You are very correct on dirt and debris degrading the efficiency of any heat exchanger
. The OP and others should always clean the heat exchanger
before moving on.
But I find that most systems have a very piss poor, if any fan shroud/ducting system.
Most seem to have just a "pan cake" fan, ty-wrapped to the condenser. And at best, only 60%~70% of the condenser is seeing any air flow.
Just by moving the fan back an inch or so and constructing a shroud
out of card board, generally does wonders.
But short of this, getting a fan that is the same size as the condenser, would be an improveme
--MAJOR THREAD DRIFT--
I have changed out many jugs due to heat related failures.
True, quite a bit of them have been due to loose, worn or even missing baffles <sp?>, but there have been those that failed because of pilot error due to improper cowl settings.
I was always told and taught, that the cowls were closed to reduce temp by slowing the air flow.
The Piper Tomahawk that I got my licenses in and the Aero Commanders, that were my bread and butter for many years, all were operated with the cowl vents partially closed after TO.
Locally we have a airline historical society that has what I think is the last AW (Air Worthy) "Connie". THey burnt up the first engine
due to high CHT. The replacement engine
was Zero'd timed, and it failed shortly after installation
. Same thing, high CHT.
The official explanation was the cowl linkage was messed up.....But common knowledge among the A&P's was that the Chief Pilot had a standing rule
that after climb out, all cowl flaps were to be 100% open. Okay for the other three, tired engines. With worn superchargers and turbo's. It was all they could do make TO power.
But the remaining engine, with it's new supercharger and the replacement engine with all new parts
, had no problem making TO power. So cooling
was much more critical.
I've been told that now, this engine's cowl vents now get moved to 75% after takeoff.
But, beings I have not personally worked on this plane, it is all secondhand info..