What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Overheating

RayzWorld

RayzWorld

Registered Member
Joined
Jan 2, 2025
Posts
37
Reaction score
20
Location
Houston, TX
I'm pretty much stumped. I own a 1986 Chevy K5 Blazer and ive been having issues with it over heating. I replaced the water pump clockwise, replaced thermostat 160°, took apart radiator pressure water into each hole and air pressure, flushed antifreeze aire pressure and vacuum, and added an electric fan that runs constantly.
Previous owner did not take care of the truck what so ever. I found a bit of sand in the overflow container and a bit more in the radiator. Also found rust stuck in the inner walls of the radiator hoses.
 
you literally took the radiator apart? (removed the tanks from the core?)
 
nvrenuf said:
you literally took the radiator apart? (removed the tanks from the core?)
Click to expand...
Yes, ive seen it done before. I had a clogged radiator in another vehicle and they took it apart and pushed a long metal rod that was like a brush. It's pretty similar to a a baby bottle brush.
 
Besides the gauge, what other signs do you have for overheat?

Bubbles in the radiator?
Milk in the oil or valve covers?
 
Bent77 said:
Besides the gauge, what other signs do you have for overheat?

Bubbles in the radiator?
Milk in the oil or valve covers?
Click to expand...
Driving for about 10min it tends to start raise in temp and starts to run sluggish. I have yet to see bubbles or milk like fluid in oil. I stated the truck today for around 2min and went to open the radiator cap slowly and it just shot out antifreeze as if it had a lot of pressure. The outlet line feels like it has a lot of pressure judging by the expansion and squeezing.
 
1st question is there a heater or bypass ? Will water shoot out if you start engine with cap off ? Do you have the part number of pump you used ?
 
 
RayzWorld said:
Yes, ive seen it done before. I had a clogged radiator in another vehicle and they took it apart and pushed a long metal rod that was like a brush. It's pretty similar to a a baby bottle brush.
Click to expand...

I'm aware of how it's done but most folks won't or can't do this themselves so I'm clarifying that you did this.
 
I would think that it the size of the radiator is not the main problem if it only takes 10 minutes of driving to get it to act up. I base this on my older '70 truck which has a smaller size radiator than the '73 and up big block trucks. Mine doesn't have problems, now that I replaced the faulty, brand new from NAPA water pump.
So I would be suspicious of the chrome water pump immediately. Parts aren't perfect, especially nowadays. I had to deal with the crappy NAPA one 10 years ago.

OH! And kudos to you for being able to open up a radiator yourself! I have seen it done multiple times, but I don't want to try it myself.
 
IF we're voting, I say bad water pump.
Fan should come on low if it's the only one, like 140...
 
nvrenuf said:
Are you sure the electric fan and/or the radiator are adequate?
Click to expand...
Judging by how the previous owners pattern I feel confident that he kept the original radiator. The original engine was a 350 5.7l and It seemed slapped together. The vehicle was purchased from Michigan if that explains anything. I have a bigger radiator new with dual fans, but I chose not to install for the simple fact the antifreeze was dirty and I didn't want to clog the new one. Test and trial type of situation.
 
6872xtc said:
I would think that it the size of the radiator is not the main problem if it only takes 10 minutes of driving to get it to act up. I base this on my older '70 truck which has a smaller size radiator than the '73 and up big block trucks. Mine doesn't have problems, now that I replaced the faulty, brand new from NAPA water pump.
So I would be suspicious of the chrome water pump immediately. Parts aren't perfect, especially nowadays. I had to deal with the crappy NAPA one 10 years ago.

OH! And kudos to you for being able to open up a radiator yourself! I have seen it done multiple times, but I don't want to try it myself.
Click to expand...
Thank you. I tend to dabble in many different crafts. I'm an electrician and work on control panels for industrial plants, but I have done sheetrock, plumbing, insulation, wood work, framing, roofing, flooring, painting, body work, landscaping, carpentry, small engine repair, and antique restoration.
 
Hate to say and dont want to say it, but I feel the next step would be pulling the engine and getting it rebuilt. Doing research i hear a lot about a head gasket is cracked and air is escaping into the coolant which is causing back pressure and overheating. If you are an agreement say "I"...
 
You must log in or register to reply here.

Latest Posts

Top Bottom