The problem is not how far you can pull it down, but how much trouble it would be to get everything actually clean and oil-free in order to get a good seal when putting it back together. I have removed a pan and let me tell you it's no easy task even with the engine on a stand and upside down. I would hate to try it laying on my back (or even overhead on under a lift) trying to get all the old sealant off with the front differential and engine crossmember in the way. You'd be much better off just pulling the engine and do it right.Do have to pull the pan all the way off or drop it down a couple of inches?
The internet does not seem to share your belief. From what I've read "room temperature vulcanizing" silicone will harden or cure without a heat gun or other heat source, but a heat source does not really change it.One note I would make is RTV sealant stands for room temperature vulcanization. I am of the belief using heat guns can change a whole lot.
Your picture is a good indication of how much room you'd really need. Imagine trying to unbolt that rear pickup tube bracket without the 18" or so that you have the pan dropped down. Then imagine doing it with the front differential and crossmember in the way. My arms only have one elbow each.And since the main thing that keeps the pan from coming out with the engine lifted up is the oil pickup tube, if you could raise the engine enough to unbolt the pickup tube (two bolts in the front, and one bracket bolt in the back) I would think you could pull the pan out entirely from between the block and the crossmember to enable a thorough cleaning? I just don't see why that wouldn't work, but I've never heard of anyone whose tried it.
I dont think you'd need the 12" or so as shown in my pic . . . I think you'd only need a few inches to get a wrench in to unbolt the front and rear of the pickup tube.Your picture is a good indication of how much room you'd really need. Imagine trying to unbolt that rear pickup tube bracket without the 18" or so that you have the pan dropped down.
The RTV most certainly sticks to everything else, so I'm not totally convinced that it will not stick to THOROUGHLY CLEANED existing RTV. . . I got this idea from a professional 7.3 mechanic who said that it worked for him. Like I said, however, the verdict is still open on the patch, but you're probably right, more than likely it is not a permanent solution. In which case at some point, I might get to find out if I am right when I say that removal of the pan with the engine lifted may in fact be possible.BTW, your repatch with the RTV isn't a long term solution. The problem is, RTV won't stick to already cured RTV, so there will always be a leak path, and oil will eventually find its way thru. If you can live with a seep, then I guess that's OK.
You may be right about being able to get to the rear bolt, but I still don't think it would be easy. I'd rather not fight with it myself.I dont think you'd need the 12" or so as shown in my pic . . . I think you'd only need a few inches to get a wrench in to unbolt the front and rear of the pickup tube.
I agree, there's no way it will be easy, and I wish I had gotten it right the first time - I was VERY careful and followed ALL instructions except the one about turning the engine upside down and still got it only about 90% right. But since I likely will have this problem, my thoughts are I will TRY to lift the engine and pull just the pan, and if it doesn't work, then I'll finish the job and pull the whole engine out. I think it would be worth the minor amount of additional effort to give it a try. But that's a ways down the road for me even if my fix doesnt work, gonna spend some time with the boat at the lake this summer, instead of under the truck like I did all last summer!:lol:You may be right about being able to get to the rear bolt, but I still don't think it would be easy. I'd rather not fight with it myself.
Also, the tranny would probably hit the cab floor by then as well.
Nick is absolutely correct. Heat guns can and will change the curing process of RTV. And not for the better.The internet does not seem to share your belief. From what I've read "room temperature vulcanizing" silicone will harden or cure without a heat gun or other heat source, but a heat source does not really change it. If it did, it would have a hard time surviving on a hot 7.3!
So you're probably right that I wasted some time with the heat gun, but I don't believe I damaged it.
According to Dow Corning:Heat guns remove moisture from the localized air they blow upon, and that is an anathema to the concept of moisture curing. Hence, I wouldn't bother to use a heat gun to accelerate or "deepen" the cure of a bead of RTV. If anything, the use of the heat gun may prolong the actual curing time, and leave the efficacy of the sealant in doubt.
Sounds simple enough, but turning a fully assembled approx 800 lb 7.3 engine upside down on an engine stand is a difficult and dangerous process, but maybe in addition to chemical engineering, you've mastered that as well. Should I have stripped the engine further by removing the very heavy heads so that the block could be turned safely? Maybe. It was cost vs. benefit and risk decision that I don't regret. And I don't particularly care for cigars.Following the instructions and best practices is great... but deciding to omit one instruction because it is difficult kind of defeats the purpose of following the rest of the instructions. In this case, deciding not follow the one instruction of turning the engine upside down to apply the recommended sealant and permit it to cure for at least 24 hours at room temperature... makes all of the other instructions that were dutifully followed a matter of close, but no cigar.
With all the stuff you messed with, it might have been easier just to pull the engine. JMHOThis can be done, as I just got mine out to the front. The cab had to be jacked up 7" and the engine up 5.3". Loosened the nuts holding the trans to the cross member and took out the radiator & trans cooler. I have 2001 club cab and I think a crew cab my be easier to get the pan out to the rear. Even as high as I had it, my pan wasn't even close to coming out to the rear.
I am going to install a Moroso pan & gasket per Moroso's instructions once I get the RTV off the engine block.