2005 5.3 cooling diagram

[engairuph]

Would anyone have a diagram of the cooling system for a 2005 5.3? Just got it running today and at the muffler shop but water is not flowing. Just had a brain skip and ran the hose like the old 350 and had to get the overflow tank so need to know correct flow and location for everything.

[mongocanfly]

Should hook up just like the sb. Suction hose on bottom of radiator to water pump...off the top of engine to the top of the radiator..it could just be airlocked...mine was,I had the same issue. I took the top hose off and poured the block full...that fixed it for me.

[BR3W CITY]

These don't cool the engine the same way the SBC doesn though. It won't fill with coolant if you have a thermostat in place unless its "open', so you can't just start filling the radiator and wait for all the bubbles to come out.

You can back fill it from the top radiator hose, or you can pour hot water (or lightly torch) the area near the tstat to get it to click open, then it will siphon from the resevoir/tanks.

Since you've already got some juice in the radiator, try warming the tstat area up and keeping an eye on the level. There is a noticeable volume of fluid between the heads and blocks waterjackets, so it will drain the radiator most of the way if it was sitting dry. I've also seen guys jack the front ends up to extreme angles while filling to try and force a high point for the air to bleed out. Depending whether your running a resevoir or an overflow, the way you choose to bleed it will change just a bit.

They are notorious for trapping air, so don't be shocked if you have to try a few times (or a few ways) to get it all out. Even then, keep an eye on the temp gauge the first few startups and make sure the gauge isn't bouncing or showing other signs of pocketing.

[mongocanfly]

I was also told I could undo the rubber hose on the steam bypass tube to let the air escape but I had already deleted mine which is why I undid the top rad hose.

[BR3W CITY]

Originally Posted by mongocanfly

I was also told I could undo the rubber hose on the steam bypass tube to let the air escape but I had already deleted mine which is why I undid the top rad hose.

Do you mean the steam bypass from the radiator to a vent tube, or the actual steam hard lines that go head-head?

Please don't delete the hard steam lines, you can hotspot a head or even crack one doing so. Their purpose (while annoying) is beneficial to the motor.

[crazy longhorn]

You need the front steam tube, hooked to the highest spot......my understanding,is that cross the front is "good to go".....hell, the 02 Silverado only has across the front (factory)The 00 5.3, has the tube s brazed shut, to fit the edelbrock intake in my 69 longhorn. Fill from the top hose....that said 2 times before

[mongocanfly]

I questioned deleting the steam tube also but the guy I got my 6.0 from does ls swaps for a living and he said it was common to delete the steam tube. He says it wouldn't cause any problems....I guess ill find out.

[Custom 68]

I have found it is almost always necessary to add your coolant to the top radiator hose into the engine. These seem very prone to the air pockets.
I know that was mentioned above but to save the hassles or issues I would just fill some thru that top hose right into the engine.
David

[BR3W CITY]

Originally Posted by mongocanfly

I questioned deleting the steam tube also but the guy I got my 6.0 from does ls swaps for a living and he said it was common to delete the steam tube. He says it wouldn't cause any problems....I guess ill find out.

You might be referring to the TB heater line, which is a small coolant line that runs through the bottom of the TB. Its a coolant bypass to heat the TB in winter...which IS super common to delete.

Even if he does LS swaps for a living, I can tell you from the source, it is not a good idea to delete the steam lines on the heads, you need at least one. The cars usually had a front and a rear steam crossover.

If you ever got the motor hot enough to boil over, or it didn't have a place to vent, it will pocket the air in the highest point on the water jacket in the head. You can hotspot the head, increase chances of a blown HG, or risk cracking the head if its allowed to heat up that much and then rapidly cooled.

[mongocanfly]

Yeah brew I wondered about that myself. We completely removed the line on the front and welded up the banjos, but left the tube in the rear. He told me as long as it had one that was sufficient...like I said I wondered about that.

[BR3W CITY]

At least with one, you know the steam could force it way out thru a path of little resistance.

If it become a problem, those are really easy to replace....you can always convert them to small NPT and run a braided line back under the intake to tie into the rear steam ports. Thats what some of the guys running LQ blocks with car LS heads if they want to keep a full steam crossover.

[clinebarger]

The steam line needs to "bridge" to both heads.

[mongocanfly]

Ok I guess ill be trying to fix mine back

[MySons68C20]

Old thread.....what did you end up doing mongo?