Odd Temp. Issues

Hello folks!

I've started to develop some odd overheating issues on my stock 96. I'm not sure if it could just be the massive heat wave in the midwest these days, or if I have legit problems. Here's how it goes:

Start it up, drive for ~3 miles under 30mph to get out to a county road. Temp gauge reads the temp fine, it slowly creeps up to 210, and suddenly drops down to the middle tick, about 155. This repeats exactly 1 more time. Never has this happened only once, never 3 times, always 2.

After the jog to the CR its about 7 miles to the interstate, going around 60mph. Temp holds tight right below 210 the whole drive to the interstate.

Enter interstate, cruise ~10 miles on fairly flat road going 70mph. Temp gradually climbs to about 225 or so.

Exit highway, its 2 stop lights to work. If I hit both reds, its easily 250+ by the time I pull into my lot. If I get both greens, its maybe 240-250.


About 3000 miles ago I drained my radiator (drain plug is in a terrible location) flushed it out with a garden hose, and refilled. The crud coming out didn't seem terrible in my opinion. It wasn't bright green, but it wasn't brown as dirt. It doesn't seem to be loosing any coolant, but its a nice shade of baby poop brownish green.

Without dismantling the block, I cannot see if its a blockage somewhere internal. So I'm hoping anyone has any ideas, or can recommend a good after market water pump & radiator and such.

Thanks in advance

:smoker: C. Numb

I would say make sure your temp sensor and thermostat are functioning correctly. I had temp gauge fluctuations and it turned out to be a bad temp sensor. Hope this helps!

You probably have air in the cooling system. Put the truck on ramps, remove the radiator cap, and let it warm up to operating temp while in that position. Be sure you have the heater on to circulate coolant though those passages. Occasionally squeeze upper hose to push out air bubbles ( beware of Fan!). Top off when engine reaches operating temp, and put the radiator cap on. Be sure coolant bottle is up to "HOT" line with coolant and hose is connected.

Back it off ramps and let it cool. The radiator should pull coolant from the bottle as the system cools.

-Ron

is your fan clutch fairly new? radiator cap?

*sniff sniff*

I smell tech.

http://naxja.org/forum/forumdisplay.php?f=44

dang, can I move this to the correct area or must someone else do it?

got ya moved to the right place :thumbup:

I just went through a similar problem on my 96. I ignored it for over a year until it finally showed up as a DTC a few weeks ago. The code pointed to the coolant temp sensor being out of range. I bought a new one for $22 at Autozone and it seems to have cured the problem. It can also affect your fuel economy as well as the ECU uses the temp sensor to determine when to enter closed loop mode.

Try this first.... It's worked for two of us so far as I know, and costs nothing.

Remove the connector at the temp sending unit.
Clean all contacts well using whatever method (steel wool, contact cleaner, sandpaper, etc.)
Smear some di-electric grease in it and push the connector back on.

Hopefully problem solved for zero dollars.

Coolant Temp sensor!!