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