Removing the oil pan will be a lot simpler if its oil has been drained out beforehand.
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Guess I should have read the thread again, forgot he was replacing pan.
Thanks guys. Am I right that if I use a gasket, I don’t need to use RTV?
I know how to source bolts, it’s a simple google search. I’d just prefer to not get Toyota ones. It’s difficult because Toyota doesn’t use typical markings for the grade of the bolt. So it’s not like I can go to the store and get the same bolt with four dots on it, you can only get those from Toyota. So I had to find the standard and determine that it’s a 8.8 bolt.
So Toyota Class 8T bolt is equivalent to ISO 898-1 8.8 bolts. It’s a shame that this information is so hard to find online. It forces people to get bolts directly from Toyota. But now I can get any 8.8 bolt/nut/stud, of the same length that is already on the car and not have to worry about using a bolt that is of less strength than what was originally there. I know that in this application, using a weaker bolt is probably not that big of deal. I don’t know the mechanical engineering behind it either. The engineers who selected which type of bolt would be appropriate to get the appropriate clamping force, tensile strength, etc chose 8.8 bolts for a reason, why I don’t know? But the math behind it, doesn’t look to simple at all. I’m not a mechanical engineer, and looking at how the clamping force is calculated based on the length of the bolt, grade of the bolt, etc isn’t a simple calculation. So I just want to use the same quality bolt because I don’t know what I’d be changing by using a weaker bolt. But I’d be scared of using a bolt of less strength. I’m also unsure how the appropriate torque is calculated for these bolts, so I just reference charts and the maintenance manual.
Another interesting thing I heard, is that in some cases, weaker bolts are used on purpose for failure scenarios. Meaning while a stronger bolt will work just the same of course, weaker bolts are picked by engineers in some cases so non-critical parts fall apart to indicate a problem with other parts. So the less critical part brakes first, and when you go inspect that part you see the more critical part is starting to fail. Or something like that. I don’t know.
Fastener theory is a bit interesting and complex. Since I’m not familiar with all the math and engineering behind it, I just want to use the same length and grade of fasteners.
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I understand your reluctance but I think Nevada provided the best option. Just get them from Toyota for the proper size and potential taper on the end.
Fastenal is my supplier of last resort and just used them yesterday. I needed an M6 Left hand nut for a discontinued part for one of my chain saws. Dealer, NAPA, hardware stores, etc, no have but Fastenal did. Still I would have used the dealer/manufacturer part if not discontinued. A little over a dollar a piece is not bad at all. Still I would not expect oil pan bolts to be frozen in and need replacement.
I was able to remove one of the bolts that was in ok shape. The head was indented a bit, but I got it no problems. It is tapered at the end. The bolt is about 6 mm in width. The length of the bolt is 16 mm in length. The hex head is 10 mm in length. A 10 mm socket will work. All bolts can be removed easily, as far as there are no other parts in the way.
I don’t understand why the bolt is tapered at the end? What is it’s purpose of being only partially threaded. You think that a fully threaded Grade 8.8 bolt, that is 6 mm in width, and 16 mm length, along with a washer would work?
But yea, I don’t understand the purpose of the taper. Can go get the OEM part, but I’m just trying to understand the purpose of why it’s only partially threaded.
Well I mean I don’t know that it is exactly tapered, just not threaded at the end. The part near the head is also not threaded, this makes it very difficult to get the washer off, I understand the purpose of that. The washer has a diameter that appears to be smaller than the threads. So it keeps the washer in place, from coming off the bolt. But I have no idea why it’s not threaded at the end.
Taper may be there to assist/speed up assembly. I would use only identical bolts to replace them. This one looks to be in great shape, just clean it up and use it (and I bet most/all of the other bolts).
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I see what you mean. I guess a few threads missing would save some time. Here’s what I’m dealing with for the other bolts.
I think some of them are very rusty, I don’t know I can save them. Might as well as just use new ones. Also getting a new pan as the pan itself is rusting.
You are asking an engineering question. Maybe one of the mechanical engineers here will know but a cut out of the socket would be nice to see. Maybe they wanted to make sure the bolt would not bottom out and crack the case? Maybe it insured faster original assembly at the plant like phillips screws did. Who knows. A novice cannot know the complexity of the design process and the reason for decisions made. For myself, I am less concerned about “why” something is done and instead try to just “copy” what was done. Many things in life and cars will remain unknown and frustrating trying to find out.
I believe the bolts are made that way to guide the bolt in the hole to make it easier to install by the robotic machines. and less thread stripping.
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The oil pan looks to be very dry, where is the leak?
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sorry for the blurry pictures. I changed the oil myself last time. I know that this wasn’t from me changing the oil. Seems to be a slow leak, as my oil level hasn’t gone down on the dipstick.
If oil does not drip it is considered to be a “seep”, repair is not necessary.
This Toyota service bulletin explains the difference between a leak and seepage;
I have used bolts threaded all the way in place of tapered trans pan bolts. Just screw one in first without the pan and check clearance.
All this overthinking is beyond me. It’s just an oil pan bolt, under no pressure either tension or shear. Good lord just go to Home Depot and match up a bolt and washer. Just don’t include the length of the “taper”.
When my Riv was loosing a quart a week (500 miles), I put a new pan gasket on it. I thought a quart a week was excessive.
And don’t forget to put a nice new coat of paint on the pan when it’s out, and hope the repair doesn’t leak/seep worse than before.
Nice coat of paint included!
Guys, the last picture demonstrating the seep/leak… am I the only one who sees the oil on the engine block itself? Is it not seeping/leaking from somewhere above the pan?
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Looks like it to me also.
Kinda to tell for certain in the picture. I’d definitely advise cleaning all the oil in that area with degreaser or brake cleaner and taking another look at it after driving a bit.
It’s possible that the studs are because there’s not enough clearance to back a bolt out. More likely, shanonia is right.
If you attempt to remove the studs you will regret it more than trying to drive home from a frat party.