3.4L GM lower manifold gasket replacement part 7: Installing upper manifold, alternator and more

When the lower intake manifold gasket on a 3.4L or 3.1L GM engine leaks, coolant seeps into the oil. This eight part video series addresses this problem in detail. Part 7 includes installing the upper manifold, front alternator bolt, ps pump, EGR valve, air inlet duct and coil assembly. These engines are found in many models of GM vehicles made from 1998 to 2005, such as the Chevrolet Malibu, Lumina, Venture, Impala and Monte Carlo; the Pontiac Grand Am, Grand Prix, Montana, Transport and Aztek; the Buick Century and Rendezvous; and the Oldsmobile Alero and Silhouette.
For an excellent text and still frame version of this procedure see: www.originalmec...

[@BonnieLinge]

Thank you for 14:35! I was cleaning the MAF sensor and removed that hose from the intake end but discovered it wasn't plugged in on the other end. Your video is the only place that shows where it connects!

[@TheOriginalMechanic]

You're welcome. Kind of a wonder you found that!

[@davidbaker1871]

Hey brother I have a lot of respect for you because I am almost done with this job and I don't mind telling you that it will be the last time I do this. Its been a hassle sometimes and I was whooped after the first day and I hope that this was the problem it was a learning experience my friend and the whole time I was working on it i never seen anyone come to see if I could use some help and I can understand why. I have a wire plug that I'm not sure where it goes yet but it was running down along the bottom of the front of the engine And it is oolong with two prongs in it. If you might have any idea where it goes I'd appreciate you letting us know 😉

[@Happy4Go2Lucky]

Continuing on I used a rubber bungee cord to hold the power steering pump out of the way. I saved your written comments to a webpage in Chrome and reread it for re installation. I'm glad you mentioned positioning the power steering pump ahead of reattaching the fuel rails. I hope it's not going to be in the way of the upper manifold plenum. I changed out the O-ring on the heater pipe coming off the thermostat housing and attached it to the heater core hose. KZbinr G-Body garage mechanic recommended not fooling with the quick connect. That it was easier to remove the hose off that plastic fitting than to risk breaking it and spending another twenty bucks for nothing. I disconnected the bypass pipe for the heater core return at the passenger side and left everything attached to the upper plenum so that I didn't have to fool around with those throttle body hoses. It's worrying me that those twenty-year-old hoses might develop a pinhole leak. The auto parts store does not carry half inch ID thin wall heater hose. Those two hoses that go to the throttle body off the bypass pipe is what I'm talking about.

[@Happy4Go2Lucky]

Thought I was ready to put the upper plenum on. So I turned it over and all the bolts fell out. I have 2 stud bolts. You showed one on the left back side for the alternator I guess. The other looks like it went on the EGR or the map sensor bracket. Been looking in my Haynes manual for my 99 Chevrolet Malibu as well as my photos. Still I cannot locate where the stud bolts go. they must have been holding the plenum down somewhere or they would not have fallen out when I turned it over, to find all the gasket material I have to remove. Removing the gasket material on the lower manifold took three hours with a razor blade and acetone. This time around I intend to get out the rlock that goes on the die grinder. As a side note you show a 3/8 Drive for a impact driver. I had to use it to insert the lower power steering bolt and turn it with a pair of pliers to get it started so that I didn't have to remove the motor mount. A 1/4 Drive swivel socket or flex socket 13 mm might have worked but the 3/8 Drive did not, it kept jamming on the motor mount. Also in taking apart the throttle cable I broke the plastic clip that appears to be two pieces that snap together. The auto parts store tells me they have such a device but they point me in the direction and I have no idea what I'm looking for. The Cadillac mechanic told me to tie off everything I could and take apart nothing more than I have to. So I tied the front spark plug wires to the wipers and rope the fuel rail to the garage ceiling. The Haynes manual recommends removing the hood. Several fellows have placed a 4ft shop light on the hood. I found I could have reached the back of the engine only with the hood removed. With the alternator removed I was able to get to the lower coil mounting nuts. I also replace the heater core hoses. I got a pair of flat band hose clamp pliers from the Widow of a VW mechanic to easily manage the removal and installation of the heater hoses. I have really soured on threaded hose clamps. They don't turn themselves perpendicular on their own and on a large hose like the lower radiator hose those clamps do not seal off a leak. I change the oil in a Cadillac 7 1/2 quarts of dirty oil and put it in the Chevy to flush out the antifreeze sludge left in the oil pump Drive and who knows where else. I probably should burn a filter and throw away the plugged oil Filter I put back on. I hate to throw away $5. I found nobody showed how to remove the oil pump Drive where the distributor used to be. I used a wood chisel bevel side down to get the round head to pop up enough to put a 3-foot crowbar under it and used a hardwood floor plank as a fulcrum to pop the whole thing out. In fact I use the 3ft Crowbar at least 10 times. Came in very handy for removing the fuel rail I could just gently pry and it popped loose. I found my biggest screwdriver require too much effort. The fuel rail I didn't want to break any of those fuel injector clips. So I pried very gently and it required no effort at all with a 3ft crowbar. I changed out the lower O-rings only because I could not manage the clips. I lost an hour and a half looking for a clip only to find it behind the oil pump Drive. I found a really handy tool was the was the Lisle pushrod remover model 48 300. I got all out but, I had to loosen the bolt for reinstallation on two of the passenger side front and back push rods.

[@tyeachismfoe]

What is the elbow go to by the alternator does it go to anything I caht find out

[@benlowman3991]

From start to finish (granted no stripped bolts or frozen bolts) how long is the entire process?

[@TheOriginalMechanic]

I would estimate at least 6 hard hours of work

[@benlowman3991]

Thank You! Kinda of what was thinking. Excellent instructional video! 👍

[@maharper100]

Why can't you pull the EGR valve off with the upper intake?

[@TheOriginalMechanic]

I suppose you can if you can get the exhaust tube off the valve.

[@maharper100]

Thanks! I have to replace #5 fuel injector on my 2003 Impala, your video was very helpful, After looking at my 3400 engine, I was thinking, once I disconnect the one bolt from the exhaust tube, I should be able to leave the EGR valve attached to the manifold. I intend on doing the job in a few weeks so I can pass inspection. Thanks again.

[@TheOriginalMechanic]

@@maharper100 You're welcome and good luck!

[@mississippiqueen2u]

😊