New LS3 start up but no water flow through radiator
 

Finally got my LS3 427 started but the water is not flowing through the block. All parts are new to include the thermostat and a Dewitt radiator. Temp rises but radiator is cold. This is the first few starts, so I only run it for a minute or so since the engine temp rises. First thing I think of is the thermostat but I remember seeing posts about getting the water to initially flow. thanks

Answered your other post. How hot are you allowing it to get while running? I bet not enough to get the t-stat to open

Are the fans turning on?

Don

Fans are not going because they are tied to the thermostat in the radiator. I remember this some where else so I will try this.

17. We are not ready to fill the system just yet, as you may have noticed there is no intake manifold on the engine. We will give you an update once we get the car running. Be Cool has very detailed instructions on how to properly fill the system and its too detailed to fully explain here, but here are a few things to note. Jack up the nose so the radiator is the highest point in the cooling system. Fill the radiator with the engine off. Wire the fans to run all the time, and if so equipped turn the heater on high. Then start the motor with the radiator cap installed in the loose position. Run the vehicle until the thermostat opens. When the fluid suddenly drops in the radiator, add an additional 2-3 quarts. You may need to repeat this cycle, but once topped off the second time tighten the cap. After a few heat cycles check the level one more time and you should be good.


Sources



Be Cool
Essexville, MI 48732
800-691-2667
»www.becool.com

A dewitt radiator has the fan trigger in the radiator, so unless it's flowing through the radiator, they won't turn on.

Coolant doesn't flow through the radiator until the t stat opens. If you temperature gauge isn't exceeding your t sat opening temp, you aren't running it long enough.

yup i freaked out as well. I need up putting about 3 jugs in to finally fill everything up. Just go buy a cheap temp infrared gauge and point it to the thermostat. My guess is you dont have it hot enough yet

Thanks but temp in going past 210 to 240.

I wouldn't let it go that hot again. The infrared gun aimed at the tstat will give you an indication of a faulty gauge. If gauge is ok, you have a bad stat, or some kind of blockage, ie a shipping plug left on radiator inlet, etc.
Is the TStat a GM piece? It should open, and you should see water moving in radiator before 210. If not, shut it off.

Air pocket if it goes from 210 to 240 quickly.

It does and I plan to elevate it tonight or tomorrow to see if I can get rid of it. Understand cap off?? Thanks

I agree with the air pocket diagnosis. Fill the engine through the upper radiator hose, and fill the radiator as well. Never had an issue with air pockets doing it this way.

Thanks

even though my gauge was almost pegged out the engine never got to the correct temps to open the t-stat. Use the infrared scanner and check. I also squeezed my hoses to let air pockets out. It times time but you will be fine

I also say air pocket. I've found my ls3 to be extremely sensitive to air pockets and somewhat tough to bleed whenever I'm refilling the system.

Steps I take now:
1. Jack the front of the car up.
2. Fill the engine first through the upper radiator hose
3. Then fill the radiator
4. Remove the 1/4 steam by pass line and ensure a steady flow of fluid (bleeding out last bit of remaining air).
5. Run the car with the heater bypass open and allow the thermostat to cycle with the radiator cap off multiple times.

Throughout the engine running and subsequent first cool downs ensure that the radiator level doesn't drop below the upper hose outlet at the waterpump.

Thanks will try all of this tomorrow

This may work for you as well (think some folks here and other site use this):

http://www.amazon.com/Lisle-24610-Sp.../dp/B001A4EAV0

I plan to use one when I eventually get my LS engine in my car.

Good luck :cheers:

Stupid question, but you don't have tape covering the waterpump to block interface right? I've seen it happen before to a friend that painted his waterpump.

Also I've seen aftermarket waterpumps have the impeller on backwards, fall off, or just be missing all together if it's a stock style pump.

No tape, thanks. I plan to attack this again today

I have the car elevated but not to the moon. I have started it twice and see the bubbles, this time the upper hose is warming up as is the radiator water but the temps still pass 210 and lower hose cold. I do not let it go past 210

tried elevation and also ran with heat on, heater hoses warm, lower hose cold, upper is warm, temp past 210 shut off. I think I will pull the thermo stat and test it. I tried to fill it through the heater hose but it was full or at least not taking any more fluid.

The heater hoses are warm so that's good. I bought a new thermostat, will pull and check the one I have in now. This is extremely frustrating.

Did you remove the hose at the steam vent line until fluid streams out of the steam vent (not the hose)?

Also, did you rev the engine at all once it was near operating temp (at least 2,500 rpms)?

The solution for air pockets. http://www.amazon.com/UView-550000-A...words=Air+lift As a bonus it lets you know if there is a leak in the system before you fill it because it will never reach full vacuum. Irrelevant for your problem but it will eliminate the possibility of a pocket.

Have not removed the tube and I did rev it up to 3k but it did not move. I will try removing the hose. Thanks

removed the hose from the steam fitting got fluid out via vacuum nothing changed. I will take out the thermostat today and check it and or replace it.
!^@#^^$%^$*$$(($()$(*#*#%*()**+**)_#*

I pulled the thermostat and started the car, same result except I got water through the lower hose. There must be a nasty pocket by the water jacket or????? Thanks

When you rev the engine, do it in bursts, rather than a slow steady rev. Not sure if that makes sense. I've had to do that to burp a cooling system on a water cooled sportbike when steady revving wouldn't do it.

The last thing I thought was bad was the gauge and sure enough, before the water reached a boil the gauge went to 250. Time to call auto meter, that was a hateful two plus weeks. Thanks I will let you know how the new gauge works out.

Well I checked even further about the gauge and on Auto Meter's web site they list the same symptoms I was having to a bad ground. Long story short it is a bad ground. I changed the ground and the gauge stayed at 210 while the water was boiling. Thanks for all your help, I will know tomorrow or so when I crank it back up.

http://www.corvetteforum.com/forums/...ica-kinda.html

Sounds like an air pocket. I've never had that issue on an LS, but my BMW did that after a water pump swap. It took several bleeds to get it fixed.

OOps I meant to close this it was the gauge

LOL. My bad. I read the first page and missed all the updates. Glad you found the issue.

I bought a GM crate LS2 years ago. While poking around it, I shined a flashlight up into the water pump heater hose fitting. I saw a bunch of red core sand plugging it up! I think that's why GM took it off the assembly line and sold it as a crate engine, they probably had a batch of them like that. Always take a good look at new parts.