Fixing a heavy-breathing Hemi

Feb. 26, 2018
A 2009 Dodge Ram 1500 pickup, equipped with a 5.7 L Hemi and with 112,962 miles on the odometer, came in with a concern of low power and performance.

In our shop we don’t see many Chrysler cars, but we do see a bunch of Jeeps, minivans and Ram pickups. Most of the Ram pickups in our area are sold with the “Hemi” motor in them so our chance of seeing one of them is going to be on the high side. One of the most important services that needs to be performed on this powerhouse of an engine is an oil and filter change. As we know, there are many vehicle owners who shop for the cheapest oil and filter change prices. Well, shopping for the cheapest oil and filter change usually is going to cost them in the long run. The old commercial from FRAM, “Pay me now or pay me later,” really applies, especially with these engines. Before we dive into our case studies of heavy-breathing powerplants, we need a short history lesson of where the motor came from and the changes that make it today’s Hemi engine.

The Muscle Car era

Chrysler made their first engines with hemispherically-shaped combustion chambers in 1951, but these early motors ranged from 301 to 392 cubic inches. They were called the “Red Ram,” “Firedome” and “Firepower,” depending on brand and horsepower peaked in 1958 with a dual four barrel version of the 392 rated at 390 hp, which would soon be outperformed by a 413 Wedge.. inches. They were called the “Red,” “Firedome,” and “Firepower,” depending on brand and horsepower peaked in 1958 with a dual four-barrel version of the 392 rated at 390 hp, which would soon be outperformed by a 413 Wedge.
When the 426 Hemi was introduced in 1964, it was strictly a racing engine.

That same year, four Hemi-powered Mopars swept the Daytona 500, finishing 1-2-3-4. It caught the racing world by surprise, and prompted NASCAR to impose stricter production rules on Chrysler. Instead of producing a few blueprinted Hemi motors each production year, they would have to produce several thousand and sell them in street-legal cars. The street Hemi soon showed up in select 1966 Dodge and Plymouth models. to impose stricter production rules on Chrysler. Instead of producing a few blueprinted Hemi motors each production year, they would have to produce several thousand and sell them in street-legal cars. The street Hemi soon showed up in select 1966 Dodge and Plymouth models.

Today, it’s a different story. Chrysler has their Dodge Challenger Demon 6.2L engine producing 840 horsepower that will clock a 0 to 60 mph run in 2.6 seconds. Since most of us won’t be so lucky to work on or even drive one of the 6.2L Demons, it’s time to get back to reality and concentrate on the Hemi that we are most likely to work on. The engine that I am referring to is the 5.7L Hemi that is the most common along with its sister 6.1L engine that is similar. Starting in 2003, the Hemi was used in the Dodge Ram 1500, 2500 and 3500 pickup trucks as well as their Dodge Durango, Chrysler 300C, Dodge Magnum R/T, Jeep Grand Cherokee, Dodge Charger R/T and Dodge Challenger R/T. The Hemi comes in different flavors such as a straight up standard engine, Variable Camshaft Timing (VCT) or Multi-Displacement System (MDS). Having owned a Chrysler 300C with the 5.7 Hemi that utilized the MDS, I can tell you that this engine can produce some ass-kicking horsepower. I maintained my 300C properly and changed the oil using the specified oil and had absolutely no problems with the engine, so my Hemi was breathing just fine. Now that we have covered some of the Hemi’s history, let’s move on to some real-world breathing problems.

A Hemi with a problem

Let me share our New York experience with Hemi breathing problems that we encountered in our shop. First is a 2009 Dodge Ram 1500 pickup, equipped with a 5.7 L Hemi and with 112,962 miles on the odometer. It came in with a concern of low power and performance. The vehicle owner said that she had always taken care of her Ram and had the oil changed every 3,000 miles. She proceeded to tell us that she had all the recommended work performed by her former technician.

We assured her that we would perform a thorough inspection of her vehicle to address her concerns. Since this Ram’s check engine light was illuminated and there was the complaint of a performance problem, we explained the steps we would perform. These steps would include a complete vehicle scan, along with testing the engine’s mechanical condition. I had Bill, my lead tech, scan the vehicle’s computer system, where he discovered a P0305 (Cylinder #5 Misfire) that could be the result of a mechanical, ignition or fuel problem.

