good old over heat problam,

[ljsok]

Hi folks, am i right in saying HGF, could be the fault as my stag gets very hot and exsessivepressure causes leaks on the joints.?

Q,1, why not fit an exspansion vessal and absorb the pressure?

Q,2, why not fit a auto air vent like on a central heating sytem to release the air?

Q,3, what temp should my run at safley as it runs at about 75/80 on the gauge?

Q,4, what is the cause of hgf and what does it do.

i am no mecanic and new to the stag club so any help and veiws would be helpfull

kind regards, LYNDON

[Jeff]

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Hello Lyndon,

First of all the cooling system acts on an expansion/contraction system, air is compressed whereas water cannot, hence the expansion bottle.

I have fitted a manual air release valve as the automatic type will sit too high and touch the bonnet when closed, bearing in mind it has to be fitted at the highest point in the system to collect the air.

I know you will get a good response from the others on the forum.

Jeff.

[Jeff]

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I have temporarily moved my expansion bottle to the highest possible point but in all honestly doesn't make any difference apart from being easier to top up and to see the level of coolant, just.

Do you not have an expansion bottle fitted according to your question number 1?

Jeff.

[Jeff]

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Question 3 seems about right.

[Jeff]

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Actually your temp seems a bit low, I think mine runs more 88 to 90. Could be the stat.

Jeff.

[ljsok]

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thanks for your reply,

i have the sam e sort of bottle as yor pic. my is still down by the rad where it was origanaly, im thinking of changing it and putting it where yours is.

[ljsok]

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Jeff wrote:

Actually your temp seems a bit low, I think mine runs more 88 to 90. Could be the stat.

Jeff.

ok thank so thats ok then, when or what is to hot then?

[Jeff]

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Er, when it boils over?

[ljsok]

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Jeff wrote:

Er, when it boils over?

LOL;;;;;;;;;;;;;

[Jeff]

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[ljsok]

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ljsok wrote:

Jeff wrote:

Er, when it boils over?

LOL;;;;;;;;;;;;;

what i meant was am i going to blow the head ata certaintemp?

[flying farmer]

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ljsok wrote:

Hi folks, am i right in saying HGF, could be the fault as my stag gets very hot and exsessivepressure causes leaks on the joints.?

Q,1, why not fit an exspansion vessal and absorb the pressure?

Q,2, why not fit a auto air vent like on a central heating sytem to release the air?

Q,3, what temp should my run at safley as it runs at about 75/80 on the gauge?

Q,4, what is the cause of hgf and what does it do.

i am no mecanic and new to the stag club so any help and veiws would be helpfull

kind regards, LYNDON

The only effective way of getting air out of the system is to use a header tank. Various types can be seen on the forum. The principal is to let air out by putting a T into the highest part of the top hose, then returning water to the cooling system by a larger hose from the bottom of the header tank T'd into the bottom hose or heater return. This prevents air locks forming in the system and allowed me to keep running for an extra year with two failed head gaskets

The standard thermostat used is normally set to open at 82 degrees though others are available

Head gasket failure is caused by the different rates of expansion of the iron block and alloy heads. Most gaskets seem to fail at the back of the rearmost cylinders, I suspect this area runs hot as coolant is returned to the radiator between cylinders 3 and 4 and the back of the block is only cooled by convection currents. This is why it is suggested to link the water transfer housings on the back of the block with a piece of hose, it allows a little extra water circulation

When replacing the gaskets only use the payen type as they are far more reliable and dont need as much retorquing after fitting

If the engine has not been boiled up badly there is a good possibility that the heads have not been warped yet, so it is something that needs looking at sooner rather than later

Neil

[Jeff]

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Not sure if anybody knows exact temp, but certainly any higher than the norm has it's risks.

Mine only ran a few times (few times too many) too hot for my
gaskets to go.

Jeff.

[ljsok]

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flying farmer wrote:

ljsok wrote:

Hi folks, am i right in saying HGF, could be the fault as my stag gets very hot and exsessivepressure causes leaks on the joints.?

Q,1, why not fit an exspansion vessal and absorb the pressure?

Q,2, why not fit a auto air vent like on a central heating sytem to release the air?

Q,3, what temp should my run at safley as it runs at about 75/80 on the gauge?

Q,4, what is the cause of hgf and what does it do.

i am no mecanic and new to the stag club so any help and veiws would be helpfull

kind regards, LYNDON

The only effective way of getting air out of the system is to use a header tank. Various types can be seen on the forum. The principal is to let air out by putting a T into the highest part of the top hose, then returning water to the cooling system by a larger hose from the bottom of the header tank T'd into the bottom hose or heater return. This prevents air locks forming in the system and allowed me to keep running for an extra year with two failed head gaskets

The standard thermostat used is normally set to open at 82 degrees though others are available

Head gasket failure is caused by the different rates of expansion of the iron block and alloy heads. Most gaskets seem to fail at the back of the rearmost cylinders, I suspect this area runs hot as coolant is returned to the radiator between cylinders 3 and 4 and the back of the block is only cooled by convection currents. This is why it is suggested to link the water transfer housings on the back of the block with a piece of hose, it allows a little extra water circulation

When replacing the gaskets only use the payen type as they are far more reliable and dont need as much retorquing after fitting

If the engine has not been boiled up badly there is a good possibility that the heads have not been warped yet, so it is something that needs looking at sooner rather than later

Neil

thanks neil, you obviously know a lot more about engines than me as im no macanic but i understand what you are saying so thans again for your reply.

p.s i know where to come for more info, regards lyndon

[V Mad]

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Engines should run at about 90 to 95 deg C. If you go much above that you get too near the boiling point. The system is pressurised at 20lb (Mk2) so should not boil until 109 deg (if pure water, not sure about antifreeze)