spud72

So I am down to the last couple steps to removing the LH intake manifold to access the AOS on my 99 C2, but I am having a heck of a time moving that rear intake plenum boot.

I have all the hose clamps completely loosened but that boot is so rigid it is resisting any efforts to either slightly compress it to move it, or push/pull from one side to move it the rest of the way. The front ones were a piece of cake compared to this.

Any tips on how to move that thing?

Ahsai

You need to remove the left intake manifold bolts and lift up the left manifold first. That rear plenum is not designed to be removed without loosenng the left (or right) intake manifold first.

spud72

Well, that would explain it. I was about to do that because that seemed the easiest way but the Pelican how-to guide I was following said to do that after.

Also, my 6 bolt heads for the intake appear to just be standard heads and not torx like the guide mentions. I presume just another typo?

Ahsai

The Pelican guides and photos are good reference but sometimes they may not be completely accurate. Also, they did the procedure on a specific model so sometimes there are natural variations too.

Regular hex bolts are correct.

Slakker

Also lower the engine about 3" (almost to the cross brace) to give yourself more room to work.

spud72

I've loosened the bottom bolts on the motor mounts and really didn't notice much difference in motor height. Is there something else I should loosen to lower it a bit?

e: Just to be clear, I have 5 of the 6 bolts out right now but I can tell that rear one is going to be a royal PITA. Even if I get it out, I need to get it back in when I'm done LOL and I can see any height I can get in the back being a big benefit.

Slakker

You may have to remove the motor mount nuts and support your engine with your jack, then just ease it down. Some people us a block of wood between their jack and engine but my jack has a rubber pad on the top and seems to work better without a block.

spud72

So just to make sure I understand you, you think I should pull the mount nuts right off? How far can I let the motor drop before it starts stressing out the front/transaxle mount?

I am familiar with the procedure of supporting the motor with a jack (I replaced the mounts before) but I am a little leery of taking the motor right away from them and letting it drop (albeit supported) but if that is the procedure and it won't hurt anything, I'll try it. How far can I let it drop away from the bottom stud of that mount?

I am truly stuck at that back bolt for the intake manifold - that's literally holding everything up with me right now and it has to come out.

Ahsai

What year is your engine? You need to remove the engine mount bolts and lower the engine to the max till the trans touches the cross beam support. Just make sure you release the tension on the power steering hoses, fuel line (may heed to disconnect), and O2 sensor wires (may need to disconnect them).

You won't hurt the trans mount btw.

spud72

It's a 99 C2.

I assume the PS lines would be near the AC? (I already unbolted the AC compressor as I'm doing the RH cam chain tensioner and battery cable). Where would the fuel lines be? I've never lowered the motor before so this is sort of news for me.

I presume the o2 wires will be easy to find

BTW, thanks for the help guys, really appreciate it.

Slakker

Good points Ahsai. On my '99's (same as OP) I could get it down almost to the cross brace without stressing anything but the O2 sensors wires. And simply removing the wires from the support clips provided enough relief. One note though, if you have a DOF (not sure why anyone would but my track car came with it) you will have to remove the rear sway bar to lower the engine without damaging the DOF.

The first AOS I did, I was also doing the water pump so o had the coolant drained and was able to unhook the coolant hoses which provided a lot more room along the drivers side of the engine compartment by allowing me to move everything over to the right.

The second time I swapped an AOS, I tried without moving the coolant lines and had no success. So I drained the coolant (you can reuse it) moved the lines and things went much smoother.

By the way, this little doo hickey is one of my favorite Ahsai tips. It's a filter that goes over a 5 gallon bucket and allows you to strain your fluids before reusing them. Works with oil as well.
5 Gallon EZ Strainer Insert 55 Micron for Bucket Pail Filtering Water Paint Biodiesel WVO WMO Vegetable Oil https://www.amazon.com/dp/B00QSLNLJC..._1OSayb8AGB5VD

spud72

I drained about 2L of coolant when taking the alternator out (I just removed the braket which opened the cooling system) and I might just drain it all as per your suggestion. Since I have no idea when the coolant was last replaced I'll probably just replace it all instead of re-using.

What is a DOF?

Ahsai

For that last bolt (closest to the AOS) on the left intake manifold, you need to do two things
1) lower the engine enough to get your hand from above. Use a 1/4" drive ratchet, an extension and a socket
2) loosen the AOS and push it up a bit. Otherwise it will block that bolt

Coincidentally I just replaced my AOS ('03 3.6L so it's a bit different and even more difficult due to the rearmost bolt on the AOS) while my trans is out. I was able to do everthing from the bottom but it's still not easy due to that rearmost bolt on the AOS.

Slakker

Direct Oil Feed. Some concept where you remove the outer seal of the IMS and pump oil directly to it. It's a little less invasive on mine since the engine was replaced in '06 with a factory crate engine that had the updated larger single row IMS. Still though, it's not something I would have added.

DBJoe996

This photo of mine, 99 C2, might help you understand where you are headed with the rearmost intake bolt. As said, without dropping the engine down I just do not know how you would get to that bolt, and it is still a royal PITA to remove. Remember the intake bolts have loctite on them so it is a long, slow removal process. Also, getting that rearmost bolt back in is almost as impossible. I used some painter tape to hold the bolt in a socket and extension in order to get it set in place, then a bunch of swivels and extensions to tighten over the top of the intake manifold.



Once you get the last intake bolt out, you slide the intake manifold to the left and away from the rear plenum. My AOS has already been removed and picture was taken before a major cleanup in there.