skin tank hose connections

[colin loach]

My Isuzu 42 liverpool boat temperture it has always run at 85deg, but yesterday it started running at 89deg, so i took off the rad cap to see if it was to hot but it seemed ok, the cap didnt blow off when i undone it. i did notice that the hose going into the top of the skin tank was hot and the one coming from the bottom was only warm. is this all normal, i had been running for 2 hours. colin.

[alan_fincher]

Yes,

 

If your skin tank is well designed, and doing it's job, then the top pipe should after time settle at around the thermostat temperature for you engine, but the return hose at the bottom should be a whole heap cooler.

 

This will depend on how hard you are running it - some that are fine on canals might be bad if punching against a river.

 

The return at the bottom of your skin tank being hot would actually a bad thing, as it would meanb you were trying to cool the engine with water that wasn't fairly cool in the first place.

 

A perceived 4 degrees extra isn't much, and most gauges would not allow you to be that precise, to be honest. I'm not convinced you have any fault at all!

[steelaway]

My Isuzu 42 liverpool boat temperture it has always run at 85deg, but yesterday it started running at 89deg, so i took off the rad cap to see if it was to hot but it seemed ok, the cap didnt blow off when i undone it. i did notice that the hose going into the top of the skin tank was hot and the one coming from the bottom was only warm. is this all normal, i had been running for 2 hours. colin.

 

 

Hi

As Alan said your skin tank is doing it job but I am supprised the rad cap wasn't under pressure at 89 deg.

Is rad cap spring/seal OK. The other reason that the temperature can rise is due to the 'stat being faulty.

But as Alan said its probably the gauge thats faulty or you looked at it when the stat was about to open and drop the temperature back down to 85 deg.

Also the first thing that warms up is the calorifier so the skin tank will stay cool for quite a time.

 

Alex

[colin loach]

Thanks both for you reply. The boat normally runs between 80/85, when on the Thames it can reads just over 85. The cap seal is ok but the only thing that I did make a mistake whilst driving was to knock the ignition off. I turned it on a few minutes later, could this have any bearing. My calorifier is not connected yet.

[Tony Brooks]

Thanks both for you reply. The boat normally runs between 80/85, when on the Thames it can reads just over 85. The cap seal is ok but the only thing that I did make a mistake whilst driving was to knock the ignition off. I turned it on a few minutes later, could this have any bearing. My calorifier is not connected yet.

 

I would say no, but I think extremely unlikely would be better.

 

I agree with Alan, not convinced there is a fault. You could get that apparent variation caused by parallax error if you look at the gauge from another angle.

[colin loach]

I would say no, but I think extremely unlikely would be better.

 

I agree with Alan, not convinced there is a fault. You could get that apparent variation caused by parallax error if you look at the gauge from another angle.

 

I stood on my head and it still got to 89. I have a thermometer I use at work for testing water temperature; if I was to test the water in the header tank would that give the correct temperature.

[stuart]

Whats the canal water temp these days? Does that make a difference now we have slightly warmer weather ?

[bottle]

No.

 

The correct temperature is where the the sensor is.

 

I think you are beating yourself up over nothing, unless the temperature keeps rising un-controlled but from what you say all is OK.

 

If and it is a big if there is anything wrong, three problems that it could be, 'tired' pressure cap, thermostat sticking or the impeller on the pump is worn/faulty.

 

In that order.

 

Edit: My 'no' was for Colin but also applies to Stuart.

Edited April 6, 2010 by bottle

[colin loach]

Thanks. I think your write. The gauge would keep going up if there was a fault.