We started with the basics; checked all the fluids, performed a battery test, as well as a fuel and ignition system test. The results of our basic tests all received a passing grade so we proceeded to check the engine vacuum while cranking and at idle, followed by a relative compression test. The relative compression and idle vacuum test were surprising to both of us. Neither test revealed any signs of the problem that we expected them to reveal. We were now at the junction where we had to request more diagnostic time. With the extra approval time we proceeded to remove the coils and spark plugs, and performed a conventional compression test. We explained that depending on the dry compression test results we may have to perform a wet compression test, possibly followed by a cylinder leak down test.

Bill started the compression test on cylinder #5 since that was the cylinder that displayed the DTC. Bill used our usual procedure of four “bounces” of the compression gauge needle and recorded a compression reading of 225 psi. Bill thought that the reading was on the high side, so he looked up the recommended procedure in service information finding that it was only three bounces of the needle on the compression gauge. The specification for the compression test was a reading of at least 100 psi with no more than a 25 percent difference from cylinder to cylinder. Bill retested with the recommended procedure only to discover about the same 225 psi reading. He moved on to cylinder #7 and found a very similar reading with the rest of the cylinders all about the same. Bill and I discussed the test results and thought that the compression readings were a bit high, and thought that carbon build up maybe the cause of the misfire. We proceeded to take a closer look by using our inspection camera in cylinder #5 first, followed by a look in all the other cylinders.

Our findings from our inspection camera test revealed heavy carbon build up on the valves and pistons that we though could be causing the misfire. At this point we recommended an engine decarb since it was the easiest and cheapest way to go. We continued to explain that if there was not a significant improvement after the decarb, we would recommend removing the left side (Bank 2) valve cover.

The Ram owner thought about it and decided to have us perform the decarb. Bill performed the engine decarb and retested the compression, finding lower compression readings across the board. The road test of the pickup yielded better results and the Check Engine light stayed off. We explained to the customer that if the light illuminated again she needed to come right back in. Otherwise she should drive the truck for a couple of weeks before returning to us for a recheck. Well guess what, the Ram was back in within a week with the light once again illuminated. We connected our scan tool and found the same P0305 DTC.
The vehicle owner understood from what was previous explained to her about the Ram problem and the next steps we needed to perform.

Since the DTC P0305 returned, Bill decided to go on a different path by utilizing our pressure transducers, comparing a good cylinder to the bad #5 cylinder. His findings revealed only a slight difference with running compression but enough for him to proceed without hesitation. Bill’s next step was to remove the Bank 2 valve cover, providing us a good view of the rocker arm assembly. We thought that we would find something broken or loose on the #5 cylinder that would validate the misfire. After a thorough investigation of the rocker arms with the engine off we found nothing abnormal. So, we decided to prepare the engine compartment for possible oil spills and started the engine up to see if there was any abnormality with the rocker arms.

Figure 1

Bingo! We found cylinder #5 exhaust valve rocker was not moving at the same rate as the others. As we ran the engine and looked even closer at the rest of the rocker arms, we noticed that there was something abnormal on cylinder #7 as well. With the difference we had uncovered, we were confident that there had to be a lifter or camshaft issue. We were fortunate that the Ram owner was still in the front office waiting for her elder mother to come pick her up so we had the opportunity to show her the problem. We explained with the engine running she would be able to compare the noticeable movement difference from a good and bad rocker arm. We told her that we would provide her with a detailed estimate, but we needed about four hours to disassemble the engine down to where we could physically see the problem. The coolant/antifreeze would have to be removed along with the intake plenum (Figure 1) and other associated parts before we could give her a complete estimate on how much it would be to repair.

