Oil changes and engine repair, thinking out loud..

[Torrid]

I found a small oil leak at the oil pressure sender on my LS1, where I have an aftermarket T-piece and an aftermarket sender for my add on oil pressure gauge. It appears my teflon tape didn't hold up and upon removing everything for inspection, it appeared that the factory sender used copper RTV, so I cleaned everything off and applied RTV to all of the threads and reassembled the sender setup.

Here's the question, should I shorten this OCI due to using a new sealant in direct contact with oil? It has been more than 24 hours since the repair and I have not yet started the car and cure time is 24 hours for copper RTV, so it should be fully set before the first turn of the key.

 

[skyship]

No, a small amount of sealant in the oil won't cause any harm, a new engine has quite a lot of odd sealants that get into the oil, but the filter will stop any odd traces and the rest won't cause any damage.

 

[Torrid]

Originally Posted By: skyship
No, a small amount of sealant in the oil won't cause any harm, a new engine has quite a lot of odd sealants that get into the oil, but the filter will stop any odd traces and the rest won't cause any damage.


This was my thought process was as well, just wanted to be sure. I really didn't want to dump GC anytime soon since I have less than 1k miles on it.

 

[OVERKILL]

I would check to ensure you are tightening it adequately, as it is the taper seal on the threads that is the ultimate "seal" here, not the sealant used, which is normally just applied to lubricate and make the sealing process easier. And also to act as a safety of course in case you don't quite get it tight enough

 

[Trav]

Originally Posted By: skyship
No, a small amount of sealant in the oil won't cause any harm, a new engine has quite a lot of odd sealants that get into the oil, but the filter will stop any odd traces and the rest won't cause any damage.
\
Tell that to Subaru owners that used too much RTV on the oil pump.
Any RTV in the oil passages can have catastrophic consequences.

If this were mine i would remove the fitting make sure this is clean and RTV free then use an anaerobic sealer if one is needed.
Anaerobic sealer will not cure in the presence of air. For this reason it is highly recommended for flanges where no gasket is used.

 

[Torrid]

Originally Posted By: OVERKILL
I would check to ensure you are tightening it adequately, as it is the taper seal on the threads that is the ultimate "seal" here, not the sealant used, which is normally just applied to lubricate and make the sealing process easier. And also to act as a safety of course in case you don't quite get it tight enough

The only one that is NPT is the aftermarket sender. That one appeared to not be leaking. It was leaking from around the factory sender which is a standard thread. I used a small amount of the RTV spread sparingly on each set of threads, regardless of the thread pitch, leaving the first couple of threads clean on each connection to avoid any excess falling loose into the engine or hindering the sender's ground path. I can definitely see how applying it heavily could cause small passages to become clogged.

 

[OVERKILL]

Originally Posted By: Torrid
Originally Posted By: OVERKILL
I would check to ensure you are tightening it adequately, as it is the taper seal on the threads that is the ultimate "seal" here, not the sealant used, which is normally just applied to lubricate and make the sealing process easier. And also to act as a safety of course in case you don't quite get it tight enough

The only one that is NPT is the aftermarket sender. That one appeared to not be leaking. It was leaking from around the factory sender which is a standard thread. I used a small amount of the RTV spread sparingly on each set of threads, regardless of the thread pitch, leaving the first couple of threads clean on each connection to avoid any excess falling loose into the engine or hindering the sender's ground path. I can definitely see how applying it heavily could cause small passages to become clogged.


Funky! Mine have all been NPT

For ones that require a thread sealer (like yours), Locktite makes a specific product. I have some of it, though don't remember why off the top of my head.

 

[skyship]

The OP is not changing anything but the sender as far as I understand, so unless he does something real odd like squirt it down the hole first it won't matter what he uses for a locktight assuming it conducts ok.

 

[A_Harman]

Please tell me you're not using a brass Tee-fitting.

 

[Torrid]

Works perfectly, test drive went well and no more leaks. I think I was losing pressure from the sender location as pressure increased. Idle pressure seemed to increase by 1-2psi and 3-4psi in the upper rpms. I must have been losing every bit of the oil I thought I was burning because there was a healthy trail of oil running down the transmission bell housing and coating the bottom of the pan. I'm so glad I caught this before it started dripping on the garage floor. I only found it because a fellow GTO owner wanted to see pics of my install to do the same setup.

 

[Torrid]

Originally Posted By: A_Harman
Please tell me you're not using a brass Tee-fitting.


No, it's zinc plated steel. It basically raises the stock sender up about 2 inches and the aftermarket sender screws in from the side.

 

[TuBon_gRips]

Originally Posted By: skyship
No, a small amount of sealant in the oil won't cause any harm, a new engine has quite a lot of odd sealants that get into the oil, but the filter will stop any odd traces and the rest won't cause any damage.


I'll add to this that if you get a used oil analysis on this oil, let the lab know that you did some engine work and used RTV sealant, so they can account for this in their commentary when they notice the elevated silicone levels in your sample.

 

[Torrid]

Originally Posted By: KeMBro2012
Originally Posted By: skyship
No, a small amount of sealant in the oil won't cause any harm, a new engine has quite a lot of odd sealants that get into the oil, but the filter will stop any odd traces and the rest won't cause any damage.


I'll add to this that if you get a used oil analysis on this oil, let the lab know that you did some engine work and used RTV sealant, so they can account for this in their commentary when they notice the elevated silicone levels in your sample.


I have a used oil analysis kit but I planned to wait until the next round after I did the repair.

 

[TuBon_gRips]

Good call

 

[skyship]

Sealants are odd in a used oil analysis as they can show up for several OCI's. Moly does the same as although the amount will drop into single digits it can be detected a long time after you switch to a non Moly oil.

 

[Clevy]

Originally Posted By: skyship
Sealants are odd in a used oil analysis as they can show up for several OCI's. Moly does the same as although the amount will drop into single digits it can be detected a long time after you switch to a non Moly oil.


Moly keeps showing up because it has a plating effect under pressure. It's sacrificial and wears off by design. That's why it will show up as residual in uoa.