Why you should never use RTV silicone on gaskets
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- Опубліковано 9 лют 2025
- Unless you are dealing with a metal type gasket you should be careful when using RTV silicone on gasket material for the simple reason that it creates a very slippery surface and can cause the gasket to squish out and possibly tear. Just say no to excessive RTV silicone usage and help save a mechanic.
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When used correctly...the hi temp sealer works great...I've used it for years and no problems.
Same here.
What brand do you recommend?
@@fightintheshade Permatex.
Right. I always use the right stuff on every gasket. Works great. Never get leaks.
I've gone without it for years with no problems so why make a mess for next time you have to remove it and risk clogging oil flow?
There are 3 people you can’t trust in this planet. Your lawyer, your wife and your mechanic !
If you have a wife then what about your gardner, mailman and the milk man?
@@subjektivegaming thousands of car every single month? that comes to 34 cars a day if you are not taking a single day off. seems like you are a liar or just like to exagerate or have no idea what you are talking about.
From the looks of that red rtv (brittle and no adhesion) , the vehicle was put back into service before the rtv was fully cured. The high temp red and ultra copper rtvs work great, for pretty much everything as long as they are fully cured (and then some!!) before being put back into service.
The quality of sealants, paints, glues, et cetera, has improved dramatically in the last five years. When surfaces are prepped properly, there are many situations where a good sealant alone, is the best choice. You have to pick your spots.
Very interesting, Dirko HT Red is a high temp silicone used for all manner of gasket making (has been used by stihl in their engines for decades).
My wife tells me to not make videos , Tim you have the best wife ever . Keep filming bud your the best automotive channel in Fairbanks Alaska 👍👍🇱🇷
Haha. Will do brother.
@@ThecardoctorTV Well, close enough. (ha ha)
@@ThecardoctorTV even tho you film from Alaska I been watching your vids to fix cars in the south no rust here. and south main auto is nothing but rust 3 different places thanks tim
Sorry for nitpick, but i live in Fairbanks - he’s in Anchorage.
@@matthewbrice737 He knows and is just trying to pump my nads. How is spring so far up there? I still have snow in my yard here.
Ok, aren't you showing an EXTREME example here? That person obv put like a one inch bead - way too much - What would have been the results if he used a 2 millimeter bead instead?
As I understand it, rtv is supposed to be used INSTEAD of a gasket, not with a gasket.
Yes
For this reason.
On subaru boxers you are actually suppose to supplement the valve cover gasket with rtv in several areas before reinstall.
Gaskets have a job and they do it well on a perfect mating surface without the unwanted assistance of any silicone based sealants. Few mating surfaces are perfect though so a very light smear of non setting aviation gasket sealer is all thats needed on all cork/rubber and silicone gaskets.
Amen
This just gives RTV a bad name.
Whoever did that gasket used way too much RTV, probably over tightened the bolts (deforming the pan) and likely applied the RTV to a oil soaked gasket.
I always use RTV; never had problems. However, I apply a VERY small skin coat to the gasket surface and allow it dry for 15 - 20 minutes before I attach the gasket. It helps keep the gasket in place when I attach the pan. Also, I make sure the pan is torqued down in a star pattern in at least three iterations.
RTV works great as long as you follow some basic rules. If applying to a gasket, use a small skin coat. If using as a gasket, apply a continuous bead. No matter what, you always need the RTV to dry for 15 - 20 minutes so it becomes firm yet tacky.
*skim coat
Q: What’s the best way to skim it? What side of the gasket should it be applied to? The engine side or the cover side. Thanks
@@ryanflaherty3153 Ryan, "skim"-coat is when you properly apply "skim-milk" to BOTH surfaces of the part(s) to be assembled, before applying the gasket-sealer itself.
Replaced the oil pan gasket on my minivan.
I did not use form a gasket. I did use a silicon paste. For automatic pans lots of shops use the black gasket maker but I always use a gasket.
Happy Motoring.
