1999 350 vortec K1500 head gasket

[Rufton]

My parents 350 has been fouling #4 and #6 for some time; HG or cracked head is suspect.
Recently it starting bleeding coolant out near rear intake manifold flange near drivers side head; this is major problem and has K1500 grounded.
I voted to install new engine but majority vote is to replace HG and maybe one head. I plan to check filter and pan oil for glitter/sludge today; to bad I don't have my filter cutter w/ me.

I could use some help in choosing a quality non-crack prone head.
I don't have service manual so torque specs would help.

Thanks

[Mykk]

Those Vortec 350's are known for intake gasket issues, mostly due to dexcool. Felpro has a revised updated gasket for the application.

That intake gasket separates coolant and oil from air/fuel. I would first replace the intake gasket and go from there.

If your not satisfied after that, do a compression test on all cylinders (for comparative figures) and the coolant test strips.

Cheers ~Mykk

[Rufton]

Thanks, I will look for the most expensive Felpro intake gasket.

[Rufton]

Oil filter element was nearly glitter free. Looks like Head/Intake project is a go. Apparently running a leaky HG for a few years doesn't always destroy engine. Coolant does contaminate oil post radiator pressure testing. I've heard coolant will destroy bearings but apparently bearings can survive. I found no coolant in filter though. Oil was a pretty ebony black

Maybe coolant leaked into cylinder during radiator pressure testing then leaked past piston rings over night. Maybe coolant is burned up in cylinder instead of contaminating oil. If oil was coolant contaminated maybe it would look milky instead of black?

[clinebarger]

Originally Posted by Mykk

Those Vortec 350's are known for intake gasket issues, mostly due to dexcool. Felpro has a revised updated gasket for the application.

That intake gasket separates coolant and oil from air/fuel. I would first replace the intake gasket and go from there.

If your not satisfied after that, do a compression test on all cylinders (for comparative figures) and the coolant test strips.

Cheers ~Mykk

The gaskets are a bad design, Dexcool is not to blame for that.

Originally Posted by Rufton

Thanks, I will look for the most expensive Felpro intake gasket.

Fel-Pro MS98000T are gaskets you want, I agree with Mykk....Sounds like intake gaskets.

[Rufton]

Thanks for PN cline.
#4 and #6 have lower compression and foul plugs. That's why I suspect bad HG in addition to bad intake.

[Rufton]

My bad, #3 and #5 are the low compression plug fouling cylinders.
I was impressed; no sludge at all under VC after 160,000 miles w/ pennzoil dino oil.
Dropped pan oil and no water after recent coolant pressure test; did have water when I pressure tested last year.
Unless I'm missing something head needs to be pulled due to low #3 and #5 compression.
There was black buildup on aluminum intake under plastic intake; not sure why.
Have yet to figure out how to remove bracket attached to back of engine; pass side plug wires under bracket; bracket also attaches at coil.

[Rufton]

This may be the #3 and #5 coolant plug foul leak. It is very hard to see. Slight discoloration under correct light.

[Rufton]

Filled intake ports then exhaust ports w/ gas. Some valves leak about 1 tsp per hour.

[Rufton]

More pics shows how faint leak evidence is.

[crazy longhorn]

The bores don't look too bad for a 160,000 mile engine....with the valves leaking a little Liquid, You might opt for a mag/grind & surface on the heads? AL

[Rufton]

I can't feel any ridge at all w/ finger nail (in the carbon free areas of course).

Yeah, at the cross roads deciding what to do w/ head(s).
HG still suspect but just not sure why #3 and #5 fouling.
Plan to pull valves tomorrow.
I would like to get prices on decent heads for compare to machine shop costs; any advice for good cyl heads?
Could a head crack that has leaked for a few years still be invisible to naked eye?

[crazy longhorn]

I ? a couple spots on the heads....Maybe Cline will chime in....he is the Gm tech, & well respected by all AL

[Rufton]

What is that junk in the intake runners?
Some EPA stuff?
The injector spider leg portion of intake is coated w/ it.

[Rufton]

Found why 3E failed gasoline leak test. Don't think that is enough to foul plug. Maybe enough to cause lower compression reading.

[Rufton]

Smart camera auto-focus thinks I'm taking picture of face.
That's a head, silly camera

[clinebarger]

A cracked head &/or a blown head gasket will put combustion gases in the coolant, Displace the coolant....Then the engine will get hot. I didn't read any of this as a symptom in your posts??

Coolant fouled plugs are a symptom of the engine sucking coolant on the intake side.....Vortecs are Notorious for doing this, I saw one a few weeks ago that filled #2 cyl. full of coolant & hydrolocked with NO external leaks at 50,000 miles....It was just intake gaskets.

If your head is cracked it would be in the intake port, That is Highly unlikely.

Compression test are just about worthless...Unless something major is wrong.
Ive seen engines with a low of 120psi & a high of 160psi on different cylinders run fine. What was your readings anyway??

A leak-down test is the only true way to know a cylinders ability to seal.

Get the head Magna-Fluxed, Lap the valves yourself, & Put it back together.

[Rufton]

Thanks cline. I am planning to lap valves and feeler gauge flatness. I will price magna-flux job.

Compression test last year. FWIR readings roughly 135 to 165.

Ran perfect until plug foul. Mpg seems off. temp perfect. Coolant looked good till stop leak; I flushed out yukky stop leak. Mild oil consumption.

Worst fouled plug is #3; seems far from intake port.

Only time it got hot was after blew a plastic hose fitting. Hot event caught early. Ran less than 1 mile uphill to safe shoulder. Engine didn't seem that hot and it was winter time. Temp gauge climbed but don't think it pegged.

Engine never had low oil pressure event.

[Rufton]

Felpro offers 2 head gasket sets. Not sure which is better?
Maybe the PermaTorque Severe Duty® head gskts shown below?

[Rufton]

Riverside Machine Shop does good work. The owner looked at head and plugs, and considered symptoms.
Diagnosis is most likely worn oil control ring plus slight head gasket seepage.
Head gasket seepage is not uncommon after many years of thermal cycles.
Not sure if coolant leak affected oil control ring.

[BarryB]

Pm me, if it turns out you need parts or Heads. I know a (used to be a member on here)friend in greenville, that has all kinds of parts for these trucks. Since your in Knoxville. It wouldn't be a bad trip.

[Rufton]

Originally Posted by BarryB

Pm me, if it turns out you need parts or Heads. I know a (used to be a member on here)friend in greenville, that has all kinds of parts for these trucks. Since your in Knoxville. It wouldn't be a bad trip.

Thanks. Right now my parents are interested in buying a K2500 L31 HD 4 bolt main 12530283 engine to replace the K1500 L31 2 bolt main 12530282 engine.

I think it will be a bolt in deal.

Differences seem to be:
4 bolt vs 2 bolt main.
small stem vs 3/8" stem valves.
HD vs SD vlv seats.
12 month vs 3 year warranty.
4L60E vs 4L80E flex plate and starter.
$40 price difference.

Similarities seem to be:
head bolts
harmonic balancer
upper intake
lower intake
pan
H2O pump
crank shaft
balance shaft
oil filter
etc

[Rufton]

Got the 4 bolt today and it mated to the bell and engine mounts fine. Next I will clean the nasty intake. I'm deleting all proprietary heater hoses all the way to rear core. I deleted the 4 nipple heater hose valve. I'm deleting oil cooler also. May delete the pain in the... bracket attached to rear pass head. I'd like to delete more in the interest of maintainability but I'll behave.

[clinebarger]

The bracket needs to stay, It supports the harness & shields it from the plug wires.

[Rufton]

OK. I'll behave w/ the bracket.