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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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Discussion Starter · #1 ·
WEEKEND UPDATE:
Well I learned some VERY interesting AND surprising information this weekend!

* Issue #1: So a few weeks ago, my 2000 was suddenly starting rough on 5 cylinders in the mornings, but would quickly clear up and drive great the rest of the day.
* Issue #2: It also developed a seemingly unrelated random lifter tick about the same time, which randomly comes and goes.
* Issue #3: The 3rd issue was about a week later when I almost overheated getting on the highway (temp spiking up and down), only to discover when I got home my radiator was almost empty.

I've continued to drive for a couple weeks or so under these conditions, now keeping an eye on my coolant level, learning that something is drinking my coolant. It's not leaking. Oddly, the van can sit for days over an entire weekend, and radiator still has quite a bit of pressure when I loosen the cap, so no leak there. Also note, the reservoir is no longer exchanging or feeding coolant, even though it can be full and the radiator empty (reservoir level never changes). Hose and new cap are fine, and reservoir has always worked properly for years.. suddenly it's not.

My work and daily life is SO slammed.. I finally got a moment to get my OBD codes, and discovered cylinder #5 showing misfires, which makes sense but as to what's causing it for certain would still be unknown whether it's electronics or mechanics.

So I decided to do a "leak-down" test to see if I have an issue. It's well known that a "compression test" may not reveal all issues, where a leak-down will offer different results.

So I purchased a nice leak-down tester I found at my local Harbor Freight. There were cheaper generic Chinese models, but with horrible reviews, often breaking first use. This one is built well and reviewed well.

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I pulled 6 plugs and did a complete leak-down test on all cylinders, saving #5 for last (so I have something to compare). I accessed all the plugs though the fender openings (both sides), it's quick and a straight shot in and out...

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Straight shot in.. both sides!
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The hardest part of doing a leak-down test is getting each piston to top-dead-center on a compression stroke (or somewhere close). Guessing without an actual indication makes it tricky. Often I'd get it close, but the compressed air would sometimes push the piston down and repeatedly open a valve. I came up with an idea of using an air-hose attached between the engine and my tester, which I could now hold at my door while cranking the engine over, attempting to get it in the right position. This worked extremely well, and made the rest of the job a breeze.

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All the cylinders came up about 90% or better, with exception of #4 (which came up 75%..I suspect possible worn valve issue).

Surprisingly #5 came up exceptional at 95% on the leak-down!
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I additionally did compression tests on all 6 cylinders.. readings varied as expected on an engine with 245K. Cylinder #4 (the one with 75% leak-down result) also came up with lowest compression result.

Here are the various results:
(leak-down column #1, compression column #2)

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Surprisingly, #5 (my suspected bad cylinder) not only came up excellent with very low leak-down, compression result was also very good!

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So... HERE'S THE SHOCKER!
While doing the leak-down test on #5.. I hear bubbling as I walked past the radiator and discovered THIS!


While I've never done a leak-down test ever before.. I suspected that I may ALSO want to keep an eye on the radiator as well, which DID expose my blown head-gasket! Surprised to learn however, the "leak-down tester" did NOT reveal any issue, and even showed this leaking cylinder to be better than some of the others. Additionally as expected, the compression test did not show an issue either.

The leak-down tester was a BUST!
It did NOT show my leak.
(I suspect results may vary depending on size of leak, and mine is very small)

I also suspect some of the "more experienced" may already know all these things, including simply watching for bubbles in the radiator. It should be noted that I did not see bubbles with the engine running, but only while under pressure from the test.

Sidenote: I have a radiator combustion tester which I didn't use.

So there it is. The leak-down tester was a waste of money (although it did reveal #4 has a possible valve or ring issue).. but the test itself did expose my problem, and exactly where the problem is too.

I have NO plans on repairing or rebuilding this engine. I'm going to try one of those "pour in your radiator" chemical additive solutions and hope I get lucky. I hear it "sometimes works"... at least for some.

New spider, new distro, new plugs & wires tune-up, new radiator, new water-pump, new steering pump, new alternator, new brakes, new fuel-pump, new transmission.. all within the past few years. I need to keep this van going.. too much invested. It's also my daily driver.

I also did something else I've never done before.. I did an "oil flush". This strong chemical additive is only meant to be temporarily run in an idling engine for 5 minutes only. Normally I would never attempt this, but I'm giving it a try.

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I'm pretty good with regular oil changes and I always use quality synthetic oil. My oil pressure is strong at 60psi typically, and about 40psi idling, which isn't bad for 245K.

Well that's it! I had a long run with ZERO issues, and now this! For now, I'll have to keep refilling my radiator every so often (for years I never touched it, and fluid was always bright green). Running a no-pressure cap seems to temporarily help (for now), and now the overflow reservoir is at least working back and forth again.

