Cooling problems

[69MyWay]

Re: More ignorance on the way...

...I thought a blown head gasket meant you'd have oil in your radiator water?
I thought it was sort of strange to advise looking for air bubbles.
Will someone please explain?
Silver

A blown head gasket can develop a number of symptoms depending on where it has blown in relation to the water jackets, cylinder, or oil ports.

When a gasket blows into a water jacket (most common), the compression of the engine gets back blown into the cooling system. The air bubbles seen running out the radiator cap are actually engine exhaust bubbles that did not make it out the tail pipe.

If it blows towards a oil port (much more rare on the sbc) an exchange of water and oil will happen. At low temps, the oil has more pressure than the water and will enter the cooling system. As the engine heats up the higher pressure in the cooling system will force water into the oil. So, you get oil in the radiator and water in the engine block. This is a more common situation on vehicles that have cracked heads or engine blocks rather than just blown gaskets.

In the same regard, coolant can escape into the cylinder causing the car to blow steam out the tail pipe with a sweet nasty smell as it cooks the antifreeze. If you shut the car down and the pressure in the radiator continues to push coolant in the cylinder, then you try to start the engine back up, you can bend a rod and trash the whole engine as the coolant that has leaked on the piston will not compress like air does and as the engine rotates to start it will dead head againts the valves and if the starter is strong enough, or the engine actually fires, you just blew an extra $1,000.

Does that help?

 

[78SilvAnniv]

Yes

Thanks.
Sil

 

[Trance_LT4]

Well, the job is done, and the problem is fixed. The heads were milled .006 and a valve job was done. All told the damage bill was $1600 parts and labor. They replaced a faulty temp sensor on the head.

It was 90 degrees out today, and I drove on the highway and in city traffic. I drove it easy and I drove it hard. The temp stayed between 195-205 the whole time.

Knocking on wood, I hope my next problem is far into the future.