While we bask in the summer sun and drive our beloved Aircooled VWs -windows down and radio up; spare a thought for your engine slaving away behind you. Here’s a few tips to help your VW aircooled engine survive summer!Air Cooled? Well, yes, your engine certainly doesn’t have any water in it; but it has an unsung hero, circulating and helping to keep the temperatures under check too.
The Type 1 engine holds a lowly 2.5 litres of oil; not a huge amount – and it’ll soon lose its charm if you don’t change it regularly. As the life blood of your engine the oil is acting as an internal coolant, similar to the way water flows through a modern engine. Which oil to use is a debate that could rage for days – check out our thoughts on the website here.
If you have a twinport engine, your standard ‘Dog house’ oil cooler will try its best to catch the cool air being directed through the tinware, which is adequate in most cases, but in the heat of summer, or with the added load of a bus on top of it, it’ll be pleased if you added an external oil cooler system to really help things out. The cooler the oil, the cooler your engine will run!
You’ve probably heard Tinware mentioned a thousand times when it comes to Aircooled VW engine cooling, the reason is this; it really does matter! Incidently – chrome tinware reflects the heat, and black tinware absorbs it..so unless you have an ‘open’ engine compartment (like in a Buggy or Baja) we would recommend sticking with normal black tinware to keep temperatures under control.
Missing tinware compromises the whole cooling system (imagine trying to heat your house while your windows and doors are open – it’s the opposite of that!) the hot and cold sections of the engine should be sealed from one another. The diagram above shows the airflow nicely; if any of the tin ware should be missing or ill-fitting it would allow for the warm air at the bottom to be drawn back into the cool zone and recirculated back over the cylinder heads, raising the core temperature of your engine.
As important as the tinware itself, is the seal that surrounds it. One without the other is just asking for trouble!
Inside your fan housing are fins to direct the air, and flaps; these flaps are located at the bottom and operated by your thermostat. First thing in the morning these flaps will be held closed; encouraging the engine to get up to temperature as fast as possible. But then the thermostat plays a vital role in your cooling system – as your engine gets warm it opens the cooling flaps within the fanshroud to allow the heat to pass through and escape. If you are unsure if your vehicle has these flaps – or a thermostat, please check! Whilst you can leave these flaps permanently open (or remove them), having them closed shut all the time will lead to almost certain overheating, and a costly bill!
The last few points to consider in battling the heat is your ignition timing, air leaks and fueling. Poor ignition timing can cause your engine to run too hot; if you don’t have a timing gun see if you can borrow a friends – it’s unlikely to be visable if its wrong (you might hear it) but it’ll save you some heartache if you catch it before it catches you!
Fuel mixture is equally important -firstly is your carburettor jetted to suit the engine capacity (a single standard carb on a 1641cc engine could be starving your engine) and raising the temperatures internally. Likewise, your carb could be perfect – but if your engine is sneaking air in elsewhere through a split hose, or a broken gasket, then the whole mixture is compromised, and the chances of running lean, and hot are increased too. Spraying the intake system with Wd40 whilst running will help to detect this – an air leak will suck the spray in, using it as fuel and changing the engine note at the same time.
Whilst we hope the above suggestions will help to keep the heat down in your engine bay, monitoring it from the comfort of your cabin is the ‘thinking-mans’ way to tackle this issue! If you notice a change, and stop in time – you can let an ‘expert’ sort it out when you get home!
An oil temperature sender mounted either in your sump plate, or as a dipstick, and linked to a gauge in the dashboard will report all the necessary information for you, removing any guesswork from the equation. We’ve put together this handy VDO kit to do just that; check it our on our website here.
Just before we round this up, please, please purchase a Fire Extinghuisher ‘just in case’. Sadly every summer is clouded by the sadness of roadside fires, some of which could have been put out if a fitted fire extinghuisher kit, like the DAUS had of been installed; alternatively they could of been tackled with a handheld bottle, at least giving the owner a sense of having tried to save their pride and joy in the event the worst happened. You can pick up a cheap one at a local DIY superstore. Don’t leave home without it!
Have a great summer, and stay cool!
The opinions expressed here are the personal opinions of the author and do not necessarily represent the views and opinions of VW Heritage.
PS: Interested in alternative methods to prevent from overheating? Read this