I have a 405 with around 225k miles on the clock which has recently started losing water. I believe it is being lost through the radiator cap whilst in motion as there is no water dripping from the car when it's stationary. When the car stops after a journey and I switch off the engine, a slight hiss can be heard from the radiator cap (the engine is too noisy to hear it otherwise). I have to top up the rad every 150 miles or so with 1/2 - 1 pint of water. I do not overfill and I release air pressure through the vents in the system a couple of times a day, but the excess air always returns. A local garage eliminated a head gasket fault and suggested that air was being sucked into the cooling system by possibly a loose jubilee clip. However, the system retains pressure for several hours which, to my mind, means this cannot be the problem. If I undo the rad cap when the engine is totally cold (8 hours after running), water often comes out of the filler neck under pressure.
I have fitted a new thermostat and a radiator cap (the latter reduced the loss substatially from a pint a day to the present level)
Incidentally, when I release the pressure using the system vents as mentioned above, and then take off the radiator cap, the water level will be right up to the top of the filler neck. If I then re-release the radiator vent with the cap off, the water level drops.
Any ideas? Is it possible that air could be being sucked into the system through the water pump? As far as I know, it is still the original pump.
Thanks, Clive.
Water loss, Peugeot 405
Moderator: RichardW
I had a lot of water loss through the rad cap once it aged. There is a very big warning sticker on many older Peugeots about the fact that the cooling system is highly pressurised and a flush every 2 years - less - is strongly advised. Air locks happen - I don't know why. There were times when it would boil through the old rad cap, coming off a motorway, even though the temp gauge was normal. Finally, a flush and a new cap fixed everything. Maybe someone learned can explain the theory behind that.
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fastandfurryous
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The symptoms you describe point to a fairly hefty airlock. The 405 cooling system is fairly poorly laid out, thus making airlocks very easy to create. The only way to get all the air out of a 405 is to release various hose clips at high points. Favourite points are the intake and outlet from the heater matrix, and (certainly on diesel models) the pipes from the top of the thermostat housing.
Many models actually have water pipes actually running at higher points than the filler neck (which is of course stupid!) so releasing air from the high points is generally the only way.
David.
Many models actually have water pipes actually running at higher points than the filler neck (which is of course stupid!) so releasing air from the high points is generally the only way.
David.
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fastandfurryous
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<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Kowalski</i>
The Xantia has special bleed points built into the system. Presumably, this evolutionanry step happened after the 405 was built, each model getting the fixes for the problems the previous model had.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Unfortunately not so. The first vehicle ever to receive the XUD, the Talbot Horizon, had an excellent layout, with no hidden high spots, just fill up and go. The 309 is similarly designed: no airlock points at all. The 405 seems to have been an exercise in stupidity/cheapness as it has the expansion tank built onto the rad, rather than up high on the bulkhead. This means that some cavities in the cylinder head are actually higher up than the fill point, and it's impossible to run bleed hoses from high points up to the tank, and so it doesn't self-bleed.
The Haynes BOL goes on about fitting a riser tank to the filler neckwhen filling, but this still won't allow the system to bleed properly. I am seriously considering fitting a 309 expansion bottle to my 405, and removing the 405 rad, fitting it with a higher capacity one, as not only is the layout poor, but on an aircon 1.9TD, the rad is ever-so slightly under-specified, and so when towing up long hills, the engine temperature does rise rather worryingly. (even with the fans on full-speed)
The Xantia has special bleed points built into the system. Presumably, this evolutionanry step happened after the 405 was built, each model getting the fixes for the problems the previous model had.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Unfortunately not so. The first vehicle ever to receive the XUD, the Talbot Horizon, had an excellent layout, with no hidden high spots, just fill up and go. The 309 is similarly designed: no airlock points at all. The 405 seems to have been an exercise in stupidity/cheapness as it has the expansion tank built onto the rad, rather than up high on the bulkhead. This means that some cavities in the cylinder head are actually higher up than the fill point, and it's impossible to run bleed hoses from high points up to the tank, and so it doesn't self-bleed.
The Haynes BOL goes on about fitting a riser tank to the filler neckwhen filling, but this still won't allow the system to bleed properly. I am seriously considering fitting a 309 expansion bottle to my 405, and removing the 405 rad, fitting it with a higher capacity one, as not only is the layout poor, but on an aircon 1.9TD, the rad is ever-so slightly under-specified, and so when towing up long hills, the engine temperature does rise rather worryingly. (even with the fans on full-speed)
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Kowalski
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The Xantia 1.9TD has a separate header tank, its low down at the front under the front of the sleek sloping bonnet, so the header tank method is what Citroen recommends. Gradually, cars have become more aerodynamic and sleek, so the problem has become greater, with the Xantia, its the heater that is the highest point and it's a real problem to get bled properly.
You can make the job of bleeding the system easier if you can park the car on a slope so you get the header tank to the highest point you can, I've done the Xantia succesfully that way before. When I've changed the coolant in the Xantia I've found it still had air in after I'd done it, and the coolant level went down as the air came out, this would go on for a while, so I'd have to watch levels and top up for perhaps a week after I'd done a change.
