- **Tools Required**:
- **Socket Set**: Used to remove bolts and nuts holding the radiator in place. Common sizes for a Jeep Grand Cherokee are 10mm, 13mm, and 15mm.
- **Wrench Set**: For accessing tight spaces where a socket might not fit. Adjustable wrenches can also be helpful.
- **Pliers**: Useful for removing hose clamps and any other small components.
- **Screwdriver Set**: Flathead and Phillips screwdrivers may be needed for various clips or fasteners.
- **Drain Pan**: To catch coolant when draining the radiator. Helps prevent spills and collects old fluid for recycling.
- **Coolant**: New coolant for refilling the system after the radiator is replaced. Make sure to use the recommended type for your Jeep (usually a 50/50 mix of antifreeze and distilled water).
- **Replacement Radiator**: Required if the old radiator is leaking, clogged, or damaged. Make sure to obtain one that is compatible with your Jeep model (WH/WK).

- **Safety Gear**:
- **Gloves**: Protects your hands from sharp edges and hot components.
- **Safety Glasses**: Protects your eyes from coolant splashes and debris.

- **Step-by-Step Instructions**:
- **Preparation**:
- Disconnect the battery: Use a socket to remove the negative terminal to prevent electrical shorts.
- Allow the engine to cool completely to avoid burns from hot coolant.

- **Drain the Coolant**:
- Place the drain pan under the radiator.
- Locate the radiator petcock (drain valve) at the bottom of the radiator and open it with a pliers or by hand (if applicable) to drain the coolant into the pan.

- **Remove the Radiator Hoses**:
- Use pliers to loosen the clamps holding the upper and lower radiator hoses. Slide the clamps back and gently twist and pull the hoses off.
- Be cautious as some residual coolant may spill.

- **Remove the Transmission Cooler Lines** (if applicable):
- If your Jeep has an automatic transmission, use a wrench to carefully disconnect the transmission cooler lines from the radiator. Have a rag ready to catch any fluid that may leak out.

- **Unbolt the Radiator**:
- Use the socket set to remove the bolts holding the radiator to the support frame. Typically, there are a few bolts on the top and sometimes on the sides.

- **Remove the Old Radiator**:
- Carefully lift the radiator out of the engine bay. Be mindful of any clinging hoses or electrical connectors.

- **Install the New Radiator**:
- Place the new radiator in the same position as the old one.
- Secure it using the previously removed bolts, ensuring it is tightly fastened.

- **Reconnect Transmission Cooler Lines** (if applicable):
- Reattach the transmission cooler lines to the new radiator, ensuring they are snug and leak-free.

- **Reconnect the Radiator Hoses**:
- Slide the upper and lower radiator hoses back onto the respective fittings and secure them with the clamps.

- **Refill Coolant**:
- Close the radiator petcock if it was opened.
- Pour the new coolant into the radiator until it reaches the fill neck. You may need to add coolant to the reservoir as well.

- **Reconnect the Battery**:
- Reattach the negative terminal of the battery.

- **Check for Leaks**:
- Start the engine and let it run for a while. Check for any leaks around the hoses and fittings.

- **Potential Additional Parts**:
- **Hoses**: If the old hoses are cracked or brittle, consider replacing them to prevent future leaks.
- **Thermostat**: It’s a good idea to replace the thermostat if you’re experiencing cooling issues, as a faulty thermostat can lead to overheating.
- **Coolant Reservoir**: If it is damaged or cracked, it may also need replacement.

- **Why Replacement is Required**:
- Over time, radiators can develop leaks, become clogged, or corrode, leading to inefficient cooling and potential engine overheating. Regular inspection and timely replacement are essential for the vehicle's longevity and performance.
rteeqp73

What the “blow‑by tube” is and why you may need to repair it
- Blow‑by = combustion gases that escape past piston rings into the crankcase. The engine’s crankcase ventilation (PCV) system routes those gases back into the intake to be burned. The blow‑by tube (also called crankcase breather hose or PCV hose) is the pipe/hose that connects the valve cover/crankcase to the intake or to an oil separator/PCV valve.
- If the tube, fittings, grommets, oil separator or PCV valve fail, crankcase pressure builds or oil and vapor get pushed where they shouldn’t. That causes oil leaks, oily intake/throttle bodies, rough idle, smoke, increased oil consumption, and sometimes check‑engine lights. Fixing the blow‑by tube restores proper crankcase ventilation and prevents oil leaks and contamination of the intake.

