Carduelis
Well-Known Member
My expansion tank cap is leaking slightly. It looks just the same as an automotive one. Can Anyone tell me what the pressure rating should be? The old one is too rusty to read.
Volvo 2040 pressure cap
- Thread starter Carduelis
- Start date
SwedishLass
Well-Known Member
Looks like 12.8lbf/in2 or 0.9kp/cm2
Manual here http://www.bluemoment.com/manuals/Volvo_Penta_MD2010-20-30-40.pdf
Manual here http://www.bluemoment.com/manuals/Volvo_Penta_MD2010-20-30-40.pdf
VicS
Well-Known Member
[ QUOTE ]
or 0.9kp/cm2
[/ QUOTE ] That is a nonsense.
Assuming 12.8psi is correct it should read 0.9 kg/cm² which is also equivalent to 0.88bar
BTW page 65 of the manual
or 0.9kp/cm2
[/ QUOTE ] That is a nonsense.
Assuming 12.8psi is correct it should read 0.9 kg/cm² which is also equivalent to 0.88bar
BTW page 65 of the manual
SwedishLass
Well-Known Member
Kp
Apparently a kilopond (scandinavian engine they used their units) but I would go for the old money 12.8 as it seems to work in the conversion tables. I must confess I thought pascal but too lazy to do maths.
Apparently a kilopond (scandinavian engine they used their units) but I would go for the old money 12.8 as it seems to work in the conversion tables. I must confess I thought pascal but too lazy to do maths.
Carduelis
Well-Known Member
So a 13 PSI car radiator cap should do the trick then?
VicS
Well-Known Member
[ QUOTE ]
I must confess I thought pascal but too lazy to do maths.
[/ QUOTE ] Well that was what rang the alarm bells. Not so much because the numbers would not have crunched but because kPa/cm2 would have been a nonsense. kPa yes but not kPa/cm2 (12.8psi = 88kPa)
There's not a lot of maths you have to do, just find and on line conversion site.
I must confess I thought pascal but too lazy to do maths.
[/ QUOTE ] Well that was what rang the alarm bells. Not so much because the numbers would not have crunched but because kPa/cm2 would have been a nonsense. kPa yes but not kPa/cm2 (12.8psi = 88kPa)
There's not a lot of maths you have to do, just find and on line conversion site.
VicS
Well-Known Member
[ QUOTE ]
So a 13 PSI car radiator cap should do the trick then?
[/ QUOTE ] Well yes provided it fits properly. The neck length on the tank will be critical so compare what you are buying with the original very carefully.
So a 13 PSI car radiator cap should do the trick then?
[/ QUOTE ] Well yes provided it fits properly. The neck length on the tank will be critical so compare what you are buying with the original very carefully.
LadyJessie
Well-Known Member
I have had the same problem with the same engine. It has nothing to do with the cap; it is designed to leak if the pressure is too high. You probably have a problem in your heat exchanger or somewhere else in the heat exchange channels: it is blocked somewhere. I solved this problem by taking out the heat exchanger and cleaned it, assuring that all those small holes were clean. I have not had a 'leakage' problem since. This happened four years ago and it has not reappeared.
The cap is designed to be a security valve; it is not the problem.
The cap is designed to be a security valve; it is not the problem.
VicS
Well-Known Member
[ QUOTE ]
The cap is designed to be a security valve; it is not the problem.
[/ QUOTE ] It is designed to regulate the pressure in the system. If the rubber on the bottom damaged it will leak and not maintain the correct pressure and cause a small contiuous loss of coolant.
From a computer keyboard without further info it is impossible to say with certainty if it is the problem or not! If there are no other symptoms of a blocked heat exchanger, eg a tendency to overheat under heavy load then replacing the cap if it is leaking is a simple thing to do.
There are in fact two valves in a "radiator cap" the other operates in the opposite direction and allows air in to prevent a partial vacuum forming when the engine cools. The seal on either valve could be poor. (The picture on page 62 of the manual shows both with arrows indicating the direction of flow through them)
I note that mention is made of an optional expansion tank. The cap(s) may well be different if that is fitted.
The cap is designed to be a security valve; it is not the problem.
[/ QUOTE ] It is designed to regulate the pressure in the system. If the rubber on the bottom damaged it will leak and not maintain the correct pressure and cause a small contiuous loss of coolant.
From a computer keyboard without further info it is impossible to say with certainty if it is the problem or not! If there are no other symptoms of a blocked heat exchanger, eg a tendency to overheat under heavy load then replacing the cap if it is leaking is a simple thing to do.
There are in fact two valves in a "radiator cap" the other operates in the opposite direction and allows air in to prevent a partial vacuum forming when the engine cools. The seal on either valve could be poor. (The picture on page 62 of the manual shows both with arrows indicating the direction of flow through them)
I note that mention is made of an optional expansion tank. The cap(s) may well be different if that is fitted.
LadyJessie
Well-Known Member
[ QUOTE ]
If the rubber on the bottom damaged it will leak and not maintain the correct pressure and cause a small contiuous loss of coolant.
[/ QUOTE ]Good point, that might be the problem but in my experience is it not very likely. Check that rubber seal in the cap and if it is OK you have to look more deeply into your engine to find the problem. I would still guess that you have a heat exchanger problem somewhere but you have to search that out for yourself. Sorry about not being able to be more helpful.
If the rubber on the bottom damaged it will leak and not maintain the correct pressure and cause a small contiuous loss of coolant.
[/ QUOTE ]Good point, that might be the problem but in my experience is it not very likely. Check that rubber seal in the cap and if it is OK you have to look more deeply into your engine to find the problem. I would still guess that you have a heat exchanger problem somewhere but you have to search that out for yourself. Sorry about not being able to be more helpful.
Carduelis
Well-Known Member
Yes - maybe it could be something more serious, but the engine doesn't overheat or anything. The cap itself is leaking around the rim and making a bit of a mess. Its very old and rusty and the rubber seals look perished, so I thought I'd start by replacing it.
Local chandler (Foxes) stidn't stock but I found one for £2.99 at Halfords. It appears identical. Scraped the rust off the old one and found "09" stamped on it, so I'm guessing this is the Kg figure as above.
Local chandler (Foxes) stidn't stock but I found one for £2.99 at Halfords. It appears identical. Scraped the rust off the old one and found "09" stamped on it, so I'm guessing this is the Kg figure as above.