Dodge Nitro. Manual - part 68

ENGINE OIL LEAK INSPECTION 

Begin with a thorough visual inspection of the engine, particularly at the area of the suspected leak. If an oil 
leak source is not readily identifiable, the following steps should be followed: 

1. Do not clean or degrease the engine at this time because some solvents may cause rubber to swell, 

temporarily stopping the leak.  

2. Add an oil soluble dye (use as recommended by manufacturer). Start the engine and let idle for 

approximately 15 minutes. Check the oil level indicator to make sure the dye is thoroughly mixed as 
indicated with a bright yellow color under a black light.  

3. Using a black light, inspect the entire engine for fluorescent dye, particularly at the suspected area of oil 

leak. If the oil leak is found and identified, repair as necessary.  

4. If dye is not observed, drive the vehicle at various speeds for approximately 24 km (15 miles), and repeat 

inspection.  

5. If the oil leak source is not positively identified at this time , proceed with the AIR LEAK 

DETECTION TEST METHOD as follows: 

Disconnect the fresh air hose (make-up air) at the cylinder head cover and plug or cap the nipple on 
the cover.  

Remove the PCV valve hose from the cylinder head cover. Cap or plug the PCV valve nipple on 
the cover.  

Attach an air hose with pressure gauge and regulator to the oil level indicator tube. 

Gradually apply air pressure from 1 psi to 2.5 psi maximum while applying soapy water at the 
suspected source. Adjust the regulator to the suitable test pressure that provides the best bubbles 
which will pinpoint the leak source. If the oil leak is detected and identified, repair per service 

3. Burned, warped, or pitted 
valves.

3. Replace valves.

4. Faulty coil(s).

4. Test and replace as necessary. 
(Refer to Appropriate Diagnostic 
Information)

ENGINE MISSES AT HIGH 
SPEED

1. Dirty or incorrect spark plug 
gap.

1. Set gap as needed or replace 
plug(s).

2. Faulty coil(s).

2. Test and replace as necessary. 
(Refer to Appropriate Diagnostic 
Information)

3. Dirty fuel injector(s).

3. Test and replace as necessary. 
(Refer to Appropriate Diagnostic 
Information)

4. Contamination in fuel system.

4. Clean system and replace fuel 
filter.

CAUTION: Do not subject the engine assembly to more than 20.6 kpa (3 

PSI) of test pressure.

 

2007 Dodge Nitro R/T 

2007 ENGINE 4.0L - Service Information - Nitro

  

information procedures.  

If the leakage occurs at the crankshaft rear oil seal area, refer to the section, Inspection for Rear 
Seal Area Leak.  

6. If no leaks are detected, turn off the air supply. Remove the air hose, all plugs, and caps. Install the PCV 

valve and fresh air hose (make-up air). Proceed to next step.  

7. Clean the oil off the suspect oil leak area using a suitable solvent. Drive the vehicle at various speeds 

approximately 24 km (15 miles). Inspect the engine for signs of an oil leak by using a black light.  

INSPECTION FOR REAR SEAL AREA LEAKS 

Since it is sometimes difficult to determine the source of an oil leak in the rear seal area of the engine, a more 
involved inspection is necessary. The following steps should be followed to help pinpoint the source of the leak.

If the leakage occurs at the crankshaft rear oil seal area: 

1. Disconnect the battery.  

2. Raise the vehicle.  

3. Remove torque converter or clutch housing cover and inspect rear of block for evidence of oil. Use a 

black light to check for the oil leak. If a leak is present in this area, remove transmission for further 
inspection. 



Circular spray pattern generally indicates seal leakage or crankshaft damage.  



Where leakage tends to run straight down, possible causes are a porous block, oil gallery cup plug, 
bedplate to cylinder block mating surfaces and seal bore. See proper repair procedures for these 
items.  

4. If no leaks are detected, pressurize the crankcase as described in step 5 under ENGINE OIL LEAK 

INSPECTION. 

5. If the leak is not detected, very slowly turn the crankshaft and watch for leakage. If a leak is detected 

between the crankshaft and seal while slowly turning the crankshaft, it is possible the crankshaft seal 
surface is damaged. The seal area on the crankshaft could have minor nicks or scratches that can be 
polished out with emery cloth. 

NOTE:

If oil leakage is observed at the oil level indicator tube to block location; remove 
the tube, clean and reseal using Mopar® Stud & Bearing Mount (press fit tube 
applications only), and for O-ring style tubes, remove tube and replace the O-
ring seal.

CAUTION: Do not exceed 20.6 kPa (3 psi).

CAUTION: Use extreme caution when crankshaft polishing is necessary to 

remove minor nicks and scratches. The crankshaft seal flange is 
specially machined to complement the function of the rear oil seal.

