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high 912uls CHT values

  • fvanpelt
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8 years 3 weeks ago #196 by fvanpelt
high 912uls CHT values was created by fvanpelt
On longer or grass taxi-ways and if I have to hold for a longer time before lining up the runway the CHT always rises to critical values (120 degr. C or more !!). The coolant is conventional (50/50).
Summer or wintertemp. gives no big differences.
In cruise CHT always comes back to normal values (95-100 degr.C).
The problem exists since new, now I have 90 hours.
What can be the cause ?

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8 years 3 weeks ago #200 by Roger Lee
Replied by Roger Lee on topic high 912uls CHT values
Hi Frans,

I few different things could cause it and here are a few to consider.
Poor coolant circulation i.e. coolant line has a reduction, too tight of a bend (small kink) (how is the oil temp)
rpm while sitting
prop pitch (what is your WOT rpm at your normal cruise altitude)(is it too course), prop pitch can have a significant play in temps
tightly cowled engine with poor air flow

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell

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8 years 2 weeks ago #322 by rhtrudder
Replied by rhtrudder on topic high 912uls CHT values
Sounds like the radiater is not getting enough air

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2 months 1 week ago #22582 by Patarnaud
Replied by Patarnaud on topic high 912uls CHT values
Hello
one of my two sensor of CHT gives very irregular values on my 912uls (VL3). It rise above 130°C several time during the flight, not specially when i'm climbing.
The other sensor is very constant, oil temperature is also constant.
I replaced the sensor but i've the same results.
somebody could help me?

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2 months 1 week ago #22593 by PeterKl
Replied by PeterKl on topic high 912uls CHT values
Hi,
I suggest you swap connecting cables to rule out the wiring as a cause for high or erratic CHT values. If the high/erratic reading switches over to another cylinder the cause is neither sensor nor „real“ temp.

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