Clear Ethanol Proof Fuel Tank Sealer for Tanks up to 33 Litres

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Clear Ethanol Proof Fuel Tank Sealer for Tanks up to 33 Litres


The only truly Ethanol proof fuel tank sealer that has been available for over 30 years

The amount of Ethanol in fuel now is causing a problem in older Metal fuel tanks and a bigger problem in Fibreglass and Plastic fuel tanks making them porous, this problem will only get worst as the volume of Ethanol added increases in order to make Petrol more Environmentally Friendly.

Using our Fuel Tanks Sealer will create a solid seal within the fuel tank, and make it Ethanol proof permantley, If your Metal fuel tank has had a tank seal fitted previously, this would need to be removed before applying the new sealer, most Kreem and POR15 sealers will fail, sometimes very quickly, so we have developed a Products that will remove these products.

This product works on Vapour and Liquid, so 1 Litre is enough to clear the old sealants from the largest fuel tanks  

If you need a Fuel Tank Seal Remover then please CLICK HERE>>>, and this will take you straight to the product, were you can add to cart. You may also find that you fuel tank is rusty, and you will need to remove the rust first before applying the Tanks  Sealer, Again we have developed a product that is specifically for removing the rust in fuel tanks, Simply Mix 1 Litre with 9 Litres of water, and leave overnight, and this clean you fuel tank thoroughly and after a wash out is ready to seal Our "Rusty Metal" Rust remover, can then be placed in a bucked, the rust sieved out, and used again and again on other fuel tanks, and anything that you would like to De-Rust. If you need a Rust Remover please Click Here>>> and this will take you straight to the product were you can add to cart.

If you use a thinners to wash out the fuel tank, please only use Lacquer Thinners as most others contain chemicals that could react and cause the seal to weaken, some people use normal thinners and have no problem but without knowing what the thinners contains we can not guarantee this  If you need all 3 products, than it would be cheaper to buy our renovation kilt, which you can find here  by Clicking Here>>>

Fibreglass and Plastic Fuel Tanks

We advise against using our Tank Seal Remover in Plastic or Fibreglass Tanks as its to aggressive, the only way to remove the old seal is manually, once you have removed as much of the old seal as you can, it is best to wash out using Hot Water and a Dish Washer Tablet mixed, if there is any of the old sealer still in the fuel tank, as long as it is stable, it os OK to seal over the top

Painting Fuel Tanks after Sealing

If you are think of painting a Fibreglass or Plastic Fuel tank that has become porous, after you have applied sealer. please wait up to 4 weeks, after application, as there will still be Ethanol in the tank structure, and by painting you will trap the ethanol between the sealer and the paint and it will push back through, let it breathe out of the Fibreglass/Plastic, before applying the correct primmer  




Would you rather have someone do this for YOU? The following companies are using Caswell products for their tank lining service!

Motorcycle Restoration Company  (Saffron Walden, Essex)

Our team of five restorers have between them over 80 years experience working in the classic motorcycle restoration field.  They are supported by a comprehensive machine shop, and a wealth of historic technical data relating to the classic scene.  They are based in Saffron Waldron, Essex.

Contact them on Saffron Walden (01799) 542 323.

Hartlepool Radiator Company - Fuel Tanks 

This company based in the North East of England has a tanks division which has been doing fuel tank restoration on all types of vehicles for some time.  

They have used GTS1750 in-house and now offer a service to the motorcyclist/ car restorer in tank restoration.  Call Stan Lamb on (01429) 236300 and discuss your tank with him. Also look on the web page at

JBH Motorcycles (Andover)

Call John at JBH Motorcycles who runs a motorcycle company and a tank restoration service.  
John uses GTS1750 and can be contacted on 07507 827375

Anything Goes Racing (Waterlooville)

Jeep knows everything there is to know about using GTS1750, as the previous owner of Caswell Europe, he has promoted and used the product for many years.

He has worked on motorcycle and small car tanks aged from a 1909 SINGER to modern YAMAHA R1. If you need a tank resealed, Jeep can be contact on: 07778 265726 


Web Page:


Please note that our shipping prices are a higher than it would cost to send a normal parcel via the post, the reason for this is because any product that contains chemicals must be sent and packed as per the "hazardous goods" regulations, and be transported by a carrier that is licensed to be able to transport. we are unable to send by regular post as it is now a criminal offence to send undeclared hazardous goods, for postage rates please click on the tab above.