I'm glad to hear you say that. In the next couple of weeks I'm going at a leaking axle gasket despite good practice with no silicone, just a cork gasket. The mating surface isn't quite right, the cast iron is broken right beside the sealing edge. So I'm going to try to build up the broken cast iron steel to a flat surface, and have been tempted to consider a little RTV at that spot because of the unusual situation. Maybe I'm better off going with RTV alone.... It seems the slippery nature of RTV can interfere with the sealing property of gasket material.
Hello Dave. Looking forward to that video. I've had terrible luck with differential cover gaskets. Its to the point where I only use the gear oil rated Permatex and no gasket. I also let it set up for 48 hours before putting any fluid in if at all possible. Did this when I replaced the seals in the front D44 of my 98 Ram same as you did. No leaks!
Agree with El Cheapo, loose the gasket and put a nice bead of ultra gray on it and you’ll be golden. I’ll watch for your vid as well. Blessings gents.
The person that did the job probably used the old gasket and siliconed both sides and charged the person for a new gasket. Know a few shady mechanics Tim. Keep
Them coming.
oh I remember being young and foolish. That was many mistakes ago. Thanks for the trip down memory lane Tim
yup, used a cork ebay gasket on an oil pan once, didn't have a torque wrench rated for inch-lbs, had to go back later with the recommended rtv
Sounds like my father in law every time something happened it was someone vandalized it 😷😂
My father in law was the other guy. Putting silicone caulk on everything! Cringe worthy.
The vandals took the handles
Looks like somebody didn't have a new pan gasket so they used the silicon on a oil soaked gasket.
🤣🤣🤣🤣🤣
IMO diy gone wrong
He would have been better off completely removing the old gasket and applying a continuous bead of RTV and letting it set up for 15 - 20 minutes before torquing it down.
@@lizardking8388 Just a guess, but, the bolts were loose, so he probably put a big bead of silicone on the oily gasket, put it on finger tight, and then forgot to tighten after 20 minutes. The previous mechanic is lucky he's not replacing a motor TBH.
atleast they should of used black 1 minute gasket maker
This is standard practice on the Toyota 4AGE. It comes off easily with the handheld drill and a wire wheel attachment. The best way to do this is to put a 3 mm line on the inside of the screw holes on the block, then you set The oil pan on top and push it a little bit, then tighten it down after a couple minutes. They make an oil pan tool for this really easy to use.
On something very large like an intake manifold, I will not use RTV. I started buying a lot of gasket paper so I can make my own gaskets. Generally, I would prefer to wait for a gasket for max of 30 days instead of using RTV.
I used RTV on the thermostat housing because it is nearly permanent and does not require removal fo service. It worked great. Bu I don't want to use this on the throttle body even if the throttle body gas low spots or holes on it. I wait patiently for the gasket. There are many things to do on the engine bay.
Good day from Ont. It was good that you showed this. It is certain that the person who done this did not know, if mechanic he could keep on doing it. Thanks
I’m sure they are still doing this thinking it’s a good thing. Maybe they will watch the video and learn something.
I think what has happened here is the original gasket maybe started leaking and they haven't had ramps to lower the sub frame so just released the bolts enough to prize the sump open to squeeze rtv in and used far to much. Dealers cutting corners to save money 😩
I like your restraint. So carefully not ranting about knuckleheads. 👍
Wow, That was a mess. The bad guy in this deal. Was the guy who put all that silicone on the oil pan. Awesome video thanks for sharing. Stay well and safe.
There should be laws against it for sure.
The customer fortunately made the correct decision, they brought it to you. Now the job will be done the right way. Semper Fi, USMC.
I appreciate the vote of confidence but sadly after driving a short distance the customer returned complaining of vibration on acceleration. I had replaced one of the CV driveshafts while it was here and the part was defective. I felt like an idiot and should have test drove it better (not just 50')
@@ThecardoctorTV wasn't a Dorman shaft was it?😉
All of us have made that boo-boo, where after the fact, we stop and ponder about our intelligence,LOL. Guarantee that overlook did not harm your reputation!
Thanks to your wife. We all need all the videos you can make. Thanks a.
She’s the best!
The EXACT same thing happened to me ...you can't use silicone with a gasket.....the silicone sticks better to the gasket than the metal and when it dries the "siliconized " gasket is so slippery it breaks in thinner places like around the pan bolts and splits open. If you attempt to snug the pan down, even to a low manufactures torque of around 8 ft pounds, the gasket squirms and breaks even more and the leak increases. Who knew??
