Decided to repair the 2.5 E300
 

We where close to scraping it honestly, then my job informed me I will be working in a different location.

Which means my brother can no longer use my car to drive himself to work since I NEED it now.

We have to drill out and re thread intake manifold bolts and repair glow plug wiring.

We put it off because we knew acquiring all the right tools will be expensive

Ended up spending nearly $700 at lowes on a drill, drill bits, wires, wire cutters, electric heat gun, tap and die set and other miscellaneous stuff. I'm honestly just going to drill them all out.

We should start today.

why not rebuild it better

I don't know how remove and replace a cylinder head, I also don't have a garage either.

So massive jobs like that won't happen for while.

Also a full rebuild on Mercedes engines is ludicrously expensive.

You could build yourself a fully forged bottom end + aftermarket block V8 for the same price or less.

With the manifold still on you can't get a straight shot to drill the bolts out. Why not try to twist out the bolts maybe apply heat, penetrating oil, and hitting the bolt with a drift and hammer before trying to twist. The bolts should just twist out.

Instead of ruining yet another MB engine, how about using some penetrating oil, some patience, and an external bolt extractor? Drive it down over the head of the allen bolts and they'll either come out or snap off. If you used penetrating oil and waited, they should come right out, they're not that tight to begin with.

Why does the intake manifold even have to come off? If it's that crusty and crappy, leave it. Remove the injector hard lines and go at the glow plug wiring from the sides. You can get in there with a long extension and some patience. Key word: PATIENCE.

I 2nd the recommendation of using fluted bolt extractors and some heat along with penetrating oil.

I drowned seafoam the bolts in seafoam deep creep a day prior and sprayed more on the day of the repair And it still stripped and one broke my tool

Use a real penetrating oil like Liquid Wrench or Kroil. You're dealing with steel fasteners into an aluminum casting. Lube, time, heat, and percussion will get it out. Use quality tools, don't use round-tip allen bits. Give the bolts a good sharp hit with a hammer 3-5 times before trying to undo them. They will come out. Patience.

Ok

I'll grab a torch at lowes and another hex key set, and bolt extractor

Was going to start yesterday, but we decided to grab an oxy acetylene torch sometime today.

Some say a propane torch isn't hot enough, I have a lot of reading up to do before I even touch it.

Acetylene torch? This isn't suspension you're working on, it's intake manifold bolts. Penetrating oil, percussion, quality tools, and patience are all that's required.

Use quality non-ball end socket style Allen bits. After soaking with penetrating oil, clean out the recesses in the heads and make sure the bit is fully seated. Smack it a couple times with a hammer to shock the bolt. Use a U-joint or a spherical swivel joint (my favorite) to get access to the allen bit. Give it a sharp twist to break torque on the bolt. It should then thread out. If you strip a head, hammer the bolt extractor on it, it'll come out.

These things are only torqued to 25nm. They're not that tight. Unless this car was dredged from the Titanic wreck, going full gorilla with a torch is just asking for bigger problems, especially an acetylene torch which will happily melt a hole in your aluminum head, valve cover, intake manifold, or any wiring it encounters.

Ok I'll back off the acetylene torch, I'll buy a big hammer and punch and start working on it

These threads are soooo painful to read. Do what Diesel300 says, it's very unlikely that they're not going to come out. And stay away from torches, or we'll be hearing aobut how aluminum melts...who knew?

If the allen hex is really stripped, use a Dremel and grind just the head off. When you remove the intake manifold, the remainder of the screw can be removed with a pipe wrench.

Holy yes maybe best to forget about applying heat.
Just how big of a hammer are you going to get?

$700 is a lot of money to spend on tools to try to remove the intake manifold. I just took out the manifold of an OM603 engine so I know what I am talking. The bolts at the front are easy to remove. Hope you have removed those. This is what I will do.

1) I hope only 2 to 3 are stuck out of the 10 in total.
2) remove the injectors. The hard lines if possible.
3) Use a good allen keys. If you strip the bolt then try to use an extractor or an oversized imperial Allen key, hammer it in. Don't drill as the space is tight.
4) if all failed, cut the bolt head off with reciprocating saw or a saw blade by hand. It is slow but it can be done.
5) remove the manifold and try to remove the studs. You have about 1/4" stud left to grip.

Good luck.