1999 Venture 3.4l Engine Exchange

I have a 99 venture that had te coolent leak, had intake gasket changed and a few hundred miles later the cam broke. Can someone tell me if the newer 3.4 engines will interchange and what problems will I have.

Hello DrayCasey,
I just replaced the engine in my 98 venture. I used a 3.4 engine from a 2002 pontiac montana. I went to the dealership and the machanic supervisor printed the specs on the 3.4 engines and they were compatible. You will need to use your intake manifolds (upper and lower) along with the collant pipe that connects to the thermastat housing(change rubber Orings on each end). I used the main coolant pipe from the 2002 engine because it was designed to allow coolant to flow to the oil filter (the 98 engine did not have that feature). Make sure you replace the rubber Orings on this pipe as well.
Also, use the fuel injectors and electrical connections from the 99. You should also use your exhaust manifolds also. There is a pipe that comes off of the rear exhaust manifold that connects to the EGR valve(use the 99).
I did not have to change the timing chain cover but I did have to use the 98 altenator brackets and belt tensioner. I would replace the oxygen sensor. Make sure you get the one for a 99 engine.
This is also the best time to put new spark plugs(use the factory) and wires.
I used a WhiteOut marker to number all of my electrical connections. I bought a box of sandwich bags and used them to put my parts and bolts in (I labeled them).
I will be at my home around 6pm(est time) today (Mon 3/14) and tommorrow (Tues 3/15). Feel free to give me a call. My number is 336-605-0680.
Good Luck!
Jwheels

Hello DrayCasey,
I also wanted to let you know to go ahead and replace the thermastat($10) and waterpump($28). Have the radiator flushed, cleaned, and checked for leaks(cost me 40 bucks).
Jwheels

Thanks, your reply helped very much. I have talked to my local dealership and could not get any help. Now I have a few more years to work with. You are very right about changing and changing everything that can cause problems later.
Again thanks,
draycasey

Glad I can help. Keep us updated!
Jwheels

I am in the process of getting a 2003 engine. I talked with a mechanic at the local dealer and the engines should be compatable. what problems did you have under the van, pulling the old engine, and did you have a lift or not.
thanks in advance
Don

I used a two ton engine hoist to lift the van off of the sub frame. I let the sub frame rest on a floor dolly (the subframe weighs about a thousand pounds).
You need to remove the fans and radiator. Unbolt the compressor and starter and move them aside. Remove the front engine mounts. Disconnect and label the wiring harnesses (3 of them). Remove the transmission lines from the transmission. Remove ground wires that are bolted onto the transmission bell housing bolts (front drivers side).
If the engine is not locked up, remove the three bolts that join the flywheel and torque converter. You can get to them once you remove the starter. If your engine is locked up, wait until your remove the subframe.
Make sure your wheels are pointed straight and remove the front wheels. Disconnect the calipers and put them aside. Unplug the ABS wiring connector. Unbolt the two large strut bolts that connects the strut to the spindle.
Rest the subframe on the dolly and remove the FOUR subframe bolts. Once you remove them, you can raise the van up and off the subframe.
If your engine is locked, remove all of the spark plugs and see if it will turn. One cylinder on the compression stroke can lock up an engine. If your cam shaft broke, you could have a cylinder locked on the compression stroke. Do not worry! You can remove the engine with the torque converter attached.
Once you unbolt the transmission bolts and the passenger side engine mount bolts, the engine should come up and out of the subframe.
I believe that is it. I hope this is not too long.
I used a white-out pen to label my electrical connections (it dries really fast) and I put all of my bolts and small parts in sandwich bags and labeled them with a magic marker. If I think of anything else, I will let you know.

Jwheels

Thanks again, you have helped very much! I'm sure I will have more questions once I get started on this project.
Don

When you dropped the engine down did you pull the axles or leave them attached? Also where did you hook engine hoist to lift van?

I had to put my project on hold for a few mos. but planning on the last week in July when I am on vacation. I have been talking to a local mechanic and he told me the easier way was to take engine out from the top. I'm not sure what I will do yet.
Don

I had to put my project on hold for a few mos. but planning on the last week in July when I am on vacation. I have been talking to a local mechanic and he told me the easier way was to take engine out from the top. I'm not sure what I will do yet.
DonWhile I haven't ever measured for sure, I'm not sure if the stripped engine block will come out from the top. There isn't a lot of clearance coming out of the top. Cars with the 3400 engine may be able to remove the engine from above, but I would want to hear from others if they have removed it from topside before attempting to. I've been had too many times from well-intended "local mechanics" that ended up not having a clue what they were talking about.

I can now answer your question, it will come out the top. It is very tight but will make it. Be sure to remove coil packs, alt and oil filter. Tilt engine about 30 percent angle to rear and bring it out. like I said it is very tight. No I did not remove axles.
DRAYCASEY

I can now answer your question, it will come out the top. It is very tight but will make it. Be sure to remove coil packs, alt and oil filter. Tilt engine about 30 percent angle to rear and bring it out. like I said it is very tight. No I did not remove axles.
DRAYCASEY

...along with the collant pipe that connects to the thermastat housing(change rubber Orings on each end). I used the main coolant pipe from the 2002 engine because it was designed to allow coolant to flow to the oil filter (the 98 engine did not have that feature)...

Heya, jwheels - I know this is an ancient thread, but can you elaborate on what you mentioned about "the coolant pipe that connects to the thermostat housing" a little bit?

I'm curious now if there's something other than a bleeder screw & upper radiator house outlet on the newer (00+ I'm assuming) 3400s, because I think that's what you're saying...

My '97 just has the bleeder & house outlet; no connection to the oil filter as you mention. Does anyone have a picture of this newer version of the housing by chance? cdru, I know you like posting pictures on this forum... :smokin: