I have a 87 s10 blazer, haven't had any problems until last night. It started shaking when I was driving (worse in 2nd gear), today when we looked at it, there is a white/green/ grey colored "stuff" coming out of the head from the radiator hose (the upper hose). Hoping someone would know where to lead me to start trouble shooting.

 

Check your oil cap and make sure that there's no foam on it. If there is then you've got a blown head gasket. Also a few pics would help too. This also happens when stop leak has been added to the antifreeze.

 

Sounds like a blown head gasket.

 

I checked the oil cap and there is no foam on it. Also, the oil color is ok, and aniti-freeze. I took a couple of pictures, and read a few signs on head gasket, and the foam was the only symptom. So, was hoping it could be something else? We haven't added any stop leak to the antifreeze but we bought this blazer a few months ago. Haven't had any other problems but were told the water pump would need to be replaced soon, could that cause this problem? Thank you for your help

 

What motor is this? A 2.8? It could be that the previous owner used stop leak and then changed all of the fluids before you bought it. I'm still leaning towards a blown head gasket. Or it could also be that the head gasket is old and brittle and is just now starting to fail.