# What is the 'Best' radiator leak-stop? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [July 23, 2021, 6:15pm UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155 "2021-07-23T18:15:45Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [July 23, 2021, 6:15pm UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/1 "2021-07-23T18:15:45Z")
Yes, I know. Take it out and get it fixed. But that’s not the question today… Lots of different brands out there, but which works the best? The aluminum powder ones? The gloopy pelletized ones? Are there any car people left on the board? Gimme your opinions, please! Jeep XJ, not sure if the rad is aluminum or not. I think it is. Started leaking yesterday from the top right corner, near the inlet. Wanna do the lazy route first, at least until fall when I can work on stuff without bursting into flame. ---
**Author:** ![swampspruce](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/swampspruce/32/261_2.png) [@swampspruce](https://boards.straightdope.com/u/swampspruce)\ **Post date:** [July 23, 2021, 6:46pm UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/2 "2021-07-23T18:46:34Z")
Had an XJ, I used Bar’s on mine and it worked well. I also used it in my Legacy to help with the dreaded head gasket issue on the Ej255. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [July 23, 2021, 9:24pm UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/3 "2021-07-23T21:24:13Z")
The obvious question that arises is if you do use the radiator leak-stop will it be more difficult to finally fix when you do take it to the repair shop? The radiator is going to be filled with this stuff; won’t it be difficult to remove? ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [July 23, 2021, 9:32pm UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/4 "2021-07-23T21:32:36Z")
I used the silver powder like stuff with mixed results over the years, meaning sometimes it worked. I guess the greatest danger of using any stop leak is clogging things, and I’ve heard people clog their heater core with stop leaks, which instead of a quick repair job turned into a 10 hour ordeal to replace the clogged heater core, and still have the leak. ---
**Author:** ![erysichthon](https://avatars.discourse-cdn.com/v4/letter/e/d07c76/32.png) [@erysichthon](https://boards.straightdope.com/u/erysichthon)\ **Post date:** [July 23, 2021, 9:45pm UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/5 "2021-07-23T21:45:01Z")
> [@kanicbird](#): > > I used the silver powder like stuff with mixed results over the years, meaning sometimes it worked. Back when I was in college and drove a beater and had no extra money for repairs, that “silver powder” stuff (it appeared to be aluminum shavings) was the only thing that worked for me. I remember that it was packaged in a clear plastic cylinder. I’d be reluctant to use it now. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [July 23, 2021, 9:47pm UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/6 "2021-07-23T21:47:59Z")
🤣 > [@PastTense](#): > > take it to the repair shop I assure you, this will never happen. It will either work, or just give it a good flush. If I can’t fix it myself, I’ll grab a used one from the junkyard on half-price day and stick it in. Fairly low-priority vehicle. Only use it go off-roading with the dogs. But a clogged heater would suck. It gets cold out here. ---
**Author:** ![Dallas\_Jones](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dallas_jones/32/3277_2.png) [@Dallas\_Jones](https://boards.straightdope.com/u/Dallas_Jones)\ **Post date:** [July 23, 2021, 11:56pm UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/7 "2021-07-23T23:56:15Z")
Aaah, a Jeep. Spend as much money on it as you can afford. It won’t be enough. You may have to dip into the savings account that you keep for a new transmission. You _have_ been putting a little money aside for a new transmission haven’t you? ---
**Author:** ![Dag\_Otto](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@Dag\_Otto](https://boards.straightdope.com/u/Dag_Otto)\ **Post date:** [July 24, 2021, 12:46am UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/8 "2021-07-24T00:46:56Z")
> [@Gatopescado](#): > > I assure you, this will never happen Preach it. No reason not to just top off the coolant every now and then until you get around to the repair. Several years ago I took the same approach to a leaky power steering pump hose. Just added a bit of fluid every time every time I drove the truck, and that worked quite well until I fix it this fall. ---
**Author:** ![swampspruce](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/swampspruce/32/261_2.png) [@swampspruce](https://boards.straightdope.com/u/swampspruce)\ **Post date:** [July 24, 2021, 2:40am UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/9 "2021-07-24T02:40:15Z")
The drivetrain on the XJ 4.0 was the best thing about it other than the Dana 35 axles. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [July 24, 2021, 3:09am UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/10 "2021-07-24T03:09:35Z")
