Retorqueing the manifold bolts.....

[timfretwell]

By George I think that may be it!! I have been troubleshooting this !@#$ pinging problem for over a year now. I didn't want to believe it was the loose manifold bolt theory because I don't have the excesive oil consumption that is usually reported along with this problem. Well I've run out of thinks to check, so today for the heck of it I pull the # 5 plug and guess what I see? It's covered with oil!! Since the plugs are only a year old I figure I might be on to something here. But what scares the bejesus out of me is that I cant even SEE the manifold bolts, let alone get a socket onto them!! Maybe I'm mistaken (I hope so) but this retorqueing looks like a really big deal. I found the torque patern and specifications in my Haynes manual, but like I said, how the heck do you even get to 'em?
Thanks for any tips from the guys who have done this!!

 

[Ross-N-Chicago]

I did it a couple months ago and its not bad, just a lot of stuff to move and time consuming. It took me about 5 hours but I cleaned a bunch of stuff, replaced plugs and wires and coolant, tstat. You'll need torque wrench and just follow the Haynes, I was fine with it. Be careful around the front bolt which sits right next to a fuel injector. Mine were really loose, I could almost get a couple off by hand.

You have to remove the a/c line from the upper intake, remove the PCV valve and all the vacuum hoses on it, i think you can leave the throttle body on but you have to disconnect the intake hose and some other odds and ends--coil pack, throttle cable. Then you just take the upper intake manifold off, clean it real good and you;ll see the bolts to the lower intake, eight of them, staggered. Tighten them in the pattern in Haynes, little by little and the infamous, assembly is in reverse. I would also clean the air bypass valve while you're at it.

 

[ExplorGM]

Intake bolt Torque Specs

I noticed on another thread about this subject that someone mentioned the lower intake bolts needing a 12mm or 13mm socket to tighten them.

On my 95 I used a 10mm socket. I was a little worried about tightening them down to 216 lbs with the torque wrench.

I have two different manuals and each gives a different spec on the torque sequences. The Chiltons manual for 95-97 models gives two sequences, 1. 62-88ft lbs and then 2. 19-28. Obviously these are reversed/misprint, but only a total of 88lbs total.

The Haynes manual for 91-95 models gives 4 steps up to 216lbs.

Anybody have experience with the 95-97s? Due to the size of the bolts, I'm going to stick with the 88lbs unless someone with recent experience/knowledge says otherwise...?

Thanks!

 

[Bracken53]

Be sure to check the units when you are torquing stuff down! On my 91 I'm pretty sure it was 216 in-lbs, which works out to only 18 ft-lbs. So there is a big difference.

Good luck on the job, its really not that bad, heck I ended up replacing the lower manifold gasket on the side of the road. I really hate having to park on the street. . .

 

[ExplorGM]

Inch lbs...!!

Thanks Bracken53! That will teach me to read more carefully...

So far I have only hand tightened them down with a small ratchet. I need to get an adaptor to fit the 10mm to my torque wrench. Should be interesting to see where they are at now....! They were pretty loose to begin with.

So according to Chilton I am looking at about 7.5ft lbs and according to Haynes about 18ft lbs...

Thanks again Bracken53!