Drain/Refill Procedure; Anti‑Freeze/Corrosion Inhibitor; Radiator Fin Cleaning - Lotus Evora Service Notes

Lotus Service Notes
surface, the coolant in the header tank should be close to the 'FULL' mark, represented by the horizontal seam
running around the tank. The lowest acceptable level is 25mm below the seam.
If topping up is required, wait until the engine has fully cooled before slowly unscrewing the filler cap and
allowing any remaining pressure to escape before finally removing the cap.
In order to maintain protection from freezing damage and metal corrosion, use only an approved coolant
mixture (see below) to top up the header tank to the 'FULL' mark. Refit the cap, and turn clockwise until the
tab on the cap engages a detent, at which position an abutment prevents any over-tightening.
NOTICE: If the cap is removed when the engine is warm, the coolant may boil and a small coolant loss may
occur. The completely cold header tank level should be checked at the first subsequent opportunity.
Anti‑Freeze/Corrosion Inhibitor
It is necessary that the coolant contains an anti-freeze with corrosion inhibitor to protect the engine and
heat exchangers from both frost damage, and corrosion of the metallic elements. In order to protect against
these dangers as well as raising the boiling point of the coolant, the Evora is factory filled with a 50% concentra-
tion of Havoline XLC, which is a mono-ethylene glycol coolant using organic acid technology (OAT) to provide
increased corrosion protection compared with conventional coolant additives. A yellow label around the header
tank neck identifies the coolant type used. The corrosion inhibiting carboxylic acids in the OAT coolant tend to
remain in solution rather than being deposited on the internal surfaces of the cooling system, thus improving
heat transfer and extending service life. Havoline XLC is the only recommended coolant product, and at 50%
concentration provides freezing protection down to approximately - 40°C. Even in warm climates it is recom-
mended that the concentration is not allowed to fall below 25%, in order to maintain full corrosion protection.
The simplest means of checking the antifreeze concentration is to measure the specific gravity (density)
of the coolant at a known temperature, using a hydrometer. The following table provides a general guide:
Concentration
25%
33%
50%
The coolant density reflects the effective level of mono-ethylene glycol, and not the level of corrosion inhibi-
tors present, whose effectiveness diminishes over a period of time. The coolant should therefore be renewed
every 4 years to ensure optimum corrosion protection.
In areas where the tap water is extremely hard (exceeding 250 parts per million), use of this water will
lead to 'furring up' of the system over a period of time. In such areas, distilled, de-ionised or filtered rain water
should be used.

Radiator Fin Cleaning

At service intervals, the matrix of the engine cooling radiator and a.c. condenser should be checked for
clogging by insects, leaves and other debris. If necessary, use a water jet from both above and below to clean
the fins, taking care not to damage the fragile tubes or distort the finning. At the same time, check the integrity
of all cooling system joints, and the condition of all flexible hoses. In snowy conditions, ensure the radiator air
exit is cleared of snow before driving the car.
KJ.3 - DRAIN/REFILL PROCEDURE
Due to the configuration and routing of the cooling system plumbing, there is no satisfactory low point
from which the entire cooling system may easily be self drained. A threaded plug is provided on the radiator
bottom tank, which will drain the radiator, but little more unless the car is tilted nose down to some extent. For
access to the plug, the front undertray must be removed. Each side of the cylinder block is provided with a
drain tap, that on the left being near to the back of the a.c. compressor, and on the right, towards the rear end
of the block.
If the coolant is to be renewed, draining of the pipework can be assisted by applying a low pressure airline
to the header tank filler neck. Note that with ignition off, the heater solenoid shut-off valve is open.
To refill, secure the radiator drain plug, block drain taps and pipework, and fill the system with a recom-
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Density @
20°C 60°C
1.039 1.020
1.057 1.034
1.080 1.057
Section KJ