Chrysler 300 (LX: 2004-2010)

Weak tie rods

Worn outer tie rods are a typical problem with the Chrysler 300 because the OEM parts are not very durable. When the car is driven on rough roads, you may need to have the tie rods replaced regularly.

The solution is to use tie rods made by Moog as they seem to last longer than OEM ones. Replacing the tie rods is a relatively simple and inexpensive job. Just keep in mind that the front wheels need to be aligned afterwards.

The typical symptoms of worn tie rods are clunking noises while driving (especially when going over bumps). Another common symptom is a vibrating steering wheel at around 60mph and accelerated tyre wear. To check if the tie rods are still good, you need to lift the car and try to move the front wheels side-to-side by hand. If there is any play, it’s most likely because of worn outer tie rods.

2.7L V6 – sludge

These engines have a bad reputation for developing engine sludge because of the water pump location. In the 2.7L V6 engine, the water pump is driven by the timing chain, and it is buried deep inside the engine. The location of the water pump is unfortunate because if it starts leaking, the coolant can mix with engine oil.

Engine oil diluted with coolant has reduced lubricating properties and tends to turn into sludge. In this engine, driving with a leaking water pump massively accelerates the wear on all moving parts that are lubricated by engine oil. All the while, sludge would be building up inside the engine, clogging oil channels and restricting oil flow.

Typically, engines with timing chains have water pumps driven by the auxiliary belt, where they are easily accessible. Small coolant leaks are harmless and larger ones are usually visible. This is not the case with Chrysler’s 2.7L V6, where the water pump is hidden and difficult to get to.

These are the typical indicators of a failing water pump in the Chrysler 2.7L V6 engine:

• coolant leak from the water pump weep holes

• dropping coolant level

• coffee or milky coloured engine oil

• milky residue or sludge on the dipstick

• if the engine has been running with diluted oil for a long time, the connecting rod bearings may develop a knock (at this point the engine is in a pretty bad condition)

This last point is the worst-case scenario. There have been cases of failing rod bearings in these engines. The exact cause is unknown, but I believe that it is a result of reduced lubrication due to engine oil dilution and sludge build-up.

I recommend replacing the water pump every 70,000 miles. I think it’s a good idea not only because of the possibility of a coolant leak but also because the pump is driven by the timing chain. If the water pump bearings seize, the timing chain may snap and wreck the engine.

Unfortunately, replacing the water pump is not as easy as in most cars, so it will be more expensive. If you don’t want to replace it preemptively, at least check the coolant and oil levels regularly.

Also, remember to replace the engine oil on time. Overdue oil replacements are another big contributor to engine sludge. Using only good quality synthetic oil in this engine is a good idea too.

3.5L V6 – rough idle

Some of the 3.5L V6 engines develop a rough idle. It’s usually an intermittent problem at first, which then gets worse progressively. The rough idle is caused by carbon build-up on the exhaust valve stems. The carbon causes the valves to stick. As a result, the engine may misfire and run poorly at low RPM. Misfire related error codes may get recorded by the ECU as well.

These are the factors that increase the likelihood of carbon deposits:

• driving like an old lady (no offence to any old ladies!) – the exhaust valves start rotating when the engine revs rise above 3500 RPM, which helps break up the carbon deposits

• driving short distances – the engine cannot reach operating temperature during short trips, therefore, the carbon does not have a chance to get burned off

• poor fuel quality with low levels of Deposit Control Additives (DCA)

Once the valves develop a carbon build-up problem, there is a service procedure that Chrysler dealerships perform. It consists of removing the valve covers and rotating the valves manually.

Carbon build-up is not a massive issue, but you should be aware that this engine is prone to developing carbon deposits on the exhaust valves. To prevent it from happening (or recurring), my recommendation is to “drive it like you stole it” once in a while.

You don’t necessarily need to use full throttle. Just get the engine revs up so that the valves start rotating. Try to regularly go over 3500 RPM when the engine is at its operating temperature.

Another good idea, as far as preventative maintenance goes, is to add a detergent fuel additive into the fuel tank every couple thousand miles. Some good additives that may help are Techron Fuel System Cleaner or SeaFoam.

3.5L V6 – tapping noise

These engines can develop a ticking noise coming from the top of the engine. It occurs after a dowel that holds the rocker arm shaft breaks. When the dowel breaks, the shaft can start moving and the oil feed holes in it become misaligned. As a result, the rocker arms that sit on this shaft don’t receive enough oil. The starved rocker arms and the lash adjusters in them then start ticking.

