Really weird Pressure Problem on Vauxhall Corsa
Discussion
Hi
If anyone can help with following I’d really appreciate it, struggling this end. Vauxhall Corsa Elegance 16V, 1.2L, 2003 Reg. Car worth about £1K max so can’t invest too heavily in garage bills/parts. Having said that…we probably already have! Bit of a long message I’m afraid.
First problem – car was losing a lot of coolant. had to fill up coolant reservoir every week. No visible leaks that we could find. Oil under rocker cover had that mayonnaise look and consistency to it. We assumed problem might be head gasket.
Second problem was that heater was not working properly inside car. It blew out luke warm air but never hot. On this point, we tried flushing water through inlet and outlet hoses to make sure it was clear. Didn’t detect any blockage.
Took car to a Vauxhall dealer who tested head gasket and said it was fine. They reckoned there might be a hairline crack in crankcase behind water pump and water getting in there. This was based on them noting that one of bolts holding it in place was different to others. It wasn’t based on anything scientific. Solution seemed to be get a second hand engine.
We couldn’t see logic. How much water would need to get through a hair line crack to empty the coolant reservoir each week and also wouldn’t oil level rise up dipstick as oil floated on new water before it all burned off? We couldn’t see that volume of water burning off that quickly.
We could only think it still could be a gasket problem. Tried steel seal to fix it, this worked really well for us on a car in the past, saved a lot of time and money. Steel seal didn’t stop the coolant level falling and may actually have caused a problem by partially blocking the heater matrix but we’ll put that aside for a second.
The coolant level continued to keep going down. We changed thermostat and water pump. Heater still didn’t work. We then had a sudden build-up of pressure that forced a load of coolant out of the reservoir (past the reservoir lid) and all over the engine compartment. We could see this as when the water had dried off the steel seal in it had left a white, chalky residue all over the engine compartment.
We could only think a build-up of pressure sufficient to force the water out could have come from the pressure being forced past a weak point in the head gasket and into a water channel. So it was back to the head gasket again.
So we changed the head gasket. No obvious signs of the old one blowing when we took it out. Also checked all of the heater controls and no problem there, all working correctly.
Where we are now:
1. Heater blows out hot air for first ten seconds and then goes back to luke warm. Turn it off for a minute then on again and it does same thing. We’ve flushed water through matrix several times to try and clear out any residue from the steel seal in case that is inhibiting it. First time we did this it did seem to clear some kind of blockage that was limiting the rate at which the water flowed through it and afterwards the heater did keep blowing out hot air. Now though it doesn’t seem to make a lot of difference. We may put a new matrix in as cannot think what else it could be. We’ve checked all components linked to heating/blower controls. All seem fine, it is all based on system of flaps to divert heat, there is no valve opening and closing for example that could be causing a problem. Pipes going in and out of matrix get very hot to the touch
2. We’ve still got problem with pressure build up violently forcing coolant out of reservoir. There is no way to predict when this may happen. Again, a few days saw steel seal residue all over the engine compartment where coolant had spewed out. Interestingly, yesterday I again flushed water through the heater matrix to try and flush out any residual steel seal. When I’d finished, I topped it up the coolant reservoir as it was low. Ran engine and the reservoir started to fill up completely, well above the maximum line, lot of bubbles coming in, eventually it overflowed out of the coolant reservoir. But then about twenty seconds later the coolant level dropped and it emptied almost completely. To a lamen like me seemed as if there was something going on with airlocks etc. Seemed as if pressure was pushing it up into the reservoir then the pressure dropped and it returned to normal. This all happened while the car was running, not after I turned the ignition off
Realise this is a long explanation; it’s been a long process! My daughter wants to sell the car but I don’t want to pass on the problem to someone else, not my way I'm afraid. If anyone has any ideas would appreciate it. I'm obviously wondering if the two problems between lack of heat and this issue of coolant being forced out of the reservoir are linked but that may not be the case. :s
Thanks for any help you can give.
If anyone can help with following I’d really appreciate it, struggling this end. Vauxhall Corsa Elegance 16V, 1.2L, 2003 Reg. Car worth about £1K max so can’t invest too heavily in garage bills/parts. Having said that…we probably already have! Bit of a long message I’m afraid.
