Hows everyone getting the air pocket out of their LS with rear radiator?

bluzuk80 · Apr 1, 2015

Having a problem getting the air out of my cooling system. Im running a LS1 pump, Griffin Radiator, coolant running through chassis. When I first fired up engine I had problems getting the coolant to flow like everyone. Ended up cracking some fittings loose and adding coolant, would run here in the shop or raising hell cutting donuts and not get over 195 with one fan going. thought everything was working great. Went to Grayrock this weekend and almost everytime I would get the front end up pretty high for any good amount of time it would get hot fast. Drop it down on flat ground, bleed the steam out of the fitting closest to the water pump, add a little water and it would be fine. Or I could just turn around and set the rear end up high and the air would move to the radiator, cool off super fast like cutting a switch on. This morning I picked front end up on lift, let it get hot and tried bleeding the air out. A lot of steam/air but it still running hot. Im thinking after you bleed it with front end elevated should it cool of right away or should it after you let it sit back level on the ground where air will got back to radiator cap??? BTW I have an LS6 intake so I blocked off the rear steam ports and have the front tied together, bled it at the ports also. Maybe adding a bleeded at the pump would make it easier to get air out? Figured once its out its out though? Any help would be appreciated.

B.DRAKE · Apr 1, 2015

Nevermind....read the whole post after I posted! molaugh

greenlion · Apr 1, 2015

PM me your address and I'll mail you a bleeder valve.

bluzuk80 · Apr 1, 2015

Thanks Adam

zjtrey · Apr 1, 2015

this is common with capped off steam ports, it'll keep happening until you tie them into the cooling system...

bluzuk80 · Apr 1, 2015

I just tried bleeding at the steam port with no luck, a lot came out at the water pump though. If you notice in the water pump pic I have spacers to make the water pump line up to the crank pulley and the WOD acc kit. One spacer is already tapped for a guage/steam port etc. Think Im going to run the steam port there :dunno:

hokie_yj · Apr 1, 2015

Re: Hows everyone getting the air pocket out of their LS with rear radiator?

The steam port should ideally go to the top of the radiator on the low pressure side. (Opposite side of the inlet) A lot of people tee them into the upper radiator hose though. I've also seen a lot of people plumb them into the water pump too. Whatever you do will be better than having them blocked off.

Another thing that I've heard causing a lot of people trouble with an LS motor is when you fill the coolant system unless you fill the block through outlet on the water pump it's almost impossible to get the air out. Again I have no personal experience with that because I haven't gotten far enough to put a drop of fluid in mine yet. But it's something I've seen brought up quite a bit.

zjtrey · Apr 1, 2015

i had steam port issues when i didn't have it plumbed in.. would overheat for basically no reason… some guys seem to get a way without it, and i've seen guys ruin motors because they didn't think it was necessary. I drilled and tapped the water pump and i've had no issues in about 3 years with it, having it plumbed into the cooling system is more important than how or where its installed in my opinion, I'm sure there are more educated opinions on the subject.

bluzuk80 · Apr 1, 2015

When I first cranked it up I filled it at the water pump, temp sensor and filled the tubing up as much as possible. really helped out

hokie_yj · Apr 1, 2015

Re: Hows everyone getting the air pocket out of their LS with rear radiator?

I completely agree, anything is better than just having them capped. Capping the rear ports is normal, the truck motors came that way, but the fronts should be tied together and tied into the cooling system somehow. I can't remember the vendor but I found a kit on eBay that converted the fittings to -4 and came with a hose and tee fitting to tie them together.

bluzuk80 · Apr 1, 2015

Update After bleeding what I could out of it at the pump outlet and steamports I took the fitting loose at water pump and added about 1/2 gallon of fluid. fired it up, bled some more air out. Let it warm up till fan kicked on at 195. Then I picked up front end to 75 degree angle. Took exactly 3.5 min to get to 220. let it back done nearly level and cooled back down to 195 in less than 30 seconds. Most of the air has to be gone for it to cool that fast. Im sure I still need to plum steam port to water pump but thought that was good progress. Really don't wanna plumb it all the way back to radiator.

hokie_yj · Apr 1, 2015

Re: Hows everyone getting the air pocket out of their LS with rear radiator?

bluzuk80 said:
When I first cranked it up I filled it at the water pump, temp sensor and filled the tubing up as much as possible. really helped out

I would definitely try plumbing the steam ports to the water pump then. I think you'll see a big difference.

Here's the kit like I used. I don't remember it being that expensive though. There are some on there that are a whole lot more than that one though.

http://pages.ebay.com/link/?nav=item.view&alt=web&id=221727049940

zjtrey · Apr 1, 2015

you can bleed it all you want but it'll still build up steam over time, IIRC it has something to do with how the coolant flows through the heads and air pockets are nearly impossible to eliminate.. just tap into the port on your water pump spacer and forget this issue..

bluzuk80 · Apr 1, 2015

I'm about to tear it down and block one port off and run the other to the water pump spacer. Thanks for the help guys. And Hokie I can't wait to drive your buggy ;D

zjtrey · Apr 1, 2015

I think you should put a T in that crossover instead of blocking one off… never seen just one side blocked off

hokie_yj · Apr 1, 2015

Re: Hows everyone getting the air pocket out of their LS with rear radiator?

bluzuk80 said:
I'm about to tear it down and block one port off and run the other to the water pump spacer. Thanks for the help guys. And Hokie I can't wait to drive your buggy ;D

If I ever get it finished you're welcome to beat on it. If I get to drive yours too. Lol.

bluzuk80 · Apr 1, 2015

Deal!

bluzuk80 · Apr 1, 2015

got that kit ordered thanks again guys

hokie_yj · Apr 1, 2015

Hows everyone getting the air pocket out of their LS with rear radiator?

You're welcome! Hope it solves the problem, I feel pretty sure that it will.

redneckengineered · Apr 1, 2015

This is gonna blow y'alls minds but I run my buggy with all the steam ports blocked and it never overheats. Did it in a pinch to get running years ago when the buggy was new and never had the need to change it. That being said, go ahead and plumb it into the water pump there as that is a good way to do it. No need running it back all the way to the radiator. Have you tried calling Adam? He built your chassis and knows all the tricks for getting the air out. I know when he fills the system at his shop he uses a vacuum pump.