Volkswagen running hot? Advice Please!

[VandalHeart]

Greetings fellow Airheads,

My skadonk is giving me some uphill this last few days. I think it's overheating! so Please, can someone confirm? or is this something else entirely?

So here's whats happening.

I have a fairly long daily haul of +/- 50km on a daily basis. and then roughly that much again to get home. Volksie is running very sweetly, until I hit the highway -

Accelerating to roughly 90km/h, she starts running a bit rough. Mind you, I dont hit the highway right away - roughly 15km driving regular speeds of 60-80 km/h, and then onto the highway.

On my way home this evening, I was paying careful attention to the engine, and she started showing signs of missing intermittently, just before I get on the highway. Then, almost immediately, it starts firing awkwardly, and running very rough with a considerable loss of power. This, unfortunately, lasted my entire highway trip. Once I hopped off the highway, she was still unhappy, but after some lower speed driving, it smoothed out and purred happily for a few minutes, before it started with it's nonsense once more.

What is the state of this little engine? Standard fare 1600, I try to keep it clean as best I possibly can. But, I feel like this drive is quite hard on it.
All the valve clearances, points gap, timing, are spot on. There is good, clean oil in the engine and gearbox, the carb is tuned as correctly as I can manage (could this be the culprit? I plan on servicing it this weekend) All the engine tin is in place. I have tried to keep the engine as free from shiny chrome as possible. And I try keep the engine speed moderate, so as to keep the fan blowing air to keep it cool.

The truth is, I have never really driven the car this far on a regular basis. So this behaviour is something I have not encountered before. I have taken her on the very same highway before without a problem.

So please, before the engine blows up (I am afraid that this is what it wants to do) what is the best way to get around this? What Im going to try tomorrow is, to leave a little earlier so I can give the car a breather before I jump on the highway, hoping that will cool it enough. I will be back with the results of this, as well as how well servicing the carb goes.

Thanks in advance!

[Dawie]

Few questions...
Do you have a picture of the engine?
Are all it's tinware in place to prevent recirculation of used hot air?
Is the sealing rubber between engine and body in good condition?
The sound-deadening board-thingie behind engine- is is tightly against body or a bit loose, could it be sucked against the fan?
Standard points ignition or aftermarket electronic?

[fig]

Some common causes of overheating:
Timing too far advanced or retarded.
Valve clearances tight (heads will overheat)
Lean running (incorrect jets or vacuum leaks)
Dirty engine (have you checked under the tinwork?)
Missing cooling tins and/or engine seal
Cracked exhaust (especially where no2&4 pipes enter the silencer)
Shop rag or similar stuck in fan

A 50km trip with a mix of stop-start and freeway driving should not stress an ACVW at all. They can run all day at wide open throttle if properly maintained. Ideal revs is about 3,500. Below 3,000 revs the fan turns too slowly to cool the engine under full load. It's better to shift down a gear and run at higher revs than to lug the engine at low revs.

A quick check for overheating is to feel the dipstick when the engine is hot. If it's too hot to hold for a few seconds then your engine is too hot. Will your car idle when it starts running poorly? If it's starting a heat seize, it will cut out at idle and won't start again until it's cooled down.

[Tony Z]

other than what the others have advised, I have 1 more question
what oil are you using?
If its 20W50 or 10W60 then you will do your engine some good by changing to a 15W40 or an anythingW40

And yes, check your firewall isnt getting sucked onto the fan.
Then check the dipstick as fig said, also check your coil - same applies, if its too hot to hold, then its bad, if its warm but you hold it, then its fine.

[slak]

My engine ran exactly like what U are explaining a few years ago and i found out
that the fan came loose at some stage and buggerd up the slot that it goes into when
U drive slow the fan obviously runs with the alternator but as soon as it gets a bit of resistance from
the higher engine speed it does not push air onto the engine so just check that the fan is tight and cannot be
turned when the engine is off
otherwise it might be that the carb is icing up at highway speed and as soon as U drive at slower speed heat
gets to it and it runs normal again

[retrovan]

It could also be that you running out of fuel at speed.

Maybe your filter is blocked or the filter mesh in your tank is blocked.

So on short runs she will still get fuel, and at speed reduction she will get fuel, but on the long run, run lean, and heat up.

Did you feel the dip stick as you get off the highway ??

Herman