Figure 2

Once Bill had the rocker assembly and intake removed we knew it was going to be expensive. This Hemi was equipped (Figure 2) with the Chrysler MDS cylinder deactivation system, so there could also be an issue with the MDS system causing a misfire problem. We had to make sure that the MDS solenoids were operating as designed to rule out any problems before moving on. The MDS system deactivates cylinders 1, 4, 6 and 7 during steady low speed cruise to save fuel. When the MDS system is activated, the engine goes into four-cylinder mode providing better fuel economy. Since our main problem was in cylinder #5, we ruled out a problem with the MDS system. We still had to check and compare the conventional lifters and the MDS lifter to distinguish if there were any of them that may cause a future problem or the slight difference on the #7 cylinder. You don’t want to perform a valve job and have it come back for a part that you should have replaced. For starters the MDS system did not have any DTCs stored so that was a good sign, but the solenoids still need to be tested dynamically and the oil screens would need to be cleaned at the very least.
After the solenoids pasted the dynamic test for proper operation and current draw it was tear down time. Bill continued the tear down with the removal of the cylinder heads so he could remove and inspect all the lifters.

Figure 3

Take a look (Figure 3) at what he found on cylinder #5. The lifter was worn down and had severe flat spots on it. We knew without even looking any further that the camshaft had to be replaced. We explained to the Ram owner the tear down procedure necessary for a proper inspection and repair was now going to be a bigger job then we first anticipated. The camshaft would have to be removed and replaced along with the timing chain, camshaft and crankshaft gears and associated parts. The vehicle owner was impressed with the pictures and the detail explanation of the problems we provide her, so she gave us the approval to repairing this poor breathing Ram.

Figure 4

When Bill had the motor torn down to the point where the camshaft (Figure 4) was removed, he noticed that the oil pan was almost rusted through and would have to be replaced. This was a similar issue that we had encountered on many other Chryslers. As you can see from the picture the camshaft was severely worn causing the engine’s heavy breathing and Check Engine light to illuminate. We called the Chrysler dealer and ordered all the parts we needed from the oil pan, thermostat, water pump, timing chain, gears, camshaft, lifters, gaskets and other associated parts. Once the parts arrived, we noticed something that we thought was odd There was a $200 core charge on the old camshaft — the core price was higher than the new replacement.

Figure 5

Bill and I compared the new parts to the ones we removed and took the (Figure 5) comparison picture of the old and new camshafts so the Ram owner could really see the difference. I brought the cylinder heads to the machine shop to be inspected and rebuilt making sure we covered all our bases. The machine shop cleaned and decked the heads along with replacing a few valves including those in cylinder #5. In the meantime, we cleaned and prepared the engine block for all the new components that were going to be installed.

Figure 6

Once the engine was fully assembled we installed new factory spark plugs, specified oil and Mopar antifreeze, then proceeded to cranking the engine over without allowing it to start. As the oil pressure reached an acceptable level, we then started the engine. It was running great, with no noise, running nice and smooth, but we were not done yet. We still needed to perform another scan of all the computer system to make sure that there were no misfires present or any other DTCs for that matter. The results of the Chrysler wiTech full system scan (Figure 6) came up code free, but there were four computers that needed to be updated. Since we performed such and expensive repair we decided not to leave the computers that needed updates without updating the software. We explained to the Ram owner that her truck should have all of its computers up to date to prevent any problems and would most likely fix a few issues the vehicle had as a result of the older software. One of the updates required was for the TIPM (Totally Integrated Power Module) that is the electrical command center that incorporates many relays and fuses. The other system that needed updated software was the HVAC system that the owner had issues with from time to time. There were also two other computers that needed updates as well.

With the owner’s approval we reprogrammed all the computers, assuring that all the Ram’s computer systems would be up to date. Now this Ram was ready for a good road test, followed by another visual, fluid check and another complete computer scan. Since there were no leaks or computer related problems, Bill drove the truck home to ensure that there were no issues before we returned the Ram to the vehicle owner. This Ram was now done and running great.

Another sick Ram

Our next sick Ram is a 2011 5.7 L Hemi with MDS that only had 67,208 miles on the clock. After we performed a complete vehicle scan that revealed two associated DTCs P0301(Cylinder  1 Misfire) and a P1411 (Cylinder 1 Reactivation Control Performance) that needed attention. We noticed that the engine was misfiring and running really bad, so we were going to continue our investigation of the vehicle. We located a few other clues, with one of them being an oil sticker on the windshield left upper corner along the oil level being full and clean.

