O P E L   M O T O R S P O R T    C L U B


Cooling System

  • Suggested articles, sometimes including step-by-step procedures, are indicated with orange colored text. You can also submit YOUR Opel TechTips, for consideration by the Editor of the OMC Blitz, to: joinomc@opelclub.com
  • North American Opels unfortunately came factory-equipped with cooling systems designed for their native North European weather. In the South US, the cooling system needs regular maintenance and/or installation of cooler 160-degree thermostats and upgraded radiators; and on high-performance and air-conditioned Opels, modern thermostatic fan assemblies. Always carry a spare fan belt, and have extra hoses and a water pump handy for emergencies.

How to Order: Reprints of Individual OMC Blitz issues, can be ordered by mail from the OMC Treasurer (3824 Franklin Ave, La Crescenta CA 91214) for $2.00 each (cost includes postage). This offer is subject to availability.

Oct 2006

Opel GT Tune Up, Part II: Click here for Acrobat .pdf download
Maintenance: Parts to Inspect and Replace
Radiator: Mounting and Upgrades
Water Pump and Connected Components (fan, belts,bushings)
Thermostat and Thermostat Housing
Temperature gauge sending units
Opel GT Heater: Components, hoses and valve
"Better Living Through Chemistry" Additives, lubricants and sealers

July 2003

Electric Radiator Fan Conversion, 5 pages (illustrated)
Jim P. extensively details conversion and installation process of a   PermaCool TurboFlex 14" electric fan on a GT. Many photos too.

Nov 2000

GT Heater control repairs, 2 pages
Suggestions include: Cleaning out the heater valve, cleaning out the   heater core (from the firewall hoses, using a garden hose for pressure),   installing a higher teperature thermostat (180 or 192 degrees) for winter   driving, lubrication of heater cables and heater box vent flaps to move freely, and replacing the plastic controls with a reproduction metal control plate.

March 1989

Weber Carb Water Choke Hose Size vs. Heater Core Coolant Flow, 1 page
Note that the larger water choke hose size decreases heater performance.

May 1998

Electric fans, 1 page
Discussion of radiator airflow directions (push vs. pull) of fans, suggested application of puller fan for air conditioning condenser (when equipped), and diagnosis of cooling system problem (when car runs hot above 30-35mph).

Dec 1996

GT heater repair; 2 pages (illustrated)
Covers the often-broken control panel (cable bracket cracks off, behind the dash face) with suggestion of replacement with a reproduction metal panel, inspection of cables and dash vent hoses, cleaning the heater valve, and pressure-cleaning the heater core.

Dec 1995

Radiator petcock installation

May 1995

GT Summer Driving Tech Tips; 1 page (illustrated)

Feb 1995

GT Heater Repair Notes, 1 page

Jan 1995

GT Winter Driving Tech Tips, 1 page (illustrated)

March 1990

Radiator/Cooling System Maintenance Tips; 1 page
Roger L. suggests a 50/50 coolant/water mix, fluid replacement once a year, regular inspection of the radiator cap to ensure it holds to 14psi, and installation of an inexpensive coolant recovery system.

Jan 1989

Heater Hose Angle Fitting, 1 page (illustrated)
Cal H. suggests using a threaded 1/2" 90-degree angle pipe joint, to use straight heater hose (without a kink at the thermostat housing).

June 1987

Opel Factory Service Bulletins (Thermostat Gaskets & Engine Rods)

June 1985

Engine Overheating on 1973 GT (Tips to Avoid); 1 page (illustration)
David A. notes that an external oil radiator/cooler, mounted directly behind the grill, kept his GT below the 1/2 (192 degree) temp gauge mark. He also notes the GT likes the stock fan retained, with an after-market electric fan and larger 3-row radiator, for in-town driving in Florida heat.

May 1985

Thermostat Housing Leak Repair Tip (File Surfaces); 1 page
Tom E. suggests clamping the housing in a vise, and straightening the cylinder head contact surface with a flat file, to eliminate leaks.

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