Two eggs work sometimes. Even Click and Clack, the Car Talk guys said it was a good emergency fix to try, especially if you didn’t have any other options. RAY: The egg works – when it works – exactly as you describe. You do have to crack it open, Leslie. You pour the contents into the radiator. Then **the egg cooks and partially solidifies** , and is pushed toward the leak, where it might – if you’re lucky – lodge in a small hole and plug it up.Jan 1, 2008 ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [July 24, 2021, 3:15am UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/11 "2021-07-24T03:15:09Z")
Put some Bar’s Leak ‘Heavy Duty’ pellet stuff in. Seemed to work as expected, for a while. We’ll keep on it tomorrow… > [@Dallas\_Jones](#): > > You _have_ been putting a little money aside for a new transmission haven’t you? I bought this rig for $560 and a 6" Subway sandwich. It was Totally stock and all tore up from the floor up. But the engine was solid and ran well. But I can do shit on the cheap. Fixed the front 4x4 yolk with a few washers and a bolt. Spent a few bucks for a decent headliner from the junkyard. Rewired or abandoned a whole bunch of stuff. All the cool stuff on the outside was stuff I had laying around or fabed up. Most money I put into it was for a (new, but bought out of somebody’s garage) 2" lift kit with shocks, spacers and leaf springs. People come up to me when I (rarely) drive it to the gas station and rave about how cool it is and guess I got THOUSANDS into it. Nah. **A** thousand (net, I sold the street tires and original wheels). Yep. A thousand bucks. And some shit I had laying around. I’ve been driving it almost every day for the last several years. I know. I’m as shocked as you are. Pictures and video here: [bob smith | Flickr](https://www.flickr.com/photos/155285423@N02/with/40352136210/) ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [July 24, 2021, 3:28am UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/12 "2021-07-24T03:28:56Z")
Oh, I begged the camo paint from various sources, so that was free. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [July 25, 2021, 3:23am UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/13 "2021-07-25T03:23:30Z")
Topped it off, fired it up, let it run forever, ran the heater full-blast. Everything works great, not a single drop leaked. Best thing that has happened to me in months. Pretty sad, huh? ---
**Author:** ![swampspruce](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/swampspruce/32/261_2.png) [@swampspruce](https://boards.straightdope.com/u/swampspruce)\ **Post date:** [July 25, 2021, 11:43pm UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/14 "2021-07-25T23:43:53Z")
Just curious if you have the auto or the manual in the Cherokee @Gatopescado. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [July 26, 2021, 1:10am UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/15 "2021-07-26T01:10:36Z")
Auto (and so hammered, I have P on a flat surface, R, N, D and 2nd. No going into low for love or money). And I saw a few drips today. That Bar’s is Back-sliden’! I always find a place it won’t roll and put it into N to park. That shift out of Park is getting harder and harder. Luckily, it’s pretty easy, even in extreme terrain to find a place to do that. Aim one way, crank the Armstrong Power Steering to the other. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [July 26, 2021, 1:14am UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/16 "2021-07-26T01:14:37Z")
> [@swampspruce](#): > > Just curious so you will see this… ---
**Author:** ![swampspruce](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/swampspruce/32/261_2.png) [@swampspruce](https://boards.straightdope.com/u/swampspruce)\ **Post date:** [July 26, 2021, 3:18am UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/17 "2021-07-26T03:18:04Z")
Yeah, the AX-5 was really finicky about regular filter changes. As long as you did those and fluid changes they were pretty good. FWIW, when it finally dies you can swap in an AX-15… > **[xj trans swap auto to manual??](https://www.pirate4x4.com/threads/xj-trans-swap-auto-to-manual.300923/)** > > Can anyone tell me if you can swap a auto trans, and go to a manual. The year I have is a 1988 auto 4x4. Will a 1990 manual 2wd work? Both are 4 door, but not sure if they will work ??Thanks for any info ---
**Author:** ![Spiderman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spiderman/32/230_2.png) [@Spiderman](https://boards.straightdope.com/u/Spiderman)\ **Post date:** [July 26, 2021, 6:28pm UTC](https://boards.straightdope.com/t/what-is-the-best-radiator-leak-stop/947155/18 "2021-07-26T18:28:50Z")
Pepper. A can of black pepper, found at any grocery store & many corner bodegas will work well as an emergency leak stop to plug a hole; the pepper works much like your blood platelets do & coagulates at the hole. One definition of ‘best’ is what you can get to get you home/to your destination with the shortest delay.