my old friend astro has been very ,very good to me. he has been a part of our family for a long time. I’ve put at least 350,000 heavy duty working miles on top of the 150,000 we started with. i’m extremely impressed with its 4.3 heart. when we first got it I had to run some head sealer through it the first week an went on nicely. the little van had unbelievable pulling power.i’m a rock mason /carpenter always pulling something up an down the mountain 6 days a week most weeks loaded with tools. i took good care of it ,oil change every 25 to 3’000 miles.it just got its forth tune up. plugs, wires, cap button an filter. but all at once in the last month its falling apart. i put wheel bearings, rotors pads ,drums ,shoes all new tie rods, because if I just looked at the brake pedal, it would shake you right off the road. all that fixed the shimmy, but now there is a metal grinding metal sound like bad bearings but I can’t figure out where its coming from. braking an steering seem fine but I often have my wife an three little ones with me so it’s got me stressed. i don’t know if all the jerking around the road messed something in the motor up or it’s just at the end of its rope, but now it’s missing on the idle and take off and I can’t keep gas in it. really twice the gas it used before I replaced a few vac lines, ran a few gas treatments through it. nothing helps. it has 1/4 the power it had. i had to replace water pump and thermostat was our last deal .water was pouring out the valve thing. well it did ok for about a day an half then it kept running out of coolant every 2 to3 days but it’s not leaking at all. it’s just disappearing and running terrible. oil looks fine. there’s a bad vibration on idle. i don’t know where to go from here. is it just worn out, or am I missing something? we can’t afford anything new, especially after putting all the money in it. i will try anything, and greatly appreciate any advice. from what I’ve read on another post, I’m definitely asking the right people. we thank you so much for your time.
Those 4.3 engines are nearly bulletproof. I didn’t think GM could build a better V6 than the 3.8 but the 4.3 is just as good if not better than that engine. I would get a good independent mechanic to do a compression check on your engine. Sorry to say but it may be on it’s last legs since it has a half a million miles on it. Post back with the results…but I think your problem could be a blown head gasket maybe both.
If the coolant is disappearing, you might have failed intake manifold gaskets. That is common on the later 4.3 engines. I don’t know if the earlier engines also had this problem, but you’ve definitely got enough miles that I wouldn’t rule it out.
This isn’t a terribly complicated repair, but all that coolant in the crankcase may have damage the bearings.
Here’s an idea . . . put a large tub under the oil pan and drain the oil, after you let it warm up.
If the oil looks like coffee, you know where the coolant went.
Two things have happened to my Astro that have resulted in a difficult-to-place grinding sound. One is the rear brake shoe linings cracking right across the middle, the other is the front wheel bearing coming loose (not pre-loaded properly by the mechanic.) I would inspect those first as those are something you can remedy. Also I’ve encountered a problem with slowly disappearing coolant, it may be a slow leak in your heater core. But don’t worry, that is also very easy to inspect/replace from under the dash.
The grinding noise combined with the increased fuel consumption suggest to me a dragging brake. Jack it up and spin each wheel. Listen for your grinding noise.