Analogy
- Think of the engine like a house with a small exhaust fan (PCV). The blow‑by tube is the duct that returns air from a basement (crankcase) to the furnace (intake). If the duct cracks or the fan is blocked, pressure builds in the basement and starts forcing water (oil) through cracks and leaks. Replacing/repairing the duct or filter restores proper airflow and stops the leaks.

Components you will encounter (detailed)
- Valve cover breather port: the hole in the valve cover where crankcase gases exit. Often has a molded plastic boss or a rubber grommet.
- Rubber grommet/seal: small rubber piece that seals the breather fitting to the valve cover. These harden and crack with heat.
- PCV valve: one‑way valve that meters and prevents backflow. On some engines it’s a simple stick‑type valve; on others an integrated part of an oil separator.
- Oil separator / catch can (factory OEM separator): a small housing that traps oil droplets and returns oil to the crankcase while allowing gas to flow to the intake. Can be plastic and brittle.
- Blow‑by tube / breather hose: rubber or reinforced hose that connects valve cover/separator to the intake manifold or throttle body. Can be corrugated plastic or rubber. Clamps or push‑fit ends secure it.
- Intake port or intake manifold fitting: where the hose attaches at the intake side. May be a rigid port, a nipple on the throttle body, or a connection to the intake manifold/plenum.
- Hose clamps / spring clamps / push clips: hold the hose in place.
- Valve cover gasket & fasteners (adjacent): when you remove or disturb the breather area you may need to inspect or replace the valve cover gasket and torque bolts properly.
- Fasteners/retainers: plastic clips or bolts holding the separator or vacuum lines.

How the system works (simple)
- At idle and cruise the engine intake is at a slight vacuum. The PCV system uses that vacuum to pull blow‑by gases out of the crankcase through the breather port → through the blow‑by tube (possibly via an oil separator & PCV valve) → into the intake manifold where the gases are burned.
- The PCV valve ensures gas flows only one way and prevents backfires/pressure spikes from pushing into the crankcase.
- The oil separator prevents oil droplets from being sucked into the intake.

What can go wrong (common failure modes)
- Hose cracked, split, or collapsed (rubber hardens with heat): leads to vacuum leak or oil blow‑out.
- Plastic separator cracked or brittle: leaks oil and vapor.
- PCV valve stuck open or closed: stuck open can create unmetered flow and lean condition; stuck closed causes crankcase pressure and oil leaks.
- Grommet degraded: creates vacuum leak and oil seepage around valve cover.
- Hose disconnected or pinch/clamp missing: big vacuum leak / strong smell of oil.
- Oil sludge/clog in separator or hose: blocks flow, causes pressure buildup.
- Valve cover warped or bolts loose: causes leaks at breather port.

Symptoms you’ll see
- Visible oil around valve covers, breather hose, or intake area.
- Oil in intake manifold or oily throttle body.
- Excessive oil consumption and oil on ground.
- White/blue smoke from tailpipe or oil smell from engine bay.
- Rough idle, surging, or check engine light for lean/rich or evap/vacuum codes.
- Hissing or “puff” of oil/vapor from breather when you remove the cap/hose.

Basic diagnostic checks (quick)
- Visual: inspect hose for cracks, oil wetness, or detached ends. Inspect grommet and separator.
- Disconnect test: with engine idling, briefly remove the hose at the valve cover (if safe) and feel for steady suction or abnormal pressure/puffing. Excessive pressure = problem.
- PCV valve check: remove and shake (on some designs) — should rattle if spring exists. Blow through it (one way).
- Intake inspection: check throttle body and intake for oil contamination.
- Vacuum gauge or scan tool: can detect vacuum leaks or abnormal readings.

