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AZTEK GARAGE (Peer Support) => POWERTRAIN/PERFORMANCE UPGRADES => Topic started by: Tronman on February 01, 2018, 05:58:26 PM



Title: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on February 01, 2018, 05:58:26 PM
So while I was working on the EGR valve, I happened to check the oil.  It looks a little dirty, but still translucent and honey colored on the stick like always.  But when I pulled the PCV valve, there was this yellow gunk under it.  I stuck a finger into the oil cap hole and this came out.

I've seen it have some condensation under the oil cap in the winter, but never thick gunk like this.  There are no visible external coolant leaks such as the LIM, for which these engines are known.  But before the weeping and head gasket R and R out in the rain begins, I thought I'd run this by the ole' Aztek hive mind.

This engine has been well maintained and it has never overheated, and I've never had to take any of its lids off-however it does have 227K miles on it.


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: wstefan20 on February 04, 2018, 07:02:40 PM
Well that is strange.... usually coolant mixed with oil is milky and chocolate colored. This definitely isn't normal. Have you been losing coolant recently? If so, I'd rent a pressure tester at oriley's before condemning the engine. Any other info that might be pertinent?


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on February 10, 2018, 12:20:13 AM
Can't think of anything.  The vehicle has used slightly more coolant lately, but it's had a slow radiator leak for some time.  Due to a lean running condition which I believe to be the cause of a random misfire which causes the engine to go into OLD (basically return to a sputtering idle) like clockwork at 41 percent calculated load..  I'm taking the top off the engine for LIM gaskets anyway.

Since LIM is about eighty percent of the way to head gaskets, I'm gonna do 'em while I'm there.  Still hyped on my Aztek overall, I intend to keep it for another 200k miles..  plus the bottom end is solid, it's never used a quart of oil in total for the whole time I've owned it.


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on February 11, 2018, 01:26:44 AM
Yep, there's an internal coolant leak..

But I'm not entirely sure it's the head gaskets..  As you can see in the pic, I caught it pretty quick as the gunk hadn't even spread all the way from the rear of the engine to the front..  (left side of the car to the right..)


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on February 11, 2018, 01:31:58 AM
The other thing I noticed is that when I removed the LIM, the rearmost bolt to the right was barely tight at all, like almost finger loose.  The others were all regular torque and required some effort to loosen.  Are the LIM bolts torque to yield?  Do I need to replace them?

This is all removing factory parts, no one has ever taken this engine apart before.


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on February 12, 2018, 04:59:12 PM
Well I got the heads off..  it wasn't the gaskets.  They looked great.  No evidence of leakage, it was all the LIM :-/

So I went a lot farther than I had to..  but I'll still take the heads in and have them cleaned, checked, and the new seals installed.  I suspect they're fine.

On the plus side, I found some broken exhaust manifold studs and some leakage, and boy will those bolts be easy to extract now versus on the engine..  Also fixing those leaks will reduce the incidence of air (oxygen) being sucked into the exhaust stream, fooling the computer into thinking the engine is leaner than it is.

Also on the plus side, the cylinders look fantastic!  You can still see some factory hone marks, there is no ring groove at all in any hole!  No wonder it's never used any oil.  So I feel pretty good about putting a freshened set of heads on this seasoned bottom end.  Also, I found the cold engine clickety clatter..  when I turn the crank back and forth, you can hear the timing chain go click click.  However it's only two degrees or so of engine rotation, still tight.  Wondering if I should bother replacing it now while it's all torn down..?  It has made the exact same noise when cold since the day I brought it home, BTW.


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: wstefan20 on February 13, 2018, 08:25:53 PM
Nice work! I don't think the lower intake bolts are tty, but I always use thread sealant on them (service manual says to at least for the 3100 engines).

Personally, I'd replace the timing set since they are relatively cheap, and you'll never have a better time to do it!

Be REALLY careful on the torque sequence and tightening when you replace the heads. I personally recommend having the machine shop resurface both the block and head, but in a pinch, use acetone and a plastic razor blade to get the surfaces clean. Don't use a metal scraper (ask me how I know).


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on February 18, 2018, 09:50:22 PM
Good call on the thread sealant!  Back in the day, we used to use the white liquid teflon stuff on SB Chevy V8s for the bolts that went into coolant passages.  Will that be adequate?