The solution is to replace the affected rocker shaft assembly. There is one per cylinder head, and the part number is 4892293AC. The “C” stands for revision C, which is an updated (stronger) part. The original part number was 4892293AA.

You should be able to buy the entire assembly for not more than £250. It should be easier to source these parts in the US, so they may be slightly cheaper (around 300$).

You can also try changing individual parts, like the dowel and the shaft, to cure the tapping noise. However, I recommend replacing the entire rocker shaft assembly because continued driving with a sheared dowel pin will damage the lash adjusters due to reduced lubrication.

At such point, replacing the pin and restoring oil flow may not be enough to stop the ticking noise as the damage has already been done. Replacing the rocker shaft assembly as a whole is also easier – they are pretty much plug-and-play. It is not beyond reach for someone with some DIY skills.

Initially, the ticking noise can only be heard when the engine is cold. Over time, it gets progressively worse until the engine keeps ticking even after it has warmed up. If you’re going to buy a car with the 3.5L V6, listen out for any tapping noises after a cold start. Here’s what the ticking sounds like:

The Hemi Tick

Some of the 5.7L and 6.1L V8 Hemi engines develop a slight ticking sound. Usually, it is harmless and it’s just something these engines do. There is a lot of speculations as to why Hemi engines like to tick, but no universal cause.

Here’s my take on this. The Hemi is an old-school design – it has pushrods and a single camshaft that sits between the cylinder banks. The camshaft is driven by a very short timing chain (good design). Pushrod engines, also called OHV engines, aren’t common nowadays as they’ve been mostly replaced by overhead camshaft engines (OHC).

In general, pushrod engines tend to be louder than OHC engines because they have more moving parts and a lot more moving mass (pushrods moving up and down, rocker arms rocking). Any backlash between the valvetrain parts contributes to the noise and makes the engine sound like a sewing machine, especially when the engine is cold.

This what the V8 Hemi sounds like:

In my opinion, noise like in the video above is not a cause for concern. While the infamous Hemi tick is relatively quiet and usually harmless, anything that sounds like there’s something broken usually means exactly that, so don’t ignore noises coming from the engine.

Noticeable ticking noises are usually related to wear of the valvetrain components – it could be a collapsed lifter, wear on the valve tips or a worn camshaft lobe. It could also be an exhaust manifold leak (check the exhaust manifold bolts).

If the car sounds like the one in the video below, something is wrong even though the noise seems to quiet down after a while. My guess would be some broken exhaust manifold bolts.

If you’re going to buy a car with the V8 Hemi, ideally, try to find one that doesn’t tick (Mission Impossible music starts playing). Listen out for any ticking noises after a cold start.

I cannot tell you if any particular type of ticking noise is harmless, or if it means that something is worn out and needs replacing. The quieter and less obtrusive the noise, the bigger the likelihood of it just being the nature of the beast.

3.0L CRD – oil cooler leaks (Mercedes-Benz OM642 engine)

The 3.0 CRD engine is a Mercedes-Benz unit internally called the OM642. The pre-2010 OM642 engines were notorious for leaking oil from the oil cooler seals. The original seals (orange colour) weren’t able to withstand the heat and developed leaks. Updated seals (purple colour) were introduced in 2010.

There was a recall for this issue, so hopefully, most vehicles would have had the seals replaced by now. Before buying one, check if the seals have indeed been replaced and inspect the car for oil leaks.

The seals are cheap. However, their replacement is expensive as the fuel injection system and intake manifold need to be disassembled to get to the oil cooler. The oil cooler sits on top of the engine, between the cylinder banks, underneath the intake manifold. The symptoms of a leaking oil cooler are dropping oil level and oil underneath the vehicle after a longer stand still.

3.0L CRD – swirl flap motor (Mercedes-Benz OM642 engine)

There have been cases of swirl flap motor failures in the OM642 engines due to contamination with engine oil. The swirl flap motor is located below the turbocharger and the turbo intake tends to develop leaks in this engine. The oil leaking out from the air intake may get onto the swirl flap motor and cause it to fail.

When the swirl flap motor fails, it puts the car in limp home mode along with turning the “Check Engine” light on. The air vented from the crankcase through the PCV system contains oil vapours. The PCV breather pipe is connected to the air intake before the turbocharger – that’s how engine oil gets into the intake manifold.