The problem with the recent oil change was that it was done at a local tire store that uses bulk 10w30 no name oil and cheap oil filters for every vehicle in order to offer a “$19.95 oil change.” Hell, $19.95 was the same price of an oil and filter change many years ago when I worked at an ESSO gas station!

This engine requires 5w20HD oil in order for the MDS system to operate properly. Proper oil weight and specified rating are one of the most important things that help prevent premature engine failure. After we ran a few tests we concluded that the fuel, ignition and relative compression were all good. We suggested to the owner that we remove the valve cover on the driver side of the engine so we could observe cylinder #1 valvetrain movement. We knew from our previous experience with the relative compression test on the 2009 Ram that it did not reveal an engine problem so we would not get fooled again. Take a look at the short video on our YouTube TST channel, “TSTSeminars.”

Figure 7

As you can see from the video, the number one intake rocker arm barely moves but the barely moving rocker arm is enough to fool the (Figure 7) relative compression test. I believe since some air was still allowed to enter the cylinder, the battery voltage drop (or current if done with an amp clamp) along with the engine cranking speed stayed about the same, thus fooling the relative compression test. Remember that this was the same test results that we encountered on the 2009 Hemi motor. If there is a problem that is not uncovered in the fuel or ignition system on the engine, I would strongly suggest that you perform a pressure-style compression test with either the compression gauge or pressure transducer. After we selected the right path to diagnose the problem our next step was to write up an estimate and see if the Ram owner wanted to fix it.

Figure 8 Figure 9

The owner agreed to this very expensive repair job and understood that we may uncover other problems. As we started the disassembly of the heads we found that the engine cylinder heads had exhaust studs that were broken on both banks (Figure 8 and 9). This job was going to be a duplication of the 2009 Ram, so we knew what we had to do. Bill attacked this engine and carefully disassembled it in record time. The hardest part of the disassembly would be removing the lifters, timing cover, chain and gears because the oil pan would have to be removed. We had it down to a science since we made a pulley system out of a heavy duty pipe and ratchet straps (Figure 10) since our engine holder was not wide enough to handle the job. Our homemade engine holder would allow us full access to the oil pan removal and all the timing components that were needed to perform the repairs.

Figure 10

Important information to know about this engine is that it has the same VCT (Variable Cam Timing) camshaft phaser set up as the 2009 Ram Hemi. The lifters must be removed first and carefully inspected, besides keeping them in order since there are different ones used between the MDS and non MDS cylinders. The lifters for cylinders 1, 4, 6 & 7 are for the MDS cylinders that have two holes on the side of the lifter that are used as latching pins. Another super important fact is that the camshaft has a non-serviceable bearing, so if they are damaged the complete engine block must be replaced. Lucky for the Ram owner the camshaft bearings were in good shape, so we were able to replace the camshaft and lifters without any extra cost.
When Bill removed the camshaft and lifter (Figure 11) the problem was obvious.

Figure 11

As Bill removed the oil pan he found that it was starting to rust so we recommended that it be sanded down and painted with Rust-Oleum. We applied multiple coats of paint to the oil pan assuring that there would not be any rust through issues in the near future. Bill prepared to install the camshaft and timing components as I applied prelube and prepared the new lifters for installation. After the heads, intake and other components were torqued down, oil, antifreeze and all the fluid would be installed and checked before we cranked it over. After a few long cranks with the fuel and spark disabled, we reconnected them and the Hemi fired right up. The engine was purring like a kitten, and just needed to idle for a while so we could make sure that the engine was producing proper heat and not leaking any fluids. As the engine was running we performed a complete vehicle scan with the Chrysler wiTech to make sure there were no problems.

Figure 12

Since there were no leaks and no other issues we decided to shut the engine down and perform a few computer (Figure 12) updates and recheck all the fluids. The Hemi was now breathing as it should, along with developing the power that this engine is capable of supplying. After a few more successful road tests and computer scans the Ram was ready to go.

About the Author

G. Jerry Truglia

ASE World Class Triple Master Technician Auto, Truck & School Bus, L1, L3, F1, A9, X1 C1

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