What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[j91z28d1]

Easy there, jdpber.

I assume you're asking where we're plumbing them in. There's a rigid plastic pipe connected to a port at the rear of the driver's side valve cover, runs forward about 8" then makes a 90° curve to go to a port on the top center of the intake manifold. You'll have to pop off the beauty cover to see it.

The catch can goes inline in this circuit. So, in terms of flow, instead of going out of the valve cover and into the intake manifold, it goes out of the valve cover and into the catch can. Then, out of the catch can and into the intake manifold. How you connect the catch can to this pretty much doesn't matter as long as you have the flow correct. That plastic port on the intake manifold is very brittle and can easily crack off if you move it much at all. Safest method is to cut the plastic pipe where it makes that 90° turn a couple inches in each direction from the bend. So, you're basically removing that bend so you're left with two straight pieces of plastic pipe- one coming from the back of the valve cover and the other from that fitting on top of the intake manifold. Then, slip the hoses of your cartch can over those short lengths of pipe and secure them with hose clamps.

IMO, the best location for the can itself is on the side of the alternator, bolted to that accessory bracket. It's easy to reach for draining and doesn't interfere with anything else.

it's probably the screw on to the cap part. pretty much every adapter I've used seals badly. if it's a loner check that it's not missing a rubber seal inside. or just not the correct adapter. some bottomed out before they seal.

useful but annoying.

 

[iamdub]

it's probably the screw on to the cap part. pretty much every adapter I've used seals badly. if it's a loner check that it's not missing a rubber seal inside. or just not the correct adapter. some bottomed out before they seal.

useful but annoying.

You replied to me. I'll tag @mikez71 to ensure he sees your response to him.

 

[mikez71]

Have bolts you can screw into the hoses? You can do the same with the nipples on the reservoir, just wrap some electrical tape around a bolt to make it a plug.

Good idea, hadn't thought about using a bolt with tape in the tank, I may do a few more tests before I return the tester.
Otherwise I'm waiting for my new tank and hopefully will find some proper sized caps.

 

[iamdub]

Good idea, hadn't thought about using a bolt with tape in the tank, I may do a few more tests before I return the tester.
Otherwise I'm waiting for my new tank and hopefully will find some proper sized caps.

For an even better plug for a nipple/port, you can use a very short piece of hose that fits tightly inside it. Then, screw a bolt into that to expand it outward to make a tight seal. You'd have to have just the right size of hose and bolts, though. Electrical tape makes it "adjustable".

 

[mikez71]

it's probably the screw on to the cap part. pretty much every adapter I've used seals badly. if it's a loner check that it's not missing a rubber seal inside. or just not the correct adapter. some bottomed out before they seal.

useful but annoying.

Could be, but the rubber seems to fit snugly after releasing the sprung hose section.. and I can put the entire screw on adapter in my palm and build pressure.
Adapter does not bottom out on tank, but on top of threads. Good thick rubber gasket.
A small leak with the air volume in the reservoir might be harder to find..
Tested the pump in hand more, and it builds pressure without dropping. so the pump valving is good.

 

[j91z28d1]

tossed the catch can on.. will be interesting to see if it catches anything. Ignore the super dirty engine, I'm horrible about keeping the dailys clean under the good.



no alternator life haha.

 

[Doubeleive]

Can't pressurize the cooling system! I pump and pump and no pressure.

Seals on tool look good. I can plug the air hole on the tool with my finger and build/hold pressure.
I can see coolant in the tank moving from the airflow (the corner by the cap).

I dribbled soapy water on the seams of the tank and the small hose to radiator, and all around the tool attachment.
can't find the leak but I didn't have a sprayer for the soapy water..

Not pushing water out, so I think it's leaking somewhere in the top air part of the reservoir.
When I remove the cap with engine warm (After cooling a bit), air rushes. I think it's vacuum, perhap the leak seals with vacuum.

I have a new tank and cap on the way, will probably get a couple of the small hoses as well.
I wanted to pull the small hoses and plug the reservoir, but I don't have any caps in that size.

Let me know if I'm doing something wrong!

like mentioned it's probably the adapter you are using, if it is the big multi kit it should say which one is for GM and there "might" be 3 different gm ones
once you get that straightened out pump it up to 15 psi and let it sit

 

[mikez71]

kit ony had 1 adapter with internal threads. Snugs up on the tank properly from what I can tell.. Will rent again when new reservoir arrives..

