Coolant Temp Too High (Above 120 Deg C) or Coolant Ejected
Coolant Temperature Too High (Above 120 °C) or Coolant is Ejected
Cause/Remedy:
a) Viscofan clutch does not engage. Check operation of viscofan clutch. The fan must switch off and on at the following engine speeds (value in brackets national versions as of (AUS) (J) (S) (USA) as of 1981 and engines with energy concept with temperature and speed-controlled clutch). Check at 100°C coolant temperature.
If the clutch fails to engage on vehicles with temperature and speed-controlled viscofan clutch, it is possible that the temperature radiated by the radiator onto the bimetal spring is insufficient.
With the engine switched off, pass the palm of the hand over the radiator in the area of the viscofan clutch. If the radiator is partly cold, the cooling tubes are clogged with corrosion deposits. Install new radiator.
b) Corrosion deposits in the radiator. Flow through the radiator insufficient. Pull off lower coolant hose from radiator hose connection. If a jelly-type substance (dried up: white-grey deposit) is present in the hose connection, flush radiator with a 10% citric acid solution. If this does not help, renew radiator.
Ensure that the antifreeze concentration corresponds to the factory filling (-37 °C; 50% by vol, anticorrosion/antifreeze agent). Use only approved anticorrosion/antifreeze agent, Part No. 000 989 08 25.
c) Coolant thermostat fails to open or opens too little. Renew thermostat.
d) Expansion tank does not hold any pressure due to uneven contact surface for the cap, or due to loose insert (in the expansion tank) for the cap, or due to other leaks in the expansion tank.
Renew expansion tank.
e) Coolant escapes on the cap at approx. 110 °C because of leaking pressure relief or vacuum valve. This concerns especially caps with valve retainers made of plastic (arrow) and the stamp ,, Reutter".
Install cap 123 501 02 15.
f) Corrosion deposits in the connection of the vent line on the expansion tank, or on the inlet connection to the coolant pump. Clean vent line and connection on the expansion tank and the inlet connection.
g) Radiator gills are clogged with dirt, especially on vehicles with air conditioner. Inspect gills of radiator and condenser for external contamination. Blow out dirty gills with compressed air from the engine side. If a condenser is installed, remove radiator.
h) Direction of rotation of the supplementary fan on vehicles with air conditioner or automatic climate control is incorrect.
Check direction of rotation of the electric supplementary fan. When looking from the front, the fan must rotate clockwise. If the fan rotates in the opposite direction, the electrical connections have been confused.
i) On vehicles with energy concept, cooling capacity of radiator is too low.
As of the end of August 1984, a radiator (core depth 42 mm) with improved cooling capacity (66 cooling tubes) (previously 44 cooling tubes) is installed on vehicles with energy concept. Distance of cooling tube to cooling tube 10 mm(was 15 mm).
This radiator can also be installed on previously manufactured vehicles with energy concept.
For space reasons, a modified condenser must be installed at the same time in models 126.043/044 with air conditioner or automatic climate control up to May 1982.
Production breakpoint (radiator with 66 cooling tubes)
Model As of chassis end No.
126 093 902
No larger radiator is available for vehicles without energy concept.
k) Shortly after switching off the engine, coolant is elected due to the after-heating effect.
An overflow tank can be retrofitted to all vehicles in the event of such a complaint.
On vehicles with air conditioner or automatic climate control, the overflow tank is installed as a standard feature as from approx. 1984.
l) Supplementary fan on vehicles with air conditioner or automatic climate control switches on too late. Install a 52 °C temperature switch in the liquid tank of the air conditioner or automatic climate control instead of the 62 °C temperature switch. (production breakpoint November 1981).
Replace 110 °C temperature switch (1) for the electric supplementary fan by a 100 °C temperature switch (production breakpoint July 1981).
m) Temperature sensor for temperature indicator is still installed in cylinder head rear right. As of December 1980. in the inlet connection of the coolant pump.
In vehicles prior to manufacturing date December 1980, reposition temperature sensor for coolant temperature indication from the right-hand cylinder head to the inlet connection above the coolant pump.
For this purpose, install modified inlet connection. Close free tapped hole in the cylinder head with a closing plug M 14 x 1.5 and sealing ring 14 x 18.
Install existing electric cable for the temperature sensor so to the front that engine control is not impaired.
Spare parts
Designation Part No.
Inlet connection 117201 1230
Closing plug M 14x 1.5 915048 014000
Sealing ring 14 x 18 007603 014100
Temperature switch 52 °C (in liquid tank of air
conditioner or automatic climate control) 000 820 80 10
Temperature switch 100 °C (inlet connection) 003 545 51 24
Radiator for vehicles with energy concept 126 500 33 03
Condenser (only coupe) 126 830 20 70
Scope of delivery overflow tank 126 500 06 49
Cap 1.2 bar gauge pressure 123 501 02 15
Corrosion-antifreeze agent 000 989 08 25