My Blazer is possesed

[wheels87k5]

87 K5 350 TBI w/headers....New block, new heads, new radiator, new thermostat, new clutch fan, new water pump, timing adjusted, new sensors....WTF, it still overheats....it doesn't peg the temp gauge, but it rides just to the left of the red. With all the new goodies, the water should flow very good. There's no blockages, and it's full of fluid. So again, I ask, WTF....is it possible it's a bad or wrong waterpump?

 

[kyser_soze]

How about hoses? Weak hoses can collapse.

 

[Copasetic]

Is it possable that there may be air trapped in the system? Maybe your gauge is screwy?

 

[wheels87k5]

Forgot....new hoses too. I just tried something that I hadn't done yet...when I turn the heater on full blast, it brings it down a notch...but not to 210 or close to it. When I turn the heater off, it goes back to the redline.

 

[Jason4x4]

where did you get the water pump? When they went from multi belts to 1 serp belt, the water pump rotation changed, it is possible that you have the wrong waterpump. They both look the same from the outside, but the impelers go different directions.

 

[wheels87k5]

Took it for a short drive with the heater blasting....it would go to red line and stay when cruising at 45-50 mph. And when you slow down to a crawl, the temp would creep down to the notch between 210 and 260, but would'nt stay there for long, it would creep up toward the redline again.

 

[K-5 Bomber]

Pull the T-stat. Sometimes they're bad right out of the box If your problem goes away, test the T-stat in a pot on the stove with a meat thermometer in the water. Mine did the same thing until I swapped it out. No problems since.

 

[JIM88K5]

Make sure the thermstat is right side up.

 

[K-5 Bomber]

Yeah, and not pinched between the housing and the manifold...don't ask

 

[Thunder]

Pull the t stat ad see how it runs. If you are still overheating you have the wrong water pump. 87 was a change over year there are 2 diferent pumps for that year K5s. Some had the serpentine belt pumps that are reverse rotation and some had regular V belts and the pumps are standard rotation. You must have the type water pump to match your belt system or it will not work

 

[wheels87k5]

I bypassed the heater core to make sure it wasn't that....and it wasn't...I bought a second t-stat this morning and no change. I called about the water pump and gave them the numbers on the box. It's the right one unless the reversed prop pump was put in by mistake. But I did a thermometer test at the radiator. The thermometer never got above 200 degrees when the truck temp gauge needle was next to the red line. The red line is next to the 260* mark. Looks like my gauge is messed up. Is there a ground wire I might have missed, that would cause a bad reading, when I installed the new engine? If not, then I need a new gauge. Do they make a replacement gauge to fit where the stock on is? Or is ebay in my future? Maybe salvage yard? Thanks for all the help.

 

[dyeager535]

If you are sticking with stock gauges, someone on here can likely sell you one, easier/cheaper than buying new.

Post up in parts wanted would be my suggestion.

 

[ryoken]

The thermometer never got above 200 degrees when the truck temp gauge needle was next to the red line. The red line is next to the 260* mark. Looks like my gauge is messed up.

I called that one in your other thread....