Correct, same thing happened with me when I put RTV on my gasket to the trans pan. I only put it on one side and that was the only side leaking
The squirming on a oil pan gasket has happened to me on a brand new gasket why is that? i used no silicone and on even low torque it looked to squish around to much just like you said
I used gasket sealant for a rubber gasket on a machined surfaced for a transmission pan. Never do it. Had a leak and thankfully catched it in the shop. Use rtv only if your pan previously came with only RTV.
Hope you and family are safe and healthy during these wacky times! Nice video also!
Thanks. We are doing good. You do the same.
That you for this video ! Great information on how not to use RTV with cork.
Customer said he 'tightened' the bolts. Customer probably did the whole thing. So, customer was right; VANDALIZED!
B YENZER, yes, this is what I believe as well - customer was a BIG bosomhead for NOT researching the task at hand, + properly reading the instructons!
An old mechanic showed me to put a thin film of Vaseline on cork gaskets to keep them in place, he told me to keep a small jar in my toolbox because you never know when a guy might get LUCKY...HAHA
I would never go camping with that guy if I were you. Haha
Cork gaskets were a terrible idea. Glad they stopped using those a long time ago
No reason to use that much RTV!!! I never use that stuff other than to tack the gasket to the part. It does come in handy when you run into a situation of some bent flanges. But you can usually straighten that stuff out with a hammer. Good video on what not to do!!
It was vandalised 😅 by the shop
For some reason it reminds me of six guy's I saw replacing a cracked driveway in Los Angeles, 60 feet long, they didn't use a single piece of rebar, or grate, not a single compression joint. Just one long smooth surface lol. Six months later it was, pushed up, buckled, three inch wide cracks everywhere. I had warned them, but they just blew me off. I can't imagine what the cement truck driver was thinking as they spread it around. 😒
I hear you buddy! I see this stuff all the time and I am in the auto body industry. Great call on the alignment after loosening the sub frame. Most shops won't include on their estimate of repairs or even tell the customer of the potential of needing the alignment afterwards. Now you just need to find a good alignment tech who is committed to quality. Another freebie but you won over a customer. From the great state of Montana, Rick
Thank you! I do all my own alignments so that works out well for me and my customers.
Some vehicles don't use gaskets for the oil pans. Case in point, the Chevy Cruze. Factory uses silicone and not a gasket for the oil pan seal. The more you know.
Toyota 4ag is the same way. Alot of older hondas use just rtv on their oil main rear main to block and timing chain covers.
all those cork gaskets leak after a while .. i think people try to use rtv to stop the leaks . the rubber with metal gaskets work great or felpro or right stuff or anaerobic gasket maker with no gasket ..
had a chrysler come into my shop like this too, no idea why they used high temp orange.
That's the worst stuff to use and usually ends up splitting the gasket when the pan is over-torqued trying to stop the leak caused by the RTV...not to mention the cleanup sucks. I use Permatex 82180 Ultra Black Maximum Oil Resistance RTV Silicone Gasket Maker for the seams.
Good stuff. I use the ultra gray in a lot of applications but once it dries it’s like cement. Haha.
@@ThecardoctorTV Yep I use it also
I paid someone to reseal an oil pan on my 99 corolla LE. He used the black oil resistance RTV. is this okay?????
@@ThecardoctorTV love the Grey stuff
Old cork gaskets thing of the past aluminium sumps now use hi temp silicone preparation is the key for a good seal and keeping oil in its home 😁
Well its so obvious that the previous person who was there just silicone the old gasket and reused it... maybe he didn't want to wait on getting a new gasket or just cheap out... and yes silicone RTV like "Dirko black - my favorite" can be used on oil pans but not with a gasket like that. Actually silicone RTV does a better job that any hard gasket WHEN the bolts are properly torqued to spec.
....RTV will hold 2 stoke crankcases.
