Radiator spiking

[Hpimichael02]

Hey guys so today driving home my efan is on and working and blowing the right direction , and it was goin to 215-225 while driving and in a little bit of traffic , any ideas I think my radiator cap is goin bad cause this be it ?

[Trail X]

Is that by scangauge or by dash gauge?

[Hpimichael02]

Dash gauge , but the engine it self was much hotter than normal

[chevycrew]

radiator cap or thermostat.


I have the opposite problem. Mine wont go above 175 on the dash gauge (heater sucks because of this), full fluid, ect, guess I get to add a thermostat to the list.


Anyone know if the factory thermostats are fail safe? or commonly stick in the open position?

[The Roadie]

I6 thermostats generally fail slightly open, the coolant temp stays low, and it throws a P0128 code. Many folks change the sensor instead of the thermostat, but statistically, after 6 years on the other site, I think 90% of the reports are solved by the thermostat only.

V8's often run hot if they haven't been burped, and they added a bleed valve at the top of the piping just for that the I6 cooling systems don't need.

[Trail X]

In my experience, the dash gauge is set to read lower than actual temps to keep people from being overly alarmist. So 225 probably means 230 0r 235 in reality. Try out the cap first, simple easy first attempt. I doubt it's the thermostat.

Steve, I'd bet it's the thermostat, sounds very similar to when mine went out. PITA to change.

[chevycrew]

Yay! Ive had it a week and radiator and thermostat are both on the list...

But the peace of mind of new parts will be a plus.

[Hpimichael02]

Well my truck still over heats a little, I went to feel the air flow through the radi and it's not as strong as it was in the cold weather would the thicker air pose an issue??

[bgwolfpack]

Well my truck still over heats a little, I went to feel the air flow through the radi and it's not as strong as it was in the cold weather would the thicker air pose an issue??

Did you change the cap or the thermostat? If you did and this is still the problem, you may need to check the sending unit for the e-fan and make sure enough water is in the system. IMO

[djthumper]

What troubleshooting steps have you tried?

[Trail X]

Well my truck still over heats a little, I went to feel the air flow through the radi and it's not as strong as it was in the cold weather would the thicker air pose an issue??

Are you sure the fan was commanded to the same speed? The air temperature (which I assume is what you mean by thicker) shouldn't affect airflow volume.

[Hpimichael02]

It's a hardwired efan so it's always on , and changed the cap but not the thermostat , before I do that ima remount the fan to actually on the radiator instead of how it is now,

[DJones]

I have an e-fan and a couple of weeks ago my temperature was reading about 220 (as per scangauge) because the temperature probe fell out. Nobody has explained to me the e-fan/thermostat connection. If the thermostat went bad how would I know? The temperature is at a fixed setting.

[Trail X]

I have an e-fan and a couple of weeks ago my temperature was reading about 220 (as per scangauge) because the temperature probe fell out. Nobody has explained to me the e-fan/thermostat connection. If the thermostat went bad how would I know? The temperature is at a fixed setting.

If your thermostat failed open, your temps would never get to 200, unless you were sitting still for a really long period of time.

[Hpimichael02]

thanks for all your input but i found the issue- the issue was the overflow box/ expansion box was completely empty no fluid in there - filled it and the heating issue went away

[Zero]

This sounds odd. Isn't that box just an overflow? Could someone please explain how the system works, and why this may have fixed his issue.

Is it a simple matter of pressure or vacume for the cooling system?

[bartonmd]

This sounds odd. Isn't that box just an overflow? Could someone please explain how the system works, and why this may have fixed his issue.

Is it a simple matter of pressure or vacume for the cooling system?

Yes, the burp bottle is just an overflow that keeps the radiator at full capacity, and keeps it from sucking air in (Dexcool doesn't like air in the system, AT ALL)... If filling the burp bottle solved the problem, the radiator was probably 1/2 empty...

Mike

[Zero]

Just checked mine, and it's empty. Hahaha. I'm due for a full flush sometime soon anyways. And I think my thermostat is stuck partially open. Cause I almost never see water temp any higher than 92c, more often it's around 88-89c

[soldier32mp]

LOL mine did the samething and the that was the last thing I looked yep almost bone dry ha ha ha the simplist things we overlook..