Oh one more thing.. to add insult to injury (after this weekend), I surprisingly had a dead battery this morning! This typically doesn't happen, and nothing was left on. Fortunately the battery was only low enough not to start, and only needed a quick jump. I noted however, the red alternator light was on before I put the key in the ignition, and after starting noted my charging voltage gauge is lower than normal driving to work. It's raining this morning so I haven't had a chance to take some actual measurements, but I suspect my recently upgraded alternator has suddenly failed. The only thing hard about this life-time warranty replacement will be finding the receipt...lol

It's suddenly been crazy! In addition to a blown head gasket, ticking lifter, and possibly failed alternator... I just got done warranty replacing a failed performance aftermarket water-pump on my 92. At least it's back to 100!

Keeping busy... work all week and shows every weekend!

CRAZY TIME! :D
 
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Some good diagnosing there, and good tip on plug access!
HF has been pretty good on returns, for me anyway in VA, could probably return it if you'd rather the $$ over another tool.
I feel ya on having to keep filling the radiator, in years past I had an Accord and Trooper both of which I had to carry a couple gallons of water with me lol.
I forget now what the Accords issue was, but the Trooper was notorious for leaks developing under the upper intake. Not as bas a head gasket but still quite a bit of tear down.
Ahh the joys of vehicle ownership...
 

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bummer Mmusicman !!
this Bar's Leaks stuff bought me 6 months on a pretty good lower intake leak on my '99 (the dripping pic was taken right after last thanksgiving).
i just eeny-meeny-miney-moed it at Autozone...& i have no clue what it might do for a head gasket leak.
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it got me through the winter leak free & didn't clog up the heater core, however, it's started to drip again in the last few weeks.
i've been & still am driving my van daily.....but i'm really gentle & just tiptoe around locally.
i don't know if retorquing the head bolts would do yours any good ??? :shrug:
 

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If you go in that deep will you do it all? Or is it time for an engine swap? Great info I would have thought the leak down test would have shown the problem.
 

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What psi did you set the leak down tester too? I think mine says to use a pretty low psi, which might have been why the head gasket didn't show up there, but the increased pressure of the compression test did.
 

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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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Discussion Starter · #6 ·
I ran the leak-down test at 100psi (as pictured)
 

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Discussion Starter · #7 ·
UPDATE: Wrong call... Alternator is working fine (haven't touched it) ... charging at full power.
Something odd happened.. (I have reason to suspect possible ignition switch issue.. but unsure if that could even happen)

Head gasket however, is STILL blown... :shock:
 

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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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Discussion Starter · #9 ·
I have another V8 sitting on a stand (been there for 20+ years now).. a pretty bad-*** 400sb, roller-cam, trick heads, etc etc (used to be supercharged too). I seriously intend to put this in my 92 (without supercharger).. and maybe move the 350 to my AWD 2000 van. But even the 350 is a quite a bit too radical.. I'd rather put in a stock 350 crate motor. I want my 2000 to continue to be a nice daily driver.. strong, smooth, and quiet.

WinnieVan said:
The real question is: Is there a "double v8 swap" achievement?
LOL! The way I see it.. when a V6 dies, you replace it with a V8.
I have 2 vans, and already have 2 V8's.. why not!

But I'm just NOT ready for all this YET! :D
 

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I say start gathering parts for the swap and do it in the fall if possible. Once I gat my Astro on the road (soon I hope) I want to find another s-10 to V8. But if I do it will be a 5.3 LS with a 4l60e.
 

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Another good head gasket sealant is Blue devil head gasket sealant. If it is used following all the instructions step by step then it shows amazing results.
I have written all the instructions of using it and how it benefits you. I conducted detailed research, collected review for this product and shared all results in form of blog post. Also this product blue devil head gasket sealant is available at amazon.
You can find the FAQ's, reviews and instruction guide here ->https://thereadtoday.com/product-review-bluedevil-head-gasket-sealer/

Blue Devil Head Gasket Sealer Instructions & Review 2021
 

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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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Discussion Starter · #12 ·
thereadtoday said:
Another good head gasket sealant is Blue devil head gasket sealant.
UPDATE JULY 30:

OMG!!! IT WORKED!!!

I went with the "Blue Devil Head Gasket Sealant" and it worked.
I was surprised, but I've heard a lot of praise for the product.
I've been told the "fix" is permanent.. so we'll see.

Now I battle my other issue... lifter tick and unusually high oil pressure.
Hoping it's not something bad. Yesterday it went back to normal.

Otherwise.. all good.
Today I take my 92 out for some weekend fun.

Cheers!
 
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Thanks for the product plug/follow up, will definitely keep this mind.
Even at only 71k miles I reckon I'll have to deal with this at some point, and I'm slower than molasses getting around to things!

Edit: I see a number of varieties, mind giving a link to the specific variety you used por favor.
 

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Discussion Starter · #14 ·
Despite other similar products, numerous people I know had success and recommended this exact product. The success reviews were quite good as well, so I went with it. Here it is a year later... I wasn't disappointed.
 
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