Chevy & GMC Vans

I'm going to buy my first astro as soon as I can get going from my knee surgery I had friday. The current owner claims it has a bad head gasket. It's been a few weeks since we talked about the symptoms. He said his mechanic checked it out and came to head gasket conclusion. I do remember him saying it lost power and wouldn't go over 25 mph before he parked it in the fall.

So I've done some searching an have not been able to find info on doing a head job on a 2000 AWD. Can the work be done with the motor in the van. I'm kinda spoiled with my old 3/4 k2500 GMC trucks which are easy to work on compared to what these look like.

If the owner is right about the head gasket, what would be the symtoms? milky oil? bubbling in the radiator? compression differences? How much of this can I check without lots of work before plunking the cash down?

I think the van has about 160K with a rebuilt tranny and a bunch of other new parts so It's worth fixing. I'm hoping that it can be done with the motor in the van. Pulling one doesn't look like much fun.

While doing the work I'm also looking to do modifications that will improve mileage. I have a friend with a 99 rear wheel drive and he says all he can get is 15 mpg. I've read here that 20 or better should be attainable. I could just keep driving my old 3/4 trucks for 15 mpg numbers.

Thanks in advance.

Short answer is...yes, the head gaskets can be changed with the motor in the van. It's not an easy job but you will save youself some serious bucks if you can do it. The definitive test for blown head gaskets is a compression test. That's the first thing before any work starts.

Well I was hoping for more details.....more will be revealed I'm sure.

Does installing a 2" body lift before hand make the job easier?

Do you have a good place to work on it? Your question about the body lift has me thinking it might not be a bad idea for you to drop the sub-frame, take care of the heads, then put it back together with the spacers. Then again, I haven't had to do any of that yet.

Aaron's plan is spot on. If you combine the head gasket job with the lift the head gasket job will be about a bizzilion times easier. And while you're at it do both head gaskets.

I spoke with the owner last night, oil is a milkshake.

Doing the work in a gravel driveway, some day things will be better but at least I will be able to feel my fingers as it is warming up.

If I pull the cowling from the inside of the van would I have access to the motor?

seanmx57 wrote:If I pull the cowling from the inside of the van would I have access to the motor?

Yes. You'll be doing most of the work from inside the van.

Where are you located?

Before you tear into this motor do a compression test. There's more than one way for water to get into the motor. When I did the intake gaskets I found that water was leaking into the inside. Another hint......remove both seats before you start. Only four bolts each. Only takes five minutes and you'll need the room.

I'm in New Hampshire. I'm hoping to get this done before the state bird (mossiquito) shows up for spring

I saw the 2" lift idea in another thread. I guess I better brush up on that as well. Of course I could tear the inside apart and do an evaluation as well.........

I was wondering if something else could cause the milkshake. Yes I'm a fan of compression tests and pre-tear down evals. Nothing worse than fixing a symptom NOT the problem and having it bite you in the butt again.

Can a blown intake gasket account more crappy power and rough running. The PO indicated this was a somewhat gradual onset not an event.

I read on here where a member WAS getting 23 mpg and did something mod and his mpg dropped to 20

Anything on these vans can be done on a gravel driveway. Trust me.

yeah gravel just makes finding lost parts more fun. you guys are a bad influence. I have several 350's kicking around from my 3/4 ton trucks as well as running gear. They are all running old school carbs so I doubt I will be doing anything other than fixing the 4.3

I'm pretty tired of the bad mileage on my 350's. I have managed to get a 86 3/4 4X4 running about 12 to 13mpg with headers, torque style intake and a crane cams multispark unit.

Many may disagree, but I wouldn't bother with doing head gaskets if the oil is a milkshake and you don't know how long it's been that way.

It's about as easy to change the motor than to do the head gaskets on a van; I've done both a few times and would just as soon swap the motor now than wait for the already scored bearings and bottom end to possibly fail 5K miles from now. You'll be swapping it at that point anyway. Antifreeze and bearings don't mix.


The other option is to pull the engine and check all the bearings and then do a minor rebuild (bearings, seals, timing chain, gaskets, maybe rings and a valve job).

OR......There is the V8 route.....

thanks for the input, I didn't know about bearings being affected by the antifreeze.

"Once i first noticed the problem i drove it about 10 miles. but i only drove it about two miles cautiously once it starting affecting how the vehicle drove."

Statement from the PO.

So The lower end may be OK if a go on his word. We know how that goes........

Plan for a complete junk engine and then if the bottom end is ok, bonus! I would plan on doing gaskets and bearings as well as heads and head gaskets. You would have a fresh engine then. Don't forget the oil pump.