21532905 Level Guard | Genuine Volvo Penta Part

🔧 Product Description

Electrical coolant level guard installed in the remote steel expansion tank of Volvo Penta D8 marine cooling systems. It detects when coolant drops below the protected level and supplies the alarm/control circuit with the required low-level signal. The current service number is associated with earlier Volvo Penta reference 874327.

🚤 Compatibility

• Engine Family: D

Full model list at the end of this description.

⚙️ Key Features

• Genuine Volvo Penta coolant level guard
• Installs in remote-mounted steel expansion tank assemblies
• Used with D8 marine propulsion cooling systems
• Provides low-coolant protection input
• Direct electrical and threaded fit for the specified tank
• Engine type: 7.7-litre inline-six turbocharged marine diesel

🔌 Function

Monitors coolant level in the expansion tank and signals the alarm or engine-protection system if the level falls below the sensor.

⚠️ Common Signs of Failure

• False low-coolant warning
• No warning when coolant level is low
• Intermittent alarm caused by vibration
• Open- or short-circuit sensor fault
• Corroded terminal, leaking sensor body or damaged tank seal

🛠️ Service Notes

• Treat it as a sensor: keep the connector and its pins clean and dry, support the body when tightening and never use it as a lever or a handhold
• Fit a new O-ring or seal at the boss and tighten only to the figure given in the workshop manual for your engine — these usually thread into a plastic or thin-walled housing that will crack if over-tightened
• Make sure any float or probe is clear of obstruction and orientated as originally fitted, so it reads the true level
• Fill to the correct level with the specified fluid, then check that the alarm circuit responds and that the joint stays dry with the system up to temperature and pressure
• Inspect the harness and connector for corrosion and chafing while it is apart; a false low-level alarm is very often the wiring rather than the sensor

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 21532905 → Supersedes 874327

OEM / Related Numbers

• 874327 earlier number superseded by this part

Other-Brand OEM Numbers

• VOE21532905
• VOE874327

Aftermarket / Verified Equivalents

• Associated expansion tank: 3827367
• Associated gasket: 948884

📦 Condition

• Genuine Volvo Penta part
• Brand new
• Supplied in original or equivalent packaging

🔎 Full Model Compatibility

Typically suits:

• Volvo Penta D13C3-B MH, D13C1-B MH, D13C4-B MH, D13C3-A MP, D13C4-A MP, D13B-E MG, D13B-E MG (FE), D13B-F MG, D13B-F MG (FE), D13B-N MH, D13B-N MH (FE), D13C4-B MP, D13C5-B MP, D13C6-A MP, D13C1-A MH, D13C2-A MH, D13C1-B MG, D13C2-B MG, D13C5-A MP, D13C8-B MP
• Volvo Penta D9A2G, D9A2J, D9A2L MH, D9A2A, D9A2E
• Volvo Penta D8A5-A MH, D8A6-A MH, D8A5-A MG, D8A6-A MG