Problem #1 (These 2 problems happened within the same trip)


I drove to Delaware a few weeks ago, and on the way there I used the A/C the whole way because god forbid, my girlfriend can't live without the A/C which is no problem because it was pretty hot out. I had NO problems with the A/C the whole 2 and a half hour drive there.

When we decided to come home 4 days later (only drove the blazer to get there, didnt take it out anywhere until we left) I drove for about a hour and a half with the A/C on, I looked down at the temp gauge while on the freeway and I saw it moved past the middle mark (which it never does, but I thought to myself "FML" and kept an eye on it), well as more time went by, it kept climbing. I stopped at about 3 redlights when the temp guage was just barely touching the red. I cut off the A/C and dropped the windows and the temp gauge slowly started climbing back down, and it eventually went to normal after 15-20 minutes of driving. I thought nothing of it since it was 95+ degrees out, but now it does it even when it's dark and cooler out.

It is driving me crazy, I want to be able to use my A/C on 100+ days without it overheating.


Problem #2.

After about an hour and a half of driving TO Delaware that night, I noticed when I stopped at a toll both, when I would pull out to get back on the freeway (I didn't rip on the gas either), the blazer would jolt from first to second, almost as if a bad motor mount, and it was a little jolt from 2nd to 3rd if any at all. I drove it like that for the remaining hour to the destination, let it sit for a day or 2, and on the way home it was fine until after about the same hour and a half of driving. It would start jolting again.

What is this?

 

The hard shifting is probably a bad shift solonoid in the trans. Is it going into O/D? I had a similar problem and it turned out to be the 1-2 shift solonoid. As for the cooling issue: a thorough inspection of the cooling system is in order:flush,t-stat,rad cap etc. Good luck!

 

I may not have as much experience with Chevy vehicles as with some of the members on this forum but I have to agree with step66. I recentlY purchased a 1998 Blazed with a fair amount of miles on it and one of the first things I noticed was an erratic temperature gage. It would surge and then drop often. Many of the times I noticed it was during similiar driving conditions you have recently experienced.
Needless to say the vehicle REALLY needed a good coolant flush. I ended up removing the two main radiator hoses, thermostat, and coolant resevoir tank. Everything needed cleaning. After I finished, no problems since the cleaning.