Heater Core Problems please help

[i_love_paintbal]

Hey guys Im new on here but I have been around on ranger forums for a few years now. I finally decided to join up here too.
1999 mazda b3000 3.0

Anyways as the tile says I have a major heater core problem

Here is the story in 06 My heater core went out had it replaced. 1 year later in 07 it went out again it was under the shop warranty so they replaced it along with coolant gasket and thermostat witch I got charged for.

They showed me the heater core and it had blown up, so much pressure had built up it ballooned out the core. But hey the replaced the coolant cap just to make sure it was reliving the pressure.

So like a year and a half later in 09 I could swear it was starting again a leak that is. I tried to ignore it until yesterday when it really went out. all the classic signs fogy winds heavy smell of coolant and coolant dripping from the drain tube onto the exhaust pipe.

Took her to the shop and they said sorry we wont fix it your warranty expired 2 years from the first install. the replacement did not extend that. so its $800 after tax to fix I said no way. Had them bypass my core and top my coolant off and drove away. I decided I will tackle it myself this time its a pain but oh well. $100 for the part and thats it it will just take me a day and a half.

So my real question is why is this happening? If I cant fix the cause then there is no point to replace it. Anybody I real need your help.

If I cant figure it out Im going to replace it and sell/. trade in the *****. Witch I cant afford to only get around 4K for my truck and then try and buy something els. Im a broke college student. This sucks HELP ME PLEASE


Truck info
1999 Balck Mazda B3000 4x4 single cab, 8.8in 4.10 LS axle swap,31x10.5 Pro Comp Extreme MT, Manual Transmission with a silver bed box and A Pillar Mag light mount.

 

[master hec0]

i would replace the core but use a core from another place maybe the cores are not built very well. change the coolant maybe the coolant is eating away at the core and eventually weakening it enough to burst under pressure. if you are able to get a hold of a pressure tester i would test the rad cap to see if that is in fact the issue.

Edit: also when you remove the old core take a picture of the carnage. it might help. and when changing the coolant check for debris like rust and other crap

 

[i_love_paintbal]

Well the thing is this is the third one to go out. Stock one shop replaced it with an aluminum one it blew up they replaced it with a brass one and replaced rad cap at this time just to be safe. this third one is gone now so that eliminates all your hints. oh and every time they replace it they flush the coolant and put clean stuff in. ????

 

[cocoasranger]

I would take that new radiator cap off and watch myself while it was tested (by someone other than those that had done the repairs previously).. It should show about 15 or 16 pounds per square inch max. If the new brass core was noticeably ballooned out it's no wonder it failed. If the cap was functioning properly it would have released the pressure before there was damage.

 

[master hec0]

well it has to be one of those things. i would still lean towards the rad cap. its not like the truck just destroys cores for no reason.

 

[i_love_paintbal]

I have not taken the brass one out yet so We shall see. Also how do i test a rad cap

 

[master hec0]

you need a pressure tester. it can be used to test the rad cap and the cooling system. it should tell you if your cooling system has too much pressure also. you should be able to find it any any parts store or check your local craigslist. they look to run around 80$ and up. also you could try ebay. here is one for 71$ on sale http://www.amazon.com/Stant-12270-Cooling-System-Pressure/dp/B0002SRGWU/?tag=959media-20