Temp question; is it getting hot or bad gauge?

[dendeanda]

I recently put a 180 thermostat on my '85 350 with a stock temp gauge. When I get on the freeway and the truck is in a constant acceleration, the temp needle will go all the way up to 260 then drops down to 180-190, and never goes above 210 after that. The funny thing is that there are no signs of over heating when I pull over after the temp needle has gone that high. Its like the engine HAS to get that hot for the thermostat to open for the first time. Its onle a one time thing for the day.

1. Is my truck really getting that hot, or is my gauge bad?
2. If it IS getting that hot, why?
3. If the gauge is bad, is there like a bad wire or something?

 

[jhellwig]

I'd say that your thermostat is starting to go bad. Cheap easy fix.

 

[rjfguitar]

I would say you got a bad thermostat. It happens, bad stats out of the box is fairly common. Get that sucker out of there and exchanged for a new one! Getting up to 260 will ruin the motor if it is allowed to stay there long enough. I think Iron heads start to crack at 280.

Lots of thermostats will do that, but usually open after a 15-20* rise over the stats setting when it's opening for the first time that day. My Dodge Cummins does the same thing, lets it go to about 205* at the most and comes back to 190* and stays there. Your new stat is just staying shut for WAY too long, allowing a whopping 80* rise before it opens.

 

[hi pinion]

Now, i went trough a similar situation, i replaced my radiator 1 yr ago, it was fine,, for a while,, then i started having roblems again,,,, i replaced= The stat, the heater core, all the hoses, and it still did it,,,,,,


















I finally decided to replace the radiator again, because it was under warrantee, i knew it wasnt the stat,,, or the hoses, or the heater core,
i figued "what the heck",,,,and that was it A PINHOLE LEAK IN THE RADIATOR!!

dont cancel out the radiator man. Mine diddnt appear to even be leaking and it was still over heating, everythings fine and dandy now.

BTW,,,the "new raditor " i got before i replaced the one i have now was only like 8 months old. Might try that .


Jacob


Oh, also,, the jumping needle could be right,,, there might be a loss of pressure in the system somewhere, allowing it to heat up like that.

 

[mudslinger99]

My truck started doing the exact same thing as yours..... I had replaced my radiator not long ago so I ruled that out..... I changed the thermostat that night and it did it again the next day..... I ended up replacing my thermostat a total of 3 more times.....I had picked up all of the thermostats at the same store.... I explained my situation to the parts guy and he said I wasn't the only 1 having that same trouble with the new thermostats from his store.... He advised me to go to another store and get 1 from them and try it.... Well as it turned out that was my trouble the 1st store had got a bad batch of thermostats..... The new 1 from a different store is working fine since I installed it a few months ago.... So maybe you should try 1 from a different place then where you got that 1 from and see if it functions like normal....I hope you get it straightened out as I know it can make for a tense ride to work... Good luck