I have an 88 iroc and have been having heater core issues for quite a while. I have replaced the heater core 4 times in the past 6 years. At first I thought that it was just a junky heater core but the last time I spent a little more money and got the best one I could find. It lasted about 1200 miles and then the same thing I had coolant on the passenger side carpet from the heater core leaking all over. I can't seem to figure out what the problem is. Has anyone else gone through heater cores and found the real problem? I was reading some other threads and am going to try changing out the radiator cap and possibly rent a tool to check the pressure of the coolant system. Is there anything else that anyone knows of as a comman issue? Thanks for any help you can give.

 

The frequency of heater core replacements seems quite unusual. Have you ever had the system flushed? What kind of coolant are you using? Has the radiatior ever leaked on you? If it's not a corrosive condition, then could it be a stress fracture caused during installation? Just seems abnormal to have gone through that many heater cores without some other problem elsewhere?

 

I have had the system flushed a couple of times and all of the hoses have been changed out. I am using Prestone and mixing 50/50 with distilled water. I have never had any issues with the radiator. I suppose it could be a stress fracture caused during installation but it I don't think that it would have happened everytime it was replaced. I had a shop replace it the second time it went out.

 

I'm having the same problem I'm pretty sure its the rear of the intake manifold, because I also have a slight trace of coolant under the car. It drips down the firewall into the holes where the heater pipes go through. They usually aren't sealed well, especially for having 4 heater cores put in.

 

What's a leaking intake manifold got to do with bad heater cores exactly? How is that "the same issue"?

 

check the hoses on the back of the heater core and tighten the crap out of the clamps. these come loose and coolant flows down the pipes into the passenger compartment.

 

You have an electrical / electrolysis problem.

It should not be happening so quick, but can happen, id check out your grounds. Any and all.

Like a water heater you need a sacrificial anode that gets eaten first that you can replace in those cases. As it's a matter of the electrolytic corrosion attacking the zink instead of the other metals.

[That why water heaters go bad 99% of the time, once that replaceable rod is gone, the liner goes quick.]

Lots of places sell stuff, some drop in, some screw in, some are in the rad cap....just need to get some zinc in there.

Here is just one, GM, National Parts Depot, JCwhitney use to sell the rad cap kind.

http://www.flex-a-lite.com/auto/html/anode.html

Flex-a-lite has developed a new zinc anode kit part #32060 to be installed in the radiator as a replacement for the drain petcock in radiators that are equipped with a ¼” NPT bushing welded into the tank. Or it maybe installed in any ¼” NPT hole that is available in the cooling system.

For years Anodes have been used in Heavy Duty and Marine applications to protect the cooling systems and its many components from damage due to electrolysis or coolant additive failure/ breakdown. In some cases other corrosive material used in manufacturing and remanufacturing of engine parts and components.

Flex-a-lite now brings this protection to you. Today’s cars and trucks have many aluminum parts and parts made in combination with aluminum alloy. Aluminum parts may disintegrate from electrolysis in the cooling system. The introduction of the zinc anode will protect your cooling system from galvanic action “Eats” the zinc rather than your cooling system.

 

Wow Gumby! What a sales pitch! Makes me want to buy and I'm not having any issues! Are you getting a commission?

 

It was all I found quickly on google, not a flexalite fan really, to many trouble with their adjustable fan temp switch. [gave the sucker away]

If you get one.
I like the cap kind better, so its easy to check on.

coolant drian one, well, your gonna get wet just checking it

 

Bunch of the rad cap ones for $20 on ebay

http://shop.ebay.com/i.html?_kw=radiator&_kw=anode

Sacrificial Anode Radiator Cap Stops Electroylsis

 

If coolant is leaking out of the rear of the manifold (usually its oil, but it can leak coolant) it may blow onto the heater lines and into the passenger compartment. Read the whole post or dont comment on it.

 

Thanks for the advise. I think that I am going to try using one of these "rad caps".

 

Spend the money and get the factory part from GM. There's a huge difference in part quality. I think i'm gonna try that zinc thing too.

 

A friend of mine went through 4 cores in a 4th gen in 4 months. He finally broke down and got an OEM from the dealer. You could see the difference in craftsmanship. I don't know if GM still carries them for our cars. But if they do it might be worth a try.

 

I've gone through 2 in 4 yrs. My last 1 blew the tube off at the solder. Mine were some chineese Napa brand and they were copper. The 1 I sent in a labor claim and they denied it saying I didn't use distilled water so this time I just bought pre mixed stuff. I now put a lower pressure cap on and Im putting a shut off valve in the line. Because both of mine blew in the summer. The last 1 is aluminum made by Spectra. Looks a lot better than my last 2. I may have to try that cap also though cause I dont want to do it again.

 

I did mine about a year ago and they still had them.