The old carbureted jet ski engines were 2 piece & siliconed crank blocks, there was no gaskets. Silicone RTVs different with completely dry surfaces.
so....if you did!!!!!!!!!! use rtv, that can work....it must cure before before filling with oil or running the car....IF CURED it can work
Some people can do a lot of damage with two hands
I thought you use silicone gasket when there isn't a gasket anymore/available. But here there is still a gasket, but also applied a silicone gasket maker(and too much of it).
I’ve never used RTV on my oil pan. Plus I only use Fel-Pro gaskets on all my cars.
Why didn’t u show the gasket u are putting on? Cork, paper, rubber?
If u put it on gasket it's just lightly and mostly to hold it down. When used rtv the right way it'll last
thought you were only supposed to use one (RTV) or the other (regular gasket) not both. does the RTV also fail when it's used by itself? looks terrible.
No, its perfectly fine when you use it by itself
Any rubberized or petroleum material gasket should not be mixed with RTV as the RTV will break the gasket down. It’s on all of felpro’s instructions.
A good mechanic would not have replaced the pan like that.
Thats crazy they thought it was vandalized
Surfaces have to be super clean!! All material removed and wiped with thinner. That is what takes the majority of the time when you use silicone. The next guy has to clean it up!! Montana Rick
Carb cleaner as good as thinner?
Can you repair an oil pan gasket with permatex? I have a felpro rubber gasket that has been cut. Can I still use the gasket and seal the cut together and assemble?
Not recommended. Remove the gasket and use just RTV if possible.
I know race car drivers that use reviews silicone on there engines. But you have to apply it correctly.
That’s horrible, South Main auto had a car come in that the previous shop used black electrical tape to fix a vacuum line. Lol
oh wow, you mean the car I worked on drove all the way from here in Alaska to Eric O's shop in NY to fix my crappy vacuum hose repair??? hahaha
I've used a little bit of this stuff on slip-on motorcycle exhausts and it holds up pretty fine but this just seems really dumb, like that kind of RTV isn't made for use like that. I thought the whole point of using gasket maker was because you didn't already have a solid one lol.
Those control arm bushings are MINT!😯
I tried too tell ‘em don’t do silicone but they weren’t having or wanted the mess mess odds what they got put a modest layer on the gasket both sides we’ll see how long she lasts
I used permatex the right stuff 1 minute gasket maker on 1 ton ford oil pan work good, you have to use the right stuff
I've done exactly the same thing on an 07 Accord due to rusty oil pan from road salt. Not RTV on gasket, replace oil pan. I am surprised professional shops use gasket with gasket makers. You are lucky that the RTV stuck to the gasket and oil pan, not the lower block.
It was on the block as well but was able to scrape it off pretty quick. What a mess!
@@ThecardoctorTV Even as a DIY'er, I know not to use RTV with the gaskets. Otherwise, what's the point of using a gasket.
Good to see you again. We've missed you for a while.
I’ve seen this a lot actually lol. The number one thing I hear if it was DIY is “the guy at the parts store said I needed it” and I tell the customer yeah their is a reason most of those guys aren’t actually in the shop fixing the stuff lol. Now some of them are great but some of them ehh not so much. I seen this one guy put it on his transmission pan with the gasket and it didn’t hardly seal at all it had a bigger leak than when he started he said lol.
If I’m going to combine a gasket with sealant it’s Permatex 2
@@chuckgladfelter yikes
Hi Tim! Was the lower control arm bushing vandalized too? 😂
Yea it's torn pretty good
Lmao! Those Vandals
No, it was just plain worn out. Haha
Unbelievable. A standard replacement gasket will work best as you stated.
What are you building with all that OSB and insulation? Don't forget to silicone caulk any gaps!
Interesting! That gasket was just a bit over smoodged! Vandals and a tube of goo!
The RTV Bandits must have been making the rounds.
They went to town with that silicone!
big time! haha
I've always used a thin layer of our TV on the gasket on both sides never had a problem
The problema seems is the person WHO din’t use the rtv properly
Indeed
Thank you. I like your videos, very informative.
4:51 that's what Ned Beatty said
wowzers... someone did a hack job with all of that RTV.
I see that all the time. Especially on valve cover gaskets. It makes a big unnecessary mess.