You can make the job of bleeding the system easier if you can park the car on a slope so you get the header tank to the highest point you can, I've done the Xantia succesfully that way before. When I've changed the coolant in the Xantia I've found it still had air in after I'd done it, and the coolant level went down as the air came out, this would go on for a while, so I'd have to watch levels and top up for perhaps a week after I'd done a change.
Thanks for your suggestions and advice. I tried to quickly bleed the system tonight but don't really have time in the evenings. I'll see tomorrow whether there is any improvement but, if not, I'll have another go at the weekend when I've more time.
If that doesn't work, I guess it'll be back to square one!
Thanks again, and I'm still open to any other ideas.
Clive.
If that doesn't work, I guess it'll be back to square one!
Thanks again, and I'm still open to any other ideas.
Clive.
Saturday. Have tried again to bleed the cooling system and flush it with Holts Radflush 2 stage (cleaner and neutraliser). I was very careful refilling the system afterwards in the approved manner using a Coke bottle to extend the height of the expansion tank and I also left out the thermostat to make the engine run cooler, but to no avail. Pressure is still being released through the (new) radiator cap. Beginning to think it might be the head gasket after all!
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fastandfurryous
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Did you loosen the heater matrix supply pipes when bleeding? the amount of air held here is huge and can give similar effects to a headgasket failure.
Leaving the Thermostat out can actually contribute to overheating, as not only does the 'stat allow coolant to circulate through the radiator, it also closes off the bypass pipe. Without a thermostat in, the amount of cooling you get can be variable, as the bypass won't be closed off once the engine is up to temperature.
Is this a diesel or a petrol model? If it is a diesel, especially a turbo, and if the mileage is over 120k (ish) then the chances of it being a headgasket are greater.
Leaving the Thermostat out can actually contribute to overheating, as not only does the 'stat allow coolant to circulate through the radiator, it also closes off the bypass pipe. Without a thermostat in, the amount of cooling you get can be variable, as the bypass won't be closed off once the engine is up to temperature.
Is this a diesel or a petrol model? If it is a diesel, especially a turbo, and if the mileage is over 120k (ish) then the chances of it being a headgasket are greater.
Hi Pugsulike, I had the same problem until i sussed it was the radiator bleed screw that was letting air into the radiator when the engine cooled. The return of the water to the expansion tank when the engine is cooling draws air through the rad bleed screw, causing an air pocket/lock in the top of the rad.
I have'nt replaced the rad (not made of money) so i just put PTFE tape around the screw and a jubilee clip to grip the screw tighter, but not to much. Put the jubilee around the collar where the screw goes in.
This remedy will need to be replaced when the water starts to come out of the rad cap again, but this is now every 800-1200 miles, depending on how many times the water cools, but will last all month or more when driving long journeys.
Just to say, i also thought it was the head gasket and had it done, but it was still the same, then i found it out.
Try it, and let us all know if it has sorted the problem.
I have'nt replaced the rad (not made of money) so i just put PTFE tape around the screw and a jubilee clip to grip the screw tighter, but not to much. Put the jubilee around the collar where the screw goes in.
This remedy will need to be replaced when the water starts to come out of the rad cap again, but this is now every 800-1200 miles, depending on how many times the water cools, but will last all month or more when driving long journeys.
Just to say, i also thought it was the head gasket and had it done, but it was still the same, then i found it out.
Try it, and let us all know if it has sorted the problem.
Thanks again for your suggestions.
Firstly, I should have mentioned that it is a 1905cc turbo diesel with 225k on the clock. I did undo and remove the heater matrix pipes (re fastandfurryous reply 3/5/05) and also the thermostat housing, radiator vent (vent A) and another vent (vent B) on a small pipe that connects near to the thermostat housing, which approximates to the highest point on the cooling system. When refilling the system, I had a hose continuously feeding into a header tank extension system (I used a coke bottle wedged into the filler neck) whilst doing up the heater hoses, thermostat housing and vents. This should have ensured that no air could enter the system.
With the thermostat was fitted, after running the car and allowing it to cool, vents A & B could be undone and air would be expelled from them both. I would then undo the rad cap and the water level would be up to the neck. If I then released vent A again, the water level in the expansion tank would drop sharply, obviously because of an airlock in the top of the radiator being released. This would be repeated on every journey, more air seeming to enter the system each time.
However, with the thermostat removed, things are different. On releasing vents A & B after cooling, no air is present (and the residual pressure in the system is considerably lower), as water is expelled immediately. Also, on removing the rad cap, the water is at it's correct level. Additionally, over the past 3 days (but only about 100 miles), no water has been lost. As before though, there is still a hiss from the rad cap (but not quite as bad as with the thermostat fitted) which can be heard on turning off the engine, which I assume is excess pressure escaping. Obviously the engine is running a lot cooler than before judging by the temperature gauge, although I see the logic re the bypass pipe.
