'99 Venture Cylinder head removal

Hello all, I've got a '99 venture with the infamous intake manifold leak and plan to address it. However, given the vast ammount of work ahead here, I thought it would be advantagous to go ahead and take the heads off and have the vavles reseated aas well as replace the gaskets since the van (in alomost mint cond) has just over 120k on it. My question is, will i be able to get to that head using the engine rotation method? I'm asking because it certainly doesnt look as though I will. Also, are there any helpful hints from those that have accomplished this task already. Thanks in advance. -Drew

Its a big job, but you're right to do the heads while you're at it. I took mine to a shop to have them cleaned, but they ended up replacing both heads. I grew up with this guy so I trust him and he told me he sees these heads all the time with lots of small cracks around the valve seats.

Read the archives for tips, I found almost everything I needed here. Hard to see it, but once the intake manifold is gone there is tons of room behind the engine to get at the head bolts. I had some trouble getting those pesky exhaust manifold bolts out, two were broken--found out when I got the heads removed that they were broken at the factory from over torque--careful putting them back!
The ignition pack in the rear was the worst part I think--had to feel around quite a bit to get my sockets on the right bolts removing stuff.
The book didn't mention it, but I unplugged the coils one by one and set them on the bench so I could get more room behind there for removing the mounting plate.
The bit about rolling the engine forward really helps. Take the engine mounts clear off the car and set them aside for more space. Loosen the lower mount bolts under the pulley side and then use a strap or rope on the engine bracket to roll and hold the engine forward away from the firewall.
Borrow or purchase a crow's foot wrench to get at those two manifold bolts on the sides--those need torqued correctly on the way back in and they are nasty to reach without the crow's foot. Also, use caution unbolting the AC compressor--the bolts are tricky to locate on the bottom of the mount.
It needs to come out to get at the bracket that rests over the front head bolt.
If you need torque specs, just ask--lots of folks-myself also-have the helms manuals for the van.
Plan on one full day of work to tear it down, half day to clean the bock and parts up and then another full day to put it all together again. I took my time , had the heads rebuilt (replaced) at a shop and put it back together the next weekend.
John

Hey thanks John, I really appreciate the detailed heads up. I also plan on taking my time. We also own a '01 silverado and a '01 Pont. Grand Prix so its not like we are hurting for this van. If you dont mind my asking, where did you get your new set of heads and how much did you have to spring for them? It might just benefit me to purchase those right off the bat and not even bother with the machine shop.

Most likely you will need to have them replaced/rebuilt. The shop I went to does huge volume--stuff comes shipped in on skids from other places but they still do walk-ups. I paid $100 each for the heads and they kept the old ones, but I think the idea was just to toss 'em away for me.
That was great because a couple of those exhaust bolts were snapped off & I didn't have to deal with it. If you are interested, I'll dig out their address--I usually just drive over.
John

Thank you for the reply, however I dont think I'll be able to use the address, in all likelyhood I will probably take them to the Napa machine shop that did a wonderful job for me when I rebuilt a 350 for my '89 Silverado about 7yrs ago. Hopefully they could help me get my hands on a new set. I thought you might have purchased them from a somewhere on the web or something. I've already pulled the upper and lower intake's and now just need to pull the heads.

Again, thank you, your advice really does help. This is the first minivan I've worked on this deep into the motor and man they really do cram it in there, lol.

Remove the EGR to get to the back coolant bypass hoses.
leave the fuel rail and throttle body on the upper intake.
unplug rear spark plug wires from the coil pack and don't
worry about pulling plugs and wires. Remove the 2 coil pack nuts from underneath and behind motor.

Leave the exhaust manifold on the rear head when removing. Easier to work on the bench.

On the front head you will need to pull the exhaust manifold off (Unless you can get the dip stick tube pulled). Be real careful with the bolts and nuts. Hit with some PB Blaster a day before.

My machine shop charges $20 per hole to rebore /thread bolt holes.

Ya gotta go with folks you know:wink: Let them check out your heads; could be they are reusable. One thing worth mentioning while you have your engine torn down and lots of room under the hood--replace all those heater hoses back on the firewall! Those are nasty to get to while the engine is in place. I didn't replace any hoses on mine & ended up doing so one by one in the first few weeks after putting it back together. The worst ones are those in the back and the two down on the oil cooler in front. Not all engines use the oil cooler, but its another nasty job after the engine is assembled.

