a motor that got HOT...

[midwestls]

Alright, so things aren't looking so good for me in my search for an engine for my Astro up here. It turns out it's a 94-95 only 4.3 Vortec. I've been to a couple different Astro forums I've found and basicly no help as to why a 96 one won't work other then it's OBD 2. I understand this part, but if I have both complete motors lay'n in front of me why can't I swap wiring and sensors as needed? I have a 96 Blazer avail to me for next to nothing that's wrecked. My other thought is to get some opinions on what I might have/be able to do to fix the motor in the van. Long story short, the guy I got it from was on his way home (on the highway somewhere) when the water pump went out. Of coarse he didn't notice it till he stopped and heard an outrageous knock. It's bad. So she got hot. But it starts right up and still feels like it has lotsa power (from the little bit of movin it around I've done). What do you guy's think I should do? I'm guessing bearings, but what else? Hopefully it didn't heart the heads, I'd think it would be lacking power if it screwed them up right??? I'm tryin to find the most cost effective way to fix it. It'd be cool if I could do it still in the van, but I'm sure I'm not that lucky. Idea's guys?

 

[Uncletruck]

I know a guy who is a retired GM dealership mechanic. He replaced engines in those Astro vans frequently due to overheating. It usually gets the head gaskets before the bearings go, so if the bearings are gone, I would venture on the whole engine being toast, and probably not worth doing a bearing job just to find out. When this mechanic got an Astro and heard it had overheated badly, he just recommended replacing the engine because if he didn't, the vans would just keep coming back with more engine problems soon down the road. He replaced more 4.3 engines in Astros than any other GM vehicle during his career.

-UT-

 

[pontiacgp]

an over heated engine will give you some heavy spark knock so you may have got lucky since it seems to be running ok. If it was a bearing knock that knock won't go away unless you threw a banana or 2 in the crankcase...

 

[dan2286]

If it was a bearing knock that knock won't go away unless you threw a banana or 2 in the crankcase...

Have you actually tried that??

 

[pontiacgp]

If it was a bearing knock that knock won't go away unless you threw a banana or 2 in the crankcase...

Have you actually tried that??

yup...I'm real ole school. It can work for a while and it's best if you don't peel them first... 8)

 

[midwestls]

Yeah, it's defiantly more then a spark knock unfortunately. I guess I don't get why it still has good power!?

 

[Uncletruck]

The engine was likely shut down before scoring occurred to the rings and cylinder walls or the valves burned. Thus it probably still has good compression and power. But the head gaskets will probably leak, the heads can be cracked, the lifters and cam are likely shot, etc. It just winds up being easier to replace the long block rather than repair the engine.

-UT-

 

[midwestls]

Thats what I was figuring. Just figured I'd get some opinions though. Anyone got a 4.3 they wanna get rid of? I was almost thinking, at a time, about puttin a 350 in it. People on the Astrovan forum will tell you all about that but won't really talk about anything else. Anybody know why I couldn't use a 96 4.3 in my 95. I know the later 95's had a crank position sensor in the timing cover and 96 was OBDII. And the interchange says 94-95 only. But if I had my complete engine layin in front of my, and a whole truck with the 96 motor can't I make it work by switching and swapping sensors and wiring??? I know with Chryslers (some of them) you can. I put a 97 motor in my 94 LHS I had and was able to just change some parts around. But nobody has been able to tell me anything with this.

 

[pontiacgp]

Yeah, it's defiantly more then a spark knock unfortunately. I guess I don't get why it still has good power!?

I had a 2.8 come into the shop when I was working in FL and it had a busted crank at the 2nd main journal and I mean the crank was broken in 2 pieces........and it wasn't towed in, he drove it in with it knocking and the pulley wobbling...

 

[midwestls]

damn