The GM 3.4L V6 in my brother's minivan decided to blow a gasket and dump its coolant into the lifter valley. He has requested my assistance in repairing it.
How difficult is this job? I could replace the intake manifold gaskets in a typical small block Chevy V8 in an afternoon. Are there any trouble areas in this model V6? I understand that the push rods run through the intake gaskets and have to come out, which is no big deal. Anything else? It's a 2000 model (Chevy Venture, same as a Pontiac Montana, right?).
The dealer parts counter sold him a whole pile of 'recommended' parts for the job (gaskets, EGR valve, intake bolts, and a bracket of some kind). He'll have a haynes manual and a case of beer waiting for me.
Figured I'd answer my own question, since nobody had any comments.
As a former pro automechanic, when I say that the job sucked it means it's probably not a typical do-it-yourself job. It took most of an entire weekend (6 hours + 8 hours). If they'd put the damn engine in straight it would have been cake.
The worst part of the job is the coil pack on the rear cylinder bank. There are two nuts that hold it on. It takes hours of pain to get them off - even with the engine mounts removed and the engine moved up against the radiator. On reassembly, I just bolted the front half of the pack and left the whole EGR support bracket off. It's just too much crap all in one place that you can only reach with one fingertip.
One of the studs for the coil pack is directly in the way of a valve cover bolt. I had to customize an 8mm wrench with multiple bends to finally get that one bolt out/in.
Remove the windshield wiper linkage that's in the way. Chiltons didn't say that.
It is impossible to torque all the lower intake bolts. The four at the perimeter are too far under the runners to get a socket on them. I had to guess-o-meter those and hope it works.
The lower intake gaskets are 1/8 inch thick plastic. The sections around the coolant passages had collapsed completely and damn near fallen into the hole. Clearly a defective design.
No need to adjust the valves - just torque down the rocker bolts.
"Gently rock the fuel rails and pull the rails and injectors out as a set". Yeah right. The injectors are seized into the lower intake. Yank for all your worth and pray you don't break one. The tips of all the injectors pulled off and were still stuck in the holes. One injector came off the rail, bending it's retaining clip. Thank god we found all the injector tips and managed to get them back on the injectors. Buy new o-rings ahead of time - you'll need them. Someday someone will thank me for the anti-seize I put on during reassembly.
Anyways, it saved $900 in labor. I hate front wheel drive cars.
But then how do you get the gasket out from under the pushrods?
It looked near impossible to get the alternator out of the way with the wiper rod in place. Of course, if you leave the coil pack and rear valve cover in place, there'd be no need to pull the alternator.
Yep. I didn't have a thread chaser, though, so the loc-tite probably isn't doing much good in the dirty threads.
I tried the OEM parts first. The dealer supplied a recommended "kit" containing several gaskets and new bolts. Not one single part was correct. The "kit" even came with TWO sets of lower intake gaskets - neither of which were right. Ended up hitting Advance Auto where they had a Fel-Pro set in stock.
Right, but I had to eyeball it to 30 degrees.
Yep. Actually, I used a little grease on the o-rings and a light coating of anti seize compound around the holes in the intake. Not enough to plug anything. I just didn't want the o-rings to roll up or tear. If anti-seize degrades rubber, please don't tell me.
Oh well, I guess that's why I gave up that line of work. I was never very good at it. If I die and go to hell, I know that my hell will be an endless line of Ford Tauruses that need wheel bearings and heater cores.
Lisle makes a tool that grabs the rocker arm allowing you to lift it up and slip the pushrod out from under. Can also be done with a flare nut wrench. Two versions of the Lisle tool, a long handed one for all other 3.1/3.4 engines and a short handles version for the minivans.
The less you take apart on these, the better.
Oh, I dunno... Loctite expands when it cures, you'll be okay.
Fel-pro has two versions of gaskets for these engines, hope you got the 98xxxT version. Steel backbone all encased in molded rubber. No plastic to fracture.
Another good reason to not take them apart, plus, the torque + angle really stresses the thread in the head, I've had to Helicoil more than a few.
I don't think it does...
Naaah... hell is an endless line of rotten brake and fuel lines. BTDT. ;-)
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