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AAZ Engine Overheating: Causes & Solutions

 
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LaurenzBo
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Post17-12-2009, 21:15    Subject: AAZ Engine Overheating: Causes & Solutions Quote

Hello,
This morning, after a long uphill stretch at full throttle (approximately 160 km/h), the ribbed belt on my AAZ engine broke. Fortunately, I noticed it immediately, and the next exit was only 1 km away, so I was able to coast there. The engine was quite hot from the climb, but the water temperature was still between 75-80°C thanks to the oil cooler. Since my family was in the car and we had an important appointment, I drove about 1 km to a workshop using as little power as possible. At one point, the temperature rose significantly, so I immediately turned off the engine and waited for a while before continuing. The coolant didn't boil, and neither water nor steam leaked out.
"At the workshop, they had a belt available and installed it. After that, the engine started perfectly again, and it ran smoothly for the next 300 km without any issues (no noticeable loss of power, although I only revved it up to about 4300 RPM). The oil is fine, but the engine noise seems slightly different above 4000 RPM (rougher), which might just be my imagination."
My questions:
Can a slipping ribbed belt (e.g., for the air conditioning or power steering) overload the timing belt, and should it be replaced as a precaution, especially since it has approximately 90,000 to 100,000 kilometers on it?
- The first candidate for damage caused by overheating is the head gasket; I already have the stronger version installed, and so far there are no signs of a blown head gasket or cracked cylinder head. I'll measure the compression soon. Is it possible that you might not notice a crack in the cylinder head initially?
- Are there any other potential damages that the overheating could have caused, and what would be indicators of such damage?
I hope the AAZ (charge air cooler and oil cooler, but not modified) survived that ordeal well...


Translated on 30-07-2026, 5:00.
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BM
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Post17-12-2009, 23:39    Subject: AAZ Engine Overheating: Causes & Solutions Quote

Quote:
The oil is fine, but it seems to me that the engine noise changes slightly above 4000 RPM (becomes rougher), although that might just be my imagination
.

Yes, that could be possible. You wouldn't be the first.icon_wink.gif

You could check if the belt drive is running smoothly and quietly. With this engine, the crankshaft pulley sometimes comes loose.
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Translated on 30-07-2026, 5:03.
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LaurenzBo
Blaumann
Blaumann


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Location: Erlangen

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Post20-12-2009, 23:52    Subject: Timing Belt Sprocket Quote

No, I already know that issue - I already have the reinforced screw installed.icon_smile.gif


Translated on 30-07-2026, 5:04.
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