HOT KOMBIS FROM THE TROPICS.
By Lance Plahn
Working for a VW repair business in Central Queensland, we are inundated by many VWs travelling from the North, South and West. However many seem to limp in suffering a common ailment, "Engine overheating". So in the next few paragraphs I would like to address some of the problems causing the 1600cc single and twin port engines to overheat and possible solutions.
First, to determine how hot the engine is getting, it would be best to fit a warning device, e.g. oil temperature gauge. Just feeling external engine components with your hand is no real indication, as a few degrees could mean the difference of safety or destruction.
What oil temperature should the engine run at? Most agree to a minimum operating temperature of 80 degrees C., with a maximum of 110 degrees C., but for prolonged driving it would be best to keep it to around 100 degrees C..
The most common causes for an engine to overheat, from experience, would include driving too fast, overloading, including roof rack, ignition timing incorrect and or distributor advance not working, engine covered in oil and or dirt, oil requiring changing, engine and or tune in poor state, not getting full throttle. The most common of all would have to be missing, damaged, or poorly fitting tinware, along with the poor condition of, or non existence of spark plug rubbers, engine bay seal, fresh air hoses (fan housing to exhaust), Also paper or rag in the cooling fan, (usually the one used to check the oil).
You don't want any cooling air to escape from the engine before doing its share of cooling. It is essential to fit all tinware and compartment seals, ensuring it is in good condition and fitting properly. VW could have saved millions if all the tinware wasn't essential.
Engine bay seals and the tinware not only seal against dust, but also keep hot air from the exhaust and cylinders out of the engine compartment so that the cooling fan receives cool air for maximum cooling, because recalculating air gets progressively hotter and hotter.
Removing the oil cooler inside the fan housing, for whatever reason, reduces the airflow to the exact location at the correct velocity, causing the head temperature to increase. Even the thermostat air flaps are directional devices to direct air to the proper location.
We have found different brands and viscosity of oil affect oil temperature, also noting the oil to increase in temperature after approximately 3,000km, as a result of contamination and the additives breaking down. Our best results have come from 30-40 wt oil using an oil additive.
To improve cooling on the 1600 single port engines, we fit the fan housing set up from the 1600 twin port engines. To do this you need the off-set (or dog housing) fan housing plus the chute, duct and the fan, which is a few millimetres wider, oil cooler and stand, and the front tinware over the flywheel. The 6mm stud in the crankcase will have to be replaced with a longer 8mm stud. Ensure you obtain the correct cooler seal to fit the cooler stand to crankcase.
On the 1600 twin port engines, we replace the stock 5-row cooler with the 7-row cooler from the 1.7,1.8 or 2 litre Kombi engines. To accommodate the larger cooler, the dog housing has to be cut and widened approximately 10mm.The two longest studs in the cooler stand will have to be lengthened using the ones from the 1.7, 1.8 or 2 litre engines.
On closing, if you want the engine to last a little longer, remember to service it on a regular basis, including changing the oil, and cleaning the oil strainer, cleaning the air cleaner and adjusting the tappets. A shot of upper cylinder Ube every so often will help too, then maybe that engine will go that extra mile for you.