I used an upgraded LIM gasket kit that had no plastic parts as well. It came with new bolts too.

I had the tranny shudder problem as well and just went ahead and replaced the solonoids while I waited for the heads to come back. If you have that issue, its pretty easy to reach back to the steering coupling and take it apart for lowering the engine frame without that engine assembled. Not sure if that's a problem you have, but now is the time to deal with it.

Remove the EGR to get to the back coolant bypass hoses.
leave the fuel rail and throttle body on the upper intake.
unplug rear spark plug wires from the coil pack and don't
worry about pulling plugs and wires. Remove the 2 coil pack nuts from underneath and behind motor.

Leave the exhaust manifold on the rear head when removing. Easier to work on the bench.

On the front head you will need to pull the exhaust manifold off (Unless you can get the dip stick tube pulled). Be real careful with the bolts and nuts. Hit with some PB Blaster a day before.

My machine shop charges $20 per hole to rebore /thread bolt holes.

Thnaks for the heads up but by the time I read this I had already pulled the fuel rail, but did leave the throttle body on the UIM. I have pulled both heads, but have not detached the rear exhaust manifold yet. I did however break one of the front exhaust manifold bolts when removing...Argh, broke it flush too,...double Argh!!!

Ya gotta go with folks you know:wink: Let them check out your heads; could be they are reusable. One thing worth mentioning while you have your engine torn down and lots of room under the hood--replace all those heater hoses back on the firewall! Those are nasty to get to while the engine is in place. I didn't replace any hoses on mine & ended up doing so one by one in the first few weeks after putting it back together. The worst ones are those in the back and the two down on the oil cooler in front. Not all engines use the oil cooler, but its another nasty job after the engine is assembled.

I used an upgraded LIM gasket kit that had no plastic parts as well. It came with new bolts too.

I had the tranny shudder problem as well and just went ahead and replaced the solonoids while I waited for the heads to come back. If you have that issue, its pretty easy to reach back to the steering coupling and take it apart for lowering the engine frame without that engine assembled. Not sure if that's a problem you have, but now is the time to deal with it.

LOL, you completely read my mind. I was using some paper towels to clean the coolant out of my cyinders after removing the heads, and was just thinking the same thing about those hoses. Changing those babies now would be about as easy as swaping out a light switch, and my enigine does incorporate the oil cooler as well. Dont really have any issues with the tranny, in fact had it not been for the coolant leak, I wouldnt have had any complaints about this vehicle at all. Always rode, shifted, and accelereated nice.

The heads will go to the shop tommorow and I'll touch back here in these forums to let outline results. One question though, where did you get your upgraded LIM kit? Thanks again!!! -Drew

I had to go back and look for the order to find it. I had been getting stuff from all over prior to doing the job. I got belt tensioners from one company, tranny parts from another, head gasket kit from another etc, but this came from www.1aauto.com:

Product : Quantity : Price
[1AEIM00014] 1996-2003 GM 3.1L & 3.4L Intake Manifold Gasket Kit With Bolts : 1 : 39.95

The gasket I took out was a plastic frame with rubber seals around the passages. The replacement was a steel frame with the rubber seals. The new bolts came with sealant on them already too.

My reading of this forum and my own observation of the old gasket tends to support the idea that the problem was the plastic frame deteriorating from dex-cool and heat. I think the upgraded gasket will last for the life of the engine now. (no more dex-cool for me either!)

John

When you put the fuel rail / injectors back in, lube the o-rings for an easier install. They should push right in.

Merc, thanks for the gasket info, I thought I would have to pony up a bit more for the set. Thanks for taking the time to look it up!

Nitro, ya think lubing the old ones is alright, or should I spring for a new set whilst its out? The old ones look to be on ok shape.

If you have the rail off, I'd get a new set of O rings. Its not like the price is gonna break the bank. Order 'em from the same place you get the gasket kit. Mine were ugly.

Replace if needed. It really depends on how they look. You will still need to oil/lube them to get them to go in easily even if replaced.

I use lithium based engine rebuilding oil/lube. Straight engine oil would be okay as well.

Anyone know the Gm spec on cyl head torque? My Alldata says 37ft lbs + 90deg. Just wanted to make sure that matched what GM reccomends.

