Blowing heater cores every few months

[roastposi]

I have a '91 Caprice with a 305. She's got some milage and keeps on blowing out heater cores for no apperent reason. I have replaced it 4 times in the last year and a half. The last time it was replaced I only got 500 miles out of it. I know what I am doing as far as the R & R goes and it doesn't seem to be a manufactures defect because the cores I get have been coming from different suppliers. Someone mentioned a similar problem on Ford F-150's. It turned out to be a ground wire with paint under it going from the intake to the fire wall. Causing the coolant to become electricly charged and blowing out the side of the Core. Has anyone heard of anything like going on with a Caprice? And if so how the hell do you fix it!?!

[capriceman]

That's a new one on me.
I'll give it some thought.
When You say "blowing out", do You mean electricly?, or does it start to leak?
If it's electric, You may have the same type of problem.
Make sure that You have the correct amperage fuse for it.
If You let too many amps. in, it will blow out more air, but it will fry the motor on it.
Do the heaters in these cars have thier own blower?
I've never had to mess with mine.

[94_teal_bird]

I had a similar problem with a Cavalier. We replaced the heater core each summer for two years straight. I heard that an electrolysis effect can eat holes in the cores. A solution to this is to put more ground straps on the engine or to do what I did. I grounded a wire on the body of the car and clamped it to the heater core pipe then put the hose on behind it and clamped it down. Voila, I haven't seen the car since. Hope this helps. You can check to see if the voltages in your coolant are dangerous with a voltmeter. If they read above 4 volts, I believe, they can cause problems. Good luck man
-Rob

[Swamp Wolf]

Well, I kept going through heater cores until I put in my own screw bearing (spiral drive) servo motor (home made PLC's all over the place in my car). I limit the flow and pressure buildup in the heater core. The first few times I shrugged off blown heater cores as coincidence (first coincidence was when i removed the vaccuum operated flow control found in most 1987-1990 caprices and just ran straight hoses to and from the engine/pump/core and always blew them in the winter because I may not have let the car warm up before I drove it harder)(second coincidence was the fact I let someone other than myself work on changing the heater core and when i pulled out the second heater core in the car's life it had a huge dent in it). Third time no problems existed, currently running 50/50 mix of coolant(prestone)/water, no problems exist after 3 years yet... The screw bearing valves I made have 3 positions, open, mid-way, and closed. I programmed it to close with a throttle position sensor at more than half throttle (enough on my ZZ572 572 CID engine to eat a viper), So far I have not been able to run WOT without almost crapping my pants (the car spins the tires again when I am already moving at 55 mph and floor it). I currently have a collection of 11 differentials in the backyard, all blown up in different ways over the years of me swapping cars and engines. Currently own 1979 impala, did own 1980 caprice w/454, 1986 caprice w/454 from the 1980 caprice, now upgraded to a fresh new ZZ572 after retiring my 454 at 430,000 miles and parking it for a rebuild to 610 CID.