Use gaskets only. Or if it is siliconed only use silicone. Never us gaskets and silicone there is no point
Agreed. The Honda guys would only use silicone here by the way.
You made this video 2 years ago. But I prefer Permatex Ultra Black or Gray by itself. No gasket. Specially the cork gaskets. Toyota which is what I have does not even specify a gasket for the oil pan. You can get a gasket in gasket sets But not from Toyota.
If both surfaces had been cleaned thoroughly and evenly torqued could it have worked?
I doubt it.
08 Chevy 4l60 with the exhaust crossed over right in the way so the gasket and filter has to get put on after the pan is past the pipe Otherwise I never would have went for the suggestion I told em to return it once I saw the gasket material cork and paper yes rubbery silicone type gasket clean and dry on a true surface no exceptions maybe tacky red assembly stuff that’s it!
As long as there's a gasket. Sitting here staring at a Ford Escape 2.5 AWD where they don't have a gasket for it but rather "Ford" recommended gasket sealant.
Just have to make sure everythings good and clean.
Doing it mobile you have to use Brake Parts Cleaner.
I think there was a hack in there or either the owner tried to possibly repair it thinking it had a leak after it had been in? Either that or being if customer says it was vandalized maybe they're trying to get it covered by insurance on their car due to damage from vandalism is about all else I can think of.
Have a good one, back to the grind now.
I've used RTV on oil pans and never had this issue. Who ever did this was negligent or didn't know how to use it properly.
The issue was that the tech used RTV in conjunction with a gasket.
So the last shop didn't take the time to scrape off the old gasket or is that a new gasket? In any case way too much sealer was used.
It looks like the silicone was from the last repair. They were very liberal with their application.
@@ThecardoctorTV I see that same problem all the time. People using three times too much silicone gasket maker, don't follow instructions. Just finished installing an oil pan on a 2004 Corolla. OEM used only some type of silicon sealer, no gasket. Went back with Ultra Black, had very little press out around the edge, no leaks. :)
I ran something over is a chunk of a curb lol. and I got seepage around my transmission pan.and I've watched a couple videos already that say if you use r t v silicone on rubber paper it's going to leak.. I was told by an experienced mechanic to use Grease.. I've heard it cars getting keyed andr tires getting slashed but I never heard of a vandalized oil pan 🤣👍 that was funny thanks for the video appreciate it..I'm going to try the grease on the new pan and maybe I'll make a video and see what happens.
The only one that will dislike the video is the Lembrain that did that!
If I may ask .what are the torque specs? 16' lbs chevy s10 2004 my brother has one
8.7 ft lbs. for the oil pan bolts here tightened in stages. The manual recommends using only liquid gasket sealer (not paper gasket)
"Why you should never use RTV..." after watching the whole video, the only explanation as to why a person shouldn't use RTV on a pan gasket was "It's gross" That's it? It's gross? That's the reason? How about a reason other than "It's gross"
Yep. Its gross.
Good video tim
Can i use Permatex Ultra Black RTV with a black metal gasket? I'd hate to vandalize my own car. lol
That’s a great combo.
I will never use silicone in those parts, thanks.good video.
At least the customer didn't own a Trailblazer/Envoy/etc. with a 4.2 I6! The axle runs THROUGH the oil pan. Whole bunch more work to change one'a them beasties!
I try not to do those nightmare jobs. There’s a great 4X shop down the road I send them junkers to. I’m too old for that kind of work. Maybe I’m just lazy too.
ok, no doubt that wasn't done properly, but to say never use silicone RTV is non sense. There are many vehicles that use silicon (or some form of liquid applied sealant) right from the factory. I have made several oil pan gaskets this way and they hold up great, in fact they are sometimes a bit difficult to remove. Last time I pulled one, just for fun, I left the oil in, pulled all the bolts and still had no leaks.
Cleanliness is most important, like you would eat off it clean.
Most of the products I have used, instruct you to hand tighten all the bolts, let dry for an hour and then crank them done. This allows for compression of the gasket, thus making the seal. Hearing the details about the bolts being loose makes me think they never snugged up those bolts, and what you showed is about what I would expect to see if that did happen.