Sales to European Countries outside of the UK will be charged VAT, if you are VAT registered in a European country, please send us your VAT Number, Verification of VAT numbers must now be carried out manually via the EU Commission VIES Validation website, once we have your VAT number we can then get validation and can either credit back the VAT or issue an invoice free of VAT 

We are unable to verify your VAT at our checkout process, as the EU Website does not allow third party integrations from external websites 

For customers in Bosnia & Herzegovina, Gibraltar, Liechenstein, Norway and Switzerland, the invoice produced will be free of VAT, but there is a charge of £21.75 for import clearance 

please complete our contact page form, or email us on, alternatively you can call us on +44 1252 560515





19 Reviews
  • 5
    easy to use

    Posted by Unknown on 11th Aug 2016

    Cleaned all the fibreglass tank out as per the instructions and once dry mixed the two tins taking note of the pointers on temperature and then emptied into tank swilled round and hey presto job done all in all just follow the instructions included

  • 5
    Triumph Tiger T400 1995

    Posted by Jochen on 8th Aug 2016

    New tank buyed from Triumph in 2014 because the old 1995 tank does suspend inside.
    The carburetors was finished inside with plastic residues from the old tank, so i have to clean them.
    Sign of disintegration after a few weeks in the new tank !
    Again extensive cleaning of carburators after a few weeks
    the carbs where gridlocked with plastic residues.
    Cleaning the tank inside without success.
    So i have to clean the carbs for the third time.
    After fast supply of this Tank Sealer i am hopefully looking forward.
    Easy handling by good preparation and perfect temperature.
    In a few years we will knew if success is steady.

    Best regards, Jochen

  • 5
    Saved a Tiger

    Posted by Stephen North on 2nd Jun 2016

    Read various forums and Caswell Tank Sealer is highly recommended. Email sent to company to clarify details was promptly replied to. Kit fairly expensive. Attempted to use the kit on a warm day after watching various You-Tube demonstrations. Read the instructions and started. Think it was too cool on the day as the sealant remained fluid for longer than the directions said it would so there were problems trying to get it to set.
    I left the extra in to give extra protection over the captive nuts in the tank sides.
    Finished article back on the bike (had to drill and file the plastic to get the petrol tap in - but that is my fault for not emptying the extra material out) and is working fine so far.
    Would I recommend using this again - certainly (ask me in a couple of years if the seal is still working!). BUT PAY ATTENTION TO THE AMBIENT TEMPERATURE AND TEMPERATURE OF THE TANK. Think what saved me was the tank is Black!

  • 5
    Ducati tank lined

    Posted by Unknown on 19th Oct 2015

    Product arrived very quickly and with good instructions, easy to use and appears to have done a good job but time will tell.

  • 5
    Gas tank Sealer

    Posted by Marc sommer on 7th Sep 2015

    Comsonic 650 left my tank looking like new inside.To keep it that way I used Gas Tank Sealer.The results are simply amazing.The tank now has a healthy shine inside and continues to look as good, or even better than new.Simply amazing.

  • 5
    Z1300 tank revival

    Posted by Marc Sommer on 31st Aug 2015

    I had to see the results to believe it; my irrelpaceable,internally rusty, petrol ravaged fuel tank has been bought back from the dead- not only that it also looks better than new inside. Quite simply unbelievable.

  • 5
    Expensive but worth it.

    Posted by Wayne Tobin on 24th Jul 2015

    High cost but it saved my rare 1968 fastback fiberglass tank so well worth the cost

  • 5
    forget the others

    Posted by bob on 15th Jul 2015

    if you have an acerbis plastic motorcycle tank from the 90s and onwards it will eventually succumb to ethanol vapours and warp,swell blister,etc (mostly ducati,triumph and aprilia are affected)
    i have now used this product on 2 x aprilia and a triumph and its easy to use and the colours show the coverage inside and does a perfect job,i cannot recommend this product highly enough

  • 5
    simply the best i've used

    Posted by IAN MURRAY on 14th Jan 2015

    to coin a phrase does what it says on the tin

Question. My Fuel Tank has an existing seal from another product that has started to flake due to the high ethanol content in fuel today, will Caswell GTS1750 suffer the same problem Answer. Unlike other manufacturers that claim there product is ethanol resistant, ours is 100% guaranteed, we sell 1000s of Sealer Kits each year and have never suffered a failure from the ethanol problems. Question. Can I apply the Fuel Tanks Sealer over my old tank seal that is flaking. Answer. We would highly recommend that you remove the old seal first, we sell a Fuel Tank Seal Remover that will remove the old seal, it costs £16.68 a litre which should be sufficient for most size tanks, its simple to use, just pour in, and it will reduce the old seal back to a resin type material that can be poured out.