'87 Suburban, help diagnose engine problems (long)

Hell I live in the Great White North, with copus amount of salt, and around here we oil spray every year to keep rust at bay. My 89 astro's body is as pristine as the day I bought it and it is now at 350,000 km with original tranny and motor and still running strong and burning no oil.

Reply to
chrome
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I'm not talking about my personal vehicle(s).

I can only exert influence on a small portion of the 3 million or so vehicles running around on Wisconsin roads.

Reply to
Neil Nelson

Maybe thats why no one knows how to fix them?

Kinda like you? you mean?

dubious,

Reply to
DJ Hatt

So do I!

Hatt

Reply to
DJ Hatt

chrome, what is this "oil spray" all about?

Hatt

Reply to
DJ Hatt

mechanic

No denying that Ian, but I'm not as stupid as I was anymore.

Hatt

Reply to
DJ Hatt

No one? That's an awful lot of people. [snip]

Yeah? maybe? like? me?

Reply to
Neil Nelson

Used to see a lot of people doing this. You basically pop off panels and wash out the crud, then spray motor oil or trans fluid into the body cavities like you were doing undercoating but it doesn't dry out. Then you wait till it finishes dripping out and spray under the body as well and inside the frame rails. Done every 6 months to a year it will really keep the rust away. I also know at least one person who also wipes down the entire body with oil but I think that is a bit too far.

Reply to
Steve W.

The technology has moved on from the days of using motor oil or tranny fluid. In canada we have two franchises, crown and rust check that that use specially formulated oils designed specifically for rust proofing. Along with them there many independent shops using various concotions. The system I use is from a body shop I know. The use a thicker gel type oil spray on the undercarriage and thin oil in the panels. The oils are special mixtures used on ships and rigs in marine enviroments where special oils sprays for corrosion control (as you can imaging, salt water is a tough enviroment) are very common. Very powerful stuff. The best out there. I do it before every winter.

The other dimension to body preservation is external paint care. This envolves checking for paint chips and sealing them (clear nail polish for small one is great, body shop for major ones), and waxing with high quality wax twice a year, once before the summer and once before the winter.

My brother is into the same maintence (also very frequent oil, tranny, power, diff etc fluid changes ) as me and he has an 87 astro with 750,000 km with only a tranny rebuild at 500,000 along with some front end renewal, the roads are hell around here) and the van looks like new and the motor is still in decent shape. Not bad for a vechicle driven year round in winter climes with lots of salt.

We both drive astros, with corvettes (2003 convertibles) for second cars. It is amazing the money you save when you drive an easy and cheap to maintain vechicle for decades.

Reply to
chrome

This is an interim update. We still haven't solved all problems, but I think we are much closer to doing so. Some problems we discovered were due to spark plug wires. The first replacement set DH installed melted (a big block engine will do that, if you don't know to buy wires that will hold up to the heat). Then, the second "idiot mechanic" who looked at the engine neglected to re-attach one spark plug wire. I knew the engine was "off" when I got it back but I did not see why; DH saw the unattached wire as soon as I got the truck home from the shop.

Taking the throttle body apart, DH found extreme wear, to the point that the valves tended to stick and when closed could not prevent flow. That alone could explain most problems with the engine, and also explained the chronically "sticky" gas pedal. DH replaced the TB core and all gazillion gaskets; soon after, the truck started to stall when coming to a stop or near stop, and would not start again easily. Taking the TB apart again, we found the new gaskets were leaking. So, DH installed a second new set of gaskets. Now, for the first time since we bought the truck one year ago, the engine runs very smooth and idles slow. The service engine soon (SES) light still comes on as soon as the engine reaches normal running temperature, but now that may be due to a fouled O2 sensor. (The only code ever pulled off the computer is the 02 sensor complaining about a lean fuel mix; reading the sensor directly shows it was seeing alternately too rich and too lean fuel mixes, that mix way out of whack.) The current sensor is only a few months old, but the constant fuel flooding from the worn-out TB may have fouled it already. So, the next step is a new O2 sensor. If that doesn't do it, then a visit to a good (non-idiot) mechanic with diagnostic equipment to monitor readouts while the engine runs.

By the way, we also discovered that a previous owner removed the engine thermostat, which DH promptly replaced, grumbling about "yahoos". When we first bought the truck, the engine could not reach its normal running temperature; the missing thermostat was the reason why. Did some idiot remove it in an attempt to "fix" the chronic SES light and "lean fuel mix" error code from the O2 sensor?

Old problems remaining from September:

  1. The speedometer and odometer both are inaccurate, by the same amount. This is still true, and the problem has to be the wrong speed/odometer gearing inside the transmission. Leave it alone until the transmission needs work for another reason; meanwhile, take extra care not to speed.
  2. Engine oil is now dripping from the back of the engine, where it joins the transmission. Still dripping, but seems to be slower; keep an eye on it and plan to fix it reasonably soon.

New problem:

  1. Cruise control died. Don't really need it, so fix it later. Una
Reply to
Una

[...]

That's a code 44, FWIW.

I guess it was more than they wanted or were able to take on, but they chose not to say so. Because they were not up front with me, they will get no more of my business.

This shop at least took a stab at the problem but they did not get far with it. Instead they tried swap-parts-until-it-goes- away, beginning with just about the most expensive part. Pass.

More than a year later, I found Shop #3, and Shop #3 fixed the SES code 44. A previous owner had the transmission replaced, in which job the wiring harness got pinched. So the computer was getting garbage data from the O2 sensor. The fix: patch the wiring harness. Cost: $180.

Of course, to *find* the source of the problem took hours of work, during which many other problems were found and fixed (mostly leaks: vacuum lines, gaskets, fuel injector), so the total cost came to $1800, but that is money well spent! Shop #3's compression test showed a nominal 140 (outstanding!) on all cylinders. So I don't need that $6,000 new engine block.

This truck suffers rubber rot (no surprise given its age and the climate here in New Mexico) so a lot of money is going into replacing the gazillion hoses and tubes under the hood, as well as all door seals...and the tires...and and and. But still it is a good deal, financially. New, a 3/4 ton Suburban with the functional extras this one has would cost $40,000. And because depreciation has run its course, I feel comfortable driving it where few people would risk driving an expensive newer truck.

Una

Reply to
Una

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