Oil Pressure Gauge

[DingyHarry]

In flight, my oil pressure gauge has shown high pressure on several occasions. On the ground, it does not do this. Yesterday I flew for about 2 hours, 8K ft, 60 degrees and it showed that the pressure was normal. Is it possible that the gauge is failing? Or could there be a real problem? My maintenance shop told me that they would just run the plane on the ground and if the pressure looked fine, there really wouldn't be anything they could do. Just want to be sure nothing is unsafe here. Thanks. 

[Guitarmaster]

The only way to really determine if the gate is no functioning is to put a manual oil pressure gauge on it. Your mechanic should be able to do this no problem.
I did this when I first got my airplane that was showing high oil pressure. The manual gauge showed pressure was normal. My problem was the gauge, but you really need to know for sure.


Sent from my Pixel 2 XL using Tapatalk

[DingyHarry]

12 minutes ago, Guitarmaster said:

The only way to really determine if the gate is no functioning is to put a manual oil pressure gauge on it. Your mechanic should be able to do this no problem.
I did this when I first got my airplane that was showing high oil pressure. The manual gauge showed pressure was normal. My problem was the gauge, but you really need to know for sure.


Sent from my Pixel 2 XL using Tapatalk
 

Thanks. And if it helps at all, my oil temp never exceeded about 185 degrees regardless of the indicated oil pressure. 

[Andy95W]

Okay, so a little guesswork is needed here.

By your avatar picture, it appears your back window is medium-sized, so that narrows down your model to either an M20J or M20K with either a Lycoming IO-360 or a Continental TSIO-360 (which are very different animals, by the way).  Your paint job is from the mid-80's which could apply to either airplane, but your windows aren't rounded (from what it appears from your low-definition avatar picture, at least), so that makes it a 1986 at the latest, IIRC.  You mentioned flying for two hours at 8,000', so either you were west bound in a 231 or you are flying a 201.

I'm going to guess you own an M20J with a Lycoming IO-360A3B6D.

(This would be so much easier if you mentioned your airplane type in your post.)

[jaylw314]

20 minutes ago, Andy95W said:

Okay, so a little guesswork is needed here.

By your avatar picture, it appears your back window is medium-sized, so that narrows down your model to either an M20J or M20K with either a Lycoming IO-360 or a Continental TSIO-360 (which are very different animals, by the way).  Your paint job is from the mid-80's which could apply to either airplane, but your windows aren't rounded (from what it appears from your low-definition avatar picture, at least), so that makes it a 1986 at the latest, IIRC.  You mentioned flying for two hours at 8,000', so either you were west bound in a 231 or you are flying a 201.

I'm going to guess you own an M20J with a Lycoming IO-360A3B6D.

(This would be so much easier if you mentioned your airplane type in your post.)

I think I also see a wing step which would be an older J.  Do any of the M20K's have a wing step?

[Hank]

40 minutes ago, jaylw314 said:

I think I also see a wing step which would be an older J.  Do any of the M20K's have a wing step?

What, nobody flies F models anymore, with the one-piece back window?

[jaylw314]

18 minutes ago, Hank said:

What, nobody flies F models anymore, with the one-piece back window?

How many of those were there?

[Andy95W]

That's a great point, Hank.  I should look up how many F models were produced (only 1976, I believe) that had the 1-piece back window.  And I've always wondered how many previous years' were modified later.

[Igor_U]

4 minutes ago, Andy95W said:

That's a great point, Hank.  I should look up how many F models were produced (only 1976, I believe) that had the 1-piece back window.  And I've always wondered how many previous years' were modified later.

I think large number of Fs were converted to one window (and 201 windshield). >50%??

The fact we can see step on small avatar could mean F since the retractable step tube is much bigger and easier to spot.

[jaylw314]

21 minutes ago, Igor_U said:

I think large number of Fs were converted to one window (and 201 windshield). >50%??

The fact we can see step on small avatar could mean F since the retractable step tube is much bigger and easier to spot.

Oh wow, I didn't realize it was that common.  I wonder how many of ones I thought were J's from a distance were actually F's...

[DingyHarry]

2 hours ago, Andy95W said:

Okay, so a little guesswork is needed here.

By your avatar picture, it appears your back window is medium-sized, so that narrows down your model to either an M20J or M20K with either a Lycoming IO-360 or a Continental TSIO-360 (which are very different animals, by the way).  Your paint job is from the mid-80's which could apply to either airplane, but your windows aren't rounded (from what it appears from your low-definition avatar picture, at least), so that makes it a 1986 at the latest, IIRC.  You mentioned flying for two hours at 8,000', so either you were west bound in a 231 or you are flying a 201.

I'm going to guess you own an M20J with a Lycoming IO-360A3B6D.

(This would be so much easier if you mentioned your airplane type in your post.)

It is a J model (1978) with a lycoming

[jaylw314]

27 minutes ago, DingyHarry said:

It is a J model (1978) with a lycoming

Hah!  I win! 

Sorry, I know that doesn't help you.  Just to clarify, you're getting high oil pressure during cruise, right?  High pressure shortly after startup can be normal under some circumstances (cold weather)

Edit: oops, never mind, you did say in flight in your OP

Edited May 23, 2019 by jaylw314

[ArtVandelay]

Could be the sensor as well, but until it fails consistently, you won’t know. The sensor is about $160, and it’s easy to replace.

Of course there is the option to replace all with a certified engine monitor.

 

 

Tom

 

[carusoam]

1 hour ago, DingyHarry said:

It is a J model (1978) with a lycoming

Time to update the avatar data...

high pressure and normal oil temps is a way of saying look to the gauge to not be telling the truth...

OilP and OilT have a way of backing up each other...

PP thoughts only...

Best regards,

-a-

[Guest]

Either the gauge or the transducer.  Have your maintainer plumb a second gauge in the oil pressure line to the transducer to verify the readings.

Clarence

[DingyHarry]

After a few additional flights, we determined that the oil pressure gauge was likely accurate and the manifold pressure was being kept too high for too long causing the oil pressure to spike. Has anyone else seen this? After running the motor for extended periods of time at 25" of MP or less, we did not experience an oil pressure indication above normal. We also determined that the oil temp probe was faulty and has since been replaced but that was unrelated to the pressure gauge. 

[RobertGary1]

On 5/23/2019 at 10:25 AM, jaylw314 said:

How many of those were there?

There are 3 of us at my field with the original factory single rear window on our F's. This was not a J thing, the single window was introduced in the F.

 

-Robert

Edited June 10, 2019 by RobertGary1

[N231BN]

After a few additional flights, we determined that the oil pressure gauge was likely accurate and the manifold pressure was being kept too high for too long causing the oil pressure to spike.

I would love to hear someone's explanation for this diagnosis.

When you say high oil pressure, do you mean the gauge is pegged high or it just reads 20-30 psi higher than normal?

[RobertGary1]

Oil pressure is maintained by an adjustable bypass valve (simple ball on spring). It should be adjusted to avoid red line on take off. 

-Robert

[DingyHarry]

On 6/10/2019 at 7:07 PM, N231BN said:

It was reading just above the green

 

I would love to hear someone's explanation for this diagnosis.

When you say high oil pressure, do you mean the gauge is pegged high or it just reads 20-30 psi higher than normal?