The heads are in the machine shop now, I'll talk to Wes (NAPA North Bend, WA machinist w/30+ years experience) tomorrow and see how it's going.  I'm considering having a little port work done if it's not terribly expensive..  hey, while the heads are in hand, right?  I'll take 8hp if I can get it.

Will straight edge the block after careful cleaning.  But the engine never got hot, so I'm kinda doubtful that anything warped.  Also good advice about the plastic scraper, as I would have just cleaned it like every other cast iron deck I ever cleaned-and smoothed out with a fine flat file.

Slightly on a tangent..  I'm perusing the Fiero and F body forums and seeing people put rather a lot of work into the old '80s 2.8 version of this engine.  They're doing aftermarket cams that are good to 5000 RPM, and putting all this money into flogging those ole' small journal horses.  Seeing as how the far superior, lighter, 3400 version has modern day alloy heads with 50cfm better flow, (oops, it doesn't have roller rockers, I meant to change this before this went up) and will do 6200 RPM no sweat..   and can be had for a dollar fifty a pound at any wrecking yard in the country because GM made a gazillion of 'em and no one hops up minivans..  why would anyone not simply go this route instead?


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on February 28, 2018, 07:15:49 PM
The machinist said my heads looked great-very minimal warpage although he did mill them a little.  Had the stem seals installed too, he said the valves and sealing surfaces looked great, also passed a vacuum test with flying colors.


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on March 21, 2018, 09:16:49 PM
I got my heads back from the machine shop today.  Also worked on cleaning the block decks.  They're even cleaner than in these pics, but I think they're getting there.

My question tho, is which way the head gaskets go in.  All the holes seem universal, like the gasket could go in either side up and everything lines up the same-but the steel rings are discreet on one side of  the gasket, and connected on the other.  See pic..  which way should go up towards the aluminum head surface?  Does it matter?


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tom Moog on March 27, 2018, 05:46:55 PM
Your project seems to be going very well and it sounds like your engine is in really good shape. I don't know that I would be looking to increase the power unless you are doing rings, rods and bearings. Those hard parts may have weakened from heat in an engine with that many miles on it.  

As far as your question about the orientation of the head gaskets, if it is critical, it will be marked. if it isn't marked, it doesn't matter which side you put up. What brand of gaskets are you using?


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on April 02, 2018, 08:40:49 PM
Well I've got the right head on, though not torqued.  The bolt kit came with the correct number of bolts, plus an option for the big stud sticking out the front left head bolt where the dogbone mount goes.  The kit also comes with another short length head bolt having a smaller threaded stud sticking out the top of it.  I can't remember if I took one like this out or not and I foolishly recycled the old bolts already.  Does the right bank lower front head bolt on the Aztek have the smaller stud sticking out of it?

Other than that conundrum, it's going well, if seemingly infinite in its fiddly little details that have to be right to do a good job.


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on April 03, 2018, 11:42:48 PM
Today was frustrating.  Got the rear head torqued down, which went fine.  Then the radiator installed, which didn't..

Never buy the cheap radiator from Amazon.  See that gold colored metal clip?  It was in the wrong place, and I had to drill new holes to hold it in the right place.  Also those little black rubber nubs that go between radiator and A/C condenser?  No holes for those in the new radiator either, so I made some in the same place as the factory radiator.  Which, it turns out, wasn't really bad either, it was just leaking subtly from a hose port.  Well, it won't leak now.

Especially since the lower hose came from Amazon, even tho it was a Gates part, too short!  It seriously looks like someone cut the end of it off and then returned it, so I'll just buy the right one from NAPA in the morning.  More hassle..  so after installing this radiator the first time and not being able for the life of me to get the fan module to sit correctly (see misplaced metal tabs above) I installed it the second time and it went in.  Only just..  I think how they want you to do it is evacuate the A/C and crack open the condenser fittings, then put the whole shebang together on the bench and then install the assembly.  I didn't do that, so it took for freakin' ever to get all those little tabs and bolts holes to line up.  And then, just to spite me..  the little nipple where the overflow line goes into the radiator WAS TOO SMALL!! I almost started throwing things.. However, the little rubber cap they seal it with for shipping, was just the right OD to match my tube.  So I snipped the closed end of it off, put it back on the nipple and then slid the hose over it, then the clamp held it securely.

So I don't have any extra parts and everything is straight and tight :-)  Tomorrow: the other head, the valve gear and maybe if I have time the dreaded LIM..