Some pressure is still retained for several hours which indicates that the system is air/watertight. I will still try the suggestion made by BagStar, although his problem was air being sucked in on cooling. With the thermostat fitted, I can release any air in the rad when cold, run the car and air will again be present before cooling (ie. if I release vent A on switching off the engine, air will be released which can only have entered the system whilst the car was in motion. NB. This MUST be done very slowly to avoid the plug being forced out under pressure, followed by possibly very hot water).
With your help, I am confident that a remedy will be found, it's just a matter of time.
Thanks again.
Firstly, I should have mentioned that it is a 1905cc turbo diesel with 225k on the clock. I did undo and remove the heater matrix pipes (re fastandfurryous reply 3/5/05) and also the thermostat housing, radiator vent (vent A) and another vent (vent B) on a small pipe that connects near to the thermostat housing, which approximates to the highest point on the cooling system. When refilling the system, I had a hose continuously feeding into a header tank extension system (I used a coke bottle wedged into the filler neck) whilst doing up the heater hoses, thermostat housing and vents. This should have ensured that no air could enter the system.
With the thermostat was fitted, after running the car and allowing it to cool, vents A & B could be undone and air would be expelled from them both. I would then undo the rad cap and the water level would be up to the neck. If I then released vent A again, the water level in the expansion tank would drop sharply, obviously because of an airlock in the top of the radiator being released. This would be repeated on every journey, more air seeming to enter the system each time.
However, with the thermostat removed, things are different. On releasing vents A & B after cooling, no air is present (and the residual pressure in the system is considerably lower), as water is expelled immediately. Also, on removing the rad cap, the water is at it's correct level. Additionally, over the past 3 days (but only about 100 miles), no water has been lost. As before though, there is still a hiss from the rad cap (but not quite as bad as with the thermostat fitted) which can be heard on turning off the engine, which I assume is excess pressure escaping. Obviously the engine is running a lot cooler than before judging by the temperature gauge, although I see the logic re the bypass pipe.
Some pressure is still retained for several hours which indicates that the system is air/watertight. I will still try the suggestion made by BagStar, although his problem was air being sucked in on cooling. With the thermostat fitted, I can release any air in the rad when cold, run the car and air will again be present before cooling (ie. if I release vent A on switching off the engine, air will be released which can only have entered the system whilst the car was in motion. NB. This MUST be done very slowly to avoid the plug being forced out under pressure, followed by possibly very hot water).
With your help, I am confident that a remedy will be found, it's just a matter of time.
Thanks again.
Bagstar, tried the trick with the PTFE tape (see 9th May, above), but it made no difference. I think it may be because the tape is not intended for such a coarse screw thread as on the plastic plug. Additionally, the seal is formed by a rubber washer and not the thread,(It may differ from your model, of course) so I also tried some copper grease as a lubricant/sealant, again without success.
Thanks for the idea.
Thanks for the idea.
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fastandfurryous
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Hi,
Just thought you might like to know that my car is running a lot better now. Trouble is, I don't know exacly why, altough I strongly suspect it may have been an obstinate air lock.
I tried sealing a garden hose into the expansion tank filler and running water at mains pressure through the cooling system with all the vents open, the heater hoses disconnected and the thermostat housing loosened. I then tightened each one up in turn until I got very wet with water under pressure spurting from the filler neck.
I also drilled a small hole in the thermostat (2mm) to allow pressure to equalise more easily around the system. At least, that was my theory, and, although I had no idea whether it would do any good, I thought 'what the heck, I've tried everything else'.
Anyway, the car has run for a week now (300+ miles) without any coolant loss and, more significantly, no air entering the system. (Previously I had to release air through the cooling system vents once or twice a day). Also, the temperature gauge is remaining steady whist the car is in motion whereas it used to fluctuate by 5-8 degrees.
Anyway, thank you everyone for all your help, without which I wouldn't have known about the airlock problems on the 1.9TD engine and consequently would not have persevered with trying various solutions until finally (I hope) finding a remedy.
Clive.
Just thought you might like to know that my car is running a lot better now. Trouble is, I don't know exacly why, altough I strongly suspect it may have been an obstinate air lock.
I tried sealing a garden hose into the expansion tank filler and running water at mains pressure through the cooling system with all the vents open, the heater hoses disconnected and the thermostat housing loosened. I then tightened each one up in turn until I got very wet with water under pressure spurting from the filler neck.
I also drilled a small hole in the thermostat (2mm) to allow pressure to equalise more easily around the system. At least, that was my theory, and, although I had no idea whether it would do any good, I thought 'what the heck, I've tried everything else'.
Anyway, the car has run for a week now (300+ miles) without any coolant loss and, more significantly, no air entering the system. (Previously I had to release air through the cooling system vents once or twice a day). Also, the temperature gauge is remaining steady whist the car is in motion whereas it used to fluctuate by 5-8 degrees.
Anyway, thank you everyone for all your help, without which I wouldn't have known about the airlock problems on the 1.9TD engine and consequently would not have persevered with trying various solutions until finally (I hope) finding a remedy.
Clive.