The 5.7 Hemi is equipped with multiple cylinder deactivation solenoids. Sometimes, these solenoids become damaged and need to be replaced. To do so, you must know about the 5.7 Hemi cylinder deactivation solenoid location.
These deactivation solenoids are typically located beneath the intake manifold near certain cylinders.
In today’s article, we’ll learn about the location of the 5.7 Hemi deactivation solenoid and its removal. We’ll also discuss several symptoms and solutions of a bad cylinder deactivation solenoid.
5.7 Hemi Cylinder Deactivation Solenoid Location
As we already know, the 5.7 Hemi uses cylinder deactivation technology. But this technology is also called the Multiple Displacement System. In short, MDS.
The MDS includes several solenoids to deactivate the cylinders and increase fuel economy.
To locate these solenoids in a 5.7 Hemi, first, we should know about the firing order of a 5.7 Hemi.
At this point, the firing order is 1-8-4-3-6-5-7-2. Here, 1, 3, 5, and 7 are mounted on the driver’s side, while 2, 4, 6, and 8 are located on the passenger’s side.
Among them, the MDS cylinders are the 1, 4, 6, and 7 cylinders. So, the cylinder deactivation solenoids for cylinders #1 and #7 are mounted in the engine valley below the intake manifold on the driver’s side.
On the other hand, #4 and #6 cylinder deactivation solenoids are positioned under the intake manifold on the passenger side.
How to Replace a 5.7 Hemi Cylinder Deactivation Solenoid?
The cylinder deactivation solenoids on a 5.7 Hemi can often go bad for various reasons, like a faulty MDS, low fuel pressure, or a defective engine.
In this case, you will need to replace the bad MDS solenoid to prevent such problems. Here’s how it goes:
Step 1: Safety First
First and foremost, safety must be prioritized. Car’s engine is always risky to deal with. Moreover, it contains electrical connections everywhere. So, remove the negative battery cable to ensure your safety.
Step 2: Remove the Intake Manifold
As we mentioned earlier, the MDS solenoids are located underneath the engine’s intake manifold. So, locate the intake manifold and remove it. To do so, follow the following steps:
- Disconnect the air filter and open the hose clamp.
- Remove the vacuum line and fuel line that is connected to the carburetor.
- Now detach the carburetor and intake manifold by disconnecting the bolts and attaching them.
- Remove the distributor and upper radiator hoses.
- Remove the bolts connecting the intake manifold with the engine and finally pull off the intake manifold.
Step 3: Discharge Connectors
After removing the intake manifold, you will locate multiple connectors and a wiring harness connected to the MDS solenoid. Remove these wiring harnesses and connectors as they are required.
Step 4: Remove the MDS Solenoid
Now, you are only one step away from disconnecting the MDS solenoid from the cylinder. Disconnect the hold-down bolts using a flathead screwdriver. Once these bolts are removed, pull the MDS solenoid off. Here’s a detailed video on it.
Step 5: Install the new MDS Solenoid
Once you remove the old MDS solenoid, install the new one and reattach the hold-down bolts properly.
Now reverse the steps you took to remove your 5.7 Hemi MDS solenoid. After that, reconnect the negative battery cable, and you’re done!
Symptoms of a Bad 5.7 Hemi Cylinder Deactivation Solenoid
Once a 5.7 Hemi cylinder deactivation solenoid goes bad, it will come up with some particular signs and symptoms.
Here are some of the most common symptoms of a 5.7 Hemi cylinder deactivation solenoid:
- Low fuel economy
- Engine misfiring
- The MDS system is malfunctioning
- Low fuel level
- Ticking sounds
- Poor engine performance
- Lifter issues
- MDS is going on and off
- Excessive vibration
Bad 5.7 Hemi Cylinder Deactivation Solenoid Fixing
We have discussed the symptoms of a bad 5.7 Hemi cylinder deactivation solenoid. So, if you detect any of these symptoms, troubleshoot your MDS solenoid and fix the issues. Here’s how it goes:
Check the exhaust pipe: Fix the holes
Leakage in the exhaust pipe is one of the major causes of a bad MDS solenoid. So, first of all, check the exhaust pipe for any cracks, holes, or rust. If it becomes damaged, you can fix it using aluminum tape, exhaust tape, or epoxy bond.
Inspect the wires and connectors: Replace the bad one
Usually, the engine’s intake manifold and the solenoid consist of many plugs, wires, and connectors. These elements can be rusted, broken, or bent over time.
Somehow, if any of these connectors or plugs become defective, it can cause the MDS solenoid to go bad. So, check the wires and connectors for potential problems and replace them if faulty.
Check the MDS: Disable the MDS if needed
A faulty MDS solenoid can also cause excessive vibration. To avoid such problems, the solution is to disable the MDS on your 5.7 Hemi. The easiest way to disable an MDS is to get a tuner.
Inspect the MDS solenoid: Replace the bad solenoid
If you find that all these possible parts are working well, but you are still experiencing such issues, then the solenoid itself might be the culprit. Use a multimeter to check the solenoid.
If the result is under 5 ohms, then your 5.7 Hemi MDS solenoid is bad and needs to be replaced. You can check out the YouTube video on how to test a MDS solenoid to learn it practically.
How Much Does It Cost to Replace a Hemi Cylinder Deactivation Solenoid?
Replacing a bad Hemi cylinder deactivation solenoid is pretty difficult. Moreover, it requires long working hours.
It’s because the mechanic should have to remove the whole intake manifold and reinstall it.
So, the labor for replacing an MDS solenoid is approximately $500. But the price of the parts will depend on the part’s quality and its marketplace. However, the average cost of an MDS solenoid is between $50 and $170.
Are you looking for more information regarding the 5.7 Hemi cylinder deactivation solenoid? Below, we will answer a few possible questions related to MDS solenoids.
How many cylinders are MDS on a 5.7 Hemi?
Four cylinders are designed on a 5.7 Hemi engine with multiple displacement systems among the eight. As we also mentioned earlier, 1, 4, 6, and 7 cylinders are the MDS on a Hemi.
Do the 5.7 Hemi Cylinders have MDS?
Yes, the 5.7 Hemi cylinders have MDS. In 2006, this technology was first designed for the 5.7 liter Hemi V8 engine.
Can you delete MDS on the 5.7 Hemi?
No, you can not delete MDS on the 5.7 Hemi. They are not designed that way. You can simply disable it if needed using a tuner.
Can I turn off my 5.7 Hemi MDS?
Yes, you can turn off your 5.7 L Hemi MDS. To do so, install a high-performance camshaft in your 5.7 Hemi engine.