97 K1500 5.0 Coolant in Cylinder 1

[L31MaxExpress]

I can't argue that. I would, however, expect to see a "clean" path where the hot coolant flowed from the coolant crossover in the intake manifold into #1 intake port; and I'd expect to see the evidence of hot coolant "steam-cleaning" the intake port. But the photos don't show the floor of the port, only some of the roof.

Another reason to use the leakdown tester--if he pressurizes the cylinder for a minute or five and can find no bubbles in the radiator, the likelyhood of the coolant passing by the intake gasket increases. I'd think a big leak like he has would show up under ~100 psi if it were a gasket, and maybe even if it were a cracked casting. Not guaranteed...but likely.

My leak did not show up until the van was parked for 3 weeks. It was a seaping through, but it only takes ~70cc of liquid to hydraulic lock a L30 and like ~80cc to lock a L31. My #2 intake port had coolant standing in it after the catastrophic event.

 

[Trig]

Thanks for all of the replies. After getting a backorder notification on the leakdown tester I went ahead and pulled the drivers side head.

 

[Trig]

Few more pics. Did the best I could on trying to get the valve area inside the heads.

Based on the lack of apparent gasket failure and no obvious cracks that I can see, coupled with the condition/pics of the #1 intake valve from above and below I believe I had coolant leaking from the intake manifold into that intake which then got into the cylinder. I'm seeing coolant gunk (brownish) built up on the stem and stem side of the valve and surrounding are. None of the other intake valve areas have similar condition.

Agreed that there's no clear smoking gun as far as intake gasket failure but it was pretty gnarly in that area. Coupled with my observation of the front bolts being easier to break loose compared to the rears maybe they didn't get their final round of torquing. Obviously speculation.

Going forward I'll tap the valves on the passenger head and repeat my previous pressure test to see if those valves will re-seat. And I'll acquire a leak down tester to see what I have going on that side before I remove that head if that's what is suggested. At this point removing it seems like a drop in the bucket compared to what its taken to get to this point.

Again, thanks for the help - greatly appreciated.

 

[Trig]

I redid the pressure check on the passenger side and I'm not getting the blow by on the intake valves now. I tapped them with a mallet as you guys were saying.

And is this good on the intake or do I need to get those tubes out as well? Ty!

 

[Schurkey]

is this good on the intake or do I need to get those tubes out as well?

"Good" for what? Looks like it's ready for proper cleaning.

I'm guessing the tubes don't need to come out, but I could be wrong.

 

[Road Trip]

An advantage you "airplane guys" have is that the FAA regulates the orifice size and shape of leakdown testers. There's no "industry standard" or SAE standard for leakdown testers in the automotive world. Tool makers can do whatever they feel like, and there can be huge variations among manufacturers that would make one tool read "high leakage" and another "low leakage" on the same cylinder under the same conditions.

The orifice in the tester (NOT the "Master Orifice") has as much effect on the indicated leakage as the actual cylinder leakage. I can make a cylinder show any leakage a customer might desire, by screwing with the orifice size. Which is why the Master Orifice is so useful. It sets a lower limit on the allowable pressure indicated, to keep folks honest. Otherwise, as I said--you have to use the automotive tester on known-good cylinders of the same bore size to get an idea of what your questionable engine should show for leakage.

Despite what the magazines and piston-ring advertisements say, it's NOT as easy as deciding that 2% or 10% or "whatever" percent is "acceptable" and readings above that magic number are "bad".

^^ Like he said.

I'm a big fan of backing up backing up a compression test with a
more comprehensive leakdown test in order to get a sharper
picture of what's going on.

Re: no industry standard orifice size. Schurkey, you speak the absolute truth. Well stated!

 

[L31MaxExpress]

I redid the pressure check on the passenger side and I'm not getting the blow by on the intake valves now. I tapped them with a mallet as you guys were saying.

And is this good on the intake or do I need to get those tubes out as well? Ty!

Get a plastic bucket, a bottle of simple green, mix it up with 4:1 Water/Simple green let it sit 24 hours. Mine looked almost new after some soaking and periodic brushing.

 

[Trig]

Is this what I'm looking for on the gasket set? Looks like it has the intake manifold gasket that people say to get (Felpro Permadry Plus), however the head gasket seems thicker than what Schurkey mentioned previously.

FEL-PRO HST8510PT6

 

[Schurkey]

Is this what I'm looking for on the gasket set? Looks like it has the intake manifold gasket that people say to get (Felpro Permadry Plus), however the head gasket seems thicker than what Schurkey mentioned previously.

FEL-PRO HST8510PT6

The Felpro rubber gaskets are equal garbage. The only thing I will use now is the composite fiber paper ones.

Seems I've been proven wrong about the intake gaskets. Maybe you shouldn't take my advice.

I really thought the revised gaskets from Fel-Pro or GM were reliable. I know that the original GM intake gaskets had problems--but they're probably all gone by now, having failed previously and been replaced already.

So--I guess you should look for the fiber/paper intake gaskets.

I did not see a thickness listed for the Fel-Pro head gaskets. I'm thinking the originals were .028 thick, but I'm not sure of that. Perhaps measure the thickness of your old gaskets at the fire-ring around one of the cylinders.

 

[east302]

Is this what I'm looking for on the gasket set? Looks like it has the intake manifold gasket that people say to get (Felpro Permadry Plus), however the head gasket seems thicker than what Schurkey mentioned previously.

FEL-PRO HST8510PT6

Felpro sells two versions of the gasket- one without the metal backing and one with which is the Permadry. The one with the backing is supposed to address the stock-style issues if what we read on the internet is true. Never had an issue with the metal style…probably have 90k miles on one set of them.

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