Cooling System - Coolant Level Checking/Adjusting

90bmw04

Group 17 Radiator
Bulletin Number 17 01 90 (3037) Page 1 of 1
Woodcliff Lake, NJ March 1990 Service Engineering
SUBJECT: Checking Engine Coolant Level

MODEL: M5 (E34)

Situation: The S38 engine uses a pressure cooling system slightly different from other models. The coolant overflow tank, located on top of the right fenderwell, contains a Schrader-type air valve whereby the coolant system air pressure is adjusted to 7.2psi (0.5 bar) with the engine cold.

PROCEDURES: 1. COOLANT LEVEL CHECK WITH CAP ON:
a. Cold engine: coolant reaches "COLD" mark on transparent overflow tank.
b. Warm engine: coolant between "COLD" and "MAX" marks on tank.

2. TOPPING UP COOLANT:

a. Cold engine: fill wfth coolant to reach "COLD" mark. If more than 1.1 qts. (1 Ifter) is required (tank empty), go to Step 3.
b. Warm engine (temperature gauge needle in lower third of scale):
go to Step 2a.

3. FILLING COOLING SYSTEM - ENGINE COLD:
- Fill with coolant to "MAX" mark on tank.
- Start engine.
- Turn heat controls to maximum settings and/or activate windshield defrost button.
- Bleed the system at the heating valve near the battery remote terminal (left side of engine compartment above brake vacuum booster) until no more air escapes from the valve.
- Top up coolant to "MAX" mark.
- Rev up engine to about 2500 rpm.
- Close the tank cap as soon as the coolant level stabilizes at
"MAX" mark.
- Pressurize the tank at the tank valve to 7.2 psi (0.5 bar) using a tire valve hose.

CAUTION: DO NOT OPEN COOLANT TANK CAP WHEN ENGINE IS STILL HOT. SCALDING FLUID AND STEAM CAN BE BLOWN OUT UNDER PRESSURE.