Sohc 1.6 Uno turbo engine - (almost) overheated

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Ev0luti0n_

Sohc 1.6 Uno turbo engine - (almost) overheated

Post by Ev0luti0n_ »

Due to a stupid fault of mine, the fan did not turn on whilst the car was idling for a short while. I was looking at the water temp gauge from time to time, as i was checking something on my exhaust/engine. it must of passed 2, maximum 3 minutes and the water temp reached 130º degrees. (The maximum temperature the dash clocks indicate is 140º) I promptly activated the fan manually till the temperature was down to 70º, a few minutes later.

-Oil and water: ok
-no apparent cracks on the back of the block, close to the core plugs
-no apparent coolant leak; other than a few minuscule water bubbles on the expansion tank, below the water level, attached to the walls
-didn't smelled nothing burned with heat
-spark plugs are ok

Drove the car for 20 minutes and it all seemed fine with the temperature, going no further than 90º at idle, and lowering while cruising at low/moderate speeds to 70/73º +/-. After driving the car, i left it idling for 5+ minutes, and the water temperature was always stable at close to 90º, with the fan switching on multiple times. (As before). It seems ok, but i am afraid there will be mid/long term consequences might be.

Any help or tips will be appreciated.

Edit #1: a few hours after doing all that indicated above, i opened the expansion tank, started the car and left it idle. The minuscule air bubbles are still there, and the car warms up normally till the correct temperature, but if i give it a little go on the throttle there are lots of bubbles on the tank. The water level raises a just a little bit but doesn't spill out of the tank in any way. There is also a bit of water on the tailpipe and the weather is still warm...


engine specs :
Lancia dedra sohc 1.6 | uno turbo exhaust valves
Headgasket: spesso racing 1.9mm
scat forged rods
wossner forged pistons
arp head studs

There were two white lines remaining on the temp gauge when it overheated...
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fingers99
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Re: Sohc 1.6 Uno turbo engine - (almost) overheated

Post by fingers99 »

The bubbles do suggest that the head gasket may have gone. But the obvious way to be sure is a compression test.
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Urbancamo
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Re: Sohc 1.6 Uno turbo engine - (almost) overheated

Post by Urbancamo »

Nah, engines in common aren't that weak. Otherwise they would broke down all the time. If you had proper pressure in your your cooling system and you used proper antifreeze it might not even boiled the liquid.
Small air bubbles in expansion tank really don't mean much if they don't exist all the time.

I would just continue driving.

Though if you want to check, go to the nearest shop where you can find exhaust 4-gas analyzer and ask blokes to measure from expansion tank air. Seal the probe in the expansion tank mouth with shop rag.
If there's very much hydrocarbons in the expansion tank compared to open air, it might indicate a head gasket failure.
One engine wich truly had a faulty headgasket measured over 2000 ppm hydrocarbons in the expansion tank!
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