92 GMC pickup 4.3 questions

Hi I have a 92 GMC Sierra 4.3 V6 about 127K miles. I bought it a little over two years ago from the original owner with about 92K. The truck was pampered and came with a thick stack of receipts for repairs and maint
done over the years. I have had absolutely ZERO problems of any kind --until now. The cooling system went from nice green coolant to rust almost overnight. This morning I topped it off and let it run for a few minutes. Looked in the overflow tank and saw bubbles. I know that usually means head gasket, but can intake manifold gaskets also cause that? I know some GM engines had bad problems with them. Is this engine one of them? It also recently started getting a "check engine" light intermittantly, and the almost unbelievably great gas mileage-- about 20-- dropped to about 16. There does not seem to be any water in the oil. I am not driving the truck anymore until I can get it to a friend's shop, and get it fixed, but I'm just curious, and a little worried. I love the truck and am going to keep it regardless of what it takes to fix it-- just wanted some idea what to budget for. As to a previous thread about 20 year old vehicles-- here's a 19 y/o, and this weekend I'm going on a 500 mile round trip in my 86 C10 6.2 Diesel-- since the problem with the other truck. (high school reunion -- shudder -- 40 yrs) . FWIW, I don't see that many new style Tundra's here, and "here" is San Antonio, where they are made. Don't know anybody who has one, other than a friend who had a rental while the ins. co. was settling on his totaled 03? F150. He said he didn't care for it that much and would never buy one. Any and all info/advice on the 92 V6 will be greatly appreciated. Thanks Larry
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Lp1331 1p1331 wrote:

I would bet you need intake gaskets and probably new O2 sensors as well.
The bubbles were more than likely air being purged out of the engine as it warmed up, after you topped off the coolant. The color change could be air or more likely the coolant got low and air in the system formed some flash rust that colored it.
The bad intake gasket is letting coolant get into the intake runner, this gets run through and causes the O2 sensors to be contaminated. You get crappy mileage and a check engine light as well.
Make sure you use the good steel cored gaskets and follow the new torque specs when you install them.
--
Steve W.

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Hey, thanks for the replies. I haven't done anything with it yet. Hopefully this weekend I can get my neighbor to help me get it to my friend's garage. I could do the work myself, but my friend need some a/c work done, which is my trade, so we help each other. About the O2 snsor(s)-- are they rnied? I guess when they are contaminated they cannot be cleaned? Just wondering-- I really don't care what it costs as long as it is fixed right. BTW, took the old 86 Diesel on the trip-- not a minutes problem with it and about 22 MPG. HS reunion was absolutely fantastic! WebTv is great for usenet and Email and that's about it. It's days are numbered with me. I would have gotten rid of it sooner but needed to keep the same Email address for the updates on the reunion. A freind who messes with computers is getting me one. I had one along with this, but it was a POS, and finally quit. When I get one I'm gonna call WebTv and tell them I'll give them $10/mo (or maybe less) for their service and they can take it or leave it. Thanks again for the info on the truck Larry
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On Wed, 28 Oct 2009 22:47:47 -0500, Lp1331 1p1331 fired up the etcha-a-sketch and scratched out:

What steve said.
You have a 17 year old truck with 127K miles. You need new gaskets.
People still use webtv?
--
perfectreign
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