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Author Topic: Does this gunk mean I have an internal engine coolant leak?  (Read 787 times)
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Tronman
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Any car gets great mileage when you ride your bike


« Reply #15 on: April 13, 2018, 09:49:27 PM »

Here is one of  the culprits which began this whole valvetrain replacement adventure..  NAPA doesn't catalog the original rocker arms for this vehicle, although they do have the pushrods.  My machinist found a source for them..  most of $400 for twelve rocker arms..  

[Edit to include a picture of old and new rockers side by side.]
« Last Edit: April 13, 2018, 10:31:27 PM by Tronman » Logged
Tronman
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Any car gets great mileage when you ride your bike


« Reply #16 on: April 13, 2018, 09:58:09 PM »

So I decided to go the aftermarket route and get some Comp Cams roller rockers, about $248 for all twelve.  These are the catalog listed rockers for this engine.  The ratio looks right at 1.6:1, however there are other problems.  The roller tip is a little bit higher than the stock rubbing block, so the pushrods become too short!

Also, I'm pretty sure these are meant for a studded head application, because they come with bolts which you could adjust and then tighten an allen head inner lock bolt.

Well, the diameter looks close on the roller shaft versus the OEM ones, but..  nope.  It's bigger.  I got out my micrometer and measured the difference.  Also, the factory pedestals would hit the aftermarket rollers before rocking back and forth enough to open and close the valves.  I could enlarge the diameter of the circular portion of the factory pedestals, which would then lower the rockers.

Oh, and one other thing..  the new rockers have this lip which protrudes below the roller rocker, and it's bigger than the difference between the valve head height over the keepers.  So I'd have to take some of that lip off too.  That'd be the easy part of this operation..

This is turning into quite the old school back yard hot rod project here!
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Tronman
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« Reply #17 on: April 17, 2018, 05:38:25 PM »

Well crap.  It turns out that the old number of 12576628 that I'd gotten from several sources for this rocker arm is an invalid number now from GM, and is no longer in their system.  I finally called the dealer and they have, for $38 apiece, in two different out of state warehouses, all twelve of PN 19333180.  That's the good word on the actual rocker arms for  this engine.

I'm having my local (independently owned, not a Corporate store) NAPA cross this number and find something more reasonable in price.

I sent the Magnums back, as I don't have the time to fabricate stuff right now (maybe later, when it's not such a time crunch situation..) and Jeeezus this has been a headache!!
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Tronman
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« Reply #18 on: April 24, 2018, 06:56:15 PM »

After an arduous search I finally found the twelve rocker arms and pushrods..  that set me back an extra $497!!

After fussing and working and solving a thousand little puzzles and using every torque wrench I own, I finally got it together and..

IT PURRS LIKE A KITTEN!!!

I've so missed my car!!

I couldn't remember how one of the firewall (right side of engine) spark plug wire holders bolts down, so it's just sort of dangling, which I know is incorrect..  but I haven't yet found the right diagram for it.  Meanwhile however, it sounds fan frickin' tastic and as soon as I get the muffler for it tomorrow, I'll be able to verify that it no longer does the power fade thing at 40 percent of calculated load..  Hey, I know for damn sure there aren't any vacuum leaks or a bad EGR valve now!!
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Tronman
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Any car gets great mileage when you ride your bike


« Reply #19 on: April 26, 2018, 06:25:09 PM »

Well shoot.  On the plus side, no leaks :-D  and it runs great until..  41 percent calculated load than OL Drive mode crap out, no power.  Fudge.

It's still running lean, and I by Gosh know *there aren't any vacuum leaks!!*  I had all the manifolds cleaned and tested/inspected by my machinist and was religious about following torque specs and sequence.  So now I'm thinking fuel pressure regulator or injectors? I don't know where else to look, so I'd love to hear any suggestions.

Here are a couple of pics showing the exhaust heat shield that I rebuilt out of roof flashing aluminum.  The old one had melted when the muffler blew out, so I repaired it.  At least the exhaust system is right.
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Tronman
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Any car gets great mileage when you ride your bike


« Reply #20 on: May 18, 2018, 10:30:22 PM »

Well here we are with the pistons once again seeing daylight when I open the hood..

75 miles in, and a crankcase full of coolant contaminated oil.  Again.  Ffffuuuudddddggge..

I took it all apart and I couldn't for the life of me see anything leaking and it all came apart like I'd been OCD about torque specs and sequence..  well I noticed a couple of the rear head bolts seemed like they weren't as tight as the others.  So I beat myself up pretty good over that for a couple days, even tho I *knew* I triple checked everything..  then the machine shop calls.

Wes asked me if I'd had him pressure test the heads.  I told him I said to, but he didn't because "these engines don't ever crack heads, they're a pretty solid casting."  So I told him to pressure test it *again* and guess what..  I didn't screw up.  The rear head had TWO BIG CRACKS BY THE CENTER CYLINDER VALVE SPRING SEAT AREA and that, dear reader, is where the coolant was leaking into my oil and why it is that even tho they hooked me up, doing a bunch of the work for free and selling me the gaskets at cost..  I'm out an Aztek for another  three weeks and another five hundred bucks in machine work, bolts and gaskets.

WHY AM I A SINNER IN THE HANDS OF THE ANGRY AZTEK GODS?!?!  I mean apparently I must be, cuz I've kinda been smote..  smited..  smitten?  Cursed? I dunno..  Crap.  Well at least my valve gear is all new this time  Grin Grin Tongue
« Last Edit: May 18, 2018, 10:52:24 PM by Tronman » Logged
Tronman
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Any car gets great mileage when you ride your bike


« Reply #21 on: Yesterday at 10:57:54 PM »

I got about ten minutes of run time out of it this time..  before it turned the new oil orange again with Dexcool.

Yep, it's gone bad three times now.  But on the plus side:  my brake harness wiring repairs worked and the ABS  and AWD disable indicators are both out now!!  I fixed the electrical problem, yaay!!  Except for the part where I can't drive it because the engine's full of coolant.

I'm ready to give up and sell it as a mechanic's special.
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