Burped coolant incorrectly ? 1996 5.7

[Isaacmacleod]

Hello all, this is my first truck, a 1996 Chevy c1500 crew cab long bed, 5.7.

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I just replaced the water pump, and fan clutch,
The upper and lower radiator hoses, thermostat,
And the heater inlet and outlet hoses.
At 54,000 miles.
I bought all gm genuine parts, and watched every YouTube video I could on the process.

I even fixed a ground wire which connects the rear passenger side of the engine block to the frame.

LONG STORY SHORT.

I replaced all the aforementioned parts.

Then on level ground, using the fancy no spill funnel,

I refilled with 50/50 dexcool until it stopped filling up, then started the engine and let it warm up with the fan on low, heater on high.

Upper radiator hose got hot, I squeezed the hose to burp it, got lots of air bubbles out of the radiator cap, more coolant got sucked in.

Then after about 15 minutes, no more air bubbles, steady coolant level.

Turned her off and refilled overflow reservoir, replaced radiator cap (with brand new one).

I thought I was done! Job well done I thought.

But when I tried driving the truck to work later that night, I noticed immediately when starting the engine, it jumped more than usual, you could literally see the front of the truck bounce up when I started it, and it sounded louder, more metallic gear noise.

Then when driving it, gurgling sound. Sloshing water sound coming from heater core area, (passenger side of cab). AND a faint but scary clicking noise.

I noticed at this point the coolant reservoir was empty.

P.S ; I read in the service manual that upon EVERY coolant drain and refill on this make and model you must add two AC DELCO coolant sealant tabs into the radiator or else the water pump may leak much sooner! This was information I didn’t see ANYWHERE else, wanted to share that here.

But anyways I’ve now reburped it three times following the same procedure. A little bit more air bubbles cames out each time.
I even jacked up the front passenger side a bit to raise the radiator to the highest point and help air escape.

I also never opened the drain plug on the engine block as I didn’t know it existed. I’m guessing I now have air pockets stuck In the heater core and engine block which would explain the rough start, noisy ride, and sloshing sound ?

Any advice greatly appreciated

My main goal in life is to make this truck last longer than I do damnit. and I’m 21

 

[rebelyell]

Nice looking '96 truck ... and Only 54K miles, sweet!

Even with only 54K ... Perhaps your block and/or heads and/or radiator and/or heater core and/or overflow bottle etc etc are clogged or fouled with sediment and sludge (DexCool has been known to offend; reference TSBs). Often times, a simple water flush or even a flush w/ common FLAPS chemical cannot cut through it.

If system's heavily constipated, and a flush won't cut it, CLEANING w/Strong chemicals may be required (like what WERE once on FLAPS' shelves; but are no more). Google discontinued Prestone AS100 aka nowadays weak reformulated GM 12346500 and how their original content of a Strong Acid is Oxalic acid (DAP wood bleach crystals) with a Strong Neutralizer being Sodium Carbonate powder (Arm & Hammer Super Washing Soda). About 1999, GM issued a TSB (#99-06-02-012D) on these matters; detailing a Very good, comprehensive procedure for CLEANING (not simply flush). Must wear eye protection & gloves; told ya! Done right, it takes about a half-day of run @ hi-idle, cool down, repetitive phases. I don't care much for DexCool; instead prefer final mix of conventional Prestone + deionized water. Per the TSB, replace Both rad cap & T'stat with New after those strong chemicals. I've run entire procedure; it works very well w/ great results! Oh, ya HAVE TO open those block drains found on Either side of block; just above oil pan rails. IIRC, one or both have a knock sensor screwed in there (and functioning as block drain). If block drains don't flow freely, jiggle-thrust some coat hanger in as far as ya can.

 

[Isaacmacleod]

Update: I drove the truck to school tonight because the coolant stayed in the reservoir overnight finally.

The brand new fan clutch sounded like it was engaged for almost the whole ride, especially in the first two gears starting after a stop. The jet engine noise would get louder as RPMS increased, then after it up shifted up a few times the noise disappeared.

It sounded good on the highway.

But the time I got to school, everything sounded good.

Maybe just the new fan clutch breaking in???

However the temperature stayed at about 180-200. Never even reached the middle of the gage.

Whereas before changing the thermostat/ water pump it would rise to the middle and past easily when warmed up.

Is this related to fan clutch being overactive?
What is the optimal operating temperature?
Should I even be worried that the temperature seems lower than before? Or maybe that’s a good thing?

I definitely should have flushed the coolant out but I actually paid a shop to do that when I bought the truck, so I figured a simple drain and refill would suffice this time.
I never touched the drain plugs,