Frozen manifold pipe nuts!
 

Hey all you awesome Chevy folks! New to the forum after a friend told me to research online. I hope someone here has some kind of experience with the older model suburbans, or can point me in the right direction. So here goes…
I have a ‘99 K2500 454/7.4 LT suburban. It’s been good to my family and I for many years, but lately hardly gets driven now that my kids are older and no longer interested in hanging out with mom & dad. My youngest is going to be a junior in HS and he’s got his learners permit. Hopefully his license by Fall. I’ve asked him what kind of vehicle he’d want, but keeping in mind it’ll be his first and we’re not breaking the bank, also he’s a big boy, and an even bigger presence on the football field. 6’5 and about 350lbs of solid mass. So I couldn’t be more proud when he said, “Dad, can we just put some money into the ‘beast’ and make it mine?” And so our journey has begun…
Re-upholstered driver and passenger seats because leather was worn. Installed entirely new exhaust w/ 40 series flowmaster and 4” rolled tips. New speakers in cargo and all 4 doors with a new Pioneer Bluetooth stereo. My local tire shop guys are replacing inner/outer tie rod ends, upper/lower ball joints, etc. and I have new AC compressor coming by this weekend. Also having carpet shampooed this weekend. But here’s where we’ve hit a hiccup. Ordered all the tuneup parts from Rock Auto and tore it down last weekend. Found that the valve covers are leaking. We go to remove the manifold air intake pipes the run along top of valve covers and these nuts are FROZEN! 2 days we fought with them and no luck. We ended up finishing the tuneup and putting it back together. The leak isn’t too bad, but now these frozen nuts are messing with me in my sleep! 22yrs and they’ve never been removed. Does anyone have any advice or knowledge of this? Also, my son would like to place the drivers seat back about 5 inches. It’s powered. Is this something that is possible?
Thank you to those who took the time to read my novel.

Great kids car! My son took over our 93 Sub in highschool, drove all the way thru college, now back in my driveway for once in a while use. At over 350k it doen't owe me a dime! Sounds like you have a smart young man!!

That’s awesome! Ours just hit 200k so hopefully he gets a solid 150k out of it. Thank you!

I did change the transmission at 200k but otherwise a routine maintenance vehicle

AeroKroil is my go to penetrant for stubborn stuff. Makes PB look like it's water. Few applications and some soak time it's the best I've ever used.

Okay. So I just ordered a can of Knock’er Loose last night. I’ve seen reviews of people saying it’s just as good, if not better than Kroil. I’d also found some info online that if I run the car to normal running temps then try getting it off while the manifold is still hot, that helps a lot. So, I’m getting the penetrant either Saturday or Monday. Hopefully one or both of these procedures combined will remedy this problem. I will keep you posted. Thank you for the advice!