First problem – car was losing a lot of coolant. had to fill up coolant reservoir every week. No visible leaks that we could find. Oil under rocker cover had that mayonnaise look and consistency to it. We assumed problem might be head gasket.
Second problem was that heater was not working properly inside car. It blew out luke warm air but never hot. On this point, we tried flushing water through inlet and outlet hoses to make sure it was clear. Didn’t detect any blockage.
Took car to a Vauxhall dealer who tested head gasket and said it was fine. They reckoned there might be a hairline crack in crankcase behind water pump and water getting in there. This was based on them noting that one of bolts holding it in place was different to others. It wasn’t based on anything scientific. Solution seemed to be get a second hand engine.
We couldn’t see logic. How much water would need to get through a hair line crack to empty the coolant reservoir each week and also wouldn’t oil level rise up dipstick as oil floated on new water before it all burned off? We couldn’t see that volume of water burning off that quickly.
We could only think it still could be a gasket problem. Tried steel seal to fix it, this worked really well for us on a car in the past, saved a lot of time and money. Steel seal didn’t stop the coolant level falling and may actually have caused a problem by partially blocking the heater matrix but we’ll put that aside for a second.
The coolant level continued to keep going down. We changed thermostat and water pump. Heater still didn’t work. We then had a sudden build-up of pressure that forced a load of coolant out of the reservoir (past the reservoir lid) and all over the engine compartment. We could see this as when the water had dried off the steel seal in it had left a white, chalky residue all over the engine compartment.
We could only think a build-up of pressure sufficient to force the water out could have come from the pressure being forced past a weak point in the head gasket and into a water channel. So it was back to the head gasket again.
So we changed the head gasket. No obvious signs of the old one blowing when we took it out. Also checked all of the heater controls and no problem there, all working correctly.
Where we are now:
1. Heater blows out hot air for first ten seconds and then goes back to luke warm. Turn it off for a minute then on again and it does same thing. We’ve flushed water through matrix several times to try and clear out any residue from the steel seal in case that is inhibiting it. First time we did this it did seem to clear some kind of blockage that was limiting the rate at which the water flowed through it and afterwards the heater did keep blowing out hot air. Now though it doesn’t seem to make a lot of difference. We may put a new matrix in as cannot think what else it could be. We’ve checked all components linked to heating/blower controls. All seem fine, it is all based on system of flaps to divert heat, there is no valve opening and closing for example that could be causing a problem. Pipes going in and out of matrix get very hot to the touch
2. We’ve still got problem with pressure build up violently forcing coolant out of reservoir. There is no way to predict when this may happen. Again, a few days saw steel seal residue all over the engine compartment where coolant had spewed out. Interestingly, yesterday I again flushed water through the heater matrix to try and flush out any residual steel seal. When I’d finished, I topped it up the coolant reservoir as it was low. Ran engine and the reservoir started to fill up completely, well above the maximum line, lot of bubbles coming in, eventually it overflowed out of the coolant reservoir. But then about twenty seconds later the coolant level dropped and it emptied almost completely. To a lamen like me seemed as if there was something going on with airlocks etc. Seemed as if pressure was pushing it up into the reservoir then the pressure dropped and it returned to normal. This all happened while the car was running, not after I turned the ignition off
Realise this is a long explanation; it’s been a long process! My daughter wants to sell the car but I don’t want to pass on the problem to someone else, not my way I'm afraid. If anyone has any ideas would appreciate it. I'm obviously wondering if the two problems between lack of heat and this issue of coolant being forced out of the reservoir are linked but that may not be the case. :s
Thanks for any help you can give.
Edited by PhilR666 on Sunday 10th February 20:53
Could be a circulation problem. It sounds as if there is restricted flow through the engine, so the heater initially blows hot, then somewhere the water overheats, boils and blows itself out of the tank. Once the water level drops, the heater will be starved of water and blow cold.
Could perhaps be a localised hotspot (caused by steel-seal?) or water pump not moving enough water around the head. Are these the water pumps which are prone to shedding impellers?
