I replaced the radiator and t-stat today. Now the temp.is going up and down. it goes to the line before the 210 mark then back down to the normal spot. it will do this while driving and just ideling. I thought I bought a crappy t-stat so I got another one different brand (failsafe one). I bled the hell out of the system. Let it burp with the radiator cap off with the heater on high. I have done radiator swaps before but never had a problem. Any suggestions??
up and down temp.
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This actually seems normal to me. I did this same thing in a 95 I had and it'd go between a high of 200(or slightly higher) and back down to 180(or slightly lower) after the radiator and tstat change.
96ProCompTahoe
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mine stays around 180-190 all the time once the t-stat opens. new rad. hoses, t-stat, water pump, no bouncing here.
Moving up and down continually is not normal.
Is your overflow/reserve tank filled to the line and that hose attached to the radiator? How old is the radiator cap? Replace that with a Stant for $11.00 if it's more than a few years old, make sure the radiator is holding pressure.
With the cap off, squeeze the top hose slowly and see if you can burp anything when it's cold. Put the cap back and leave it on there, don't remove it again. Drive it for short trips, just to get the t-stat to open. Park the truck and let it cool down. Check that overflow tank and make sure it's at the line for hot or cold.
Is your overflow/reserve tank filled to the line and that hose attached to the radiator? How old is the radiator cap? Replace that with a Stant for $11.00 if it's more than a few years old, make sure the radiator is holding pressure.
With the cap off, squeeze the top hose slowly and see if you can burp anything when it's cold. Put the cap back and leave it on there, don't remove it again. Drive it for short trips, just to get the t-stat to open. Park the truck and let it cool down. Check that overflow tank and make sure it's at the line for hot or cold.
retorq
Full Access Member
I did a Vortec swap and have been chasing down a cooling issue ... the temp up and down is definetly NOT normal. My thermostat bypass is kinda screwey, I drilled a few hols in the lip of mine and that helped a little. Still gets hot enough to kick the fans on but registers 180ish to the computer.
2K6TBSS
Member
I am experiencing the same problem with my 99 Denali. I replaced the intake manifold gasket, and since everything was already out (or very easy to access) I did a coolant system refresh. After bleeding the system, I noticed the gauge was going from about 210 to under 175ish.
I hooked up my scanner and looked at the coolant temp live data and it was sitting right at about 185, even when the gauge was reading 210.
Is this "normal" probably not, but I know that in my instance the vehicle is not running with drastic temp changes, even though the gauge is telling me different.
I hooked up my scanner and looked at the coolant temp live data and it was sitting right at about 185, even when the gauge was reading 210.
Is this "normal" probably not, but I know that in my instance the vehicle is not running with drastic temp changes, even though the gauge is telling me different.
SunlitComet
OBS Jedi-Do Good
What condition is your fan clutch in as well?
Sweet_N_Low
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Temperature sending unit?
NorCalBryan
Member
Wouldn't the ECU get the temperature from the same place, though?
---------- Post added at 12:49 AM ---------- Previous post was at 12:48 AM ----------
...nevermind, I was reading 2K6TBSS response.
fyremanpat
Fyremanpat
Is it possible that there still might be a little bit of air in the line?
ok...i fail to say I do have a new rad. cap on it. this morning I could hear a few bubbles go thru the heater box under the dash. So after work I stopped by a steep boat ramp to try to get the air to come up,it helped a little but still have the same issue. I also pulled up on the red lever on the radiator cap to relieve some air but it only seemed to help a little for a moment then back to the same bouncing. On a side note coolant DIDENT come gushing out like I thought it would. I only got a little to squirt out. is that normal? (it was at operating temp.)
The fan clutch seems to be fine. no movement in it.
The coolant tank and the hose for it are clean and clear
The fan clutch seems to be fine. no movement in it.
The coolant tank and the hose for it are clean and clear
fyremanpat
Fyremanpat
You might not have enough coolant. It definitely should have come out.
retorq
Full Access Member
That sounds overfull ...
fyremanpat
Fyremanpat
you can have a clog in the line from the over flow and be full to the neck with a less than full coolant system. When you crack the cap at temp it should have gushed out...ps you probably shouldnt do that..Ive see WAY more 2nd and 3rd degree burns then I would like to cause of that. (Ive been a medic for 9 years)...but it definitely seems like you have a bubble some where
Ya, I am thinking it has to be a bubble somewhere. I will just have to keep trying to bleed it. The upper hose is hard but when I release the pressure from the cap the hose goes back to feeling normal. so its got to me air.....I hope.
fyremanpat.....Your right I shouldent be letting the pressure out while at temp. I did have 4 rags covering the cap when I did this. (not that its much better.)
fyremanpat.....Your right I shouldent be letting the pressure out while at temp. I did have 4 rags covering the cap when I did this. (not that its much better.)
Sweet_N_Low
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Maybe, wasn't sure whether the gauges were mechanical or electric
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