The Cessna 120-140 Association Forum

I have a C90 engine.I recently replaced my oil temperature gauge and I took it up on a 30 F day to see how it works. It took ten minutes inflight at cruise RPM for the temp to move off the 100 F mark and the it moved only to 125 F p. So I talked to my AMT and he suggested a oil cooler block off kit. Is that good advice? He said the temperature will be warmer and rise faster. Is there a kit available? Can I get it at A & S? If it does exist to buy what is the part number or official name?

Thanks

Thayne inman

You might want to test your oil temp gauge if you haven't already done so. Not familiar with the C-90.

Blocking the air flow through a cooler is the time honored way to increase oil temps.
Problem is I don’t believe a C-90 has an oil cooler does it?
What I do on my C-85 is to block off the two small holes in the cowling under the prop,and to block off the blast tube that directs air to the strainer.
The holes under the prop direct cooling air under the case to cool the oil and of course the blast tube exists to help cool the oil.
I don’t fly in real cold weather, maybe just below freezing and that’s about it. For those that do fly in cold weather, I guess they shorten their oil change interval and just wait for Summer?

On edit, I just use tape, I use the blue masking tape so that it won’t pull the paint off, if you use duct tape I’d suggest not leaving it on as the glue will be tough to remove if you do.

Correct in that the 120/140 didn't have an oil cooler. It is possible to add one. If you had one it would be behind the rear cylinder on the left (pilot's) side.

Otherwise, the following steps can be employed:
1) at ambient temps below 70 degrees F. block off the opening of the oil screen blast tube.
2) between 70 and 40 degrees F install the oil tank "blanket", available from Wag Aero.
3) at 40 degrees F block off the two oval holes below the prop opening.
4) if all else fails, block up to half of the openings in front of the cylinder barrels. Always block the inner half, not the half in front of the cylinder heads.

I would not apply takeoff power until the oil temperature gauge moves off of the peg. Aim for 180 degrees in cruise.

6643 wrote: ↑Wed Mar 03, 2021 1:05 pm Correct in that the 120/140 didn't have an oil cooler. It is possible to add one. If you had one it would be behind the rear cylinder on the left (pilot's) side.

Otherwise, the following steps can be employed:
1) at ambient temps below 70 degrees F. block off the opening of the oil screen blast tube.
2) between 70 and 40 degrees F install the oil tank "blanket", available from Wag Aero.
3) at 40 degrees F block off the two oval holes below the prop opening.
4) if all else fails, block up to half of the openings in front of the cylinder barrels. Always block the inner half, not the half in front of the cylinder heads.

I would not apply takeoff power until the oil temperature gauge moves off of the peg. Aim for 180 degrees in cruise.

Thanks John,

I'll take your advice.

Thayne Inman