Cadillac DTS Northstar Engine: The Cadillac DTS is a very popular luxury sedan that General Motors built from 2006 until 2011. Every model during the five-year run had a Cadillac Northstar V8 engine providing good power. A well-maintained DTS holds its value relatively well on the used market and often comes with an engine that has good life left in it.
Unfortunately, commonly occurring 2006 Cadillac DTS engine problems persisted throughout all five years of the model’s production due to the same engine powering all five model years. The following gives you a closer look at seven commonly occurring problems with the Cadillac DTS Northstar engine and common fixes for them.
- Carbon Collecting in Cylinders
The Northstar engine has been notorious for collecting carbon buildup in the cylinders. Excessive carbon affects compression and accelerates the wear and tear on the pistons and cylinder walls. also
You can spot excessive carbon buildup by checking the spark plugs for each cylinder and looking for carbon buildup. You also could pay for a compression test that will determine which cylinders are within spec and which ones are showing reduced compression that could be caused by carbon buildup.
A simple fix can cure carbon buildup and is very affordable. Running some Sea Foam engine cleaner by adding it to the oil and to your fuel tank can remove the carbon buildup inside the cylinders. So can a quality engine cleaner.
- Prematurely Worn Piston Rings Cause Excessive Oil Consumption
The most common problem with the Cadillac DTS Northstar engine regards oil consumption. There are many possible causes of excessive oil consumption that could make that happen. Oil leaks are notorious for even well-maintained motors.
The most common way in which the Northstar engine consumes oil is via prematurely worn piston rings. Worn piston rings enable oil to enter the combustion chamber and mix with the fuel and air.
If you notice oil consumption with no signs of leaks, odds are you have bad piston rings in one or more cylinders. The previously mentioned carbon buildup in cylinder heads is among the leading causes of wear and tear on piston rings. You can identify excessive consumption by regularly checking the oil level and looking for dark smoke coming from the exhaust.
The fix is to replace the piston rings and keep the engine clean. The cost to replace piston rings can be relatively high due to the amount of labor involved.
- Valve Cover Oil Leaks
A valve cover protects the valves on the Northstar motor against contamination from dust, dirt, and debris that could get under the hood. The valve cover also keeps oil contained inside the motor.
Unfortunately, the valve cover often develops hairline cracks and fractures that enable oil out and reduce the amount of oil pressure inside the engine. The problem typically is minor at first, but it always gets worse once it begins.
Eventually, the valve cover will leak oil that creates the smell of burned oil coming from the engine bay or in the air conditioning vents. You also might notice rough idling, misfiring, and low oil levels in the motor.
The only fix is to replace the valve cover and the gasket beneath it. You can pay close attention to signs of oil leakage to determine if the problem recurs.
- Blown Head Gaskets
Head gaskets are important for preventing oil leaks and maintaining compression. Virtually every production year of the Northstar engine has had issues with blown head gaskets. It occurred on model years prior to the Cadillac DTS’s debut and continued after GM ceased production of the DTS.
Head bolts that are overly tightened are the most common cause of blown head gaskets on the Northstar motor. Once the bolts are overly tightened, they stretch and no longer provide the heads and gaskets with the staying power needed to prevent blown gaskets and resulting oil leaks and loss of compression.
Checking the bolts to ensure they are properly torqued to factory specs will help to prevent damaging them and the head gaskets. Replacing the head gasket is the only solution for a blown gasket.
- Rear Main Seal Oil Leaks
If you have consistently low oil and see signs of oil dripping from the rear of the engine block, your Cadillac DTS Northstar engine might have a leaking rear main seal. The rear main seal leak was especially frequent on Northstar engines manufactured prior to their use in the DTS. Cadillac switched to pressed rear main seals on the engine blocks starting with the 2000 model year.
Although less frequent on the Cadillac DTS and other Northstar-powered models after 2000, the rear main seal still is prone to leakage. If you notice oil leaking at the back of the engine block, applying some sealer might take care of the problem. If not, you need to take your Cadillac in for a costly rear main seal replacement.
- Oil Pump Failures
The potential oil woes for any Cadillac DTS Northstar engine include potential oil pump failures that could lead to catastrophic internal damage to the motor. When the oil pump fails, the oil pressure drops, and the engine overheats and suffers internal damage.
The oil pressure gauge will show low pressure when the oil pump is not working as designed. The engine temperature gauge likely will show that it is running hot. Replacing the oil pump is the only suitable fix to prevent potentially catastrophic damage to the motor.
- Water Pump Failures
Another of the commonly occurring 2006 Cadillac DTS engine problems that could affect any DTS model is the potential for water pump failure. You might notice coolant collecting beneath the engine compartment, low coolant in the radiator, and the engine overheating. That combination is a strong indicator of a bad water pump.
Replacing the water pump is the obvious solution. Unfortunately, the water pump is located at the back of the engine in a hard-to-reach spot. It takes time and labor to swap out the water pump.
Many Cadillac owners take very good care of their vehicles and do not abuse them. Others might have bought a car that is outside their realistic price range and allowed it to go into disrepair.
Knowing the commonly occurring Cadillac DTS Northstar engine problems can help you to look for them while shopping for a used model. Careful scrutiny can help you to find a good model with relatively low miles on the odometer and lots of good life left in the engine.