For 20 years (holy buckets I’m old!!), I’ve been an automotive hobbyist - I love a good wrenching session.

For the past 4 years, I’ve been a professional auto mechanic for an independent shop. I remember when I was going through school that one of my instructors stated that the cooling system is the most ignored system when it comes to maintenance of any kind - most people don’t worry or think about it unless there’s a problem. And in the time I’ve been doing this professionally, I’d say that’s generally true - only a few of our several hundred customers request preventative maintenance for the cooling system (flushing and cap replacement as required).

Well, the picture below shows you why you should be more intentional about it. These are head gaskets off a 2005 Equinox, 3.4 engine that I’m currently replacing. All the orange/rust colored spots are passages in the gaskets that are supposed to allow coolant to pass between the heads and the block. They are plugged up with crud due to a lack of cooling system maintenance for an extended period of time (engine has about 150k on it - I don’t know if it’s ever been flushed) - this, in combination with a faulty system cap, ultimately caused the head gaskets to start leaking and the engine overheating.

Although I have flushed the block, radiator and heater core after I removed the heads and a good deal of the crud was removed, I’m going to perform a cooling system flush using a machine after the repair is complete as well. I wouldn’t be surprised if the radiator and heater core both require replacement within the next year.

It’s important to note that this repair (approximately $1500.00) could’ve been avoided had 1 or 2 system flushes been performed as regular maintenance, at a cost of about $100.00 each. This is certainly the worst one I’ve seen, but plenty of other GM engines, in their 3.0 liter family, from this era have problems with crud formation in the cooling system.

 

Was that the 2 year coolant, or the 5 year HOAT coolant in that Equinox?

 

I couldn’t say for sure - I’d guess it was probably a mix of whatever was available when it needed topped off. Although the owner is a faithful customer, they haven’t owned it for very long, so who knows what was done by the previous owner.

 

+1
and if the cooling system has a leak, don't use stop leak products. find and replace leaking part.

 

+1,000!!!!

We occasionally get customers that ask for stop leak or similar products. We will advise against them but ultimately it’s up to the customer, so my boss just tells us they want “head gasket in a bottle.”