Well after miles and miles of dealing with a coolant issue in my monte and STILL loosing coolant I decided to take it into the shop and sure enough my intake gaskets finally went. Also told me I have the wrong coolant in the engine. I stopped putting dexcool in once I owned it.

I've been looking around here and got the basics down to doing this swap out. I'm not paying 800 bucks for a shop to do it.

So far I've gotten these tips to get it done.
-Watch out for the fuel line o-rings
-keep track of each pushrod tube(seems obvious)
-sealant between the heads
-Revised torque value for intake bolts
-removing the motor mount to get the power steering up off?
-Replace T-stat while its apart
-Replace the oil pump driveshaft O-ring before it leaks(looks like a LIM leak)

There are two kits that I'm seeing. One that looks like its just the LIM and the upper gaskets. The other also has the valve cover gaskets and some other gaskets along with it. Think the EGR gasket is in there as well. Are all the other ones needed? I've been reading some people replace the throttle body gasket as well.

 

What drive train and year do you have?
Also, when looking for gaskets for a 3100/3400/3800, get the aluminum gaskets (if you don't get aluminum gaskets, you are not getting the most for your money IMO).

Also, if you car came with Dex, you can use Dex or it can safely be flushed out and replaced with the ol' green stuff. It does not matter. FYI - If you get coolant that claims "compatible with any color coolant".... It's green....

 

He has a 1998 3.1

 

I didn't change the throttle body gasket because i left it attached to the plenum. Same thing with the fuel injectors i just left the whole rail attached to the LIM. I also put a little thread locker blue on the LIM bolts because I didn't replace them. Don't know if it's needed but the torque spec is so low that I used a little for some peace of mind. The felpro kit was about $70 on amazon so i just went for the complete set.

Also if it hasn't had a tune up in a while might as well do it while everything is easy to access.

How many mile do you have on it?

 

He has about 156k miles...

 

^Stalker!^ haha

I'll probably just get the $85 kit so I can replace my valve cover gaskets as well. Been reading along and have seen most re-use their intake bolts with no problem. I will grab some blue loctite and some thread sealer to put on them.

Planning on leaving the throttle body and fuel rails in place. Not sure if I want to try and find the tool to compress the rocker spring to make getting the rods out without taking the arm off. I have a snap-on torque wrench so Im confident the torque will be spot on. However I've heard a few stories of folks stripping them though.

Right now I have the green stuff in there. There shouldnt be hardly any dexcool left in the engine. Most the coolant was drained when I had to replace the timing cover gasket, and before that I have been fighting this constant coolant loss issue for almost a year and never have been adding dexcool. But after the LIM fix I will probably take it somewhere to get the coolant flushed. The shop I took it to noted it was the "wrong" coolant. I'm afraid any shop I do take it too will want to put the factory dexcool back in it. Anyway I'm not going to be able to get to it this weekend the weekend after I will be tackling this job. Plenty of time to read up on the tips and tricks and read the pages in my Chilton manual.

Any other help I'll take it.

 

I've successfully reused all the nuts and bolts when I did my LIM stuff on 3100/3400/3800 cars. As for injector o-rings, I replaced the ones that sit in the LIM, as I take the fuel rail off the LIM. I also use this as a time to clean the LIM as best I can (less gunk the better).

Also, I've always taken the rockers and push rods out on 3100/3400 engines doing this job. I also soak and clean the parts before re-installation. It's really no big deal, but I did put everything in marked baggies so I placed the rockers and push rods back in the way they came out.

 

Well coincidentally got a call from my brother who states he is changing his intake gaskets on his 03' Venture and wanted a hand. Figured it would be good practice when I get to do mine next weekend. All I can say is I am glad I don't own a mini van. Half the damn engine is under the firewall! We took the torque arms off and ratchet strapped the engine forward to get at the rear valve cover and distributor pack. Was kind of a PITA but overall wasn't too bad.

If it can be done on a mini van with half the engine hardly visible I think my monte will be a walk in the park Tempted to try and do this on the side and make a little income and charge half the price of a dealer or other shop. I'm sure there's others out there with a 3.1 or 3.4 powered vehicle that has no mechanical aptitude and would rather have it be done by someone else. Looks intimidating until you just get in there and start digging into it.

 

yes it really is not difficult at all just time consuming good luck

 

You'd need to be certified and have insurance to do it successfully or you could run into some big trouble

To everyone trying to do it...

Use this!

D-tips

and this

LIM Gasket & Head Gasket Change Walkthrough & FAQ (3400) - Florida GM Club