost definitely at a guess your air con compressor and pump failing run engine look under bonnet at pipes from compressor my guess is they are too hot also try just turning aircon off and see if noise disappears
 
Also you can tell if the coolant is flowing through the matrix by feeling the hoses that disappear into the bulk head both should be hot the way the cooling system works the heater matrix is constantly in the loop if the coolant does not go through the matrix it doesnt circulate temperature inside the car is controled by the blend flaps they adjust both temp and direction if there was air in the system the pump would push it through at 1500 to 2000 revs and as there is no coolant loss I suspect the compressor lets know how you get on
 
Worth taking expansion tank cap off and run it at 2000 revs once at temp you sould see a steady jet just inside the neck of the expansion tank this gives an indication of the condition of the water pump and the stat
 
Had this on my V8 Grand Cherokee. It's water rushing through your heater matrix and you're hearing it because there is air in the system. This 'air' is probably gas from the engine and you probably have a head gasket issue. Best get it looked at before it gets worse!
 
Thanks for all the replies. At work currently so can't test much until tonight, but tried turning a/c on/off on the way in this morning and seems to make no difference. I also set the heater to 'LO' both sides and then to 'HI' - handbook sign came on when setting to 'HI' so I think the blend motor is sticking and causing that. Air on passenger side was still only lukewarm.

I did head gaskets on my 3.9 Classic - twice - so looked for signs already. There's no rise in temperature (rises to middle and stays there) or water loss that I'd typically expect with HGF. I have both towed and had loaded up with PA equipment in last few days. Checked oil either Friday or Saturday and no signs of emulsification then either (I know HGF doesn't always allow water into oil either). I did think air in matrix was a probable suspect, but if so it's been there a while and I've not had to add hardly any water since I purchased in Feb (< litre in that time). I've done around 3K including to Malvern & back twice and Yeovil & back, any of which I would expect to show up a HGF - mixed driving, long runs, queued traffic etc. I guess it's possible that the system wasn't bled properly and the air has been there all along? I would have thought that it would work it's way to the highest point - i.e. the radiator or expansion tank...

I'll work through suggestions and try bleeding out the air too - assuming that's what it is! Will post results. :)
 
Try & get the O/S front end up as high as possible & run with expansion cap off while squeezing pipes & hopefully you can 'burp' the air out (watch the temp guage though).
Hope it's not HG's, i had both of mine go within months between middle cylinders so no overheat, water loss etc, just started mis-firing.
Good luck ;)
 
The air temp at the pasenger side is likley to be due to the blend motor as the handbook is on!
When you set to cold does the pasenger side go cold? If no defo blend motor stuck
However the water noise is unlikley to be related that does indeed sound like an air lock/traped exhaust gasses however they should blow through with a good boot full from the right leg

I know its not the same car but i once had a vectra that had a hissing noise coming through the air vents when the ac was on, went away if i turned it off!
When you turned your ac off how long did you leave it off? Cos my ac remains on and blowing cold for about 20second after i turn it off (ac off is light on daft i know but thats the way they made it)
seams my hevac is quite slow to do anything yours might be too
 
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Do you have lpg installed ? If so the heater matrix can be bypassed by the vapouriser and air can get trapped in the matrix it moves inside the matrix and when revs reduce it trickles back down and it is an absolute mare to get rid off this I know from experience
 
Sorry rob just noticed you say it is lpg so trick is to run at approx 2000 revs with cap off and if poss clamp the feed to the vapouriser therefore purging the matrix - check the t joints abnd make sure you dont have a slight weepmine did but of course evapourated before you could see it and onlt weeped under heavy load so no noticable loss of coolant as air was in the matrix substituting the volume
 
Ok, gone through most of the above and currently the water trickling sound has gone. I think it was probably air working it's way up and out of the matrix, but the worry is I suppose how it got there!

The A/C seems ok - on idle, it runs for about 10 seconds in 90 with internal temp set at 20 deg C. Doesn't seem excessive and one pipe to compressor very cold, one warm.

Added about 100ml water to expansion tank this morning after a good blast last night in sport mode (goes like the proverbial :)D) off the shovel in sport, but I suspect so does the LPG! :( )

Vaporiser pipework doesn't run anywhere near the area from where the noise was coming from, so can rule that out I think.

Will check again tonight and run for a while without expansion cap. I have some ramps so will run front up and try shutting off vaporiser shunt as suggested. I could be that the air has now gone and provided I don't need to add water or hear water trickling sounds then all may be sorted. Can but hope! :beer2::beer2::beer2:

Thanks again for the sugestions: :tea:
 
gfromleeds said:
i once had a vectra that had a hissing noise coming through the air vents when the ac was on, went away if i turned it off!
Click to expand...

I had a Cavalier (company car) that did that one day but it also filled the car with what I assume was aircon refrigerant gas and left the dash air vents covered in frost!

Fortunately I was driving it in to work to get it exchanged for a brand new car anyway so I wasn't bothered about the car, but the taste of the gas lingered for days!


Pete
 
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