Tools and supplies you’ll need
- Basic hand tools: ratchet, sockets (8–15 mm), extensions, small screwdriver set, pliers.
- Hose clamp pliers or flat screwdriver (for worm clamps).
- Torx or Allen if applicable for separators or valve cover fasteners (verify before starting).
- New blow‑by hose (OEM or quality aftermarket), new clamps.
- New PCV valve and/or oil separator if faulty.
- New valve cover grommet(s) if brittle.
- Clean rags, brake cleaner or throttle cleaner (for degreasing), small pick for removing old grommet.
- Torque wrench (recommended for valve cover bolts).
- Gloves, eye protection.
- Service manual or factory torque specs and routing diagram for your exact engine.

Step‑by‑step repair procedure (general; adapt to your engine)
1) Safety and prep
- Park on level ground, engine cool. Wear gloves and eye protection. Gather parts and tools.
- Disconnect negative battery terminal if you’ll be removing major electrical connectors or intake components (optional for simple hose swap but safe).

2) Access and removal of intake/air tube
- Remove the air intake tube or engine cover as necessary to reach the blow‑by hose, PCV valve and separator. Loosen clamps and remove the air box snorkel if needed.

3) Locate components
- Find the hose from the valve cover to intake or separator. Note routing and clamps. Take a photo for reference.

4) Remove hose and components
- Loosen clamps at both ends. If the hose connects to a PCV valve or separator, remove the PCV valve from the valve cover first (pull or twist depending on design).
- Remove the hose. If an oil separator is bolted on, remove the fasteners and carefully take it off. Expect oil residue.

5) Inspect
- Inspect the valve cover port and grommet. If grommet is cracked or loose, remove it and replace.
- Inspect the intake side port for oil and debris. Use rags and cleaner to wipe off oil. Don’t push debris into the intake.
- Inspect the hose — if oil‑soaked internally, likely clogged; replace.

6) Replace parts
- Install new PCV valve (push into grommet until seated). Replace separator if cracked. Fit new hose onto nipples and secure with clamps. Replace grommet and/or valve cover bolts/gaskets if needed.
- If removing valve cover or disturbing gasket, clean flange surfaces and install new valve cover gasket; torque bolts to factory spec in the specified sequence to avoid warping.

7) Reassembly and test
- Reinstall intake components removed earlier. Reconnect battery if disconnected.
- Start engine and let idle. Check for vacuum leaks, listen for irregular idle. Inspect new hose, grommet, separator for leaks (oil and air). Smell for fuel/odors.
- With engine warm and idling, visually check for abnormal blow‑by or oil leaks. If necessary, test drive and recheck.

Testing and confirming success
- After repair, idle stability should improve and idle vacuum should be consistent. Oil leaks or oily deposits around the replaced parts should stop.
- If you had oil in the intake, you may need to clean throttle body and intake to restore correct idle and prevent issues.

Common pitfalls and how to avoid them
- Using wrong size hose or clamps: get OEM or exact fit; too small a clamp will crush hose, too loose causes leak.
- Dropping debris into intake: cover intake throat with a rag while working to prevent dirt or tools falling in.
- Not replacing grommets or separators; only replacing hose leaves old brittle parts to fail soon after.
- Over‑ or under‑torquing valve cover bolts: use torque wrench to factory spec to avoid warped covers or leaks.
- Ignoring underlying causes: severe blow‑by (excessive pressure) can indicate worn rings or other engine wear — replacing hose fixes leakage path but not root cause. If blow‑by is massive, do a compression/leak‑down test.

When to replace more than the hose
- If PCV valve sticks, replace it.
- If oil separator is cracked or filled with sludge, replace/clean it.
- If valve cover grommets or the entire valve cover are damaged, replace them.
- If excessive blow‑by persists after fixing the plumbing, inspect rings/cylinders (compression/leak‑down).

Disposal and environmental note
- Clean oily rags properly and dispose of used oil/contaminated parts per your local regulations.

Final tips
- Photograph hose routing before removal for straightforward reassembly.
- Keep small parts organized so clamps and fittings go back where they belong.
- Factory service manual or a repair guide for your exact engine (3.7, 4.7, 5.7 HEMI, or diesel CRD) will give exact part numbers, torque specs and diagrams — use it for specifics.
- If you’re unsure about large disassembly (valve cover removal, intake manifold removal), consider a shop — but replacing the hose, PCV valve or separator is a routine beginner mechanic job.

