1981 Air-cooled : Really hot, what should I check?

[troglodisme]

Hi again, 

I am still getting to know my van a little bit and after more than 1000 miles done this August between France and Italy, I am starting to get scared about the van overheating. It's a 1981 2.0 CU engine with the two carbs. How does it cool itself?

The previous owners had a temperature gauge on the dashboard but it never worked and I am not sure where it was measuring temperature from. Also the heat exchanger underneath was removed, does it mean the famous 'cooling flaps' I have been reading about are gone too?

As I am going to be driving back to the UK this week, is there another way to make sure all is ok during the trip? How does the engine cools itself and does it shut itself off in case it gets too hot? 

Any help or pointers highly appreciated! 

[Davegrohl99]

From my experience always check the oil each morning on a level surface.

These engines are extremely finicky giving wrong readings when just barely off level. Dont ask how I found that out.

Keeping it topped up to just below the top mark and I never go above 100km. I usually am happy to toddle along anywhere between 70-80kph. It seems to be happy there.

I always try and stager journeys too. Plan to do 80km then have a coffee etc and give the engine a break to cool down.

They are quite robust engines but the dash mounted temp guage will only give you heart failure.

Best tip is to change the oil as often as you can and keep a good eye on it and enjoy the long journey!



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[sarran1955]

Hello,

You are welcome to make a pit stop here...
PM me..

Cordialement,

[Funkychops]

There's a huge wealth of info on the web for keeping air cooleds cool. Out of all the advice I've read, the answer boils down to this: the engine already has everything it needs to keep cool. Or at least it did when it left the factory! People drive these things in Australia, California etc, so the cooling must be pretty effective...

General principle is cold side on the top (where the cool air comes in from the ducts), through a fan, and hot side on the bottom (and out the back). Make sure everything is air tight between the top layer and bottom because you don't want hot air coming back up. Make sure the oil cooler isn't gunged up.

When driving, don't be afraid to keep the revs high. It makes the fan spin faster which improves the air flow. Struggling up hill in too high a gear is a bad plan.

I'm still paranoid about overheating mine, but it hasn't happened yet!

[troglodisme]

Thanks everyone. I will check the oil again and try to make everything air tight. I have noticed the engine bay seal is partly broken in some places so that might be a big issue?

@Funkychops. When you say cold side on the top, what are you referring to? Mine is definitely not cold at the moment, so I wanted to make sure the cool air comes in in the right way. Do you have any pictures or diagrams to help me understand how things should be? That would be super useful. 



Thanks! 

[bigherb]

@Funkychops. When you say cold side on the top, what are you referring to? Mine is definitely not cold at the moment, so I wanted to make sure the cool air comes in in the right way. Do you have any pictures or diagrams to help me understand how things should be? That would be super useful. 

Thanks! 

Basically the area above the engine bay seal is considered the cool part, as that is where the cooling air is drawn into the fan via the side vents. That is why the tinware and engine bay seal should not have any gaps so it can not draw in air from the underside hot part of the engine where the hot cooling air is exhausted.
Make sure the cooling flaps are in place, even if the thermostat is not working,  they are sprung to be held in the open position, there are some clowns who take them off, they are important to direct air through the oil cooler when they are open.
 

[OldSmithy]

I’ve only driven with type1 Aircooled engines not the type you have but the principles are the same. The advice above is sound. Regular maintenance including timing g checks and oil changes will keep it in good order. A damaged seal is highly unlikely to kill it in the short term but you should replace it when you get back. Make sure you have all of the correct tinware too as this directs the cooling air around the parts of the engine that need it.

I never had a temperature gauge (just makes you paranoid) and in 20 years never ended up with an engine overheating or on the back of a breakdown truck. I kept it all simple and serviced it all at least annually. Having replaced air for water cooled in the last couple of months I know the T25 is going to present me with some initial and different challenges so I’ve got a feeling my breakdown duck may go but once you get on top of things and know what you have done to it you will start to relax.

As said by others, I never pushed mine to the limits either. The journey is part of the holiday in my eyes with these older vehicles so relax, slow down and enjoy it. Taking a bit more time but feeling good about it is better than pushing things and feeling concerned all for the sake of a little bit of time.

Enjoy!

Steve

[Funkychops]

@bigherb pretty much answered but yes, that is what I meant

Have a look online, some of the better resources I've found (even if not totally relevant to the CU engine) but there are lots:
http://www.vw-resource.com/overheating.html
https://www.youtube.com/watch?v=Q2_dzR1qJ6A

Easiest way to monitor temperature is to take out the dipstick and hold the oily end - instant finger burn = too hot, moderate discomfort = probably fine. Very scientific

[troglodisme]

Thanks everyone for their help. Northern italy and france were much less hot than I thought and everything went well, now I can take the time to go through the suggestions and be ready for next spring  

G