First Start Oil Circulation Question

[tom1394racing]

I recently installed a freshly rebuilt 3.2 short stroke in my 914-6 GT project.

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In preparation for first start I turned the engine over a couple of times for 30 sec each to build oil pressure and check for leaks. I found a significant leak at the bottom of the brand-new CSF engine oil cooler that I had leak tested before installation.



I assumed the leak had to be from the large return line at the bottom of the cooler as I would not have expected to have flow through the top holes that feed the radiator portion of the cooler in a cold engine with the T-stat closed. I removed the cooler to see what the problem was and found this.



The oil tracks appear to show leakage from the top holes past the seal and down to the area where I had observed the leaks.

My first question is, why would I have flow into the cooler with a stone-cold engine with the T-stat closed? Maybe something to do with starting a fresh engine with no oil in the engine?

The second question is the seals. I have seen recommendations to use the green O-rings rather than the red O-rings that came in the gasket kit that I used for this build.

Can any of the experts here offer any suggestions? What am I missing?

[gled49]

First, the oil system fills with oil, all the air is purged out. When the thermostat opens it just releases hot oil into the cooler. This includes any auxiliary cooling systems. Red seals green seals, doesn’t matter. Something’s wrong. Show pix of the seals u removed. Hard to imagine excessive oil pressure just cranking.

[tom1394racing]

Gordon

Thanks for chiming in. I appreciate your clarification of the initial oil filling process.

I retested the cooler this morning with the Stromski kit. When I built the engine, I put the seals in the case first and then mounted the cooler on the case. When I did the test, I first mounted the seals in the Stromski sealing plate and then mounted the sealing plate on the cooler to duplicate the build assembly process.

I first used the green seals that came with the kit. They dropped nicely into the recesses on the kit mounting plate. When I laid the plate onto the cooler, I could feel that the seals slipped nicely into the recesses in the cooler holes. I put 40 psi into the cooler dropped into my wash basin full of water. No leaks.

I then retested with the red seals I had used in my initial assembly. Same process, onto the plate first and then onto the cooler. I noticed that the red seals were larger in diameter than the green seals and had to be squeezed to fit in the recesses on both the kit mounting plate and the cooler. When the seals were squeezed into the mounting plate, they expanded slightly and did not seat into the cooler recesses. When bolted together, they distorted and did not seal, Failed leak test.

I think this is likely the cause of my cooler leak. The seals did not seat against the cooler recesses. I found the same problem with the larger red seal for the oil return tube at the bottom of the cooler. Did not fit easily into the recess in the CSF cooler.

I re-did the leak test with the upper red seals where I inserted the seals into the cooler first and then "guided" the seals into the recesses on the Stromski test plate. No leaks this time.

My conclusion is that both the red (brown) seals and the green seals work but that one has to be careful when doing the assembly to make sure the seals seat properly

[gled49]

I always use DC111 silicone on the seals, allows easier assembly, and allows them to squirm into place and relieves any tension that might be in a dry seal.

[tom1394racing]

Thanks for the recommendation.

[Henry Schmidt]

First, we only use brown Viton seals from Wrightwood Racing. Never see leaking from this area.
Next: We have returned two CSF engine oil coolers the manufacturers complaining of a silicon/glass bead contaminant inside the cooler.
I like the coolers so we have just adapted a cleaning procedure (sonic and chemical) before we install the cooler.

[sebastianroher]

Originally Posted by Henry Schmidt

First, we only use brown Viton seals from Wrightwood Racing. Never see leaking from this area.
Next: We have returned two CSF engine oil coolers the manufacturers complaining of a silicon/glass bead contaminant inside the cooler.
I like the coolers so we have just adapted a cleaning procedure (sonic and chemical) before we install the cooler.

Henry,

Thanks for posting about this issue you've encountered as I was thinking about purchasing a CSF for my spare 2.7. Can you elaborate on the process? I was thinking an alternative method could be sending to pacific oil cooler for cleaning and test just for the added peace of mind. Thanks again,

Sebastian

[tom1394racing]

I reinstalled the cooler today. I used the brown Viton seals for the top radiator holes and a new green seal for the lower return tube. I applied plenty of Dow 111 to lubricate both the seals and the recesses in the case and cooler before installation. No sign of leaks in the cooler this time.