Do you have an oil leak on your Northstar 4.6 equipped Cadillac? There are several common areas these engines will leak from. Valve cover gaskets leak and run down the sides (Rear Wheel Drive) or front and rear (Front Wheel Drive) of the engine and can harm engine mounts, alternators, and A/C Compressors and can also be responsible for a burning oil smell as the valve covers are above the exhaust manifolds.These gaskets aren’t typically responsible for large oil leaks. This is a job within the capabilities of most reputable shops or capable Do-It-Yourselfers. Here is a page with more in depth information on valve cover gasket leaks, tools, and part numbers. Northstar Valve Cover Gaskets
The next most common leaks are the oil pressure sensor and the oil filter adapter. These leaks are low on the engine and may only be noticeable as spotting in the driveway. These seals handle pressurized oil anytime the vehicle is running and can be responsible for large amounts of oil loss. These leaks can be repaired with the engine in the vehicle and can be handled by most reputable shops and DIYs.
Oil pan, oil manifold, oil level sensor, oil drain plug and lower crankcase seal leaks are also common and low on the engine and are likely to only be noticed as spotting while parked. But, there are pressurized passages inside the oil manifold and lower crankcase half. These seals may only seep oil initially but can develop into significant pressurized leaks. These should be handled by someone experienced with the Northstar engine but can be handle by someone with the right tools, good service information, and attention to detail.
Less common oil leaks include the timing cover, and front and rear crankshaft seals. These leaks are fairly uncommon. Most of the leaks I see in these components are only after someone has “repaired” them. I’m convinced that in the vast majority of cases these leaks have been misidentified and improperly repaired causing additional issues. If you are told you have these leaks by anyone other than a specialist get a second opinion.
These leaks typically start at around 65,000-70,000 miles. But time and maintenance are considerations and low mileage vehicles may leak sooner while well maintained vehicles may not leak until later. Synthetic oil will not make the leak any worse and can continue to be used. Stop leak products do not stop these leaks and contaminate the oil system. They should be avoided.
Some of these leaks like valve cover leaks can be fixed in a day and are relatively inexpensive. Others like oil pan or lower crankcase seals require extensive labor and can be more expensive, in the range of $2000-$2500 are common. These repair prices are only for a fraction of the seals on the engine. But at RB Auto Service we specialize in Cadillac. After repairing these leaks on so many Cadillacs we developed a system to seal these leaks that is effective, efficient, affordable, and adds value to your luxury car.
All Northstar 4.6 engines will eventually experience the same seal failures and oil leaks. Whether you drive a Deville or a Seville, a DTS or an STS, an XLR or an SRX, and Eldorado or an Allante. All of these engines will experience lower crankcase seal leaks, oil pan leaks, valve cover leaks, and rear main seal leaks as well as leaks from sensors and filter adapters. The gaskets simply will not last forever.
Our Northstar Reseal Process
Our process takes into account the fact that all of these seals will eventually leak, and that the factory sealing system is flawed. For that reason we recommend and offer a comprehensive reseal process with updated materials approved by Cadillac that last longer than the original seals. Resealing just the oil pan at a reputable shop can cost in the range of $800-$1000. Returning later to replace a rear main seal can cost $600-$800. Performing these two repairs alone can cost upwards of $1800 and still leave many vulnerable aging seals in place that may already be leaking. When you need to replace the lower crankcase seal you can add another $2000-$2500 to the cost at most shops.
The costs add up quickly when these leaks are repaired separately, without adding in valve cover seals, timing cover seals, etc. Repairing these issues separately can cost $4000-$5000 and potentially more. Then there are coolant seals and intake seals that typically outlast the oil seals but will also fail eventually. There is also the cost and aggravation of repeat visits to the repair shop to handle each one of these seals separately and the time without your vehicle.
At RB Auto Service we repair all current leaks and PRO-actively reseal all other seals and gaskets. This represents considerable labor savings. And this process only takes five business days to assess the overall condition of the vehicle and give you the information to make the best decision for you, consult with you about the vehicle condition, make the necessary repairs, and test extensively post repair to ensure you don’t have to come back and see us for a while. Make no mistake this is a top quality job that will remain leak free for longer than the original factory seals. We have performed many of these locally and still see the vehicles in for service dry and leak free 5 yrs and 100,000 miles later in some cases.
What You Get For Your Money
- All external oil seals replaced.*
- GM approved engine sealant to improve the sealing of the lower end of the engine.
- Mobil1 oil and Mobil1 filter
- ACDelco Dexcool coolant.
- All other necessary fluids.
- Crankshaft seals installed with authentic Cadillac service tools to ensure a proper fit and installation every time.
- Engine and engine compartment thoroughly cleaned.
- Vehicle washed inside and out.
- 3 year / 36,000 mile fully transferable warranty against oil leaks.
*individual seals and components included
- Valve Cover Gaskets
- Front Crankshaft Seal
- Rear Crankshaft Seal
- Oil Pan Seal
- Oil Control Manifold and Seal
- Crankcase Half Seal
- Timing Cover Seal
- Oil Filter Adapter Seal
- Coolant Manifold Seals
- Intake Gaskets
- Heater Pipe Quick Disconnect Fitting
- Oil Pressure Sensor
- Oil Level Sensor
- Camshaft Actuator Housing Gaskets
- Camshaft Actuator Magnets
This service returns your engine to a leak-free status in the most cost-effective manner possible. If you plan to continue ownership of your Cadillac this service represents a great value. We understand that this repair exceeds the resale value of some of these vehicles. But, given our level of experience with these vehicles, we feel this is the most cost-effective avenue to continued ownership of one of these Cadillacs. While we are primarily a local service center we have had Northstar equipped cars from all over the East Coast and the Southeastern US brought to us for this service. If you have any Northstar questions or questions about this service feel free to contact us and a Northstar expert will look into your questions and get back to with whatever help we can render.