Anyone change an intake manifold gasket on a Vortec 350?

[ram57ta]

Just wondering what kind of headaches I'm in for on my 98 GMC Sierra. Leaking coolant OUTSIDE the block and from a quick internet search its a very common problem on the Vortec 350's. NO WATER IN THE OIL. It never overheated...just started leaking about a week ago. Still runs great.

[shumpertdavid]

Felpro makes an improved intake gasket set, steel core instead of plastic and heavy silicone for.sealing area than plastic. Also get the quick disconnect for.the heater hose. You need a scantool to look at data and art procedure to correctly set tje camshaft/crankshaft correlation, its not set with a timing light. You'll have to remove one valve cover to get the intake off, you don't have to pull the upper plenum, get a tube of ultra black silicone to seal the valley rails. Might as well replace the thermostat as well. I think that covers the more technical points.

[ktm300hater]

I just changed one out on a 98. I just marked the distributer location to the intake and rotor location to distributer.

[whitetrash]

It's easy. 2-3 hour job at most

[JC316]

Ah, I have to do this same job today. It's not bad at all.

[ram57ta]

I got MOST of the stuff removed today but I haven't figured out how to mark the distributor and still have to remove the fuel lines (it got dark). Also having a tough time understanding how to get the front left bolt out without pulling off the A/C compressor/pwr steering pump bracket because there is NO clearance to pull the bolt out otherwise.

[shumpertdavid]

I got MOST of the stuff removed today but I haven't figured out how to mark the distributor and still have to remove the fuel lines (it got dark). Also having a tough time understanding how to get the front left bolt out without pulling off the A/C compressor/pwr steering pump bracket because there is NO clearance to pull the bolt out otherwise.

You remove the compressor from the bracket, lay it off to the side, remove the 2 bracket to cylinder head bolts and 1 nit amd stud, remove the bolt from the bottom of the bracket by the power steering pump, and pull the upper part of the bracket away from intake, there is one nut below the exhaust manifold you can remove if you want the bracket completely loose. As far as the distributor, you just need good reference marks to reinstall it. Spec on adjustment for cam/crank correlation is 0 degrees plus/minus 2 degrees. If you get it off by.mich you get a check.engine light. If you get it off too much you get poor performance.

[shumpertdavid]

Take the fuel lines loose at the rear if the intake, leave the hard lines going into the plenum on the intake.

[ram57ta]

Yeah not too long ago I replaced the power steering hoses and had to pull all those brackets off that held the AC compressor/pwr steering pump on. It pisses me off that GM put that ONE damn bolt under there without access so the only way to get the intake off is to loosen all the bolts/nuts and pull the bracket forward. Almost makes me want to take the bracket off and grind off the part in the way of the bolt...but I hope to never have to do this gasket repair again. I also am a bit pissed because Autozone sells at least 6 different gasket kits for this job...the Felpro kit for 59 bucks doesn't include new intake bolts/studs (which they HIGHLY recommend), and it only comes with ONE valve cover gasket (and I still don't see why I would need to open up the valve covers for this repair) so I would need to spend additional money to replace the other valve cover gasket as well as buy new bolts (again I fail to see why I need to replace them). The 79 dollar Dorman kit has both valve cover gaskets AND new bolts/studs...but isn't in stock ANYWHERE. If I'm going to change one VC gasket...I'm doing both. Why do I need to change the intake bolts/studs?

[shumpertdavid]

I've never replaced the bolts, I clean them and the intake holes of any debris/buildup. I use the improved felpro set. You have to remove 1 valve cover in order to get the intake out. Leave them both bolted down and try to remove it, you'll understand when it wont clear. I generally pull the upper fan shroud and fan for extra room. Having to pull the bracket out of the way isn't a big deal, at least for me, bit I do auto repair everyday. Dont make it harder than it has to be.

[ram57ta]

It's easy. 2-3 hour job at most

like hell it is

[whitetrash]

like hell it is

I've done it. It's just an intake on a pushrod motor. Effin simple

[JC316]

like hell it is

Took me two hours to get the intake off from mine today and I was filming the process. I even took the upper plenum off to show people how to do that.

[ram57ta]

I've never done it before so I am being extra cautious not to make any mistakes or break any of the other parts that will cost more money to fix. So far my list of parts will be the intake gaskets, fuel line O-rings, one of the PCV 90* rubber adapters that split as I was trying to remove the PCV/vacuum lines, 1 wiring harness retainer thingy, 2 valve cover gaskets, PROBABLY a new distributor cap and rotor (225k miles...this original one looks kinda bad), some RTV for the intake rails, brake cleaner/engine degreaser...so far I think thats it. I've been troubleshooting this coolant leak for a while so the thermostat/water pump/radiator and the hose clamps are all fairly new. Should I coat these intake bolt threads with some kind of sealant once I put it all back together or should I do em dry (I'm pretty sure they need some kind of sealant since they go into the water ports)?

[JC316]

And just for shits and giggles, my instructional.