Never use RTV silicone ON GASKETS. Silicone ok. Gaskets OK. Both at same time. Not OK
@@ThecardoctorTV agreeed
thanks tim take us thru a alignment on your machine like how you are honest and don't swear on your channel bye the way is high tac ok to hold the gasket on your thoughts please
I use high tac. It’s great. Super weather strip adhesive is excellent as well. Blessings.
The Mechanic that put the silicone didn't prep the area at all....
Any tips on my CJ7 rear diff cover? I've tried rubber gaskets, cork gaskets, permatex ultra red and ultra black multiple times. I hear folks get so fed up they end up welding them shut. Any thoughts appreciated!
Assuming the two surfaces are not warped, gouged, burred and the cover actually fits proper and you are still leaking then I have a few suggestions. For me the only sealant issues I face are due to poor clearance or not enough room to work, thus scraping or knocking the gasket out of alignment or smearing sealant (example- sliding an oil pan back into a 4wd truck). This shouldnt be a problem with a rear end so I'd rule that out and move to the next most common issue I face which is over tightening the bolts. Make absolutely sure you are using a torque wrench and torque to spec, never over or else you risk pinching the gasket. Let's say you know all this and have dont it correctly, yet it still leaks. How far apart are the bolts/bolt holes? More than a few inches? If so you may be missing gussets or hold downs. Generally flat or "L" shaped brackets that stretch from one bolt hole to the next and help press the area between the bolts down (often times covers are thin stamped steel and will bow between large gaps in bolts). Let's say none of this applies to you....one last trick to apply, is after getting your surfaces super clean and dry using brake cleaner so there is absolutely ZERO oily residue carefully make a 1/4" bead of black rtv all the way around on the surface of the pumpkin. When I say bead I mean a pretty, circular, wormlike bead. DO NOT smear or spread it, and DO NOT install a gasket or your cover yet. Leave the gasket out this time completely. Grab a beer and wait 10-30min (based on heat/humidity/location) until your bead is starting to be semi solid. It should still be tacky but not squishy (you should be able to leave a fingerprint in it, without it squishing out). At this point carefully and evenly press/install your cover onto the bead and work all your bolts evenly just a little at a time so one side doesnt pull in before the other. If this doesnt work and none of the rest work then it is clearly operator error, maybe a little outside your realm of expertise. Sometimes knowing how to do something doesnt mean you are good enough to do it or have the right touch. Definately not cutting you down, just have no idea what I'm dealing with and the problem seems really strange or like a problem a mechanic wouldn't have. Hope this helps. I'm happy to follow up if you have questions or want more info
@@TheMuddman74 I disagree!! This time of year it may be 2 beers!! You pretty much covered things. Rick
@@rickfreeman9530 haha! You're probably right. I miscalculate every time I drink! Cheers
I use rtv no gasket but get the Grey rtv is the best
When someone tries to reuse an oily old gasket with goo anything can happen.
so, only use the dry cork gasket, no grease ever for oil pans?
You can use just rtv on oil pans. Dont put rtv on a gasket. Oil pans that have a grooved gasket you cant. Some manufacturers use just rtv on oil pans toyota 4ag is one off the top of my head. I know the 90s hondas use just rtv on the oil pump and rear main too block.
@@kylecalobtraceharper thanks!
What if you use silicone only? Loctite and permatex swears by eliminating gaskets entirely when it comes to stamped parts. or valve covers and oil pans. They even recommend it for the use of high temp aircraft engines. So I think everyone is just as confused as the other.
If they sold gaskets, they'd say the opposite. 🤣
Tim this doesn't beat the brake pad video!!! Both sides!!!
no, they have used silicone on an old gasket, thats is very obvious
Some vandal got under there and mucked with my oil pan gasket. That sounds like something a paranoid schizophrenic or bi-polar person might say. Has this guy been looked at by a doctor?
No shortcuts.. no cutting corners.
Do it right or don’t do it at all..
Did the "other" shop have 6 employees (thumbs down)? I've used gasket maker before on little areas like on the front and rear seals of an old small block Ford intake manifold but never on an oil pan.
I guess it is just one guy and twenty cases of RTV hehe