Oil Drain Plug: Thread Tape? New Washer? None?
03-04-2015, 02:21 PM
#16
Registered User
What are your qualifications?
I never did research this to get a definitive answer. Doing the first oil change on this car I looked at the diy to see how the washer was to be installed.
I'm still curious why they indicate this direction over the other. Maybe examination of a used/crushed washer will reveal something. Perhaps the oil pan has more imperfections than the bolt.
Another unusual bit, why is the washer this unique design and copper. Most other vehicle use aluminum washers. Our early 2000's GM w/ 3800 gen 2 engine has an embedded washer in the drain bolt. Every motorcycle I've ever done an oil change on has used a basic aluminum washer. The trans (mt) and diff both use an aluminum washer on this car.
I guess it's just a Nissan thing with the copper crush washers. My first Nissan was actually a 1992 Infinti Q45, and they used the exact same crush washers back then. In fact, I still had a few left over from a whole bag that I had bought at that time and tucked away in my tool chest. When I got my G, I pulled them out when I started doing oil changes and used them up.
I think they are actually a superior crush washer design, as they seal very well with just an appropriate amount of torque applied. Plus, unlike a regular aluminum (or copper) FLAT crush washer, they clearly deform and therefore leave less inclination to reuse them. This reduces the likelihood of over-torquing the drain bolt too, since an even greater torque must be applied to an 'already crushed' (aka USED) flat washer for it to seal again. A regular aluminum washer will work equally well on our cars though; there's certainly nothing special about the sealing requirements on them. You just need to be sure to go ahead and change them in spite of the relatively minimal difference in their appearance after being used.
.02
03-05-2015, 08:40 PM
#17
Registered User
I was reading over a DIY on installing an oil pressure gauge on a 370z forum, and the instructions were to remove the oem pressure gauge, install done form of T fitting and then put the oem pressure gauge back on.
Teflon tape was suggested to help seal the threads.
Comments?
Teflon tape was suggested to help seal the threads.
Comments?
03-05-2015, 09:34 PM
#18
Registered User
I was reading over a DIY on installing an oil pressure gauge on a 370z forum, and the instructions were to remove the oem pressure gauge, install done form of T fitting and then put the oem pressure gauge back on.
Teflon tape was suggested to help seal the threads.
Comments?
Teflon tape was suggested to help seal the threads.
Comments?
First off, the notion of adding a T fitting is is not a good one. The problem first becomes one of just fitting it all in without hitting the sway bar and such, but an even greater concern than that is the long term potential for breaking the fitting off right where the threads screw into the oil pan.
With the added weight of some of the large oil pressure sender units, plus the original pressure switch, plus the T fitting itself, plus the fact that all that weight is being borne some distance away from the thread base (think lever arm), plus the fact that the fitting is typically made of a soft metal, you end up having a very real possibility that with time, metal fatigue resulting from all the inherent harmonic vibrations basically 'shaking a weight at the end of a stick' can and will take their toll. In a word, T fittings do break, and that is one particular place you most certainly do not want to ever experience a break, as you'd have virtually instant loss of oil pressure, and it would most likely occur when vibrations were peaking (i.e. FULL THROTTLE and HIGH RPMs).
Next, for my thoughts on why you don't use Teflon tape, let me show you some pics from my own DIY thread:
PART 2: Using a test gauge on a G37
...
After the testing was done, I removed the fittings. Clearly, you see where I used teflon tape on the NTP threads, but not on the BSP.
And here is why I didn't use the tape in the BSP threads (besides the fact that those threads sealed quite well on their own) you don't ever want to use teflon tape on any kind of oil sensor/sender that is screwed into your engine. That sliver of teflon I pulled out can remain in the hole and, upon removal and reinsertion of the sensor, can be pushed on down into the oil passages, potentially wreaking havoc on the delicate hydraulics of the variable valve timing mechanisms.
Instead, you'll want to use a thread sealant like this. Even then, you only want to apply it to the rearmost threads. You should have 3-4 threads bare threads in front of the sealant.
and here it is all back together again.
...
...
After the testing was done, I removed the fittings. Clearly, you see where I used teflon tape on the NTP threads, but not on the BSP.
And here is why I didn't use the tape in the BSP threads (besides the fact that those threads sealed quite well on their own) you don't ever want to use teflon tape on any kind of oil sensor/sender that is screwed into your engine. That sliver of teflon I pulled out can remain in the hole and, upon removal and reinsertion of the sensor, can be pushed on down into the oil passages, potentially wreaking havoc on the delicate hydraulics of the variable valve timing mechanisms.
Instead, you'll want to use a thread sealant like this. Even then, you only want to apply it to the rearmost threads. You should have 3-4 threads bare threads in front of the sealant.
and here it is all back together again.
...
.02
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