The left side exhaust manifold is leaking considerably on my 1987 E350 Van (460/C6). I'm planning on pulling it over the next few days some time and am looking for any advice that you folks can offer. I'm already soaking the bolts with penetrating oil. I've heard that you want to heat the bolts red hot, but it seems to me that will only expand the bolt in the manifold making it harder to turn. My feeble brain tells me to heat the head as hot as possible while not heating the bolt, creating a temperature differential between the two to help free up the bolts. Of course, heating the head and not the bolt is pretty much impossible! So, is it true that heat is not the way to go? I haven't tried to turn any but the most accessible bolts so far, which did turn. My experience tells me that the bolt that will break is the one in the most inaccessible spot and I want to do everything possible to avoid having to pull the head also. Any suggestions would be greatly appreciated.
On a slightly different topic, does an exhaust leak affect performance noticably? I have been having trouble with the idle and am wondering if the exhaust is likely to cause any idle problems. This idle problem is a little wierd as it only manifests itself after an extended warm-up (>20 min., well after the choke is fully open and the engine is fully to temp.) The engine idles fine in Neutral (auto transmission, C6), but bogs down and dies when I put it in drive and don't give it any gas. Once I'm under way, the truck drives fine, it just doesn't want to idle with the trans. in gear (forward or reverse). Is it possible that the torque converter is not unlocking when warm?? Thanks for your replies.