Coolant questions

[Logan R]

I have recently done a coolant flush on my 90 c1500 with the 5.7. I used a lot lot of water and some Prestone radiator flush stuff. After adding about 1.5 gallons to the radiator (after I drained water) and to the resivor thats all it took. Drove it for a while ran the heater and it still didn’t take much, also installed a 180 degree thermostat at I felt 195 was a little too hot for my liking. And I plan to only use this vehicle when there is no road salt. Any suggestions if im missing anything? And does everyone think that a 180 degree thermostat is a good idea for my type of driving. Thanks!

 

[PlayingWithTBI]

After adding about 1.5 gallons to the radiator (after I drained water) and to the resivor thats all it took. Drove it for a while ran the heater and it still didn’t take much,

Did you drain the block too? The Knock Sensor near the starter is screwed in to the water jacket. You may have to stick a wire inside the hole to break up the crud inside before it starts draining. There's a drain plug on the driver's side too.

And does everyone think that a 180 degree thermostat is a good idea for my type of driving. Thanks!

A 180° T-Stat will work but, your emissions may not pass, you'll be high in HCs.

 

[Logan R]

Ok, well I live in a state that we dont have emissions tests or vehicle inspections in general. When I drained the system I opened the petcock on the drivers side and then took the lower radiator hose off and got a good amount of water out of there too. Also during this whole time of cleaning out the system there was no thermostat in the motor. I have since installed one once I started to fill it up

 

[Schurkey]

When I drained the system I opened the petcock on the drivers side

"THE" petcock? On the driver's side of WHAT?

Guessing it's on the driver's side of the radiator.

It's silly to "flush" a cooling system and not drain both banks of the V-type engine (V8, V6). There's a gallon or more of flush water still trapped in the block when the radiator is empty. As said, the knock sensor ahead of the starter motor on the passenger side is the block drain (it goes back in with sealer on the threads, and a specific torque spec.) There's an iron or steel hex-head (9/16 wrenching surface) plug on the driver's side. Again, sealer on the threads and a torque spec. It's common to pull one or both plugs out and get no coolant draining, because there's so much sediment at the bottom of the water jacket that you have to poke a screwdriver or awl through the "crust" to get to water.

Probably also means that the antifreeze protection is crap--antifreeze too diluted. Which means you still need to pull the block drains, and basically start over with the coolant refill. Always pour the correct amount of antifreeze into the engine (saving enough for the overflow bottle) BEFORE adding water.

"Road salt" means NOTHING when it comes to the cooling system, except for potential corrosion of the radiator air fins.

there was no thermostat in the motor. I have since installed one once I started to fill it up

You should pull the 180 'stat back out, and install a proper 195. The computer programming along with the clutch fan are designed for 195--200 degree engine operation.

 

[Supercharged111]

Ehh, 180 won't mess anything up from a drivability standpoint. It's close enough to 195 that the truck won't be quirky or have fits in closed loop. I've found the 350 holds about 2 gallons by itself, at least my LT1 does. Can't imagine it being much if any different. That's a good half or more of the total coolant capacity. Draining and refilling the radiator as a flush is about as effective as doing the same to the brake fluid reservoir without then bleeding the system. Or a filter change and refill on the trans. Lots more nastiness still in there.

 

[Logan R]

Ok well the book says there is 18 quarts total in the system. Does anyone know where the location of the drain plug for the block on the drivers side is? And yes I uses the petcock on the rad.

 

[Supercharged111]

Same general area as the knock sensor on the other side.

 

[Schurkey]

On my own vehicles, I remove the iron/steel block drain plugs and install a brass draincock instead.

Makes things much easier the next time I need to drain the coolant.

'Course, that doesn't help on the side that has the knock sensor in the drain hole.

 

[Logan R]

Yea, in my trucks fashion took a 9/16 half inch drive socket and ratchet out there and it was rusty and bécame rounded off like almost every other fastener I feel like I’ve touched. Extractor socket here I come. What drain valve did you use for the drain bolt side?

 

[thx1138v2]

IMO, the 180F thermostat is too cold. It will run OK but its going to cost you in gasoline.

I did a chart on the coolant temperatures some time ago. It's posted below. The thing to keep in mind is that water boils at 212F but you won't be running only water since the water is diluted with antifreeze which is mostly glycol with some added chemicals to keep every thing (seals, etc) lubricated properly. So at 50% water and 50% antifreeze the mixture will boil at about 266F rather than 212F. So I would stick with the 195F thermostat. And the 50/50 mix is good down to about -36F so there's no need to change it in the Winter unless you are in a really cold climate.

These engines are designed to run at warmer temperatures. I had to change the thermostat out in my wife's Ford Explorer so I just took the thermostat out to get it home. It ran terribly all the way home. The best I could do on the freeway was 55 MPH with the pedal to the floor. As soon as I put the new thermostat in it ran fine.