Running a little warm ? Air in system ?

[6600DURAMAX]

Truck isn't mobile yet - working on the hydroboost brakes ( bleeding them takes forever) - so I have been starting the truck up and letting it run for three to four minutes then shutting it off - doing that a few time noticed the temp around 220.

I did only notice that one of the two fans were kicking on so I am asking my tuner if thats in the settings or if there is another issue but it just doesn't seem like it should be getting that hot just idling .........

Specs - Blueprint LS3 -408
Aluminum radiator with dual fans
185 degree thermostat

Do I have air in the system ? what gives ?

[mongocanfly]

Did you fill the engine with coolant or just the radiator?
You could have a air pocket..
I always fill the engine thru the top radiator hose until all air quits coming out, then reconnect hose and fill radiator..
Also do you have the heater hoses connected? Blocking those off or having them valves off where coolant cant get around the thermostat will cause it to run hot quick

I had the same deal on my C30 where only one fan would run.. what we found was my ecm was designed to support only one fan.. they reprogrammed it so both fans would run. Fan 1 175deg..fan2 at 185deg..

[Joyridin]

I didn't have any problems bleeding the hydroboost system. Neither the actual hydroboost nor the brake system. The easiest way to bleed the actual hydroboost that I found was to jack up the front so the wheels are not touching the ground. Then turn the steering wheel lock to lock about 10 times. Check the P/S fluid and add if necessary. Keep doing this until the air is bled out.

If you are using a factory ECM system of some sort on the LS3, there is no way to adjust the fan temperature. You can adjust which fan comes on and whether it is a PMW system, but not the actual temperature. This is for a Gen IV system. A Gen 3 system can be adjusted.

I put an aftermarket fan set-up in both my truck and car. The truck uses a PMW system with dual fans, and the car uses a Dakota Digital fan control with a 2 speed fan. If your thermostat is 185, 220 is too hot. Both of mine run around 200.

[6600DURAMAX]

some pics of my setup

[6600DURAMAX]

I fill the radiator, then added more fluid as it went down - one thing I never thought about was cycling the heater on to ensure that the Vintage air heater core was circulating water - could that be the issue ?

[6600DURAMAX]

I also have the radiator overflow can but it doesn't have any fluid in it - do I need to add antifreeze to that ?

[mongocanfly]

Gotta fill the engine before the radiator..

Some people have no problem here but some have..
What I was told is dont block off the heater hoses..with the thermostat on the suction side,it wont open if it doesnt see hot water, it needs flow to do that..so in your case the heater control valve needs the bypass feature..not the total block off..not sure which you have..
My truck has a 165 thermostat..fan 1 at 175 fan 2 at 185..my truck never runs over 185..even towing 9000lb+ trailers in mid summer temps

[6600DURAMAX]

So trying to figure out my next steps ............should I take my upper radiator hose off and fill from it, then reattached before I start the engine?

I'll need to see if the Vintage Air valve opens when I turn the heat on - wonder if this is causing an air pocket issue

[6600DURAMAX]

What are you meaning when you say "bypass" Didn't see that in the instructions for the Vintage Air unit

[Joyridin]

Where do you have the steam ports on the heads run to? The radiator? Is the outlet above where the steam ports are located?

I have drained/filled my LS3 about 10 times and never had an issue. I fill the radiator, then fill the overflow about 1/2 way. Run it until the thermostat opens, then shut it off and let it cool. Check levels and add to both if needed. Do the same thing again. You might have to add to the overflow, but usually not the radiator.

I had one of those SS overflow tubes like you. When it got hot, it would overflow slightly. When cold, it was empty. Maybe yours is bigger than mine was, but it didn't work really well.

[6600DURAMAX]

maybe I need this in the heater hoses so the coolant has a loop and isnt deadheaded when the Vintage Air valve is closed( not requiring any heat in the cab).

[mongocanfly]

The bypass I'm referring to is the valve for the heater core..some completely block the water flow..the bypass version allows water to flow to the valve and back to the radiator..but not thru the heater core..
Like I said earlier..not everybody has a issue here , but I've seen it happen..
I had to change the water pump on my truck once before and thought I could get away with not filling the engine.. it immediately overheated..
Remove the upper hose from the radiator..I tie it up with a bungee.. fill engine til all the air quits coming out..
Even with only 1 fan running you shouldn't be overheating that quick..
My best guess is you have air trapped in the engine

[mongocanfly]

The heater valve I have works like this..

[87chevy.com]

http://67-72chevytrucks.com/vboard/s...d.php?t=836499

if you have a block off valve installed its now not OEM, youve blocked off the coolant return flow to the thermostat.

if you remove the valve from the system, then the vintage air system wont be as cold as it should be, if you leave it in there, then its, well back in the same predicimant.

option is to run some cheap aftermarket chineasium valve that will probably fail and look like poo... or run something like this:

https://www.lojkits.com/products/ls-...r-bypass-block



about as clean as it looks.

if your cheap and handy, you can braze up you own if the pex pipe fittings fits your hose



sand down the "T" with a file carefully, solder them up



ad its the same thing, little bulkier, paint it black and its almost hidden...

my bmw x5 swap