Lotus 2004 ELISE Service Notes page 261

Lotus Service Notes
exchanger to the heater water return pipe. This device transfers heat from the engine coolant to the oil after a
cold start, and conversely, in conditions of high oil temperature transfers heat from the oil to the coolant.
Front Mounted Air/Oil Coolers
On cars so fitted, front mounted oil/air radiators are mounted ahead of each front wheel arch and fed with
air from intakes either side of the main engine radiator intake in the body nose. 'Single oil cooler' cars are
equipped with an oil cooler ahead of only the LH front wheel, but use the same hoses as twin oil cooler cars,
with a joiner union attached to a bracket in place of the symetrically opposite RH cooler.
On all cars with front mounted oil cooler(s), the oil/water heat exchanger is replaced by a sandwich plate
incorporating oil take-off feed and return unions, with the redundant coolant hoses interconnected by a 'U' pipe.
A thermostat incorporated into the sandwich plate begins to open at 72ºC, and is fully open at 80ºC. When
open, oil is directed from the sandwich plate via a flexible hose within the RH sill panel, over the front wheel
arch liner to the top connection on the RH oil cooler (or joiner union on single oil cooler cars). From an outlet
union at the bottom front of the cooler (or joiner union), another hose runs beneath the crash structure to the
bottom of the LH cooler, from the top of which oil is returned via a third hose, running through the LH sill, back
to the return union on the sandwich plate.
Oil Cooler Layout
Cooler feed hose
in RH sill
Cooler
inter-
connection
hose
Air deflector
panel
pl4603mt
Each cooler is secured by a two stud bracket to the side of the crash structure, and positioned immedi-
ately ahead of the engine radiator mounting panel side extensions, which incorporate airflow apertures and
additional deflector panels on their front surfaces. Louvres in the wheelarch liner front sections allow air to
exhaust from the coolers into the wheelarches.
Cooler
mounting
plate
Nut plates
Oil cooler
sandwich plate
Cooler return hose
in LH sill
LH oil
cooler
Section KH
Oil cooler
thermostat
Heat exchanger
hoses or by-pass
Oil/water
heat exchanger
Page 9