Edit: Just spotted you've already changed the water pump - sorry.
Could perhaps be a localised hotspot (caused by steel-seal?) or water pump not moving enough water around the head. Are these the water pumps which are prone to shedding impellers?
Edit: Just spotted you've already changed the water pump - sorry.
Edited by littleredrooster on Monday 11th February 10:19
Thanks Rooster.
I was concentrating on potential for pressure from piston for example to have forced coolant out of reservoir and so didn't consider potential for it to boil and force out that way.
funny thing is thought, this blowing out of the coolant doesn't happen every time we run the car, it just seems to happen at random times. It could not lose coolant for a week or so then suddenly we notice it has blown out again. But the heater just continues to blow out hot air, then go lukewarm. Turn it off and leave it for a few minutes and then turn on again and yes we have hot air but only for a few seconds then lukewarm again. But as mentioned, this isn't necessarily accompanied by the coolant being forced out of the reservoir.
I'll try changing the matrix as we do have a spare to try and rule out a blockage in there.
Am I right though that if that doesn't work and blockage is somewhere in the engine then id have to change the engine? Or do you know of a product that might help free the blockage?
I will flush fully with water but not sure if that will do the trick. Thanks again for your help
I was concentrating on potential for pressure from piston for example to have forced coolant out of reservoir and so didn't consider potential for it to boil and force out that way.
funny thing is thought, this blowing out of the coolant doesn't happen every time we run the car, it just seems to happen at random times. It could not lose coolant for a week or so then suddenly we notice it has blown out again. But the heater just continues to blow out hot air, then go lukewarm. Turn it off and leave it for a few minutes and then turn on again and yes we have hot air but only for a few seconds then lukewarm again. But as mentioned, this isn't necessarily accompanied by the coolant being forced out of the reservoir.
I'll try changing the matrix as we do have a spare to try and rule out a blockage in there.
Am I right though that if that doesn't work and blockage is somewhere in the engine then id have to change the engine? Or do you know of a product that might help free the blockage?
I will flush fully with water but not sure if that will do the trick. Thanks again for your help
Edited by PhilR666 on Tuesday 12th February 18:40
With the engine running and the coolant filler cap removed, check that coolant is flowing back into the header tank from the small diameter hose that goes to the top of the tank.
This hose allows the cooling system to continuously degas and bleed its self and if blocked, will certainly cause random blowing out of coolant due to localized boiling and may affect the heater to some degree (although the symptoms you have with the heater are classic blocked matrix).
This hose allows the cooling system to continuously degas and bleed its self and if blocked, will certainly cause random blowing out of coolant due to localized boiling and may affect the heater to some degree (although the symptoms you have with the heater are classic blocked matrix).
Hi
we really struggled with this. We couldn't find the fault and do reckon it was possibly a cracked cylinder head letting compression pressure into the water system. The fact that the water had just literally shot out suggested something like that.
We eventually bit the bullet and bought an engine from local scrap yard for £350 and fitted it. All then went well and we breathed a sigh of relief after several months of changing and trying different things and spending many hundreds trying to find the fault
A week later someone drove into the back of the car and wrote it off. No-one was hurt. We sold the whole car back to the guy who had sold us the engine for £125. My daughter got insurance payment.
I'm sure there's a punchline to this story somewhere?! Suppose if I hadn't spent all those days and cash tryng to fix it I'd only have spent them despairing over West Ham's weekly performance
Thanks again to everyone who offered help, very much appreciated
we really struggled with this. We couldn't find the fault and do reckon it was possibly a cracked cylinder head letting compression pressure into the water system. The fact that the water had just literally shot out suggested something like that.
We eventually bit the bullet and bought an engine from local scrap yard for £350 and fitted it. All then went well and we breathed a sigh of relief after several months of changing and trying different things and spending many hundreds trying to find the fault
A week later someone drove into the back of the car and wrote it off. No-one was hurt. We sold the whole car back to the guy who had sold us the engine for £125. My daughter got insurance payment.
