[New Eight Guy]

Gentleman thanks for your info on tracing the overheat problem. We have some more info to add to the puzzle.Oil temperatures were measured going into and out of the cooler with the engine hot and under load (tied down securely and making power). Oil temps going in and coming out were both the same(185F for this short test). Temps were also tested immediately after landing with a laser thermometer with the same result. Do you guys think this could indicate a thermister valve problem(oil not diverting to the cooler once up to temp.)? Or maybe a plugged oil passage? Thermister valve is brandnew($) and was tried as a fix incase the old one was the problem. Any ideas?

 

[rvbuilder2002]

Gentleman thanks for your info on tracing the overheat problem. We have some more info to add to the puzzle.Oil temperatures were measured going into and out of the cooler with the engine hot and under load (tied down securely and making power). Oil temps going in and coming out were both the same(185F for this short test). Temps were also tested immediately after landing with a laser thermometer with the same result. Do you guys think this could indicate a thermister valve problem(oil not diverting to the cooler once up to temp.)? Or maybe a plugged oil passage? Thermister valve is brandnew($) and was tried as a fix incase the old one was the problem. Any ideas?

I am not at all surprised by your ground test results. Their is not a lot of airflow through the cowl at a static run up so there is not much airflow through the oil cooler. I also don't think you could measure much of a temp difference on teh oil cooler unless you could take the measurement in flight with a high volume of air flowing through it
It is doubtful that the Vernatherm thermostatic valve is the problem since it is new. As has already been posted in the previous thread, historically, RV-4's typically run too cool and efforts have to be made to keep the oil temp in the normal range. I haven't read through the other thread... but have you verified the gage reading with the sensor in some boiling water? If so, then I would be looking at something related to the cooler installation, I.E. incorrect gasket (or incorrectly positioned) used on the oil filter adapter, etc.