Tech Tip: Cadillac 4.6L DOHC Cylinder Head and Block Cautions – UnderhoodService

Tech Tip: Cadillac 4.6L DOHC Cylinder Head and Block Cautions

I have a couple of tidbits on the Cadillac 4.6L DOHC engine. The first is one of those that you may never see unless you painstakingly look for it or it bites you on a warranty. However, it becomes obvious almost immediately if you need to resurface the block deck.

By Roy Berndt
figure 1: the aluminum 4.6l cadillac block may crack outside the cast iron cylinder liner and is extremely hard to detect. the above crack became visible only after the deck face was machined.
I have a couple of tidbits on the Cadillac 4.6L DOHC engine. The first is one of those that you may never see unless you painstakingly look for it or it bites you on a warranty. However, it becomes obvious almost immediately if you need to resurface the block deck.

The problem is cracking of the aluminum block casting around the cast iron liner (Figure 1). Knowing that this possibility exists, I strongly suggest that you take the time to make a close examination of the deck prior to doing any machining at all – and before you then spend numerous hours installing cylinder head bolt repairs.

The second tip involves cylinder head c/n 3533989 and 12554607, which would be the left head (or front, in the transverse mount engine) that has an alternator bracket bolted onto it in some applications. This head will always have Figure 2: The cylinder head on the top has the bolt holes drilled and tapped for the alternator bracket when used. The head below does not but both have the same casting number. To avoid potential warranty issues drill and tap all heads.the bosses for this mounting bracket but both of them may or may not be drilled (see Figure 2). 

If you want to avoid problems I recommend that you drill all of them, thereby eliminating the possibility of having a warranty problem upon installation and also reducing head proliferation. 



I hope these tips help keep you out of the firestorm that sometimes surrounds us in the engine-building world.

Roy Berndt has been in the engine rebuilding and remanufacturing industry for over 30 years. He is an ASE Master Machinist and co-author of SAE documents and standards. He is Program Manager for LKQ Remanufacturing, a PER in Springfield, MO.

You May Also Like

Tools To Service Serpentine Belts

Servicing the serpentine belt on some vehicles is a tough task.

Servicing the serpentine belt on some vehicles is a tough task. Without the right tools it is almost impossible. Here are six tools your shop needs to make your next belt replacement more productive.

Don’t Fight It
If you are still fighting belt tensioners with 3/8” breaker bar and wrenches, there are better solutions. There are serpentine belt kits that can help you get the right angle and attachment point on a tensioner to remove the old belt and install the new belt.

Battery Charging and Diagnostics

Here are six tips to use when diagnosing a vehicle with a dead battery. 

Why Do Timing Chains Stretch?

As the timing chain wears, it can change the timing of the camshaft and crankshaft.

Carbon Deposits and Direct Injection Engines

The primary cause of these problems is that fuel and added detergents are not hitting the back of the intake valves.

Acura Turbo Engine Service

It is important to check the operation of the solenoids that control vacuum to the actuators.

Other Posts

Subaru EJ25 Head Gasket Problems

Most of the EJ head gasket failures occur around the 100,000-mile mark and start as a slow oil or coolant leak.

Honda Electronic Throttle Body Service Tips

Using care and following OEM procedures will help you to avoid unnecessary parts replacement and comebacks.

New Oil Specifications

Many 0W16 oils have a new donut certification mark on the bottle called API SN-PLUS and SN-PLUS Resource Conserving.

Solving Intermittent Overheating

New cooling systems anticipate and influence changes in coolant temperature.