 

[07Burb]

Tried replacing the running board motors on Deathscalade but no dice! motors are corroded to the bracket so returning the running board motors and reordering the motors with new brackets which are $$$ I guess this is the perk to driving older stuff but I was hoping I could replace just the motors and not the motor + bracket since the price increase is substantial


/rant

 

[89Suburban]

nipple

 

[Doubeleive]

get the one from autozone it's a big suitcase type kit with probably 10 or more different caps
powerbuilt

 

[mikez71]

get the one from autozone it's a big suitcase type kit with probably 10 or more different caps
powerbuilt
View attachment 402621

Will try them next!

I got one from oreilly's, only had about 5 adaptors.
But honestly I can't see how it would be leaking because I can seal it on my hand..

and it screws on the reservoir with a thick rubber gasket which I can feel compress.

starting to wonder if its an internal head gasket leak or cracked head, and the smell might be coming from tailpipe. doesnt smell in the engine compartment before starting.. noticeable after starting briefly.. exhaust could be blowing back under the car. Bottom of engine and heads looks dry everywhere I can see from underneath..

Video on a cracked head

Might have to pull my valve covers and have a look..

 

[Doubeleive]

Will try them next!

I got one from oreilly's, only had about 5 adaptors.
But honestly I can't see how it would be leaking because I can seal it on my hand..
View attachment 402630
and it screws on the reservoir with a thick rubber gasket which I can feel compress.
View attachment 402631
starting to wonder if its an internal head gasket leak, and the smell might be coming from tailpipe. doesnt smell in the engine compartment before starting.. noticeable after starting briefly.. exhaust could be blowing back under the car. Bottom of engine and heads looks dry everywhere I can see from underneath..

then you can rent the block tester those are like $10 but you will probably have to order the fluid because it's usually not in stock and is not included with the tool rental.
but....this is why I say to mark the reservoir tank level when it is cold as this gives you a better idea of how fast or slow the leak is and a slow internal leak can possibly be addressed without huge cost. if you can smell coolant in the exhaust then your sniffer works much better than mine. look under the oil filler cap for any snot, should be nice and clean though.

 

[Docky50]

I dedicated a lot of time to some mods on my Tahoe this weekend. I replaced my low beam halogen lights with one of HID Guy's kits, plasti dipped my chrome surround on my grille, tried to repaint my front bowtie (FAIL!), replaced my interior lights with LEDs, installed my holster under my steering column, and replaced a seatbelt latch on the driver's seat. Now I'm waiting on my rear door actuators to come in as well as the billet bowties I ordered. As soon as they get here I'll get to installing them too. Long weekend but I got it done. What did you do to your Tahoe/Yukon?

Nothing. It's raining here and I wanted to get it detailed. So I'll just vacuum it out later. I want to replace my bowie with a red lighted one

 

[gooffeyguy]

Harbor freight sells a combustion tester and also sells the testing fluid for it.

 

[mikez71]

Harbor freight sells a combustion tester and also sells the testing fluid for it.

Thanks for that. I'm also thinking there is a chance if the crack is around the intake that no combustion contamination would be present.
Oil cap, tailpipe and coolant seem normal.. Hoping it's something simpler but there is no sign of exterior leaks..

 

[mikez71]

but....this is why I say to mark the reservoir tank level when it is cold as this gives you a better idea of how fast or slow the leak is and a slow internal leak can possibly be addressed without huge cost. if you can smell coolant in the exhaust then your sniffer works much better than mine. look under the oil filler cap for any snot, should be nice and clean though.

yep i had it filled to the line, now it is below, however Im not sure I refilled after bypassing the heater cores, but I think I did..

Cant smell coolant in exhaust while running, just speculating it gets pushed out on first crank..

Might try those coolant tabs after all, but I'm going to see if a new reservoir does anything. (and i will check with autozones pressure tester also)

 

[Tonyrodz]

yep i had it filled to the line, now it is below, however Im not sure I refilled after bypassing the heater cores, but I think I did..

Cant smell coolant in exhaust while running, just speculating it gets pushed out on first crank..

Might try those coolant tabs after all, but I'm going to see if a new reservoir does anything. (and i will check with autozones pressure tester also)

Nvm

 

[mikez71]

After starting the truck, I ran to the exhaust pipe.. Smelled coolant.
I'm hoping it's headgasket and not a cracked head at this point. Might pop the valve covers little later

 

[Sparksalot]

After starting the truck, I ran to the exhaust pipe.. Smelled coolant.
I'm hoping it's headgasket and not a cracked head at this point. Might pop the valve covers little later

Doing a block check test can help narrow it down too. It detects combustion products in the coolant.

https://www.amazon.com/Block-Tester-BT-500-Combustion-Leak/dp/B06VVBSFTF