Gasket vs RTV?

Messages
17,136
Location
NH
Thinking I botched this one... I have a slow ATF leak, I noticed that I didn't tighten the bolts all the way from when I did it 3 years ago. Figured the Autozone rubber gasket was probably toast after 80k (no squish left) so after some reading here it sounded like Permatex Ultra Grey might be best. Pulled the pan, cleaned it best I could, put a thin bead around the pan perimeter, on the raised lip that this has. Put on finger tight, waited an hour, torqued to 5 ft-lbs. I then disobeyed instructions and filled. I haven't started it but while messing around with other things I noticed that I seem to have a leak from around one of the bolt holes... I have to double check on this before I condemn it (got dragged away). Where it's not a dead flat surface on the pan is a gasket better? As in, RTV best on flat not convex surfaces?
 
Last edited:

supton

Thread starter
Messages
17,136
Location
NH
Originally Posted by kschachn
Does the pan have the raised bumps on the perimeter that limit the squish of the gasket when tightening?
Has raised surface, but they are right between the bolts. Not to limit squish on the gasket, but rather they look like the "bite into" the gasket material, compressing it it looks like. Didn't think to get a photo. Hoping I don't need to!
 
Messages
16,144
Location
Upper Midwest
Does it look like this? This kind of pan won't seal correctly with RTV no matter what. Also if your bolt holes are stretched out and aren't flat it won't seal either. [Linked Image from felpro.com]
 

supton

Thread starter
Messages
17,136
Location
NH
Originally Posted by kschachn
Does it look like this? These are actually flattened down: [Linked Image from felpro.com]
Nope. Just realized, I had saved a DIY on this, and it has a photo: [Linked Image] Edit: I ran the Permatex right on that rail, and then around the bolt, but not around the bolt twice (didn't want any to fall into the pan.
 
Last edited:
Messages
2,318
Location
WY
I prefer gaskets myself. You are right in making sure the pan flanges are flat if you do use a gasket. Not easy to get a truly consistent bead of RTV like the machines in the factory does. I have seen some RTV mess in my day from people that believe that more is better and also don't have a torque wrench and torque pan,transmission pan and valve cover gaskets to something north of 30 foot pounds it seems.
 
Messages
4,177
Location
Texas
IF the mating surfaces are OK , in general , I prefer a gasket , if available . I usually use sealant to adhere the gasket to the " removable " part . This holds the gasket in place during assembly . If you ever have to do it again , it is easier to remove the gasket / sealant from the " removable " part , than from the " fixed " part .
 

supton

Thread starter
Messages
17,136
Location
NH
Doah! definitely looks like a fail, nice puddle out there. Time to drain and pull, and decide if I want to get a gasket.
 

supton

Thread starter
Messages
17,136
Location
NH
Found the issue. Didn't goop around the bolt holes, and that's precisely where it leaked. Had a good seal elsewhere.
 
Messages
23,094
Location
CA
That pan should seal fine with RTV. Bolts need to be torqued immediately with Toyota RTV, not sure about the Permatex product. But I have never heard of anyone letting RTV "skin" before tightening the bolts. Try it again, but with a longer cure time?
 

supton

Thread starter
Messages
17,136
Location
NH
I think I see the problem--I should have gone 360 around the bolt. I went around the outside, thinking I didn't want to chance any being on the inside and falling off. Right amount used, a 2mm wide bead or so, but it should have done 360 around. This is the bolt that was leaking--I had overfilled it, as I was going to run it and pump out thro the cooler. So with a very high pan level... it leaked. So I think it'll be worth a second shot. [Linked Image]
 
Messages
769
Location
Under the hood
After having to dealing with a coolant system leak, even with new components, I've become a fan of hylomar, as a supplement to a gasket if needed. It's tacky, so it can be used to keep gaskets aligned, and doesn't set or harden, so it won't have to be scraped off the next time it's pulled apart. It's also good enough to act as a gasket on its own, under most circumstances. Oil and fuel resistant. No matter the goop, moar is not better.
 

supton

Thread starter
Messages
17,136
Location
NH
I think I got it. It's leaking worse now it seems, but I don't see from where, and I don't care at the moment--it could be that it's running off from various places. I did find I left the crush washer off the diff fill plug so it's possible that is one of the leaks. Will have to jack up and replace that.
 
Originally Posted by The Critic
That pan should seal fine with RTV. Bolts need to be torqued immediately with Toyota RTV, not sure about the Permatex product. But I have never heard of anyone letting RTV "skin" before tightening the bolts.
Now you have. I spoke with the Permatex rep. When you start to tighten after the waiting period, and see anything ooze, you stop and wait some more. Ultra grey uses humidity in the air to set. The lower the humidity the longer you have to wait. Here's a screen shot of the instructions.

E39B844E-FE6C-4CC3-B737-D1D179F6C6DC.png
 

supton

Thread starter
Messages
17,136
Location
NH
Originally Posted by bbhero
Is this on your Camry ??
Yes, the '99. The '11 doesn't have an ATF pan to mess with. Apparently a far superior design--one less thing for me to screw up. smile Just checked on it, and something is still leaking, but it might just be the drain plug--I reused the crush washer as I couldn't find my stash (think I found some). I think I see how RTV could work but I may well prefer a gasket next time. At least for an ATF pan where it needs to come off periodically. My truck could use an AFT change and I think... I'm not going to mess with that pan!
 
Messages
517
Location
Canada
Originally Posted by Lubener
This is the reason I will never use RTV on an oil pan.....Leaks and PITA when removing the pan for maintenance next time.
I would think RTV is superior for sealing, but only if properly applied. Gaskets have the benefit of being easier to clean off for parts that eventually will have to come off (eg. ATF pan). But I would argue that an oil pan should never have to come off so using RTV is acceptable there.
 
Top