Cooling system issues

My 2008 4.0L (149k miles) has been giving me issues with the cooling system, the first issue noticed was a gargling sound under the dash at start up and after shut down, and intermittently while driving. The truck is fitted with a Flex-a-lite electric fan kit which has an unusual (to me) reservoir which I first honed in on as a possible issue as it was empty when I first started to troubleshoot. The next thing I did was open the radiator and saw the level was a little low so I added some coolant. I decided to do a full drain flush and refill. I didn't have good luck getting all the flush solution out so it took quite a while longer than I expected. I noticed the liquid coming out was ever so slightly milky but the oil was very clean. I followed steps I found on here to drive the vehicle for a bit, let it cool and remove the cap again and squeeze hoses to help get bubbles out. Did this NUMEROUS times and now a few weeks have passed and the gargling is starting back up again. I noticed the hose clamp was maybe a 1/4-1/2 turn loose on the upper hose into reservoir. I also noticed the hose clamp on the large hose going into the rad. Over the time since doing the flush and even today was noticing a discharge out of the overflow tube from reservoir in the morning. Talked to the previous owner and he informed me he did replace the water pump and the thermostat. The Flex-a-lite turns on when the coolant reaches a certain temp and I have the switch turned all the way to the lowest temperature. I noticed the fan is not always on when I shut the truck off but seems to cycle on after shutdown for some reason...

 

When you say discharge, is it coolant or air bubbles?
Is the coolant level staying full in the radiator?
Why did the PO install an electric fan?

The fan might come on due to the fact that coolant and engine bay temps can be come warmer when an engine is first turned off. The engine can heat soaks with out air flowing across it. It depends on the cooling fan set temperature.

I would look at the reason you are low on coolant first.

 

Thanks for the reply TnSHOOTER, The previous owner stated the AC did not work as well as he expected in AZ traffic... but with the flex-a-lite the issue was remedied. Toyota tech recommended going back to stock fan...What do you recommend?

The coolant level is staying just about full in the rad but the res kept emptying...I think the hose clamp being ever so slightly loose could have contributed to that but I will see over the next few days. Not exactly sure where the fluid was coming out at but most likely the overflow tube on the reservoir.

 

It not an uncommon complaint that the AC on these trucks isn’t good at slow speed or idle.
I have no experience with an electric fan on theses trucks.
But it seems 50/50. I personally would stick with OEM style.
I don’t have an issues with it, and I’m not in traffic all the time.

I’d have to look, but last I remember these trucks run constant tension clamps.
They don’t have screw clamps. This isn’t a bid deal, but I like the other style better.
Anyways, if you didn’t see signs of an external leak at the clamp it probably wasn’t the problem.

When the engine cools, it can draw coolant into the radiator.
You still may have another leak. I’d still pressure test the system, and look for leaks.

Again, did you see signs that the clamp was leaking?
It’s usually pretty easy to see signs of the leak with the type coolant Toyota used in these trucks.

 

if the clamp was leaking it was a very small amount will watch it closely for the next few days and let you know