Replacing the swirl flap motor is not as painful as replacing the oil cooler seals, but there is still a lot of parts in the way, and the motor itself is not that cheap.

For this reason, people came up with a way to disable the swirl flap motor using a simple resistor to trick the car’s ECU into thinking that the motor is working. This solution is cheaper than replacing the faulty motor at the cost of more pollution.

The swirl flaps are not essential for the engine to run – they are there to improve emissions and disabling them has a minimal impact on engine performance. Keep in mind that disabling emissions controlling equipment is considered illegal in most countries.

3.0 CRD – Black Death (Mercedes-Benz OM642 engine)

The OM642 diesel engine may develop leaks from the fuel injector seals (copper washers). When a leak occurs, the gases and the diesel fuel from the combustion chamber can escape and cover the area around the leaking injector with burnt, hard, tar-like substance.

“Black death” is a dramatic name for something relatively inexpensive to fix, provided that you catch it early. Any leaks should be visible once the plastic engine cover is removed. 

If there was a leak, you will see a black mess on top of the engine. You may also smell diesel fuel inside the car when the engine is running. If the leak is large enough, the engine may sound like a steam locomotive due to gases escaping from the combustion chamber.

If left untreated, it can become very expensive to fix – injectors seized in the cylinder head, damaged injectors seats and massive carbon build-up to clean.

Gunfire

The Chrysler 300C is considered to be a gangster car in some circles. Please try not to get shot. Peace, yo!

You can think of the 300C as a poor man’s Bentley or as an affordable, old-school limousine with a bit of a gangster look.

It’s up to you, but I think I’m with the gangsta limo crowd…

Summary of problems & additional information

• The Chrysler 300 is based on a Chrysler platform but uses Mercedes-Benz designs for many components – suspension parts, ABS, ESP, some interior parts and a 5-speed automatic transmission (MB: 722.6, Chrysler: NAG1). Quite a few parts come from the Mercedes-Benz W210 E-Class, which I consider to be a good thing for reliability. The W210 may be a dated design, but it is quite reliable.

• If you compare the Chrysler 300 to its Mercedes-Benz competitor, the W211 E-class, the Chrysler 300 never had the SBC or the Airmatic suspension, which is a good thing for reducing maintenance costs. Also, a second-hand Chrysler 300 should be cheaper to buy than a Mercedes-Benz E-class.

• The V8 Hemi is an iconic engine. It’s called the “Hemi” because of its hemispherical combustion chambers. The Hemi engines have a long history that goes back to the 1950s. The third-generation engines mounted in the Chrysler 300 are likely to be the last of the Hemi family. Oh, and it’s not really a Hemi – the engine head has a more complex shape – it’s a polyshperical engine head.

• The V8 Hemi engine is a good unit. It’s got plenty of torque, and it is fairly reliable. A robust timing chain is a bonus. It’s all good as long as you don’t mind the slight ticking noise these engines are known for. Before buying a car with this engine, listen out for any ticking noises that stand out from the gentle valvetrain clicking. Do it after a cold start, and check one more time after the engine has warmed up. Once you buy it, use a good quality engine oil to minimize the risk of wearing out the valvetrain components.

• The 6.1L Hemi is geared towards maximum performance. It’s bored out to increase the displacement to 6.1L. It has a more aggressive camshaft and stronger internals. The cylinder heads are also modified for better airflow. There is no Multi-Displacement System (MDS) in this engine.

• The V6 engines in the Chrysler 300 have a couple problems. The 3.5L V6 may develop issues with the rocker shaft assemblies, while the 2.7L V6 is susceptible to sludge if the water pump starts leaking. Out of the two, the 3.5L V6 is the better choice, because of the terrible water pump placement in 2.7L V6.

• The 3.0L V6 diesel engine in the Chrysler 300C is a Mercedes-Benz unit, internally called the OM642. Click here for an article that might help you decide if a modern diesel engine, like the OM642, is the right choice for you. The OM642-powered 3.0 CRD was only available in Europe and Australia.

• Apart from the 3.5L V6, which has a timing belt, all other engines in the Chrysler 300 have timing chains. Read more about these key components, and why it’s important to make sure they are in good condition.

Petrol engines – specs & performance figures

Diesel engines – specs & performance figures

Petrol engines – technical details

Diesel engines – technical details