Hi van has 147,000 miles on it. turns over but will not start. dos this motor have a timing chane or plastic belt?

TAKE IT TO NOONE ELSE BUT A CHEVY DEALERSHIP AND HAVE THEM RUN A DIAG GIVE YOU AN ESTIMATE. I LOVE THOSE OLD CHEVY ASTRO VANS I HAVE HAD 3 OF THEM. SIMETIMES IT IS CHEAPER TO JUST REPLACE THE OLD VANS RATHER THEN SPEND MONEY ON THEM. THE LAST VAN I HAD I HAD PUT OVER 700,000 MILES ON IT BEFORE I GOT RID OF IT.

I would start at the starter relay have you ever changed your starter it may be that the brushes in the starter are worn way down preventing a good connection at times

have you replaced the timing belt?? it may be shot and vehicle is out of time. replacement interval is 105 K miles or 84 months which ever comes first.

I think it is i will probably have to pull the timing belt, it sounds like it probably skipped due to the serpentine belt cords wrapped around something under the timing belt cover, any other suggestions on alternate causes before I start pulling the brand new timing belt?12

Not knowing the size of the motor you have in the van,i would start looking at the timing belt or timing chain causing the 20 degree swing. If it is a 3.0 liter engine there maybe some wear on the distributor drive gear causing the problem. The only function the flywheel plays is in starting the engine from starter. Has no direct bearing on the timing. The only thing you would have with a distorted or cracked flywheel would be vibration during driving and starter problems (grinding noise starting) (complete lock up of starter if the teeth on flywheel did not line up with starter. Also the engine does not have to be removed from van to inspect the flywheel. The transaxle can be removed from van with the engine still setting in van to inspect the flywheel. If the van has over 60,000 miles on it then i would look at the timing chain or belt. Also on the slipping of the transaxle during the time it was drove i would say that the bands in transaxle need to be adjusted to correct the problem with the transaxle. Hope this will help you.

Running then suddenly and abruptly stopped with no spark = broken timing belt. The Camshaft is not turning due to the timing belt being broken so you will not have any spark.

It sounds like to me that you mite have a bad fuel injector.... try running motor and 1 by 1 unplug each injector harness pluging it back in after each check.. no more than 1 off at a time a good injector slows the motor noticably.. a bad one when un plugged chanes nothing at all..hope this helps

Your truck is going to take about 5.5 quarts.
Since your motor have some high miles on it, I would use non-synthetic 10w-30 oil that has the high mileage formula.
Synthetic will cause leaks on an old engine because the molecules are smaller and will go through gaskets easily.
High mileage formula will help recondition the gaskets.

Probably the timing, get a tune up.

If you are in the habit of overheating the car you timing belt might be bad.

leaks ..it has a leak, i suggest you to dismount the radiator it may be has a leak that could be dried due to the heat, you can also try to check all bypass hoses.