Caprice exhaust manifold bolt

Manifolds to tailpipes, this can be quite exhausting
Post Reply
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Caprice exhaust manifold bolt

Post by kevm14 »

Just thought I'd post this for completeness. I had been having to tighten the rear driver's side exhaust manifold bolt like every 2-1/2 months. It was fine for years and years then all of a sudden it decided it wanted to constantly loosen. Surprise: this is another non-stock component. And I don't just mean that I am running LT1 exhaust manifolds. The manifolds were modified to accommodate the rear bolt location on the L05 heads. We drilled and milled the heads (in like 2004 at the WPI machine shop) and the hole was so close to the collector pipe that not only did I have to use an allen head cap screw, but I couldn't even fit a washer in there. No wonder it backs out.

Anyway, as of this week, another 2-1/2 months had elapsed and I heard the faint ticking of a slightly loose exhaust manifold bolt. This area is also one that is the closest to my single O2 sensor, and the risk is extra air is pulled in past the small gap between the manifold and the cylinder head, which the O2 would read as a lean mixture. The ECM would enrich the mixture, hurting fuel economy, emissions and drivability. Not that I've ever really noticed these effects with this issue.

Since I had purchased Loctite blue for the excavator drive sprocket replacement, last night I got the bright idea to remove the bolt completely, clean it off, and reinstall with Loctite blue. So I did. I torqued it down (to "tight") and time will tell if it holds. Loctite makes stronger formulas which I will consider if this does nothing.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Caprice exhaust manifold bolt

Post by kevm14 »

It's ticking again but that lasted way longer. But I wonder what happens after I tighten it...
Post Reply