Replacing an engine myself

So I have to replace the engine in my 1999 Denali. I can do the basic work like changing brakes, tuneup, etc. I would actually like to pull the engine myself (don’t worry, it’s a spare car) to save $1500 or more and to be honest, it’s something I always wanted to try. How hard would it be to learn to do myself (I have 3 shadetree mechanics on my block that could look over my shoulder as I do it)?

If you are basically mechanical it should not be too bad of a job. You can look things up on you tube if you run into problems. Just be careful disconnecting your electrical connections some of them are sticky and if you break the locks it will come back to haunt you later.

It’s doable. I pulled mine on my rx7, rebuilt it and am preparing to reinstall it. Get a good manual, read it THREE TIMES, and take lots of pictures of things you remove or disconnect.

With a good lift, lots of shelves and bins, and a couple rolls of masking tape it’s more about organization than anything.

Label every connector with tape and take lots of pics.

A factory manual is preferable to a chiltons.

Pulling and replacing an engine in a 1969 anything is a piece of cake. Replacing an engine with 10 miles of wire harness requires careful labeling. If you feel confident you can take enough pictures and label everything then it should go just fine.

If you’re buying a long block then take the old engine out complete and set it next to the bare engine and swap the parts out.

Take lots of pictures.

Make sure your shade-tree neighbors are actually willing to actively help you for the engine hoisting phase. Especially if you’ve never done it before you absolutely don’t want to be doing it alone. If you can figure out a good lifting setup, it shouldn’t be too terribly difficult but there’s definitely potential to severely injure yourself.

One thing I did once when I didn’t have a place to do an engine swap was I got everything ready to pull and then towed the car to the junkyard that sold me the engine where they did the actual swap for an extra $150 or so (IIRC.) But I suppose that makes you do all the boring little fiddly stuff and not the actual fun part!


I’ve swapped two engines. Both times I rented an engine hoist and had a friend or two help with the actual heavy lifting.

Have everything disconnected from the engine before your friends arrive.

Exhaust bolts will be a royal pain in the backside. You’ll probably end up breaking some instead of removing them.

Make sure you have a decent set of tools, including a breaker bar for those pesky exhaust bolts.

Make sure you have a Chilton or Haynes manual for your car. It will show you step by step what you need to do to swap the engine. Get familiar with the procedure before you start working on it.

And if you can, talk to someone who pulled that engine from that truck before. Not only are exhaust bolts a problem, you’ve got to get to the rear tranny bolts with very little clearance between the firewall. Then you’ll have the same issues getting the new engine in, only this time you have to line it up before you rip the skin off the back of your hand getting at those bolts.

Quick question. When replacing the hoses should I attach them to the engine before or after the swap?

I put all of the hoses on after the swap.

You’re going to want the engines stripped down as much as possible before the swap. Anything hanging out like a hose or wiring harness can get caught up in something and make your life much more difficult.

2016 Chevy Colorado - 31 mpg … just saying …

$Howmany per month?

1999 Denali = free. :slight_smile:

The problems come with stuff like the AC unit, charging it, etc. Most modern electrical connections only match one female fitting, so that’s not a real challenge. The problems would the little hassles, like getting to the exhaust bolts to undo them, or other stuff that requires special tools (long reach, etc.) to reach. I would even consider it without air tools. Bolts are old, rusted in place, stubborn, broken, etc. It’s all that little stuff that makes the job a bitch. Bit, if you have time, AND AIR TOOLS, (or the cordless kind) do it.

But if you do, do like suggested above - bins, labels, pictures and patience. Lots of patience.

Another tip from those who have been there:

Wash the engine & compartment thoroughly before working. Get some spray on degreaser & use it liberally. Create massive illegal water pollution at your local coin-op car wash.

Believe me it’s the best hour you’ll invest in easing this project. Other than buying the aforementioned high powered tools.

Hint about air tools: They’re fairly cheap. But of you don’t already have a $400+ compressor to run them they’re useless. The toy compressors you can get for less might be fine for running a paint gun or filling a tire. Not for this when you need sustained high impact output.

Brake cleaner works really well on engines and compartments. The crud just drips right off.

What about the battery impact wrenches? I’m trying to justify buying one. If removing an engine what HP should I look for.

Then again, I could use an air compressor. Can you set an air impact wrench to tighten to a set torque?

Except that it’s a 1999.

Not really. At least not for the kind of torque precision you want on engine parts.

The impact wrenches used at tire change places are supposed to be regulated to a reasonable max torque. But they don’t have much precision or repeatability.

I’d sure never use one on something like a cylinder head or manifold. It may well be that the car factories use high precision air tools to assemble this stuff ab initio. But that’s not the kind of equipment I’m talking about, nor the kind you can buy.

nm. doublepost.

I thought that was a misread at first, too, but what he’s actually saying is that a 1969 engine is easy because it doesn’t have “10 miles of wire harness”, but a more modern engine which does have “10 miles of wire harness” (like the 1999) is going to require you to keep track of a lot more connectors and therefore isn’t quite so easy.