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Oil overheating

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I finally finished my annual and flew my CT for the first time in many months. I did not have anyone local with any CT or Rotax experience, so it took me forever and a day, ha ha. 

I flew it 3 times and decided I had to tear into it again!!! I have had problems with overheating on climb out, but this time it was oil temp more than CHT. I had cleaned the radiator last year but never got out all the "goop" (oil soaked dust). Now that it is removed I can see the clogged cooling coils and they are more in the center part of the radiator (where the oil cooler is).

I researched for a local radiator shop and we have one, but he didn't seem like he really wanted to do an aluminum radiator (you cannot "boil them out" like a normal radiator because of the caustic solution used). I decided (since my clogging is mostly exterior) I will put my radiator in a milk crate and take it to the local coin operated car wash! For the interior flushing I will make sure and "back flush" by having the inlet side down, and blast thru the outlet side.

So, tonight I went to make sure of the flow direction and by chance I turned on the battery and noticed that my oil temp gage went up to 140 degrees! And, after staring at that for about a minute, it popped up to about 180 degrees! So, I was pretty relieved that the overheating is probably not as bad as it was showing. But, I know I needed to clean the exterior of the radiator. Next year I'll come up with a better way to clean it without removing it. I have a degreaser sprayer, but I need to make a right angle nozzle so I can spray from behind the radiator. And, I'll heat the 505 degreaser liquid while I'm spraying. 

Question: Anyone have a source for a new oil pressure sensor?

Regards all . . .

ET

Pic of radiator.jpg

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There was a recent thread that has the part number for both oil pressure and temp sending units. The only that might not be there is pressure if it is remote mounted.

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Looks like you did a nice clean job.

You can check to see if you have a bad oil pressure probe by swapping out the left side CHT wire to the oil temp probe. These two senders are identical. Swapping wires will help rule in or out a probe and see if it is a wire issue. The VDO temp probe is a very rare failure and usually last forever. You could if you want swap the CHT probe and oil temp probe. Like I said they are identical.

The oil hose on the right side (the one just out of the picture) that makes a 180 turn from the radiator back to the oil pump housing most times is the culprit. I ALWAYS put a spring or two where that hose makes the 180 degree bend. I have found that this many times will drop the temp by 20F. As that hose gets hot it gets soft and is more likely to pinch down and reduce its ID radius which slows oil flow which increases temps. Making that hose a 180 was never a good idea, but is easy to fix. All you have to do is pull the hose off the radiator fitting and shove a spring down its throat. I use a 12" long 1/4" ratchet extension turned backwards to push the spring down the hose. The back end of the 1/4" extension is a perfect fit.

Don't forget to silicone your exhaust springs. Don't forget to put the drain hose on the fuel pump.

Double check to see if any other oil hose has a flattened spot under the fire sleeve after it is hot. You can feel them.

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1 hour ago, Roger Lee said:

. . . Don't forget to silicone your exhaust springs.

Roger,

What is the brand name of that red compound found on most of those springs?

A web link to that stuff would really be appreciated. I need some of it.

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It's just high temp red silicone RTV. You could use the black if you wanted, but it must be high temp. Any auto parts store or Ace Aviation. The spring coils should be stretched enough to have a 1mm (fingernail width) between coils. When you apply the silicone you work it in between the coils. It needs to have enough body to do some good so make the silicone bead about 3/16" thick and about 3/8" - 1/2" wide. This is in the manuals and an SB. This is for vibration dampening.

 

DO NOT fill the coils like Vans does. This practice was abandoned many years ago due to the spring retaining too much heat and causing early spring failures. The spring needs air flow to help dissipate heat.

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Thanks you guys!

Roger, you always amaze me with your effort to help others here. If I didn't love Kingman, Bullhead City, and Laughlin so much, I would consider relocating to the Tucson area!

I'm pretty sure I have a bad probe or wire connection by the fact that my gage goes up to 140 degrees when I turn on the battery with a cold engine. Then, if I wait an extra minute or 2 it pops up to about 180 degrees. The fact that it jumps up makes me suspect that I also have a sticky  gage. I'll have to keep an eye on that.

I will definitely try swapping the leads and cleaning the clips/terminals with acetone.

As far as the hoses, extra heat shielding, etc, that was done by Rex Johnson at the Riverside Airport in Tulsa, OK when I bought the airplane (5 year rubber change).  

Thanks again . . .

 

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1 hour ago, WmInce said:

Roger,

What is the brand name of that red compound found on most of those springs?

A web link to that stuff would really be appreciated. I need some of it.

I think I use Permatex Red, as do the two RV-12s on the field.

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4 hours ago, Roger Lee said:

Permatex owns Loctite

 

I thought that before, but looked it up. Loctite is owned by Henkel AG & Company, KGaA, while Permatex is owned by Illinois Tool Works.

I do believe at one point in the past they were owned by the same company. I know permatex has been bought, sold, bought again.

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6 hours ago, FlyingMonkey said:

I think I use Permatex Red, as do the two RV-12s on the field.

Thanks Andy!

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7 hours ago, Roger Lee said:

It's just high temp red silicone RTV. You could use the black if you wanted, but it must be high temp. Any auto parts store or Ace Aviation. The spring coils should be stretched enough to have a 1mm (fingernail width) between coils. When you apply the silicone you work it in between the coils. It needs to have enough body to do some good so make the silicone bead about 3/16" thick and about 3/8" - 1/2" wide. This is in the manuals and an SB. This is for vibration dampening.

DO NOT fill the coils like Vans does. This practice was abandoned many years ago due to the spring retaining too much heat and causing early spring failures. The spring needs air flow to help dissipate heat.

Thanks Roger!

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1 hour ago, Anticept said:

I thought that before, but looked it up. Loctite is owned by Henkel AG & Company, KGaA, while Permatex is owned by Illinois Tool Works.

I do believe at one point in the past they were owned by the same company. I know permatex has been bought, sold, bought again.

Hi Corey,

Not sure where I got that, but you're absolutely right. Here is a little history.

https://en.wikipedia.org/wiki/Loctite

http://connection.ebscohost.com/c/articles/4109905/permatex-buys-own-brand-related-business-from-loctite

2005
ITW Acquires Permatex

Permatex was acquired by ITW (Illinois Tool Works Inc.), a NYSE listed U.S. based corporation. ITW was founded in 1912 and is a Fortune 200 diversified manufacturing company with more than a 90 year history. ITW’s decentralized business units in 49 countries employ 50,000+ people focused on creating value-added products and innovative customer solutions.
Permatex Partners with Jay Blake and Follow A Dream NHRA Racing Team

 

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