I still have a mountain of wires, tubes, and mounting brackets to remember where they go..


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on April 03, 2018, 11:45:36 PM
For the curious..  these aren't taken with a phone..  mostly Fuji X100T except today I shot a Fuji X-E1 with 35mm f2 WR lens.  It's just like a Leica only not five grand.. ;-)


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on April 08, 2018, 01:24:01 AM
Well I had dreams of getting this bad boy running today..  but nope :-(  Went to reassemble the valvetrain and found 11 of the 12 pushrods hadn't been rotating so they'd worn grooves in their ends and in the rocker arm seats.  Two of the rockers were starting to crack out, even tho the valve heads look perfect and there's clearly no lack of oil in the pivot bearings either.

On the one hand, I'm glad I discovered this now, versus 100 miles away from Mom's house in nowhere, Idaho with a car full of kids and bikes and a severe miss in two cylinders.  On the other hand, now I gotta find a new valvetrain for it.  Crap.


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman 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.]


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman 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!


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman 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!!


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman 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!!


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman 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.


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman 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  ;D ;D :P


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on May 25, 2018, 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.


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Buymyaztek on May 30, 2018, 07:43:30 PM
Oil cooler. Been there, done that. It's located at the oil filter.


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on June 07, 2018, 11:53:26 AM
Siigh..  I wish mine had that oil cooler!  But it doesn't.  The oil filter just threads into the block, there are no extra lines or coolant lines or anything oil cooler-esque anywhere near it, or anywhere else, for that matter.  Every coolant line is accounted for, including  the transmission cooler lines to the brand new radiator-the only auxiliary cooler lines to the radiator, and they had Dexron fluid dripping out of them when I changed 'em over.

I wish it had the oil cooler, cuz that'd be the easy way out..


Title: Re: Does this gunk mean I have an internal engine coolant leak?
Post by: Tronman on June 11, 2018, 06:44:00 PM
Well, this time before I put it back together, I decided to pressure test it.  So, I had one ratcheting coolant hose squeezer with which I blocked off the lower radiator hose.  For the other hose, I used a Fernco rubber cap with not one but two sizes of old radiator hose to shim it down to the tiny size of that coolant neck outlet.  Next, I bypassed the heater core and the throttle body coolant lines were simply connected together.

I used the funnel and hose arrangement to fill the coolant, mixed with a bottle of UV leak tracer dye, right into the LIM coolant pipe, which goes right behind the thermostat and into the LIM coolant passage to both heads.  With the engine full of coolant, I was then able to thread in the old brass hose adapter from my Cadillac and use some tubing and an old bicycle tube stem.  This takes the place of the $125 coolant pump tool, supplanted by the bicycle tire pump with its attached pressure gauge.  Serious shade tree action..  but anyway..

I put 25 PSI into it, and it's been holding for over an hour.  It hasn't dropped at all.  Meanwhile, I drained most of the oil out, and I figure that any notable internal leak will make its way into the remainder of that oil, and I'll be able to see it with the light when I drain it after a couple more hours of pressurization.

While I'm here, I also remembered to plug that dang cam angle sensor plug back in!!  Geez, I can't believe I forgot that last time.  Also, I withdrew the cheeseball Chinese new eBay "Delphi" fuel injectors for return, because they were making it spew black smoke and one of them was notably leaking externally.  I had the originals tested and verified good, so my injectors are now correct.

I hope this works out, I really need my car back!!  And, new cars suck.  I want to keep my Aztek.


Title: Does this gunk mean I have an internal engine coolant leak?-Epilogue
Post by: Tronman on June 16, 2018, 12:57:47 AM
Well I got it all put back together, carefully running it only a minute or  two at a time to allow the coolant to be inhaled from the the recovery tank.  I drove it around, gave it a full tank of high test unleaded, and..  IT RUNS PERFECTLY WITH ZERO COOLANT IN ITS OIL SUPPLY!!

I am so relieved.  Oh, and since I fixed those ABS wires up front, the ABS light now no longer comes on, the AWD disable warning is no longer warning me and..  the falling down on acceleration is GONE!!  For the first time in several years, Aztek now has full power!!  And the dashboard has zero trouble lights.  I keep looking down at trouble free instruments and I'm almost in shock..  I'd been limping along with it that way for quite some time.

So now it's time to wash it and clean the interior and fix that dent from the semi tractor sideswipe incident :-)