replace broken camshaft (GM 3.4L V6)

[shiden_kai]

Hi, I have a 97 Chevy Venture with a broken camshaft. Does anyone know

if

there is a way to replace the camshaft without removing the engine from

the

vehicle ?
If that is not possible, can someone tell me how high I will have to jack

up

the vehicle for engine removal. I am thinking about dropping the engine
onto a hydraulic jack, pump up the vehicle, and then slide the engine

out.

It's not possible to remove the camshaft with the engine in the vehicle.
Plus, my experience with broken camshafts on these engines is that
you will find so much damage, it's not worth trying to salvage the
engine. Usually, the camshaft bearings have seized to the camshaft,
which is what causes the breakage. Often the cam bearings spin
in the block, which renders the block useless

This usually means that you
have had an extended lack of maintenance, or an extended period
of coolant being mixed into the oil. Big surprise on these
engines.

Depending on how low you can get the subframe before the
lift the body off the engine, you probably still have to lift the
body about 4 feet.

Ian

[DL]

Thank you for your reply. Yes indeed, coolant has entered the engine. I am
now in debate with GM regarding warranty repair. The engine failed without
any warning. The only thing is the low coolant light turned on a while
back, and coolant was added. Oil seemed normal during last oil change. It
has only 36K miles on the odometer. I can still start the engine, but it
will stumble and stall right after. Any chance that the block not damaged ?
Cost to replace engine is $4000 - $5000. Any way to lift vehicle 4 ft off
the ground that a "do-it-yourself' er can ?

Post by shiden_kai

Hi, I have a 97 Chevy Venture with a broken camshaft. Does anyone know

if

there is a way to replace the camshaft without removing the engine from

the

vehicle ?
If that is not possible, can someone tell me how high I will have to jack

up

the vehicle for engine removal. I am thinking about dropping the engine
onto a hydraulic jack, pump up the vehicle, and then slide the engine

out.
It's not possible to remove the camshaft with the engine in the vehicle.
Plus, my experience with broken camshafts on these engines is that
you will find so much damage, it's not worth trying to salvage the
engine. Usually, the camshaft bearings have seized to the camshaft,
which is what causes the breakage. Often the cam bearings spin
in the block, which renders the block useless
This usually means that you
have had an extended lack of maintenance, or an extended period
of coolant being mixed into the oil. Big surprise on these
engines.
Depending on how low you can get the subframe before the
lift the body off the engine, you probably still have to lift the
body about 4 feet.
Ian

[DL]

Oil looks quite normal. Would you see any oil sludge on the dip stick and
the oil filler cap ?

Post by DL
Thank you for your reply. Yes indeed, coolant has entered the engine. I

am

Post by DL
now in debate with GM regarding warranty repair. The engine failed

without

Post by DL
any warning. The only thing is the low coolant light turned on a while
back, and coolant was added. Oil seemed normal during last oil change. It
has only 36K miles on the odometer. I can still start the engine, but it
will stumble and stall right after. Any chance that the block not

damaged

?
You won't really know until you pull the camshaft out and have a look
at the bearings. I doubt that it will be pretty. The coolant leak on

these

engines can often be so slow, that the water part of the coolant evaps
and the remaining part of the coolant turns the oil into a dark brown
sludge.

Post by DL
Cost to replace engine is $4000 - $5000. Any way to lift vehicle 4 ft off
the ground that a "do-it-yourself' er can ?

Well, if you really just want to have a peek around.....you might want to
jack the vehicle up high, and drop the passenger side of the subframe
down low enough so that you can access the camshaft. It can be done,
but you need to take note of items that will need to be disconnected so
that damage is not done to other components as you lower the sub.
One that comes to mind immediately is the steering shaft to the steering
rack connection. That should be disconnected before lowering the
sub. I haven't done a camshaft this way in these vehicles, as the amount
of camshafts that need to be replaced on these engines due to wear is
"zero" in my experience. And in the case of the few broken camshafts
I've done....there has never been any doubt in my mind that the engine
will have significant damage if the engine has seized cam bearings. So
far, all engines with broken camshafts have been scrap.
Ian

[shiden_kai]

Post by DL
Oil looks quite normal. Would you see any oil sludge on the dip stick and
the oil filler cap ?

Usually you will see it as a thin layer of brown gunk on the
inside surfaces of the engine. Inside the valve cover, for instance.

Ian

[Barry S.]

Hi, I have a 97 Chevy Venture with a broken camshaft. Does anyone know if
there is a way to replace the camshaft without removing the engine from the
vehicle ?

I don't know of any way to do much of anything on that vehicle/engine
without pulling it out. It's really wedged in there. To get at the
camshaft, I think you'll need to take the engine out.

If that is not possible, can someone tell me how high I will have to jack up
the vehicle for engine removal. I am thinking about dropping the engine
onto a hydraulic jack, pump up the vehicle, and then slide the engine out.
Any comments and suggestions will really be appriiciated.

I don't think this a realistic job for anyone without a lift. In
order to get the engine out, you'll need to adjust the lift and a
floor/transmission jack to take the the weight off the engine mounts.
Then raise the car a little and lower the floor jack so they separate
out and then you just adjust the height of the lift to allow
everything to drop down safely. I just don't think jack stands are
going to be tall enough or provide the flexibility you'll want.

I'd guesstimate (and it's a guess) you'd need about 3 feet of
clearance at the bottom to let the engine "Drop-down". I can't really
imagine trying this at home. If anyone does, please send pictures,
I'd like to see it.

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