Author Topic: aircooled overheating (Read 6458 times)

Nurudin · « **on:** April 25, 2006, 10:34:17 AM »

Hi everyone! I am from Bosnia and Herzegovina and I own a 1989 air cooled model. It was produced in Kragujevac Serbia. Today I went for a drive with my friend up the mountain. Outside temp was about 22 Ã‚Â°C. After driving in third for about ten miles the car lost power. Pulled over and the brake pedal fell all the way through. Pumped it a few times and it felt OK. After 20 minutes started the car, drove downhill and every thing seemed normal. Now, for the loss of power I suspect overheating, but the brakes??? How do I know if my head gasket is gone? The car needs about 9 liters of fuel per 100 Km. How do I know if my valve clearances are OK? What else could be causing air cooled overheating? Does 126 have an air-intake thermostat? I got this idea on http://www.type2.com/library/cooling/coolsami.htm
I just got this car and I want to get it in top shape. Any advice is welcome.

Thanks everyone.

ChrisRLewis · « **Reply #1 on:** April 25, 2006, 11:04:20 AM »

Have you checked if the thermostat flap is opening and shutting ok? It located on the right hand side of the engine (distributor side) located on the engine cover. When the engine is at operating temperature it should be open.

Internal view of thermostat engine case

Valve clearances will have to be checked manualy, dead easy to do.
I guess the best way to check for head gasket failure is a compression test.

PaulB · « **Reply #2 on:** April 25, 2006, 01:12:40 PM »

Also check that the fan belt is tight enough - press down HARD with a finger - should flex about 1-2cm.

Also check the fan is blowing air through the cowling and through the small vents under the sump.

You may need to bleed your brakes but it sounds like either a brake has bound up or you were driving with the handbrake on. This will overheat the drum, boil the brake fluid and cause loss of pressure. This is a common problem if the car has been stood unused for a while. If you are unsure what to do with the brakes, get a mechanic to have a look, as you may have worn the lining of a pad.

A badly bound up brake will also have caused the high fuel consumption and overheating engine.

Nurudin · « **Reply #3 on:** April 25, 2006, 05:33:29 PM »

Hi and thanks.

I checked the thermostat today and noticed that the shaft for regulating flap is always in the highest position, engine cold or hot. Does this mean flap open or closed? If I push the shaft down does it move the flap?

Tried to take the engine cover of but could not reach all the screws. Can it be done without taking the engine out?

PaulB · « **Reply #4 on:** April 25, 2006, 08:27:47 PM »

You don't need to remove the engine cover - just the small section above the thermstat, held on by 2 small nuts. Look on the right hand side of the engine - just above the distributor. You'll see the flap. When the engine is cold it should be closed, but you can open it by hand (its quite stiff) If its open when cold the thermostat is broken. This isn't too bad as the engine will still cool, though it will take longer to warm up. It will need replacing before next winter.

If it is closed, take the car for a good drive, until the engine is hot - the flap should now be opening. If you think its broken then take out the thermostat and put it in a pan of water to boil. If it hasn't fully expanded by near boiling point, get new one.

Check your brakes before going anywhere. Sometimes reversing fast and slamming the brakes on releases them then resets the adjusters. But it sounds like they need checking properly, the fluid replacing and bleeding.

Nurudin · « **Reply #5 on:** April 26, 2006, 07:47:33 PM »

Took of the 2 small nuts, but still cant remove the thermostat. It feels like its attached to some kind of a spring. I pull it up but it goes back down. I don't want to break something so didn't pull hard. Looking at the picture above I don't see how I can take the thermostat of without taking of the linkage (pull rod). Should I take of the big nut of the thermostat too? Wont the thermostat fall in then?
In any case, if the thermostat is broken and the brakes OK, do you think that had caused the overheating?
Tomorrow morning Ill look into the brakes, and let you know what i found.

Thanks for your help and patience

PaulB · « **Reply #6 on:** April 26, 2006, 09:16:14 PM »

Yes, its attached via a rod to the flap. That is easily undone from underneath the flap (but less easily put back!). Leave the rod attached to the thermostat.

Once the thermostat is pulled out you can then undo the bigger nut to free it from the lid.

Its quick to remove, but fiddley to put back.

Nurudin · « **Reply #7 on:** June 18, 2006, 12:10:01 AM »

First of all long time no see. To PaulB and Cars thanks. I have found out that there was nothing wrong with the brakes, instead the nut that holds the weel and the drum... i dont know what its called (bearing of some kind i think) on the front left wheel was too tight so the whole thing overheated. Even the plastic cover on the wheel started to melt. Must have caused the brake fluid to boil. no problems sence.

Thanks again

fiatfsm · « **Reply #8 on:** June 27, 2006, 09:35:05 AM »

you mean the stub axle nut? the one that holds the bearing in place... that should just be nipped up then backed of a little, almost hand tight! for it to be done up that tight, well someone doesnt know their 126s!

Nurudin · « **Reply #9 on:** June 29, 2006, 10:30:28 PM »

Not so sure now. Took of everything today and noticed that one of the pistons in the cylinder sometimes gets stuck. Cant figure out why. Nothing looks worn.

PaulB · « **Reply #10 on:** June 30, 2006, 02:42:17 PM »

Replace it - they are not so expensive and its a fairly critical bit of the car!