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1998 cavalier, heater cores keep leaking, 3rd one this year


Sorry that this is so long, but I really don?t know what is relevant and what isn?t, so I am telling you everything. I have a 1998 Chevy cavalier which started having cooling issues last December. Coolant was leaking and the engine temperate was really hot. I took it to a nationwide chain repair shop. First, they said it was the water pump, and the replaced it, there was no change. Then the said it must be the ecm and the replaced that (turning my car into a giant paperweight and having to have it towed to the dealer) Anyway, that didn?t help either. So then they said it was my heater core. I agreed to let them try again because they offered me a discount because of the previous 2 repairs that made no difference and leaving me without a car for a week until the dealership got it running again. When they replaced the heater core, the leaks and cooling issues stopped?for about 4 months. Then the heater core started leaking coolant again (well more like pouring). This repair was 100% in warranty. Ran great for about 4 months. It just started pouring water again. Anyway the shop is covering the part in warranty again but not the labor, but I still feel like I?m stuck with them rather than paying full price. Do you have any idea what could cause a car to go through 3 heater cores in 10 months? I am hoping you can give me advice on what to have them check.

Also, there are 2 other things that may or may not have anything to do with anything:

1st. My check engine light has been on for about a year. The first 2 repairs, they couldn?t figure out why. At the third, they said my oil sensor was leaking onto my timing sensor. The fixed the leak but said I didn?t really need the sensor, so the light is still on.

2nd Since they replaced my water pump, I sometimes hear a sound when I am starting my car that sounds like sucking a mix of liquid and air through a straw. Like when your kid is at the bottom of the soda but keeps sucking on that straw making those gurgling type noises. I can?t make the car do it, I have no idea when it will, and everyone else thinks I am a little insane.

Thanks in advance for you help and any advice at all is appreciated,


I have to ask; after the first two “repairs” which did not solve your cooling problems and left you stuck with a non-functional car, why did you go back to the “nationwide chain repair shop?” I just don’t get it.

The sucking straw sound you hear is probably water circulating through the heater core, which is normal, but you hear it because there’s also air in the heater core, or an air bubble in the cooling system, which is NOT normal. There should be no air in the cooling system.

This may be related to the rapid heater core failures (antifreeze contains anti-corrosives, air doesn’t), or it may not, but it shouldn’t be happening. The cooling system should be purged of any air. Since they’ve replaced the heater core several times they’ve had ample opportunity to purge the system. You have to wonder why they haven’t done so.

I can’t explain the need for three heater cores in such a short time unless they have been improperly installed and are rubbing against something and wearing through, or they were just bad cores to start with.

Anyone who says you don’t need a sensor and it’s OK to drive with the check engine light on is not to be trusted and you should not go back to that person. The light is telling you something is wrong with the car. You, with the help of a mechanic, should figure out what that is and fix it. Ignoring the light will only result in a bigger, more expensive to repair problem.

It’s your car and you can take it anywhere you want. Personally, I avoid all chain repair shops like the plague, and I won’t go to a dealer unless there is a warranty-related issue or a recall.

Can’t you find an independent mechanic to help you take care of this car? Ask your friends, neighbors, relatives, etc, for recommendations. Independents are usually less expensive than dealers and almost always better then the chain shops.

Maybe the overheating episode caused a head gasket to start giving up. If it’s leaking slightly between the water jacket and one of the cylinders this can cause the pressure in the cooling system (and the heater core) to increase dramatically.
This in turn can fracture the heater core or cause a leak through a soldered joint.

A competent shop should inspect the cooling system for leaks (and head gasket problems) whenever there is a vehicle with a severe overheating complaint.
If a head gasket is causing this problem then it should be their responsibility to examine the heater core and determine WHY it’s failing; not just blindly throwing another one in.

Thank you for your replies. I don?t think I am ready to try the ?black pepper trick? That scares me a little, maybe once I accept that this just isn?t going to ever get fixed, but I am not there yet. I will ask them to make sure that they have purged the system of any air. And to also check my head gasket. I should say I never did actually allow the car to overheat (never had steam or smoke). I know what its normal temp is so as soon as its higher than normal, I pull it over. Plus the water light comes on before it starts to climb. I keep gallons of water in the trunk. Whether any of the shops allowed it to overheat, I don?t know

As to the questions:

  1. Miles - The car has 170000 miles.

  2. Do I trust my mechanic - I have been to roughly 30 mechanics in my lifetime and I have yet to meet one I trust. I have 100s of stories just like this one. I won?t bore you with them, but I think they are really quite funny if you?re not me. My favorite is when my power window motor stopped working when my car was in the shop for an oil change and the mechanic said that that happens to windows if they sit.

  3. Why do I keep going back ? Mainly, money and I?m an moron. I now accept that when I go to a mechanic I will get screwed. The estimate at the current shop is $250. I have called 8 other shops today and the estimates were between $600 to $900. I have actually taken the car to be seen by another mechanic (non chain) for a 2nd opinion the last time and he told me that my car was leaking coolant because of the transmission. The estimate was thousands so I declined then he added that my steering linkage was in desperate need of being lubed and that it was dangerous for me to leave without it. I left. I?m still alive. This chain shop disagreed with his assessment and has not presented me with an estimate greater than the value of the car. I have tried every shop that has been recommended to me and it always seems to work out the same way. This one and the lube guy were both recommendations. I think my friends might be morons too. :slight_smile:

  4. Does it smoke ? Nope. My windshield used to steam up a lot with heater core number 1, but that?s it.

Thanks again,

You should have got your money back on the missed diagnosed water pump and ECM

You neede to compare all three heater cores to come to any kind of conclusion, my wild guess is thet are being damaged durning installation or some other installation failure

Have the shop show you exactly where the third heater core failed (look to see if it has a puncture or abrasion, if a solder joint failed, do not put another heater core in until you know and correct why the last one failed.

Let me compliment you on rejecting the “pepper advice” you were given, your insticts were dead on.

You are going to have to be tough,when a shop makes a diagnostic error and it costs you money make it clear you will not be taken advantage of, you must pay to get your car back but let them know the court papers will be comming.

You don’t mention the State you live in but some (CA is the best with their, Bureau of Automotive Repair) have agencys that can help you sort things out.

In my humble opinion you have little to no chance of getting the car properly repaired by this “shop” and a very good chance that they will continue repeatedly flushing your wallet out. Clearly these people are incapable of diagnosing and/or repairing a vehicle. You need to find a new and reputable shop. Ask your friends and coworkers who they go to.

In addition to all the other problems and to the posts already made, it’s possible that these people simply cut your heater hoses rather than try to remove them from the spouts (they can be hard to remove) and rather than replace the hoses simply left them short. Hoses shoudl have “stress relief” ability to allow the engine to move relative to the heater core without laterally transferring stress to the heater core connections. Cutting length off the hoses can reduce this and cause premature failure at the seams where the spouts meet the ends of the heat exchanging coils.

Bottom line: the installation was likely the cause of the repeated failures. And this shop will continue to cause failures. And I’m appalled that they told you to ignore the CEL light.

Your comment about being unable to trust mechanics is, unfortunately, very very common. It’s getting hard to find one that is competant and also cares. But they are out there. And you need to find one.

I agree with the suggested mechanical issues that might cause repeated failure. Electrolysis can also cause repeated heater core failure. If you have bad engine grounds and the heater core is touching metal, you might be dissolving it that way.