Boost Leak Test - Parts, Procedure and Test Results

[eastmentCTD600]

A boost leak condition can be hard to identify if they are somewhat small. I found three leaks yesterday and I was able to fix all by re-aligning the boots on the charge air pipes.

I'd characterize the boost leaks I had by the following:

• Squealing noise during moderate (10psi) to high-boost (30psi) for about a year now, possibly longer.
• Sounded like the turbo whine changed pitch in some instances, normal boost noises other times.
• Not consistent, noises came and went with differing temperatures and boost levels.
• Developed or worsened slowly over time, snuck up on me....

Read through here a few days ago about checking for boost leaks but I didn't find much about a test setup. I thought it might be useful to post what parts I used to perform the test and one other finding about the charge air cooler.

Truck:

• 2004.5, auto, stock turbo, stock inter-cooler (metal unit), stock boots/charge air pipes.
• 168kmi.
• Smarty Touch

My Setup:

• Remove air box and pipe to turbo inlet and connect my adapter.
• Disconnect charge air pipe at the intake boost elbow and plug.
• Take care to avoid foreign material entering the turbo and charge air pipes.
• I also removed the oil filter because my air fitting setup was too close to the oil filter to allow air hose connection.

Factory Service Manual (FSM) Procedure:
Section 11 "Exhaust System" has a sub-section on the Charge Air Cooler and Plumbing, in this sub-section it has a procedure for diagnosis and testing for leaks.

FSM Procedure:

1. Loosen clamp and remove air inlet hose from turbocharger.
2. Insert Special Tool 9022 Adapter into the turbocharger inlet. Tighten tool clamp to 8 N·m (72 in. lbs.).
   CAUTION: Do not apply more than 138 kPa (20 psi) air pressure to the charge air cooler system, severe damage to the charge air cooler system may occur.​
3. Connect a regulated air supply to air fitting on Tool 9022 Adapter. Set air pressure to a Maximum of 138 kPa (20 psi).
4. Using soapy water check the rubber sleeves, charge air cooler and intake manifold for leaks.

Notice the FSM does not plug the engine side of the charge air cooler piping. I did for my test 1st test. In my second test I configured per FSM and repeated.

Note: when tightening the band clamps the FSM calls for 95 in.lb. torque.

Parts:
For the Turbo side (all Home Depot parts):

• 3" PVC end cap (rounded end)
• 3" rubber coupling adapter/connector
• 4 hose clamps.
• 7/16" drill
• 1/4"-18 NPT tap
• 1/4" air hose fitting
• Teflon tape

Notes:
You'll note the turbo inlet is 4" O.D. and the 3" PVC end cap also has a 4" O.D. This is because the cap has 3.5" I.D. because it slips over 3" PVC pipe that has a 3.5" O.D. where the pipe has a 3" I.D.). The 3" rubber adapter has a 3.5" I.D. The rubber adapter was heated using a cheapo space heater until it was flexible enough to stretch over the end cap and the turbo inlet. Mine stretched fairly easy once it was hot.
I had drilled and tapped the end of the PVC cap then installed the air hose fitting. Careful to sneak up on the tapped hole so the fitting goes in is tight!

Critical Step:
I made sure to slide the 3" PVC cap far enough into the rubber boot so that when I slipped the other end of the boot over the turbo inlet the inlet was touching the end of the 3" PVC cap. Simply put when the end of the PVC cap is butted up against the turbo inlet inside the rubber adapter. This way there is not a large area of rubber boot that is exposed to pressure. I made sure to place one of the hose clamps over the rubber boot at the joint between the turbo inlet and PVC cap butt joint to reinforce this area to resist the expansion of the boot under pressure I placed three other hose clamps to help hold it in place.

Charge Air Pipe Side:
I found a 3" OD plastic plug for the charge air cooler pipe side. This was hard to find but Big R has some irrigation fittings that had something that worked. You could probably use a 3" hole saw and make a wood plug from a 2x4 that could work. FSM says to torque the band clamps to 95 in.lb.

Testing:
Per the FSM I connected a regulated air source to the turbo-side plug and brought pressure slowly up from 0 to 20 psi. I had the turbo-side plug pop out once, so I re-heated and re-installed, waited for rubber to cool a bit and re-tightened the clamps again. Then it held.

Findings - 1st round of testing:

1. The first leak I found was at located at the 2nd band clamp away from the turbo outlet (rubber boot to aluminum charge air pipe). It only took 5 psi for this one to show up, began hissing and was easy to locate by hand. The boot has a molded ridge and the aluminum pipe has a groove. These were misaligned. removed, cleaned everything with 99% isopropyl alcohol and re-installed being careful to align the groove to the molded rubber ridge. Torqued clamp to 95 in.lb
2. The 2nd leak was at the inlet side of the charge air cooler. This one was more difficult to fix because the factory ground off casting flash and also the ridge around the OD of the inlet pipe. I suspect this has existed since I bought the truck new. I could not get the band clamp to seal. There is no groove in the charge air cooler inlet or rubber ridge on the boot at this location, just flat boot surface to flat cast aluminum OD. I'll post a pic. To fix this I used some self-fusing electrical tape (available at Home Depot), specifically 3M Scotch 2228 which is a 1" wide Rubber Mastic tape that is rather thick. Typical electrical tape won't do here. This stuff is self-amalgamating and becomes one rubber gasket. I applied one layer of tape around the inlet pipe OD. then installed the boot over the "rubber gasket" i made and torqued to spec. I waited about 10 minutes then torqued again. The tape is kind of thick and squished a bit but it sealed great. I have not driven yet or done any long term durability test but I think this will hold well.
3. The 3rd leak was at the boot that connects the charge air pipe to the intake horn, this was remedied by imply removing, cleaning, re-aligning and torquing properly. This leak squealed at 20 psi and was really easy to find.

Final Notes:

• All my leaks were large enough and easy enough to find without the use of soap and water. I simply used my ears and hands to find them.
• I did briefly raise my pressure to 30 psi, which is not recommended by FSM, but I wanted to check. My setup held at this pressure for about 10 seconds then my boot on the turbo popped off and made a fun noise. Only damaged was my pride...