Re: Help!!! Advice needed, 4.3 liter engine head gasket in a 96 Astro van

As someone else already pointed out go ahead and pull both the seats and cover the front in something you don't want anymore. I used cheap k-mart blankets and just threw them out when done.

The engine is just an engine... Nothing really special or different that will throw a person that with your experience will get hung up on. Be prepared for more than normal amount of crap to break that you weren't expecting. It gets awful hot under there and things seem to age more I would expect from a similar engine in a normal application. Also be prepared for your arms to look like you were at war with a gang of alleys cats. There is no working room in there.

Steve B.

on Sunday 28 October 2007 12:15 am, someone posing as snipped-for-privacy@gmail.com took a rock and etched into the cave:

Um, the big thing you're going to run into is that the van has the engine tucked way in the back. You might have trouble getting to things.

I have the exact same vehicle (purchased new). I have also done the exact same thing to it as you are fixing to do. I have read all the other threads and you have been given a load of good advice. Here is what I found when I did this on my van at about 117K.

1. The 4.3 is basically a small block chevy v-8 with two cylinders whacked off. If you have worked one the other should not be a problem.
2. Mine started as the intake gasket leak. Kept adding coolant as I was dreading working in the tight space. The comment that your arms will look like cats have attacked them are true. Sharp metal and corners everywhere. You will be working mostly inside the van so (like the others have said) pull both front seats and cover the floor. I put down plastic first (this van is my wife's primary and has been kept pretty clean), covered that with cardboard, and then put blankets on top. Maybe overkill but laying on the floor to work on the van was a lot more comfortable.
3. There is a special intake gasket (again mentioned in another thread) that is a must. I hard a hard time locating in town as most part stores want to sell you what they have. I ended up ordering from rockauto.com.
4. The advice on the fuel injectors is true. I learned the hard way and ended up replacing the entire spider assembly. There is a newer upgrade to the OE model out there so if this happens go for that one. I believe that my costs were about 0 to 5. I got mine at a local NAPA store (could not wait the additional downtime on internet ordering to save the bucks). As a plus once I replaced the assembly the van is now getting better mileage.
5. You will strip the front of the engine. Does it have AC? If so, I did mine without breaking any connections. I wired the compressor assembly straight up from the motor to something under the dash. I do not remember what I wired it to but it held the entire time.
6. I replaced the fan clutch, idler pulley, thermostat, all vacuum lines, heater hoses (does the van have rear heat?)(easy to get to them now), oil sending unit (leaking), and basically any thing that I felt would not last another 75 to 100K. Another thing on removing the fan clutch. I used a large (14") crescent wrench as I did not have an open end that size. It runs in my mind that this is reverse thread due to engine rotation. Also when I put mine back together I did not tighten it near as what it was from the factory. Engine rotation will always tend to tighten it so I felt OK at just "very snug".
7. It took me two solid days to take apart and put back together. 1 day downtime at the machine shop. When you go to put back together you will need help from someone. I found it easiest to have one person up front and me inside. We worked together at setting the heads and intake manifold.
8. Plastic zip lock bags, I used a bunch of them. I would take a permanent marker and write on the bag what the bolts went to. I then placed them in order, reversing them when going back together. Kind of kept me in proper sequence.
9. Distributor, before you remove it mark the housing position on the engine block. Then mark the rotor position on the manifold. The computer sets the timing so if you get it back to where it was originally it will work.
10. As someone else mentioned heat is a killer under here. I ended up replacing the ign coil, new wires, cap, rotor, and other items related. It was way easy for me to spend my own money (probably overkill but I do not want my wife stranded by a part that I could easily replace now).
11. If you have good mechanical common sense this project will not be a major pain.

Take Care, GM

Oh mann...this is a scary thread. I have a 98 Astro that leaks coolant but I haven't had a chance to investigate where from. It leaks it out onto the garage floor and appears to be coming from to front of the engine on the passenger side. It seems to leak about a quart and then stops leaking...kinda weird...and like GM I've been adding coolant every so often. So far I haven't seen any oil in water or vice-versa...I wonder if it could be something besides a manifold gasket? It only has

60K miles in it and has never overheated. Having done some work on it I don't know if I'd be up to something like this. My wife's been talking about a new car anyway so maybe it's time...

snipped-for-privacy@gmail.com wrote: Posted to alt.trucks.chevy, rec.autos.tech, alt.autos.4x4.chevy- trucks

Subject: Help!!! Advice needed, 4.3 liter engine head gasket in a 96 Astro van

Background...

At first I was going to suggest just buying another Van as it might be cheaper and definitely easier; but I was surprised at these vans resell value. If initial estimates for fixing the old van are near $1000, it might be better to just buy another van. I did a quick search on Craigslist in my area (North Texas) and found a 2000 model with an asking price $2650:

Of course you can get lower prices with older cars or different locations.

I have a 4.3L engine in my 1995 blazer, and so far have not had the water leak problems. I have had them in my 1998 Suburban, however, and had it repaired 5 years ago. My mechanic suggested using the old green anti-freeze as he has the theory that the new dexcool stuff contributes to the water leak problem. So far his theory is holding up; we've put 75000+ miles over the last 5 years and no problems. BTW, my 1995 blazer never used the dexcool; it was just before dexcool was released. However, a week after the repair and switching over to the green antifreeze, the water pump started leaking... very badly. My mechanic said that it didn't surprise him, and it was because the dexcool coats the inner parts of the pump. As the dexcool desolve, the coating that was blocking leaks goes away. I was dissappointed that he didn't tell me that before doing the job so that the pump could have been replaced at the same time (with very little extra effort). So I decided to replace the pump myself instead of hiring him; it was an easy job anyway. BTW, the actual reason for the intake manifold leak problem is because GM redesigned the bolts to go in at an angle relative to the manifold. Why they decided to change the design is beyond me; the perpendicular design was used for decades and was proven. It almost makes you think they wanted bad design.

Good luck with your repairs.

Best Regards,

John Hermann

Your problem sounds more like a bad water pump.

Bob

The passenger front is where all of the heater hoses (mine has both front and rear heat and AC so if your does not it may be different) come together along with the vacuum valves . May also be the bottom radiator hose or possible the bypass hose. Defiantly get a light and track it down. If it has been leaking for a while you can trace the stains back to the source. Mine leaked down the back of the block. GM

Mine has dual air also. I'm hoping it's a hose or valve or maybe the overflow bottle since it seems to only leak a certain amount. Someone else suggested water pump. I gotta find time to dig down into it and have a good look...can't see with all the junk in the way. It's just been too damn hot around here (Phoenix) to work on it but it's getting cooler (way down to the mid 90's this week) so I'll probably get into it this weekend or next. Just about anything would be better than a manifold gasket. Here's hoping...

If it is the intake gasket leaking and it is allowed to do so over a long period of time plan on replacing the intake manifold as well. The leaking coolant will erode the manifold. And Dexcool has nothing to do with it, or my 91 would have never failed.

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