I'm sure there's a punchline to this story somewhere?! Suppose if I hadn't spent all those days and cash tryng to fix it I'd only have spent them despairing over West Ham's weekly performance
Thanks again to everyone who offered help, very much appreciated
Your Kidding! Today was my first day off work so I decided to go mad and check everything that I could think. After reading lots of different posts I decided to dump all of the coolant and start removing hoses and blowing down every orifice. I eventually narrowed it down to a blockage in the small connecting pipe at the back of the throttle body thus not allowing the cooling system to expand properly in the expansion chamber and also not allowing the cooling system to automatically expel any trapped air.
Those small pipes are often thermostat bypass and air burping ports to allow some kind of coolant flow prior to the stat opening and are vital for cooling system function 
someone mentioned chhanging the pressure cap too good advice if you have had a couple of boil ups the caps dont always fully recover especially if you blast sediment or rad sealers through them
someone mentioned chhanging the pressure cap too good advice if you have had a couple of boil ups the caps dont always fully recover especially if you blast sediment or rad sealers through them Im havin same problems guys on a 2008 1.2 corsa head gasket done timing chain done new thermostat new water pump new temp sensor new heater matrix
Bleed all air out and get heaters all hot take it mile up road and heaters go cold again i have no clue what else it could be any help plz guys
Bleed all air out and get heaters all hot take it mile up road and heaters go cold again i have no clue what else it could be any help plz guys
PROBLEM RESOLVED
Hi guys, new to forums, but thought this might help others:
Like many, coolant loss on our Corsa has been a long term problem which two garages have been unable to fix. Done pressure testing, checks re head gasket, previous new water pump, system flush, new coolant, Steel Seal etc, with no improvement. After that noticed deposit on bulkhead indicating that cooling system was over pressurising and blowing out through reservoir / header tank pressure cap. New pressure cap changed nothing and garage advised scrapping car!
Eventually resolved what was a simple problem - a blockage in the small bore hose connecting the water pump to the throttle body. It appears that this pipe (which continues from throttle body back to the reservoir) serves as a pressure relief route prior to the thermostat opening. If blocked, system over pressurises and blows out coolant every few days.
In my case, water pump was changed by a garage weeks earlier and a small piece of debris was blocking the small exit port from the water pump. It looked like a rolled up plastic label which begs the question about the garage being careless when installing the pump.
A lot of expense (not least in replacement coolant) for such a simple problem.
Hi guys, new to forums, but thought this might help others:
Like many, coolant loss on our Corsa has been a long term problem which two garages have been unable to fix. Done pressure testing, checks re head gasket, previous new water pump, system flush, new coolant, Steel Seal etc, with no improvement. After that noticed deposit on bulkhead indicating that cooling system was over pressurising and blowing out through reservoir / header tank pressure cap. New pressure cap changed nothing and garage advised scrapping car!
Eventually resolved what was a simple problem - a blockage in the small bore hose connecting the water pump to the throttle body. It appears that this pipe (which continues from throttle body back to the reservoir) serves as a pressure relief route prior to the thermostat opening. If blocked, system over pressurises and blows out coolant every few days.
In my case, water pump was changed by a garage weeks earlier and a small piece of debris was blocking the small exit port from the water pump. It looked like a rolled up plastic label which begs the question about the garage being careless when installing the pump.
A lot of expense (not least in replacement coolant) for such a simple problem.
Crumbs ..... that small bore de gassing pipe ... i run a LPG converted 1.8 Zafira Taxi 340,000 miles+ , for the last 50,000 i was plagued with a backfire on throttle overrun + the heater being not quite “what it was or should be” ... its been in my local garage three times n there good but failed to fix find or cure this ... then last week the backfire got very chronic, plus rad fan kicking in lots ... car was overheating (coolant loss etc) looked under the bonnet, coolant pi***ing out of the small overgassing hose from a crack where it connects into the tank - pulled pipe, fixed (abro steel) the crack in the tank .. then also noticed the flange barb of the connecter was “missing” and had broken into bits and was blocking the pipe - to cut a long story short - cleared pipe topped up coolant and car no longer misfires and the heater works 100% - that small tube clearly effects lots of things if it is leaking or broken - hope that helps
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