Coolant / Antifreeze
Available in red, black and silver.

Compatible with 911/912/930 ('65-'89) or any car with a threaded lever.
Rennline's billet aluminium teardrop defrost knobs are the perfect inexpensive interior upgrade for any Porsche equipped with this feature. Factory knobs become faded, cracked, and/or unsightly after years of exposure to UV light. Rennline billet knobs are machined from 6061 aluminium and are available in red, silver or black anodized finishes for a durable, long lasting appearance. Simply unscrew your old knob, and screw our on.
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
Premium Coolant & Antifreeze for Reliable Engine Temperature Control
Coolant and antifreeze are essential engine fluids designed to regulate temperature, prevent freezing, protect against corrosion and support long-term engine health. These fluids circulate through the radiator, water pump, heater core and engine block, absorbing heat and preventing overheating. In colder climates, antifreeze ensures the coolant mixture remains liquid even in freezing conditions, safeguarding internal components from cracking or frost damage.
Whether maintaining a daily driver, preparing a high-performance engine for track use or restoring a classic car, using the correct coolant mixture is vital for reliable cooling and long-term protection.
What Coolant / Antifreeze Does
Engine coolant performs multiple crucial functions:
- Regulates
engine temperature by absorbing and dissipating heat
- Prevents
freezing in low temperatures
- Protects
against corrosion and scale buildup within the cooling system
- Lubricates
the water pump and other cooling components
- Helps
maintain stable operating temperatures for consistent performance
- Prevents overheating, especially during high-load or hot-climate driving
High-quality coolant ensures efficiency, longevity and consistent temperature control in all seasons.
Why Coolant and Antifreeze Break Down or Fail
Over time, coolant loses its protective properties due to
heat cycles, contamination and age. Common causes of coolant failure include:
- Depleted
corrosion inhibitors reducing protection for metal components
- Incorrect
coolant type or mixture, lowering efficiency
- Contamination
from oil, debris or internal gasket problems
- Evaporation
or leaks, reducing coolant levels
- Sludge
formation from old or mixed coolant types
- Scale
buildup restricting coolant flow
- Age-related chemical breakdown reducing cooling efficiency
Symptoms include frequent overheating, temperature fluctuations, poor heater performance, visible sludge in the expansion tank or coolant loss.
Why You Should Replace Old Coolant / Antifreeze
Replacing worn or contaminated coolant with a high-quality, precision-formulated mixture designed to match original cooling characteristics ensures the engine remains protected and performs at its best.
Benefits include:
- Improved heat transfer and cooling efficiency
- Stronger protection against corrosion and scale
- Reduced risk of overheating and head gasket failure
- Safe operation in freezing temperatures
- Longer water pump and thermostat lifespan
- Cleaner internal coolant passages for better flow
- Stable temperature control during high-performance driving
Fresh coolant is a low-cost yet essential maintenance step for preserving engine reliability and preventing costly repairs.