That’s the full picture: what each component does, why failures matter, how to check, and how to replace the blow‑by tube and its related parts so the crankcase vents properly and oil leaks/smoking problems stop.
rteeqp73

### Engine Gasket Replacement on a Jeep Grand Cherokee WH/WK

**Purpose of Engine Gaskets**

Engine gaskets seal the spaces between engine components, preventing oil, coolant, and combustion gases from leaking. Over time, gaskets can degrade due to heat, pressure, and chemical exposure, leading to leaks and potential engine damage.

**Common Gaskets to Replace:**
- **Head Gasket:** Seals the cylinder head to the engine block, prevents coolant and oil leaks.
- **Intake Manifold Gasket:** Seals the intake manifold to the engine, ensuring proper air-fuel mixture.
- **Exhaust Manifold Gasket:** Seals the exhaust manifold to the engine to prevent exhaust leaks.

### Tools and Materials Needed

1. **Tools:**
- Socket set (ratchet and various socket sizes)
- Torque wrench
- Screwdrivers (flathead and Phillips)
- Pliers
- Gasket scraper or razor blade
- Engine hoist (if removing heavy components)
- Puncture-proof gloves
- Safety goggles

2. **Materials:**
- Replacement gaskets (specific to your Jeep model)
- Engine oil (for lubrication)
- Gasket sealant (if required)
- Clean rags
- Engine degreaser

### Steps to Replace Engine Gaskets

1. **Preparation:**
- **Safety First:** Disconnect the battery (negative terminal) to avoid electrical shorts.
- **Work Area:** Ensure you have a clean, well-lit workspace.

2. **Drain Fluids:**
- Drain engine oil and coolant into appropriate containers.

3. **Remove Components:**
- **Intake/Exhaust Manifold:**
- Remove the intake/exhaust manifold. Start by disconnecting any electrical connectors, hoses, and clamps. Use a socket set to remove bolts.
- **Cylinder Head (if replacing head gasket):**
- Remove components obstructing access to the cylinder head, such as the timing belt/chain, valve covers, and any remaining accessories.
- Use a torque wrench to loosen the cylinder head bolts in a specific sequence (consult a repair manual). This prevents warping.

4. **Remove Old Gaskets:**
- Carefully scrape off old gaskets using a gasket scraper or razor blade. Ensure the surfaces are clean and free of debris.

5. **Inspect Surfaces:**
- Check the cylinder head and engine block surfaces for any warping or damage. A flat, smooth surface is essential for a proper seal.

6. **Install New Gaskets:**
- Place new gaskets onto their respective surfaces. If using gasket sealant, apply it as per the manufacturer’s instructions.

7. **Reassemble Components:**
- Reinstall the cylinder head, intake manifold, and exhaust manifold. Use a torque wrench to tighten bolts to the manufacturer’s specifications in the correct sequence.

8. **Reconnect and Refill:**
- Reattach any hoses, connectors, and accessories removed.
- Refill engine oil and coolant to the appropriate levels.

9. **Reconnect Battery:**
- Reconnect the negative terminal of the battery.

### Testing

1. **Start Engine:**
- Start the engine and let it idle. Check for leaks around the newly installed gaskets.

2. **Test Drive:**
- Take the vehicle for a short drive and monitor for any leaks or unusual engine behavior.

### Potential Issues

- **Overheating:** Can occur if the head gasket fails, causing coolant to leak into the combustion chamber.
- **Oil Leaks:** Faulty gaskets can lead to oil leaks, causing engine lubrication issues.
- **Poor Performance:** If air or fuel leaks occur, engine performance can diminish, leading to rough idling or stalling.

### Conclusion

Replacing engine gaskets involves careful disassembly, cleaning, and reassembly. Think of gaskets as the seals in a jar: if they are flawed or worn, the contents leak out, resulting in mess and inefficiency. Proper installation ensures your engine operates smoothly without leaks, maintaining performance and longevity. Always refer to a service manual for specific torque settings and sequences for your Jeep model.
rteeqp73