Whenn good heaters go bad - with pics

[shamaal]

Those following my threads the last month, know my car was badly overheated when the top radiator hose blew open. After changing both cracked haeds, I attacked the R12 air conditioning system. After converting to R134a (42degF) I noticed I did not have heat. After repairing the recirc air vacuum solenoid (bad vacuum line) I came to the conclusion theat the most likely culprit was the mix doors. After satisfying myself the the doors were working I felt the heater lines. The input (inboard) was very hot the exhaust outboard was just hot. Blowing on the input met much more resistance than I expected so after installing new core ($17.99 - O'Reilly) heat was restored.
Examining the heater, there is no obvious external damage, for an eight year old core I thought it looked good.
Inside however is a different story, the input side is 95% blocked, the exhaust is clear and the bottom is 5% blocked. The material that's stuck is rubber. Not chunk rubber but very sticky and malleable extruded pieces. The silver stuff is the Al from the cutting. The only thing I can figure is that as the broken hose deteriorated and it started shedding the lining. There may also be a general degradation of the hoses that I'm unaware of. Generally I think of these cores rusting up and crapping out, this one's another overheated engine casualty

 

[Spdrcer34]

wow.....

I guess I'm lucky then, `cause when my heater core went out this last winter, all it did was spray a yellow/green mist on my windshield.....I drove another 50 miles home, and fixed it the next day. Took all of 15 min from start to finish.

....may be a dumb question @ this point, but did you replace your radiator @ the time of the head replacement? Because if that stuff is in your heater core, it is DEFINITLY in the radiator too..


Ryan

 

[shamaal]

The only failures I've heard of on heater cores are holes from corrosion. I was very surprised to see how clean this one was. The reason I replaced it was blockage - no heat. You are right, the radiator will be crudded also, so far there has been no noticeable affect on performance. I've backflushed once, future backflushes may only serve to move the crud back into the heater core. This will be one of those things I'll carry in my head should I have problems.
Thanks for the alert, I had not thought of affect on the radiator yet.
Any other potential areas for crud collection? I noticed nothing in the block or the heads. Passages seemed big enough for crud clearance.

 

[Spdrcer34]

If you have that in your heater core you ALSO have that in your radiator.

At this point, the BEST way to flush the radiator is to actually disconnect it from the pump and intake, and flush it....

Ryan

 

[Creager]

wow, im buying a new heater core.