Do you know how to tell if it’s time for an engine rebuild?

Some problems can be fixed quickly, with just a few tools or a new part. However, other issues require a whole rebuild to keep that engine running properly. If you know how to tell when you need an engine rebuild, you can make sure you’re not wasting time on fixes that won’t really work.

That’s why we’ve put together this guide to the top signs that you need to rebuild your engine. Keep reading to learn what to look for.

What is an Engine Rebuild?

When you rebuild an engine, you’ll often remove the engine from the vehicle and take it apart completely. Engines can also be rebuilt “in frame,” which means they are rebuilt without being removed. If you’ve heard of a vehicle getting its engine “inframed,” that was a reference to an in-frame rebuild.

After the engine is completely taken apart, it will be cleaned and check for issues. Any damaged parts can be replaced. Then, when the engine is put back together, all new seals, gaskets, and lubricants are used.

The parts that are replaced tend to be things like gaskets, bearings, O rings, seals, oil pump, cylinder heads and oil coolers. Sometimes, more major parts may also need to be replaced. These can include the crankshafts, pistons, and camshafts.

If the engine was seriously damaged before being rebuilt, you might also need to do more intensive work. For example, you might have to bore the engine block or the cylinders.

Now, let’s take a look at the signs that you might need an engine rebuild.

  1. Knocking Sound

If you hear a knocking sound when you rev the engine, this might be a sign that you need a rebuild. You’ll want to take care of this issue right away, otherwise, it will get worse. The knocking sound is often caused by too much clearance between the cylinder bore and the piston.

Other odd sounds can also be a sign of a problem. When a piston ring is broken, it might make a rattling noise. If your engine makes a “chattering” sound, it’s likely having valve train problems.

  1. Excess Smoke

Your tailpipe or smokestacks shouldn’t have a large, noticeable amount of smoke blowing out of it. Thick, dark smoke might be a sign that you need to rebuild your engine.

  1. Oil Consumption

Lots of oil consumption, combined with low oil pressure, shows that you have a problem with your engine that a rebuild might be able to solve. These issues are often related to the space between different engine parts.

As your parts wear down, the clearance space between them grows, which makes space for oil to escape into when it’s been burned off.

This escaped oil often is the reason why your engine might be spouting dark bluish smoke. In order to prevent these oil consumption issues, you might need to replace piston rings, bearings, or valve guides.

  1. Loss of Compression

If your truck loses compression, this can be another bad sign. You might have worn-out piston rings or cylinder bores, a cylinder head with a crack, a blown head gasket, or exhaust valves that are burnt.

To figure out just what the issue might be, you can do what’s called ‘leak down testing’. You’ll use a leak down tester to see what condition your engine is in.

If your leak down testing shows that the engine is leaking 20 percent of the pressure, your issue might be a blown head gasket, a burnt valve, a damaged piston ring, or a cylinder head with a crack. An engine rebuild can help you fix these problems.

You can also do a compression test. Use a compression gauge to test the engine’s cylinders. Make sure the pressure of each cylinder is fairly similar. If they vary a lot, you might have a problem.

  1. Loss of Coolant

Another issue blown head gaskets often cause is the loss of coolant. If you find that your radiator is losing a lot of coolant, you probably have cylinder pressure that’s leaking into the system.

To check for this issue, take off the radiator cap and take a look at the coolant’s surface when the radiator is warm. If you have excessive pressure and coolant blowing out of the overflow tube, the problem is likely a blown head gasket.

Time for an Engine Rebuild?

Sometimes, you’ll be able to use these steps to narrow down exactly where the problem lies. Other times, simply going ahead and doing an engine rebuild is your best bet for fixing the issue.

Do you need help with engine diagnostics? You don’t have to do it all on your own – contact us to find out what we can do for you.