Stop Leak Additives - PeachParts Mercedes-Benz Forum

mbboy · #1 03-19-2009, 04:50 AM

I know that many people here frown on using additives to stop coolant leaks. But I have a slow coolant leak from a recently replaced head gasket or intake manifold gasket, and I don't have the time or ambition to start tearing the engine apart again. So I was thinking of seeing whether a leak stopper might do the trick.

After searching, some people swear by Bars Leaks, some by Wynn's, and others by some other brand. So I was wondering if anyone here has had any good or bad experiences with these.

The potential problem seems to be plugging the heater core and/or radiator. So I was thinking I could use a valve to close the heater core off. and since I have an extra radiator, I could put that in temporarily, and replace it after flushing the system.

I know it's not the ideal solution, but some people out there seem to have gotten really good, long term results plugging head gasket and other leaks with some of these products.

Advice on using these products would be appreciated

Dee8go · #2 03-19-2009, 08:54 AM

I've used Bars Leaks before but not on a Mercedes. It seemed to do the job as I recall. It was along time ago. I'm always afraid that whatever will stop up and bad hole, will just as easily stop up a hole that's supposed to be there.

TX76513 · #3 03-19-2009, 09:02 AM

Bars leak or any brand that contains Rhizex will work in a pinch.

winecountryone · #4 03-19-2009, 09:50 AM

The small tubes of powdered metal sealant have always worked well for me.
Make sure it isn't the glorified sawdust kind as it isn't nearly as good.
Fixed a heater core that was still holding when I sold the car several years later!

450sler · #5 03-19-2009, 11:24 AM

www.Rxauto.com makes a product called Thermagasket. I have no idea if it works or not but they have a video on their web site of a guy with a Jeep. They do a gas test on the radiator and it shows exhaust gas getting into the coolant. The Jeep smokes badly too out the exhaust...white smoke. The guy adds their priduct and in about 15 minutes the smoke stops and they test the radiatitor. No exhaust gas getting into the coolant. I have no allifilation with with this company and have NO IDEA as to if it works...but another source for you to consider if you are going to add "something". The stuff is expensive comparatively but does offer a money back guarantee.

Personally I don't believe in magic products but if the option is another tear down, what have you got to loose. If it fixes the problem until you can get the money/time to do the repair correctly...that's a good thing. Considering how small the passages are in a heater core and how hard they can be to replace...if I was going to use a sealer I'd probably bypass the heater core during whatever magic repair solution you choose to pour in and reconnect it after the solution is flushed. Good luck with whatever you try...MarkG

meltedpanda · #6 03-20-2009, 11:58 AM

I would not recommend for long term, in a pinch , with eventual repair perhaps, but even then have dealt with too many consequences of putting gunk in radiators
that said I have had success with additives to swell a steering box gasket

rustyguns · #7 03-20-2009, 01:30 PM

Quote:

Originally Posted by TX76513

Bars leak or any brand that contains Rhizex will work in a pinch.

I agree! bars stop leak contains the same additive GM puts in almost all of there new cars! GM dealer sells it as a pill. you can buy it at any GM parts store. you know what the active ingredient is? Ginger! amazing stuff been using it in cars since the 1930's

I have used it in over 50 cars! clogs leaking head gaskets and lubricates water pump and does not block radiator!

its fantastic!

PS........don't use that metal crap

mbboy · #8 03-21-2009, 04:20 AM

Thanks for all the advice. The Thermaseal looks particularly good, as it doesn't have particulates that can clog passages, and a search revealed that a lot of people have had really good results fixing blown head gaskets with it.

The search also turned up a lot of good results with K and W Block Sealer, which sells for a lot less than the Thermaseal. So I might try that first. However, I'm not sure the Block sealer will work if my leak is from the intake manifold gasket, as i'm not sure that the temperature there is high enough to catalyze the chemical reaction the product needs. OTOH, the Thermaseal people says it will seal intake manifold leaks too.

The only thing i'm still worried about is whether these products will damage the mechanism in the AC servo. I'm not really sure how that thing works, but it seems to have a lot of moving parts that could get sealed up along with the leak????

Any additional advice would be greatly appreciated.