Hi all, I just picked up a 78 280se with teh number one cylinder froze up, supposedly from a blown head gasket that may have rusted it up. Any help or ideas greatly appreciated, the mechanic already tried putting some marvel mystery oil in the cylinder and used a 5 ft bar to try and turn the motor to no avail. I have to pull the head off anyway to change the gasket, but thought someone might have some suggestions, I have never done this before, Thanks ahead, Jim
The best product I have found for loosening rusted bolts is K&W KNOCK'ER LOOSE penetrating lubricant. I am confident it will probably solve your problem if you let it soak for a couple of hours I beleive NAPA still sells it. Peter.
Now that the head is off, submerge the piston with your best rust cutter. Let the rust cutter sit for two days...... Then make a wooden block about the same diameter of the piston, lay the wooden block on the piston and smack it with a hammer. No guarantees, but the engine is already broken.
Do the job right and drop the sump, pull out the crankshaft and then remove the pistons, there is no guarantee that the piston is seized, it could be another fault just as easily. If the piston had started to melt you wont get it out with a rust treatment.
Hopefully the engine didn't get warped when it overheated and blew the head gasket. then you are into a teardown.
This process will require some patience
Remove all the spark plugs (no compression) and mix up a solution of Diesel fuel and auto trans fluid 50/50 and fill the cylinder in question, hopefully the piston is stuck at or near the bottom of the cylinder. this will allow you to pour in more of the mixture. let the mixture leak through to the oilpan then do it again and again.
After a few times then bunt the starter (if possible) or turn the engine by hand very slightly to move the piston a little bit at a time. (don't go too far at a time or you'll break a ring)
Repeat the procedure until the piston has traveled the full length of the cylinder. (up and down)
Keep repeating the procedure until the piston travels freely on it's own (take things slow so that you don't break a piston ring) when the piston travels freely, do the following. (note: if the piston is still seized, switch from the above mixture to pure white vinegar)
After you have freed up the piston (you're not done yet) the piston might be free, but the piston rings might be still seized in the ring lands. (rust) this can be solved by doing the following.
Bring the piston to bottom of the cylinder, pour in pure white vinegar, and let sit until it drains through, do it again and again until the piston rings are clear of rust. then you drain all the crap out of the oil pan and refresh with new oil and add ("Lucas" oil additive) which will make things good and slippery.
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