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Posted

My Cooling system keeps pressurising and blowing heater cores. It's the second one i've blown now but i have one more left to try and i think i'll change to a ceramic heater.

 

It's only happened since i put in the new aluminium radiator, any ideas what might be causing this.?!

Posted

Are they new cores or old second hand ones?

 

There are many points in a cooling system (like hoses) that would/should be weaker points than the heater core.

Posted

check the cap pressure, maybe the wrong one is fitted, to much pressure? ;)

Z's run about 13lbs or .9?testing pressure  is 23lbs or 1.6

Posted

Might be worthwhile checking to see if it's pressurising via a head gasket leak.

Leave the rad cap off and look for tiny bubbles after the engine comes up to temp and the thermostat opens.

Posted

When it gets hot does the cap release the pressure out of that nipple.

 

It's not releasing at any pressure

 

check the cap pressure, maybe the wrong one is fitted, to much pressure? ;)

Z's run about 13lbs or .9?testing pressure  is 23lbs or 1.6

 

It's a 13lbs cap

 

Might be worthwhile checking to see if it's pressurising via a head gasket leak.

Leave the rad cap off and look for tiny bubbles after the engine comes up to temp and the thermostat opens.

 

There are no bubbles.

Posted

you can buy a kit from repco that will show any gases in the cooling system or get a radiator place to check that.

you may have a cracked head/block that is putting the pressure/heat into the cooling system.

I had a diesel that did that

how long does it take to have the problem?

Posted

I still think that at some point the pressure should be released.

then try another cap

The cylinder head is not leaking.

I replaced everything on that diesel, never did find why it was overheating. no water in the oil so was'nt the block, only thing was the head.

how far do you drive before it overheats?

Posted

Scoot, check that the fitting on the radiator is exactly the same as an original fitting, if you have had this prob only after the new radiator was fiteed AND you did nothing else, the radiator has to be the problem :)

Posted

It doesn't overheat it's just pressure. It runs on half all the time. As to when the pressure occurs, i don't have a psi gauge hooked up to it so i don't know.

Posted

Thats what im thinking. I contacted the company that i bought it from but i think the fitting is too short and when the cap is fitted correctly there is no movement in there. Just wanted to hear from others with an aftermarket radiator.

Posted

I used a standard recovery cap, the new cap that came with the alloy rad and the uprated Kameari cap all with no problems. Is the neck shorter on the new rad, maybe that's increasing the pressure on the spring or not allowing it to open? Have you tried a new cap?  The Kameari cap is 1.2kg/cm

Posted

I have tried a new cap. I'm pretty sure its the neck.

 

 

Do you mean it's shorter than standard or out of round/rwrong shape or size..... can you measure a stock neck and compare? The inlet on my overflow bottle blocks up occaisionally, but I doubt that would hold enough pressure. It sounds like a complete head f@$k  :o

Posted

Here's my 2 cents.

 

ready ....?

 

I think that it is most likely that your cap is either a bit tight in the neck (as the neck might be a bit smaller than the std one) and therefore not allowing pressure to release

 

OR

 

The drain is a little further up the neck than std and therefore the cap seal can't travel far enough to release the pressure.

 

Now that I have agreed with Salty, I'm going to take some time to reflect.  Thank God that you agreed with him also.  We'll need a moment of reflection together next time we catch up.  (glug glug hic hic )

Posted

There are 2 types of caps which will fit. One is shorter in the spring one longer. ie one is made for an overflow tank, the other is not.

I can't remember which one is used with a overflow tank, but there is a difference.

Might be your problem.

Posted

Now that I have agreed with Salty, I'm going to take some time to reflect.  Thank God that you agreed with him also.  We'll need a moment of reflection together next time we catch up.  (glug glug hic hic )

Mate,have you been hittin the turps? LOL

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