2003 Tahoe coolant system leak or head gasket leak?

[tomloans]

Did you use oem connectors?

At first no, then realized the mistake. I then purchase OEM at the dealership. But one of them was leaking again about a month ago but stopped since.

 

[tomloans]

Decades ago on my 99 30th Anniversary Trans AM (LS1/5.7), a popular mod was to put an LS6 intake manifold on. Everyone said, buy an Oil Pressure Sending Unit - you're going to break yours putting the intake on. 21 year old me was like, nah, I got this. I broke it. LOL.

For whatever reason, I haven't broken it on the Tahoe despite having the intake off numerous times. Regardless, if the sensor is original, I recommend having an OEM unit on hand to install. So much easier with all the stuff off the top.

I am replacing everything including this one for sure. Nearly impossible to get at the oil sensor otherwise.

 

[tomloans]

Here is probably a dumb question ( but I am good at it ). I watch these videos on YouTube installing new heads. Nobody seems to care that they are bone dry. Shouldn't you pour some oil on them before first startup?

 

[iamdub]

Here is probably a dumb question ( but I am good at it ). I watch these videos on YouTube installing new heads. Nobody seems to care that they are bone dry. Shouldn't you pour some oil on them before first startup?

The bearings of the rockers should have oil or assembly lube packed into them. You don't wanna soak 'em cuz the oil can run down into the bolt holes. I guess if the engine isn't a fresh build, the oil system should still be half-assed primed so oil should get through the lifters and pushrods quickly. Definitely soak the lifters, though. I also use an old push rod to push the plunger of the lifter while it's submerged in the container of oil to purge the air out. I have two square plastic Rubbermaid containers that hold eight lifters each, vertically. I fill them up until they are submerged in the oil then plunge each one until they're solid and have no bubbles coming out. It's like 1.5 plunges each.

I always use a dab of assembly lube on each valve tip before installing the rockers. Then I pour oil all over the rockers, focusing on the pushrod ends before putting the valve cover back on.

Keep the battery on a charger and, before your first start, hold the throttle pedal to the floor and crank the engine for ten seconds. Let the starter rest about a minute then repeat. Watch the oil pressure gauge before you start the cranking, during and after. You should see a little pressure build. After that, unplug the coil packs (the big white main connector in the center of them) and crank the engine some more. This will purge the air from the fuel system as well as circulate more oil. Plug in the coil packs, clear the codes you now have from cranking with the packs disconnected, and start it up as normal. It should fire up just as it always had with no or very minimal sputtering and no or very minimal lifter ticking.

 

[mattt]

Keep the battery on a charger and, before your first start, hold the throttle pedal to the floor and crank the engine for ten seconds.

Interesting.....what does that do? Does that sequence of events prevent the engine from starting? Thanks.

 

[tomloans]

The bearings of the rockers should have oil or assembly lube packed into them. You don't wanna soak 'em cuz the oil can run down into the bolt holes. I guess if the engine isn't a fresh build, the oil system should still be half-assed primed so oil should get through the lifters and pushrods quickly. Definitely soak the lifters, though. I also use an old push rod to push the plunger of the lifter while it's submerged in the container of oil to purge the air out. I have two square plastic Rubbermaid containers that hold eight lifters each, vertically. I fill them up until they are submerged in the oil then plunge each one until they're solid and have no bubbles coming out. It's like 1.5 plunges each.

I always use a dab of assembly lube on each valve tip before installing the rockers. Then I pour oil all over the rockers, focusing on the pushrod ends before putting the valve cover back on.

Keep the battery on a charger and, before your first start, hold the throttle pedal to the floor and crank the engine for ten seconds. Let the starter rest about a minute then repeat. Watch the oil pressure gauge before you start the cranking, during and after. You should see a little pressure build. After that, unplug the coil packs (the big white main connector in the center of them) and crank the engine some more. This will purge the air from the fuel system as well as circulate more oil. Plug in the coil packs, clear the codes you now have from cranking with the packs disconnected, and start it up as normal. It should fire up just as it always had with no or very minimal sputtering and no or very minimal lifter ticking.

I think I need to send you a check! Can't tell you how much I appreciate your feedback. I also appreciate everyone else as well! Thank you all.

It was too cold today. I did absolutely nothing. I was just cold to the bone today - kind of strange for me as I am usually baking all the time. Hopefully I didn't catch COVID or something. The Cylinder heads were shipped today and should have them by Friday. Hopefully Rockauto will also deliver soon. I am going to change out the air conditioner compressor and accumulator as well while I have clean access to the compressor. It has been making noise. Had someone in town that offered the compressor and accumulator for free so I am going to install it and work my way up from there later as I dont have all the parts I want to change out as of yet.

 

[iamdub]

Interesting.....what does that do? Does that sequence of events prevent the engine from starting? Thanks.

It's a factory function- "Clear Flood" mode. Holding the throttle to the floor (it's actually above a certain high throttle open percent, but we'll just say to floor it) keeps the injectors from pulsing and the coils from firing. It's useful for when you need to crank the engine but not start it, such as to prime the oil system or when diagnosing certain engine troubles. No need to find and pull the fuel pump and other fuses.

 

[iamdub]

I think I need to send you a check! Can't tell you how much I appreciate your feedback. I also appreciate everyone else as well! Thank you all.

It was too cold today. I did absolutely nothing. I was just cold to the bone today - kind of strange for me as I am usually baking all the time. Hopefully I didn't catch COVID or something. The Cylinder heads were shipped today and should have them by Friday. Hopefully Rockauto will also deliver soon. I am going to change out the air conditioner compressor and accumulator as well while I have clean access to the compressor. It has been making noise. Had someone in town that offered the compressor and accumulator for free so I am going to install it and work my way up from there later as I dont have all the parts I want to change out as of yet.

As always- just happy to be relevant.

After doing my AFM delete (cam swap, etc.) and head work, I primed my oil and fuel systems. The engine was disassembled for three months. At the first start, it fired up immediately and without the first sputter or tick, as if it was never taken apart.

 

[mattt]

It's a factory function- "Clear Flood" mode. Holding the throttle to the floor (it's actually above a certain high throttle open percent, but we'll just say to floor it) keeps the injectors from pulsing and the coils from firing. It's useful for when you need to crank the engine but not start it, such as to prime the oil system or when diagnosing certain engine troubles. No need to find and pull the fuel pump and other fuses.

Thanks! Learned something new today and I'll be using that in the near future.

 

[89Suburban]

WHAT'S WITH THE WIRE NUTS?