Rebuilding The Chrysler 2.4L

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Mid 1996 through 2000:

Chrysler modified the oil pump when they switched to a mechanical tensioner in mid ’96. It was a 4694306 casting that was sold under a 4694304 part number.

2001 through 2006:

The FWD oil pump was changed again in 2001 when the angle of the mounting pad for the oil filter was changed. It was originally a 4781456AA casting, but the latest version is a 4781456AD casting that carries a 4781454AD part number.

FWD PT Cruiser
2001-2002:

Chrysler had to modify the oil pump in order to fit the engine into the PT Cruiser, so the engineers left the oil filter off the pump and bolted it directly onto the aluminum oil pan. This pump used the same gerotor gear set that was found in the FWD oil pump. It’s a 4694401AB casting that’s sold under part number 4777955AA/AB.

2003-2006:

When Chrysler designed the turbo motor, the oil pump was upgraded to provide 25 percent more oil for the engine because of the turbo and the “oil squirters.” This pump is part number 4884390AB, and it has “4390” cast on the inside of the pump housing. It’s used for all the turbo and non-turbo engines in the PT Cruiser from ’03 through ’06.

RWD Liberty & Wrangler
2003-2006:

The RWD Jeeps share another pump that’s unique because the oil filter adapter bolts onto the pump housing. The adapter points towards the front if it’s in a Wrangler and toward the back if it’s in a Liberty. The pump is a part number 53010487AA and it has “0487” cast on the inside of the pump housing.

PICKUP SCREENS

According to Chrysler, there are three pickup screens that cover everything.

•       The 4792304 fits the FWD cars and minivans.
•       The 4792304AC fits all the PT Cruisers.
•     The 53010488AA fits all the RWD applications.

CAM SENSORS

There have been two cam sensors used on these engines, one for the FWD applications and one for RWD Jeeps.

• The FWD sensor bolts on the back of the intake cam. It’s a round, plastic disc with a circular magnet inlaid in it. We don’t supply it with the engine.

• The RWD motors have a stamped, metal “washer” that has a larger diameter half way around it so it can be read by the cam sensor that sticks through a hole in the front cover. It must be properly installed when the engine is assembled or it won’t start when it’s in the vehicle. The “tone-ring” for the cam sensor is available under p/n 53010549AA.

INNER FRONT COVERS

There have been several inner front covers, but it only takes four to cover everything, even if you include the one for the early engines with the hydraulic tensioner.

• The FWD cars and minivans used a 4621446 cover for the engines with the hydraulic tensioner.

• The FWD cars and minivans use a p/n 4781593AA that fits everything from ’96 through ’06 with a mechanical tensioner.

• The front cover for the PT Cruiser was slightly different than the one that was used for the other FWD applications up through 2002. It was a p/n 4694318AD. However, the latest parts book for the PT lists the same one that’s used on all of the other FWD applications. Chrysler specifies a p/n 4781593AA inner cover along with the 4884409AA upper front cover for the PT Cruiser beginning in ’03. The early cover for the PT Cruiser was slightly different, but we have always modified the FWD version to fit the PT by simply cutting a small amount off the top of the inner cover so outer cover would fit over it.

• The RWD Liberty and Wrangler have a unique cover that has the hole for the cam sensor. It’s a 53010482AC.

TENSIONERS

There have been two tensioners for the timing belt, an early hydraulic version and the later mechanical one.

• The hydraulic tensioner (p/n 4621455) was used up to 1/1/96 on the minivans and 4/15/96 on the FWD cars. It’s the same one that was used on the 2.0L engines.

• The mechanical tensioner (p/n 4781570AB) has been used for everything built after the dates listed above.

• There are several differences between the hydraulic and mechanical setups including the oil pump, front cover and tensioner. The oil pump for the engines with the hydraulic tensioner (p/n 4663589) is no longer available from Chrysler, but the tensioner (p/n 4621455) and the inner belt cover (p/n 4621446) are still available and so is the water pump.

BALANCERS

Chrysler deliberately designed the turbo motor with cast pistons and lightweight, forged rods so they could use the same balance housing and shafts on all of the 2.4L motors. However, the chain, chain guides and tensioner were all upgraded with better materials to “withstand the higher loads for this application” for the turbos.

CAMS

There have been seven different intake cams and seven different exhaust cams used for these engines since ’95. The cam chart on page 44 spells it out in greater detail, but here’s a quick overview.

Intake Cams:

• Chrysler superceded the ’96 intake cam up to the ’97 part number.

•They superceded the ’98 intake cams up to the ’02 part number.

•Then, there’s another intake cam used from ’03 through ’06.

Exhaust Cams:

•The ’96 exhaust cam was superceded to the ’97 part number.

•The ’98 exhaust cam was superceded up to the 2000 part number.

•The ’01 cam is superceded all the way up to 2006.

We’ve been a little more aggressive with our consolidations; we consolidate the ’96 and ’97 cams and use all the rest in pairs up through 2006. We haven’t turned the red light on yet, but… it may not work out in the long run, so let your conscience be your guide.

A few more comments

That pretty well tells the story of all the major pieces, but there are a few more things that are worth knowing, too.

• The bolt-on “target ring” for the crank is a part number 5114417AA.

• The turbo motors have special rods, pistons, rings and exhaust valves, along with a unique, stainless steel; MLS head gasket and a special water pump. They also have special rod bearings that have squirt holes and special thrust bearings “with contoured faces to provide higher load-carrying capacity.”.

• Chrysler changed the thrust bearing to an assembled design in ’05, but it appears that the earlier bearings can be used up through 2006.

• Chrysler has adapted a new numbering system for both casting numbers and part numbers. They add a suffix to the base number to indicate that there’s some kind of a change, so rebuilders will have to pay close attention the both the base number and the suffix from now on. Sometimes the change in the suffix indicates that it’s the same part from a different vendor, but most of the time it means that there’s a change in the casting or part number, so be careful.

• The Chrysler 2.4L was used in the Stratus/Sebring sedans and the Sebring convertible, but the Stratus/Sebring coupes have a 2.4L Mitsubishi engine in them because they’re built on a Mitsubishi platform. Don’t let your customer order the wrong engine.

CONCLUSION

So, that’s the overview of the 2.4L Chrysler motors. There have been lots of variations, but they all make sense when you see how the engine has evolved over time. The good news is that there are a bunch of them out there in cars, trucks and vans that are worth rebuilding. The bad news is that these engines are already history, because they’ve been replaced by a whole new family of engines designed and built by Chrysler, Mitsubishi and Hyundai that’s a real “world class” motor. Stay tuned.

Doug Anderson is president of Grooms Engines, and has won both regional and national awards for technical articles on engine rebuilding.