A Practical Guide to the 1994-2001 Chrysler LHS Engine Intake Manifold Gasket
If you're dealing with a rough idle or mysterious coolant loss, your intake manifold gasket might be the culprit.
- Symptoms are often related to coolant leaks and overheating due to the 3.5L engine's design.
- Labor is the biggest expense; use a quality aftermarket gasket set from a brand like Victor Reinz to ensure a durable repair.
- The OEM lower gasket set is often discontinued, making a complete aftermarket kit the most practical option.
- Driving with a significant coolant leak or contaminated oil can quickly lead to catastrophic engine failure.
Is Your LHS Intake Manifold Gasket Failing?
Over time, the constant heat from the engine causes the original gaskets to become hard and brittle. They can crack and lose their seal. When this happens, you will notice clear signs that something is wrong with your engine. Ignoring these symptoms can lead to more expensive repairs down the road.
Key Failure Symptoms:
- Engine Overheating: A failed gasket can let coolant leak out. If the coolant level drops too low, your engine will overheat. This is a serious problem that can damage the engine.
- Coolant Leaks: You might see puddles of green or orange coolant under the front of your car. Sometimes the leak is slow, and you might just notice a sweet smell after the engine has been running. The leak can be external (dripping onto the engine) or internal (mixing with oil).
- Rough Idle or Misfires: If the gasket leaks air, it messes up the air-fuel mixture. This can make your engine idle roughly, hesitate when you accelerate, or even misfire. You might hear a hissing sound from the engine area.
- Check Engine Light: A vacuum leak will almost always trigger the Check Engine Light. You will likely see codes like P0171 or P0174, which mean the engine is running too lean (too much air).
Oil Contamination: A Critical Warning
A severe internal coolant leak can mix coolant with your engine oil. If you check your oil dipstick and see a milky, frothy, or light-brown substance that looks like a milkshake, stop driving the vehicle immediately. This contaminated oil will not protect your engine's bearings and can lead to complete engine failure.
Choosing the Right Aftermarket Gasket Set
For a vehicle like the 1994-2001 LHS, aftermarket gaskets offer excellent value and quality. The original Mopar lower gasket set (part number 4663852) is listed as discontinued by many suppliers, making a complete aftermarket set the most practical choice.
Aftermarket Brand Tiers:
- Good Quality (Victor Gaskets / Reinz): Victor Reinz is a well-respected brand that is often an original equipment supplier for many European cars. Forum discussions show that mechanics often consider their gaskets to be high quality, made of soft, pliable rubber that seals well. This is a reliable choice for a lasting repair.
- Standard / Economy (Apex): Apex is a budget-friendly brand that produces gaskets to meet industry standards. While they can work for a repair, some user reviews mention issues with incorrect parts being sent or concerns about long-term durability compared to more established brands. This brand is best for those on a tight budget who can verify the part is correct before starting the job.
Pro Tip: While not on your list, Fel-Pro is another top-tier aftermarket brand frequently mentioned by mechanics as a high-quality alternative for these engines. Comparing your options against Fel-Pro or Victor Reinz is a good way to gauge quality.
Known Issues, Recalls, or TSBs
Searches of the National Highway Traffic Safety Administration (NHTSA) database and other technical resources show no specific recalls or Technical Service Bulletins (TSBs) for the intake manifold gaskets on the 1994-2001 Chrysler LHS. Failures are generally due to the age and mileage of the vehicle, not a specific manufacturing defect.
Replacement Cost
The main cost of this repair is labor, as getting to the gasket requires removing several other parts. Since you are already paying for the labor, it is wise to use a quality gasket to avoid doing the job twice.
| Part/Service | Estimated Cost |
|---|---|
| New Aftermarket Gasket Set | $22 - $60 |
| Shop Labor | $300 - $480 |
| Total Estimated Cost | $322 - $540 |
Cost estimates are based on typical aftermarket part prices and national average labor rates. Your cost may vary.
Frequently Asked Questions
Can I replace the intake manifold gasket myself?
This is an advanced DIY job. It requires draining the coolant, depressurizing the fuel system, and carefully removing the intake manifold. You will need a torque wrench to tighten the bolts in the correct sequence to avoid leaks. If you are not experienced with this level of engine work, it is best to leave it to a professional mechanic.
Should I use sealant on the new gaskets?
Generally, no. Modern gaskets like these are designed to be installed on clean, dry surfaces. Applying extra sealant can interfere with the seal and cause a leak. Always follow the specific instructions that come with your new gasket set.
What else should I replace at the same time?
Since the intake manifold is off, you will have easy access to the spark plugs and potentially the fuel injectors. It is a great time to replace them if they are due. At a minimum, you should plan on changing the engine oil and coolant, as they can become contaminated during the repair.
Is the upper or lower gasket more likely to fail?
Both the upper (plenum) and lower gaskets can fail. The lower gaskets, which seal the coolant passages, are often the cause of overheating and coolant loss symptoms. The upper gasket is more likely to cause a simple vacuum leak. Because of the high labor cost, it is recommended to replace both the upper and lower gaskets as a set.
Technical Specifications
OEM Part Numbers: 4663851 4663852
Set includes upper (plenum) and lower (intake-to-head) gaskets. Seals both air and coolant passages on the 3.5L V6 engine.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Chrysler LHS: