Holts Wondarweld 500ml



Fitted bundle deal

includes Accessories + Fitting

Item: 777615

Holts Wondarweld 500ml


(Unit price: £0 per 100ml)

How can I get it?

FREE Click & Collect

  • Description
  • Reviews
  • Delivery Options
  • Buying Options
  • Holts Wondarweld

    The Holts Wondarweld is a heavy duty engine block and cylinder repair which can be used at home to repair leaks quickly and cost-effectively. It's a permanent repair which is anti-corrosive to protect against future leaks. Always read the instructions before use, and never pour into oil.

    Click here to see instructions

    Holts Wondarweld Extra Info

    • Permanently seals cracked cylinder blocks, internal & external leaks in water jacket
    • Suitable for steel, iron and aluminium engines
    • Prevents the need for engine rebuild
    • DO NOT POUR IN ENGINE OIL - always read the instructions carefully before us
    • Engine block and cylinder repair
    • Suitable for all cars
    • 500ml
    *Please note the packaging may vary in store or via delivery

    Additional Information

    This product is for experienced amateurs and professional mechanics only.

    Never pour Wondarweld into oil as this can cause serious engine damage.

    Wondarweld is not compatible with antifreeze and coolant fluids.

    Users must be strongly advised to read through all precautions, usage and dosage instructions carefully prior to use.

  • Holts Wondarweld 500ml is rated 3.0 out of 5 by 10.
    Rated 5 out of 5 by from Fixed core plug leak It is still early days as my wife's little Ford Fiesta Developed a rather major core plug leak from behind the flywheel. I decide to give this a try as the alternative was to take to a garage and for the value of the car its too much. Followed the instructions to the letter including draining and flushing the cooling system. Added the jollop to the engine and topped up with water. Within a couple.of minutes the leak had stopped. I took the car for a short test drive and all seems to be good. I suppose time will tell and if I remember I'll update this review in a couple of months but for now it seems to have done the job.
    Date published: 2018-07-12
    Rated 1 out of 5 by from Dont work Done how instructions said and it made the leak worse
    Date published: 2017-02-06
    Rated 1 out of 5 by from Classic Cars The added viscosity to the coolant means the older water pumps in classic cars cant circulate the coolant, resulting in overheating so avoid.
    Date published: 2016-09-21
    Rated 2 out of 5 by from Too complicated Having to disconnect fuel lines and spark plugs put me off using this product, i returned it for a refund and got a new head gasket instead, probably a wise if more expensive decision. If it had been a just pore into the radiator product I would have given it a try, maybe useful for others.
    Date published: 2016-06-11
    Rated 4 out of 5 by from We'll See. Stopped an inaccessible core plug leak on a 1.3 Endura Fiesta in less than 30 seconds of running. Not just amazed that it worked so quickly but that after a 30 mile drive home it had genuinely stopped leaking. What on earth this stuff is made out of i don't know, but for now its done the job. Would love to pour into the oil filler cap and rag the engine just to see how disastrous the consequences would be =D
    Date published: 2016-06-08
    Rated 5 out of 5 by from Continues to work a treat Range Rover 4.6 Alloy Heads Cast Block head gasket is a well known problem was running rough and losing approx a 2 litres of water per 100 miles ! obviously did not have any anti freeze in because of leak tipped product straight into header tank and let run for 30 minutes, then took it for an easy run ! problem solved now does not lose any water or get emulsification in oil filler cap ! this is now three years on and Im just about to try some on my my dads T5 Volvo with leaky head gasket ! oh and my RR has done 178k miles 30 since I used holts.
    Date published: 2016-04-25
    Rated 5 out of 5 by from BEEN USING THIS FOR YEARS BEATS ALL THE REST, this has been about for years now I first started using it as,a fixer in the winter for cracked blocks on tractors lorries etc as a lot did not have core plugs and the block would freeze and crack i would drain the water dry the area if you can get to it with a blow torch, push some putty in the crack if large hold a rag over it fill with water get to engine temp then add worderweld, leave ticking over for a while take the rag off then drive about worked every time,, then thought would try on head gaskets, as in the trade have been for many years, had a car would not start had been over heated we had to tow it to start it i ran on the 2 outer cyl, alloy head on cast block, kept it running got some water in it added the wonderweld after about 5 mins picked up on all cylinders, no pressure lasted until the rot got to the car about 3 years later, and used it ever since,, now on modern cars with tin head gaskets ie rovers and others it will not work, i used it 6 months ago on a 160k skoda white smoke and misfire put it in and spot on the last week it started leaking water from waterpump now done 170k so just unscrewed header tank lid, water stopped leaking topped it up left top loose no leak since, will run till next mot then sendit to scrap,, and i have all ways used anti freeze with it no problems, put all ways make sure thermo stat open or removed before using wonderweld,,,
    Date published: 2015-04-12
    Rated 1 out of 5 by from Didn't work. Bought this a couple of weeks ago, followed every instruction to the letter, it worked for about 4 days, then the gasket started leaking again. Not much more to say than that.
    Date published: 2015-02-10
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    • clientName_halfords
  • UK Delivery

    £3.99 Delivery available on orders under £40 placed by 8pm*

    Your delivery date will be communicated at checkout. Delivery times are Monday to Saturday.


    UK Delivery

    Free Delivery available on orders over 40 placed by 8pm*

    Your delivery date will be communicated at checkout and on your confirmation email.

    Delivery times are Monday to Saturday.

    *Click here to learn more.


    UK Delivery

    FREE Click & Collect - you can reserve an item online and pick it up from a store of your choice

    Simply enter your Postcode on the product page to check availability, and select Click & Collect at checkout. What's more, you pay for your items on collection. Click here to learn more.

    Items in stock - collect from 1 hour
    If your item is in stock at your chosen store, you can collect it from one hour after ordering online. We'll hold your item in-store for seven days.

    Items not in stock - collect from 48 hours*
    If your item isn't in stock, we can order it to your chosen store and it will be ready for collection from 48 hours.
    Bike delivery will take four days, and an extra day if you'd like us to build it for you.

    Please note that items sent directly from the supplier need to be ordered by 3pm for collection two days later. All delivery times will be shown during checkout.


  • You can buy this product from one of our carefully selected Approved Partners. The full list of options available are below. Simply add your chosen option to your basket and proceed to checkout when you're ready.

    You can purchase products supplied by Halfords and selected other suppliers on halfords.com.

    Checkout is always via halfords.com and all payment will be taken via halfords.com. In checkout the products will be split into separate deliveries for each supplier.

    Showing 1 - X of our buying options
    Price Seller Info Purchase

Some of the parts we sell here at Halfords have been reconditioned. These will carry a Refundable Deposit or an extra surcharge amount. When you add one of these reconditioned items to your basket, we'll add this extra cost automatically.

Once you've sent us your old item we'll check it over, and then refund you the full surcharge as long as everything is ok.

Before you return your old unit please make sure it's in re-serviceable condition. So if you're returning caliper casings, you'll need to double check they aren't badly damaged or broken. If the part you've sent is found to be unserviceable, we reserve the right not to refund the surcharge.

Please note that if you're returning your old unit to our National Returns Centre then this will be at your own expense.

Holts Head Gasket & Exhaust Repairs

Holts Wondarweld 500ml

£12.99 Fix leaks in your engine block with Wondarweld - never pour into oil.