 

2007 Dodge Nitro R/T 

2007 ENGINE 4.0L - Service Information - Nitro

  

6. For bubbles that remain steady with shaft rotation, no further inspection can be done until disassembled.  

7. After the oil leak root cause and appropriate corrective action have been identified, replace component(s) 

as necessary.  

STANDARD PROCEDURE 

FORM-IN-PLACE GASKETS AND SEALERS 

There are numerous places where form-in-place gaskets are used on the engine. Care must be taken when 
applying form-in-place gaskets to assure obtaining the desired results.Do not use form-in-place gasket 
material unless specified. Bead size, continuity, and location are of great importance. Too thin a bead can 
result in leakage while too much can result in spill-over which can break off and obstruct fluid feed lines. A 
continuous bead of the proper width is essential to obtain a leak-free gasket. 

There are numerous types of form-in-place gasket materials that are used in the engine area. Mopar® Engine 
RTV GEN II, Mopar® ATF-RTV, and Mopar® Gasket Maker gasket materials, each have different properties 
and can not be used in place of the other. 

MOPAR® ENGINE RTV GEN II is used to seal components exposed to engine oil. This material is a 
specially designed black silicone rubber RTV that retains adhesion and sealing properties when exposed to 
engine oil. Moisture in the air causes the material to cure. This material is available in three ounce tubes and has 
a shelf life of one year. After one year this material will not properly cure. Always inspect the package for the 
expiration date before use. 

MOPAR® ATF RTV is a specifically designed black silicone rubber RTV that retains adhesion and sealing 
properties to seal components exposed to automatic transmission fluid, engine coolants, and moisture. This 
material is available in three ounce tubes and has a shelf life of one year. After one year this material will not 
properly cure. Always inspect the package for the expiration date before use. 

MOPAR® GASKET MAKER is an anaerobic type gasket material. The material cures in the absence of air 
when squeezed between two metallic surfaces. It will not cure if left in the uncovered tube. The anaerobic 
material is for use between two machined surfaces. Do not use on flexible metal flanges. 

MOPAR® BED PLATE SEALANT is a unique (green-in-color) anaerobic type gasket material that is 
specially made to seal the area between the bedplate and cylinder block without disturbing the bearing clearance 
or alignment of these components. The material cures slowly in the absence of air when torqued between two 
metallic surfaces, and will rapidly cure when heat is applied. 

MOPAR® GASKET SEALANT is a slow drying, permanently soft sealer. This material is recommended for 
sealing threaded fittings and gaskets against leakage of oil and coolant. Can be used on threaded and machined 
parts under all temperatures. This material is used on engines with multi-layer steel (MLS) cylinder head 
gaskets. This material also will prevent corrosion. Mopar® Gasket Sealant is available in a 13 oz. aerosol can or 
4oz./16 oz. can w/applicator. 

SEALER APPLICATION 

 

2007 Dodge Nitro R/T 

2007 ENGINE 4.0L - Service Information - Nitro

  

Mopar® Gasket Maker material should be applied sparingly 1 mm (0.040 in.) diameter or less of sealant to one 
gasket surface. Be certain the material surrounds each mounting hole. Excess material can easily be wiped off. 
Components should be torqued in place within 15 minutes. The use of a locating dowel is recommended during 
assembly to prevent smearing material off the location. 

Mopar® Engine RTV GEN II or ATF RTV gasket material should be applied in a continuous bead 
approximately 3 mm (0.120 in.) in diameter. All mounting holes must be circled. For corner sealing, a 3.17 or 
6.35 mm (1/8 or 1/4 in.) drop is placed in the center of the gasket contact area. Uncured sealant may be removed 
with a shop towel. Components should be torqued in place while the sealant is still wet to the touch (within 10 
minutes). The usage of a locating dowel is recommended during assembly to prevent smearing material off the 
location. 

Mopar® Gasket Sealant in an aerosol can should be applied using a thin, even coat sprayed completely over 
both surfaces to be joined, and both sides of a gasket. Then proceed with assembly. Material in a can 
w/applicator can be brushed on evenly over the sealing surfaces. Material in an aerosol can should be used on 
engines with multi-layer steel gaskets. 

REPAIR OF DAMAGED OR WORN THREADS 

Damaged or worn threads (excluding spark plug and camshaft bearing cap attaching threads) can be repaired. 
Essentially, this repair consists of drilling out worn or damaged threads, tapping the hole with a special Heli-
Coil Tap, (or equivalent) and installing an insert into the tapped hole. This brings the hole back to its original 
thread size. 

Heli-Coil tools and inserts are readily available from automotive parts jobbers. 

ENGINE CORE AND OIL GALLERY PLUGS 

CAUTION: Be sure that the tapped holes maintain the original center line.

 

2007 Dodge Nitro R/T 

2007 ENGINE 4.0L - Service Information - Nitro