How to Avoid a Blown Head Gasket (GM 3.1L, 3.4L)

If you've had the misfortune of having to replace or are in the process of having to replace the head gaskets on your GM 3.1L or 3.4L equipped GM vehicle... you may be wondering if it's possible to avoid a repeat of the problem. The answer is: Yes, it is possible to avoid a blown head gasket on your vehicle and it only involves taking some simple precautions.

In this article I'll go into some detail about what you need to do, to avoid the tremendous expense that's involved with having to replace blown head gaskets.

The Root Cause of a Blown Head Gasket

Knowing the root causes of a blown head gasket (or head gaskets) is one of the key pieces of info you need to prevent this expensive repair. The two basic causes of a blown head gasket or head gaskets are:

  1. Severe overheating. Usually the result of the cooling system loosing coolant due to:
    1. Water pump failure.
    2. Intake manifold gasket failure (the most common).
    3. Coolant thermostat failure.
    4. Radiator hose busting open.
    5. Radiator busting open.
  2. Internal hot spot developing on the engine block deck due to a small coolant leak preventing the cooling system from pressurizing.
    1. This little coolant leak usually doesn't cause the engine to overheat... which leads a lot of folks to just ignore it and think it's just OK to keep adding water or coolant to the radiator.
    2. The block deck is the surface that mates with the cylinder head. The head gasket is sandwiched between the engine block deck and cylinder head.

Of course, a small coolant leak doesn't result in a blown head gasket overnight... but ignored long enough, this little leak will eventually result in a blown head gasket (I've seen this happen a lot!) Why?

... because the cooling system needs to pressurize to a certain pressure to effectively keep the engine at a normal operating temperature. If it doesn't pressurize... the engine develops internal hot spots that can crack heads, the engine block, and burn head gaskets!

Let's find out more about what can be done to prevent a blown head gasket(s).

The Most Important Thing You Can Do Is To Check For Coolant Leaks

If you have had your 3.1L or 3.4L equipped GM car or mini-van for any length of time... you've come to find out that these engines are coolant-leak prone. Especially from the intake manifold gaskets (to learn more about this particular problem, see this article: Coolant Leaking From Intake Gaskets (GM 3.1L, 3.4L)).

Regularly popping open the hood of your car or mini-can and checking for coolant leaks with a flash light becomes a must!!!

Another effective way of checking for coolant leaks (along with checking under the hood) is scanning the driveway (or whatever piece of pavement the car is parked on) for green coolant puddles (or orange coolant puddles, if you have Dex-Cool in the radiator) whenever you pull in or out will go along way to finding coolant leaks.

Another good time to check for coolant leaks is at oil change time (whether you do them yourself or take it to a fast-lube/oil-change place). Since you're already under the hood (and under the engine draining the oil and replacing the oil filter), take the time to thoroughly check the top and bottom of the engine area for coolant leaks with a flashlight.

Although the following is not an exhaustive list of things that can leak coolant, it'll give you an idea what to shine your flashlight on (while you're under the hood or under the vehicle):

  1. Radiator hoses (where the hose is clamped to the radiator or the engine).
  2. Heater core.
    1. Since the heater core is inside the vehicle, the areas you need to check for coolant leaks are the front passenger side floorboard (inside the vehicle) and by the lower-bottom part of the engine's firewall.
  3. Radiator.
  4. Radiator cap.
  5. Intake Manifold Gaskets (the geniuses at GM decided to use plastic intake manifold gaskets that are prone to breakage around the coolant ports and are infamous for coolant leaks on the 3.1L, 3,4L engines).
  6. Water pump weep hole.

If you do spot a coolant leak, what next? Well, let's explore this in the next subheading...

Don't Use Leak Sealers to Stop a Leak

If you do spot a leak, don't us a coolant leak sealer to stop a leak! Whatever is leaking coolant needs to be replaced!

It's so tempting to use some sort of stop leak in a can, because depending on what's leaking coolant it can almost cost ‘an arm and a leg’ to repair the coolant leak. And so the can of stop leak seems like the cheapest and safest fix. But, is it?

Speaking from years of experience working as an automotive tech, I can tell you that a can of stop leak may work initially, but it's not a permanent repair. To add insult to injury, this can of stop leak will help clog your heater core and radiator in the long run and eventually cause your vehicle to overheat.

So, eventually, not only will you have to repair the leak by replacing the part that's leaking coolant, but you may also have to either rod-out the radiator (or replace it) and replace the heater core, thus making this 'cheap fix in a can' an expensive one!

My advice to you is: avoid the can of coolant stop leak and replace the component that's leaking.