Intake Manifold Gaskets -What else to replace while in there

[HillcrestFarm]

It appears I need to replace my Intake Manifold gaskets on my 1994 Blazer with the 5.7 TBI. 85K miles. What else should I be replacing while I have it torn down that far?

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[PlayingWithTBI]

While you have the manifold off, look at the oil pressure switch in the back of the engine (circled in red) and inspect for leaks. It'll be a lot easier to get at. Might as well pull the valve covers and check your valve lash too. Be sure to use thread sealant on your intake manifold bolts/studs so oil doesn't seep back out into the valley next to the Throttle Body when you put it back together.

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[10mm Nut]

Swap the heater hose fitting with an upgraded (non pot metal) part.

 

[HillcrestFarm]

While you have the manifold off, look at the oil pressure switch in the back of the engine (circled in red) and inspect for leaks. It'll be a lot easier to get at. Might as well pull the valve covers and check your valve lash too. Be sure to use thread sealant on your intake manifold bolts/studs so oil doesn't seep back out into the valley next to the Throttle Body when you put it back together.

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Should I just replace the sensor, or only if it is leaking? Should I buy new bolts or just clean the ones I have?

Thanks for the reply!


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[Pinger]

Swap the heater hose fitting with an upgraded (non pot metal) part.

Is that the same part on a TBI as it is in a Vortec? If so, I'll link my earlier thread about it.

 

[PlayingWithTBI]

Should I just replace the sensor, or only if it is leaking?

If it ain't broke don't f**k with it. You'll probably get an inferior aftermarket replacement, ha ha.

Should I buy new bolts or just clean the ones I have?

That's up to you, they're not TTY so, they can be cleaned up and reused. When I did my top end, I got 12 point bolts at O'Reilly's IIRC but, I wanted something that looked good with the aluminum intake.

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[10mm Nut]

Something I forgot to add, clean out the EGR passage in the intake manifold to stave off future EGR fault codes. Those passages get quite carboned up over the years.

 

[PlayingWithTBI]

^^^X2

 

[Edward Case]

Swap the heater hose fitting with an upgraded (non pot metal) part.

I would love to punch the fairy that engineered that pos.

 

[thinger2]

Yep to all the above.
Pull the adapter for the oil pressure switch and clean it up.
GM used thread sealant to lock them in place and it dries out and leaks.
Dont use tefflon tape.
The adapter is 1/8 npt pipe thread and it is not brass. Its chem coated steel.
Chase the threads with a die a little at a time and keep trying it out untill it is about 90 degrees shy of where you want it to "clock" Then put the sealant on and let it cure
You want to thread it short of its final position because the wet sealant will lube the threads and make it turn much further than you want it to stop at.
This is important because it will make it much easier to replace the switch in the future and cures a pretty notorious oil leak.
If you have a stock O.P. switch and it works, keep it. the aftermarket ones are complete garbage junk crap.
The other thing to do is replace the ground strap that goes from the back of the passenger side head to the firewall.
Easy with the dist out and the manifold off.
A real ******* to do when all of that is in place.
You dont need the stock GM 50 dollar ground strap.
A 4 ga battery cable for 10 bucks works just fine.
That ground and all of the manifold grounds can effect everything from the gauges to plug fouling.
And, if you dont already know this..
Dont use the "china wall" gaskets no matter who made them.
Follow the instructions on the tube and use ultra grey or ultra black silicon