Pressure testing the cooling system

[richardf]

I have had a few problems with my engine replacement this week, as some water leakage from the heads was discovered. The heads are about to be refitted and the system tested. What pressure should it be tested to? The yard have mentioned 5 bar ( about mains water temp) but this ssounds very high to me, I don"t want to overdo it

[Titan]

I have had a few problems with my engine replacement this week, as some water leakage from the heads was discovered. The heads are about to be refitted and the system tested. What pressure should it be tested to? The yard have mentioned 5 bar ( about mains water temp) but this ssounds very high to me, I don"t want to overdo it

 

 

The coolant pressure cap should have a rating on it, this is what it releases pressure at, and therfore will give you a guide to max pressure the system should be regards Martin.

[richardf]

It's not a sealed system with a cap on it, water head is simply from an open header tank, high up in the engine room. Water is circulated by a Jabsco pump, around the engine and skin tanks.

[nicknorman]

It's not a sealed system with a cap on it, water head is simply from an open header tank, high up in the engine room. Water is circulated by a Jabsco pump, around the engine and skin tanks.

Radiator caps are around 1 bar, so it's perhaps inappropriate to go much over that. A cold test may not be representative because a head can seal when cold, but leak when hot due to thermal expansion / distortion etc

[Nickhlx]

It's not a sealed system with a cap on it, water head is simply from an open header tank, high up in the engine room. Water is circulated by a Jabsco pump, around the engine and skin tanks.

 

I would say then that, as not pressurised in normal use, even 1/2 a bar ( 7 psi) would be adequate - why test at much more than working pressure and risk blowing a seal ?

Some might say what's the point in pressure testing at all ?

 

Nick

[The Bagdad Boatman (waits)]

With high temperature fast running engines the purpose of a pressure cap it to increase the temperature that water boils at. With an trad engine and a non sealed system there is no need for a pressure cap.