Folks,

Please help me install my EGT thermocouple probe. It is 1/8" NPT thread so I bought a tool for tapping that thread. I have a few questions on how to do it.

I understand I need to drill it first before using the tool to create thread on the exhaust manifold. What size drill do I use? Is it 1/8 drill also or one that is smaller? If smaller, what size is the correct size considering that my final thread will be 1/8" NPT.

After creating the thread, when I screw in the thermocouple, do I use some kind of sealant or paste on the threads? Anti-sieze paste or something? I don't know what its called and I have no idea whether I need to or not.

Do I install the thermocouple before the turbo or after the turbo? When I opened my van cage, I can see 2 sides of the exhaust manifold leading towards the turbo. If I install it before the turbo, It will only be on one side. In this case, is it better to install it after turbo so I can getting the temps from all cylinders instead of just one side?

My thermocouple is adjustable as far as how deep it can be installed into the manifold. How deep should I put the thermocouple? Do I put it as deep as possible?

This is for my 2006 GMC Savanna 06 LLY Duramax Van.

Please help.

TIA
Jojo

hey welcome, hope to see a van doing some sled pulling. ha just kiddin. the manifold on the pass side is where most are installed. just before the flange. if you look up in the vendor section there is bd performance and they make a replacement drivers side manifold to eliminate the dent that the factory puts there and i believe they come with a threaded bung for a pyro gauge. just a little stonger setup. any way good luck. if not you have to use a 5/16 drill bit and make sure you put some grease on it and the tap to try to catch as many metal shavings as possible.:D

This should help;
http://dieselplace.com/forum/showthread.php?t=892&highlight=hoot+method

It's not hard to do. Just one word of advice about the hole size... you can always drill it bigger, but it's kinda hard to make it smaller!! If you are in doubt as to the size you need, go a little smaller & see if your probe fits. I don't think we can tell you specifically what size, since I would imaging that varies depending on the EGT setup you bought.

I didn't use any anti-seize. Don't plan on ever taking the probe out, and definately don't want it to loosen by itself! Mine screwed in tight enough that I don't think that will be an issue!

The correct drill size will be listed on the tap itself and/or the package it came in.

This should help;
http://dieselplace.com/forum/showthread.php?t=892&highlight=hoot+method


Definetly check out this link and make sure you use cutting oil when drilling and make sure the vehicle is running(so shavings get blown out rather than staying in)(at least I had to since mine went into the drivers side manifold)
Hope all works out for you.

Mark:)

As far as probe depth goes, you want it centered, not all the way, and not to shallow.

I used the hoot method and it went very smooth. I would suggest drilling a little bit before starting and idleing. I takes a while for the bit to go through and my manifold started to get warm. And wear I protection, once you break through there is more pressure than I had expected. It's not bad at all, it just caught me off guard. I had a metal chip hit me in the eye, no damage done, so wear eye protection.

Do the 06 LLY (same as LBZ) Duramax come with an EGT hole pre-drilled and pre-tapped at the factory? I could not find any but then again, I may not be looking at the right places.

Do the 06 LLY (same as LBZ) Duramax come with an EGT hole pre-drilled and pre-tapped at the factory? I could not find any but then again, I may not be looking at the right places.
That question fals out of my realm, since my truck is much older than that.:(

Mark:)

Do the 06 LLY (same as LBZ) Duramax come with an EGT hole pre-drilled and pre-tapped at the factory? I could not find any but then again, I may not be looking at the right places.

No, they use the same manifolds as the 01-05's.

Thanks gang, I successfully tapped and drilled my manifold this afternoon. It was pretty unerving because I wasn't sure I was not crossing the threads. I finally created the thread but it was not totally perpendicular. It was slightly angled but I installed my probe in it anyways. The probe tightened real good and there are no leaks although it was a little angled. That is good enough for me.

I installed it post-turbo since there was no place for me to access the manifold pre-turbo. The van space is really cramped in there. I was also afraid that I would damage the turbo since this was my first time tapping ever.

I took the advise of one of the gauge dealers to drill using progressively bigger and bigger bit sizes. I started with a really small bit and worked my way up to a 3/8 drill bit. The 3/8 drill bit was prefect for the tapping tool.

I did not use any fluid since I did not have either kerosene, diesel or tapping fluid. I was not sure it would work out but it went relatively smoothly.

I did not use antiseize paste. I don't know if that is bad or not.