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After working at it for a month and a half, I finally cracked into the Manifold of my 4.3L so I can take the precaution to change the Lower Manifold Gasket.
And uh... well, I found something possibly concerning.
How screwed am I?
For reference, these are the rear most intakes of the 4.3L, closest to the Firewall.
Been awhile sine I had my lower intake off, but is that a water crossover? Or just a blanked off place?
On the rear, those are blanked off passages.
Looks like you have had some interesting chemistry going on in there! Being a non-circulating part of the cooling system, I would guess it is place that would attract deposits.
Have you had any other cooling issues? A very thorough chemical flush may be in order. If you do such a flush, I would suggest you consider by-passing the heater core so as not to clog it with gunk released during the flush. Then again, that raises the issue of the radiator possibly getting clogged but at least that might be less likely because of larger passage ways.
For reference, when I did my LIM gaskets this is what I found: Left rear
As they said - blanked off ports - the amount of build up is actually normal for a spot that has no flow and is stagnant, I've seen worse up too the point it held the manifold in place.
Just make sure that after it's cleaned up there is no wash outs to the lifter valley, intake ports ECT.
Forgive my ignorance, but what do you mean by "Blanked off"?
And by interesting chemistry, I'm assuming you mean like the dreaded mixing of green and orange? The coolant I drained was green, but I suppose it's not impossible for it to have originally been orange.
So a full flush in order? Like a typical coolant flush but longer, and possibly more chemicals?
I've removed the radiator already to Replace it. Also replacing the lower and upper hoses, waterpump, and t-stat. Should I also consider just replacing the heater core and hoses for that too? Any other parts?
For reference, I Bought this Blazer to repair it. When I bought it, it drove fine with no error codes, but I didn't drive it for long before I garaged it to work on it.
Edit: also, the engine has 255k miles on it, and I doubt this has come off before
Last edited by BorderCougah; Jan 17, 2019 at 10:01 PM.
Blanked off - no water ports into the head so its a blank
The build up is a little rust and mineral deposits - it's all normal.
A water flush will not remove the mineral deposits but it will help remove any sludge.
It takes chemicals - auto parts stores carry them.
Depending on how the rest of the water ports look and while you was driving it before tear down it was not over heating I prob wouldn't do a chemical flush,
You may open a can of worms that you don't want to open
I'm scared to do mine... been losing anti freeze for a while with no sign of where... my oil doesnt look discoloured either... but the **** that came out when I did a system flush a year ago was horrendous...
Thank you all for the information. Glad to know this isn't as bad a situation it might have initially Seemed. When I first pulled that intake off and saw that, my heart dropped. Good to know it's not the end of the world at least, and that I was at least smart to follow advice and change the gasket on the motor.
Guess for me this weekend will be filled with lots of deep cleaning--something I was planning on anyway. Cheers y'all!
Either blow out with air or perferable with a shop vacuum suck out any debris that may be in the intake ports of the head, then plug them with chunks or rags or paper towels before cleaning,
I usually lay a big rag in the lifter valley too. then when done scraping and such vacuum up the mess then remove the rags and repeat cleaning out the ports after you remove the rags.
You don't want any debris as in chunks of gaskets, chunks of carbon ECT. left in there that could get stuck under a valve and reek havoc.
How bad is this...?
