Inline 6 head is on the coffee table. Now what?
12-27-2018, 11:44 AM
#11
Member
Thread Starter
Update:
Tested the EGR valve with vacuum per the Hayne's manual and it passed just fine. I removed EGR valve and upper intake manifold to carefully inspect the mating surfaces, gasket, bolt threads, etc. I reinstalled the EGR valve to the manifold on my work bench because it is much easier than doing it in the vehicle. I took extra care to clean the mating surfaces thoroughly; also blew out the valve with compressed air and cleaned it up a little bit with alcohol. I reinstalled the upper manifold and started testing. The "whistle" went away and has not returned after a half a tank worth of test driving. The exhaust leak sound under load did not go away.
After much listening with a stethoscope and trying to train my wife to listen for the leak while I put the engine under load with no success, I learned a new (to me) trick. I started the truck then jammed a rag in the tail pipe with a stick. This made the exhaust leak audible without putting the engine under load. I used the stethoscope and could only hear the leak in one specific location, so I think I found it. The culprit seems to be the A.I.R. pipe, secondary A.I.R. injection pipe, smog pipe or whatever else it is called. No big surprise to me, but the High-heat JB Weld repair failed. I have ordered a new part and will update when I have it installed.
The A.I.R. Pipe seems to be a tricky part to get. The chain parts stores don't seem to stock it. I tried to order it on Amazon but they wouldn't ship it to CA. I ordered it online elsewhere and am waiting for it, hoping it is the right fit and that it will not be a problem when I go to SMOG the truck.
Tested the EGR valve with vacuum per the Hayne's manual and it passed just fine. I removed EGR valve and upper intake manifold to carefully inspect the mating surfaces, gasket, bolt threads, etc. I reinstalled the EGR valve to the manifold on my work bench because it is much easier than doing it in the vehicle. I took extra care to clean the mating surfaces thoroughly; also blew out the valve with compressed air and cleaned it up a little bit with alcohol. I reinstalled the upper manifold and started testing. The "whistle" went away and has not returned after a half a tank worth of test driving. The exhaust leak sound under load did not go away.
After much listening with a stethoscope and trying to train my wife to listen for the leak while I put the engine under load with no success, I learned a new (to me) trick. I started the truck then jammed a rag in the tail pipe with a stick. This made the exhaust leak audible without putting the engine under load. I used the stethoscope and could only hear the leak in one specific location, so I think I found it. The culprit seems to be the A.I.R. pipe, secondary A.I.R. injection pipe, smog pipe or whatever else it is called. No big surprise to me, but the High-heat JB Weld repair failed. I have ordered a new part and will update when I have it installed.
The A.I.R. Pipe seems to be a tricky part to get. The chain parts stores don't seem to stock it. I tried to order it on Amazon but they wouldn't ship it to CA. I ordered it online elsewhere and am waiting for it, hoping it is the right fit and that it will not be a problem when I go to SMOG the truck.
01-05-2019, 11:28 AM
#12
Member
Thread Starter
Final Update.
I replaced the A.I.R. pipe and that definitely resolved the exhaust leak sound.
The temperature gauge is still reading warmer than usual -- steady on the "N" of "NORMAL", and it seems to be idling a little fast. I'll look into those things separately.
I'm going to consider the Head Gasket project a success.
I replaced the A.I.R. pipe and that definitely resolved the exhaust leak sound.
The temperature gauge is still reading warmer than usual -- steady on the "N" of "NORMAL", and it seems to be idling a little fast. I'll look into those things separately.
I'm going to consider the Head Gasket project a success.