Also, anyone have any thoughts on LIM bolt replacement? The Felpro Cyl Head kit I'm getting does not come with new ones, yet I've seen some kits for just LIM that do. Is there really no difference aside from the locktite? Just wondering if this was neccessary given the low torque, and, Alldata does not say anything about replacing these like it does the head bolts.

Definitely a great idea on the Felpro Pro Kit. I just replaced my GM LIM gasket (lasted about 5K) with the Felpro. Big difference in the rubber seals on the Felpro. Felpro instructions suggest a new bolt kit (which they do sell separtely). My GM kit came with new bolts, and I just cleaned and reused. If the motor has a lot more mileage on it, I would replace the bolts. You can clean the ones you have and put your own thread lock on them. Some say the theads "stretch" so a used one will not torgue correctly. I'm not an engineer, so I am not sure about this.

On the head gasket, most certainly use new bolts. I followed the instructions on the Felpro gasket kit I bought for torque specs. 37 ft lbs seems light. The extra 90 is only a quarter turn. The key for the heads is using the rotation pattern to tighten the bolts down slowly. In Prep work make sure you clean the head bolt holes thoroughly. I cleaned one of the old head bolts and ran it down by hand. and cleaned each hole. I used some brake cleaner and swabbed out the bottom of the holes with a q-tip. You should be able to hand tighten the cleaning bolt until it bottoms out. It takes some time as there are 16. Soak the new bolts in clean motor oil prior to install.

I wanted to say Thank you to those who helped me in this thread with valuable tips and advice. I tried to post pictures of the job, however that feature is disabled for me for some reason. Anyhow, thanks again, got motor finished today and she runs like a champ!

I am considering doing a head job as well.

Do you guys think it would be easier to drop the engine/tranny/subframe assembly instead?

"Easier"? Seems like that would be a hell of alot harder if you ask me. Its really not that bad of a job. One thing I made the mistake on is I had the van on stands and by doing that, the wheels hung too low I felt to rotate the motor forward while in neutral. So in the midst, I jacked it up higher to put ramps under the wheels. Once you have it on ramps, and disconnect the cat converter underneath, you will have pretty good access to that back (or left) side of the motor once rotated forward. It looks more intimidating than it really is. If you pm me your e-mail, I'd be happy to send you pictures I took of my job.

One last thing, if your really that gung ho, and depending on how many miles you have on you machine, if you decide to go the complete removal route I would reccomend going ahead and rebuilding the lower half of the motor. I use a very reputable machine shop where I live and the machinist told me there that while these motors are notorious for the LIM leak, the only problem these motors really have in the bottom end is that they employ a hollow cam shaft and that sometimes they can break in half. Otherwise these engines are pretty solid in the lower half. With that said, he also told me that he wasnt sure if there was even one on the market that was solid. Since my motor didnt run bad at all when I tore it down I opted against going that route. In fact, there was nothing wrong with my heads or the head gaskets, I just felt that after 120k miles, they were probably due since I had it down that far. My machinist said I certainly didnt waste my money doing them either. I would also like to mention that I went ahead and paid the extra $80 ($40 per head) to have them pressure tested for cracks. My guy told me that while the 3.1 heads are far more probable for having cracks, they do have 3.4 heads show up with them as well.

Anyway, I'll stop my tangent now, I will be more than happy to share those pics, and more if your interested. Good Luck!

Dropping the the front motor tranny carriage is pretty easy. I know that's what the GM shops do most of the time. They have the equipment to do it.

When I replaced my motor, I dropped the whole engine cradle out. I put the body up on railroad ties. You will have to calculate the clearance required to roll out the engine. I think I had the bottom of the front end 50 inches off the ground. When dropping the engine cradle, you only have to unplug the wiring to the starter area. The rest of the wiring can be undone once the cradle is down. Motor mounts, steering pinch bolt and strut tops (yes leave the stuts on the knuckle) are the only items which need disconnected.

Also remembered I had to disconnect the AC compressor and move to the front. You do not need to break open the AC lines.

Steering pinch bolt was nasty...

I used a engine hoist with a chain fall to lower the cradle out. The cradle lowered right on the hoist legs, and I could wheel it around my pole barn.

Since then I have also done the head job with the engine in.

I have done both, and because I don't really have the right equipment - doing the heads with the motor in is the easiest way.