CMartinez

Hi I have a express van that will take forever to get up to operating temperature. I suspect the fan to be over cooling maybe the termostat is stuck a bit open but it’s brand new so maybe it’s faulty. Can anyone point me on how to text the fan for proper operation if that’s not it I will change the thermostat

Triaged

Can you spin the fan by hand with the engine off?

Likely a bad thermostat.

mountainmanjoe

Mine takes at least 15 mins. Do you have rear heat?

A 4.8L won't put out as much heat.

CMartinez

no it’s a cargo van no heat to the back of the cargo area.

CMartinez

The fan spins with slight resistance

William Kisselstein

If everything is cold, engine, radiator etc check thermostat

If engine, hoses etc are hot before you get heat inside, either air in the heater core or a clog or restriction

MitchM

OP, how many minutes for the the engine coolant gauge to be showing the coolant is hot ? it's supposed to get to lukewarm in 2 mins. but my 3500 doesn't blow hot air into dash vents w it lukewarm. on my 07 3500 express it takes me a good 8 minutes to get hot air coming out of my front dash vents w the heat dial cranked to max. I don't get any dash heat if the little gauge is showing cold coolant.

is there a way to check if yr engine coolant sensor sending unit is working properly ?


out of curiosity can you put an OBDII on it at cold startup and read freeze Frame data when the status changes to open loop ? (I don't know if that change of loop status correlates to when you should be getting hot air from the fan out of the dash vents. anyone else know this ? )

William Kisselstein

A scanner with live data should be able to show you what the CTS is reading, I was able to do it on my 2002. The CTS in that instance had failed and indicated -68' F on a warm day.

Closed/open loop should be irrelevant, either the stat is closed long enough for it to get to temperature or not.

Mine has rear heat but I don't recall issues with getting heat from it. Might check if there's any valve that opens to let coolant flow though the core, that that is working correctly.