1999 V70 Heater core 'sploded (gushes out coolant)

[slm987]

So at about 4500 rpm, my heater core went pop and I started smelling coolant. It's not just a small leak, there was coolant all over my floor. I believe that the orange antifreeze that was in the system could've eaten it's way through the core because it was chemically incompatible. As far as I know, aluminum doesn't just break. Could someone confirm my theory? Directions on how to replace the heater core would be awesome too, otherwise I'll just make a bypass because I can't figure out how to do it.

[j-dawg]

Nope, the heater cores are flawed. They pop. Look for a crack or break in the plastic part. Mine also blew at around that engine speed; I think the water pump being run up to high speeds generates high pressure downstream and breaks 'em earlier, though they all break eventually.

Bypassing the core is easy and there are a ton of guides out there to replacing it, which is also easy. The pain comes when you have to clean up the mess - gotta yank the carpets and cut out the foam underneath, to clean and dry it, because the foam does not dry out on its own. (I did the cleanup job about 2 months after the core went, and it was like squeezing out a completely saturated sponge.)

[precopster]

Common issue. The cooling system is pressurized at around 10psi. Not much pressure but enough to split fatigued, heat cycled plastic. Usually the ones to explode are black plastic aftermarket ones NOT made by Behr or Swedish Car Parts. The OEMs seep at the union between plastic and alloy.

Had it happen to my wife's 850 on a 3 year old heater core. Most of us now use the OEM Behr ones or the Swedish Car Parts ones with no issues.

[slm987]

Well as far as I know I have the OEM one in there, I haven't taken a good look at it, but it isn't one of the black plastic ones of which you speak. What is the lifespan of the swedish car parts one? I think I'd go with it just because I want to buy some other performance stuff, like bushings, just because mine are terribly cracked and dry-rotted.

[JRL]

What were you doing with GM orange antifreeze in it?
That will kill everything

[precopster]

With the Swedish Car Parts core there are no documented failures (yet) on this forum or on Volvospeed. The o rings that come supplied with it have been reported to leak however OEM ones in their place have solved this.

Personally I've had one for about 3 years in my V70 and no complaints.

[slm987]

Am I able to use the old ones or do I have to buy new ones?

[abscate]

Pull them out now and see if they are still in good shape..no tears or flattening. Mine felt like new but I bought a coupling kit so I didn't reuse. I'll send my old parts to you if your on a budget