Plastic fuel tank on Stihl 038 Magnum leaking.........

[rheingremlin]

hi, I have just discovered that the fuel tank on my Stihl 038 Magnum is leaking. There is a web of micro cracks on the back of the tank ( under the back handle) and fuel is seeping out of these cracks ( not the joint).
( Very disappointed in Mr Stihl, I would have thought they would only use the best quality plastic)

Should I:

try and fibreglass patch the plastic tank? ( will that even stick?)
Buy a new after market ( non genuine) tank assembly? ( wouldn't they even be a lower grade plastic?)
or hunt around for a good used genuine Stihl tank assembly?
I am not even game to ring the local Stihl dealer for a price on a genuine new tank. Here in Australia we pay on average nearly twice the price for parts and saws compared to the listings I have seen on US sites.
View attachment 243758View attachment 243759
Any advice very much appreciated.

 

[sodbreaker]

hi, I have just discovered that the fuel tank on my Stihl 038 Magnum is leaking. There is a web of micro cracks on the back of the tank ( under the back handle) and fuel is seeping out of these cracks ( not the joint).
( Very disappointed in Mr Stihl, I would have thought they would only use the best quality plastic)

Should I:

try and fibreglass patch the plastic tank? ( will that even stick?)
Buy a new after market ( non genuine) tank assembly? ( wouldn't they even be a lower grade plastic?)
or hunt around for a good used genuine Stihl tank assembly?
I am not even game to ring the local Stihl dealer for a price on a genuine new tank. Here in Australia we pay on average nearly twice the price for parts and saws compared to the listings I have seen on US sites.
View attachment 243758View attachment 243759
Any advice very much appreciated.

Personaly I'd try JB weld on it. If it don't work you ain't out nothing because you needed a new tank anyway.

Last fall I was out in the woods with my S10 and punched a hole in the gas tank with a tree stump. I put JB weld and layers of duct tape over the hole. Just like you would tape sheet rock. Held the gas and never had a problem with it leaking.

If the JB weld don't work I'd look for a aftermarket replacement tank. Unless your lucky enough to find a new/old stock tank sitting in a dealer's warehouse some where that hasn't gone to crap from sitting from X number of years.

Sod breaker

 

[Anthony_Va.]

As far as chainsaw plastic goes, Stihl is the best in the business. Any plastic can and will crack though.

You have any pictures of the damage? From the way you describe, I would just get on ebay and find a good used tank assembly.

 

[SkippyKtm]

hi, I have just discovered that the fuel tank on my Stihl 038 Magnum is leaking. There is a web of micro cracks on the back of the tank ( under the back handle) and fuel is seeping out of these cracks ( not the joint).
( Very disappointed in Mr Stihl, I would have thought they would only use the best quality plastic)

Should I:

try and fibreglass patch the plastic tank? ( will that even stick?)
Buy a new after market ( non genuine) tank assembly? ( wouldn't they even be a lower grade plastic?)
or hunt around for a good used genuine Stihl tank assembly?
I am not even game to ring the local Stihl dealer for a price on a genuine new tank. Here in Australia we pay on average nearly twice the price for parts and saws compared to the listings I have seen on US sites.
View attachment 243758View attachment 243759
Any advice very much appreciated.

Don't use JB weld or fiberglass as they will both eventually fail. The fuel permeates the plastic of the fuel tank and will cause the eventual failure of the bond.
The only way to repair it is to either replace the tank or weld the plastic. I use a 1500 watt heat gun to preheat the area and a low wattage soldering iron (33watt, with a rheostat to adjust the heat) to weld the two surfaces back together. You don't have to use the rheostat but it will prevent scorching of the plastic, its especially important with white plastic as the scorching makes an ugly mess . Its important to frequently clean the soldering iron tip to remove excess/scorched plastic as you go (I use a wire wheel to clean the tip in my bench grinder). I modified the soldering iron tip to have a flat area as well as a point to reach deep into the cracks. If you need plastic for filler material (with this particular tank you shouldn't, because you didn't lose any material) you can use an old tank of the same type for welding material so you know you have compatible plastic. If you have an old tank, practice on that first. Pressure test the tank with 10-15 psi air to ensure the weld is good before putting fuel back in it.

 

[rheingremlin]

Excellent advice.....

thanks for the advice. That sounds like the only proper way to repair the tank.
Believe it or not, Stihl want $ 670 for the tank assembly. But on the net I can get a brand new aftermarket assembly for under $ 100 delivered. Looks identical,but how good is that plastic going to be.
Or should I look for a good used Stihl assembly?

Beats me why the plastic has failed dramatically when the whole saw is in excellent condition and it certainly was not mechanical stress that cause the tank to fail. Maybe a drunken Stihl employee peed into the plastic injection machine on a Monday after a long weekend?View attachment 243774View attachment 243775View attachment 243776

 

[SkippyKtm]

thanks for the advice. That sounds like the only proper way to repair the tank.
Believe it or not, Stihl want $ 670 for the tank assembly. But on the net I can get a brand new aftermarket assembly for under $ 100 delivered. Looks identical,but how good is that plastic going to be.
Or should I look for a good used Stihl assembly?

Beats me why the plastic has failed dramatically when the whole saw is in excellent condition and it certainly was not mechanical stress that cause the tank to fail. Maybe a drunken Stihl employee peed into the plastic injection machine on a Monday after a long weekend?View attachment 243774View attachment 243775View attachment 243776

Maybe a drunken Stihl employee peed into the plastic injection machine on a Monday after a long weekend?

Lol, I don't want to start any wars here, but that's Stihl's Achilles heal, their tanks are prone to failure especially on well used MS440/460 saws where the saw itself will outlast the tank.


The only experience with AM (after market) tanks was a 372 tank I bought awhile back and it was very good, It was darn near the same as original. The only thing I notice with the AM 038 tank is the gas caps will be the newer style and won't match yours (if that matters to you).

That is a sweet saw!