Bio Degreaser &

Coolant System Flush

Forte Bio Degreaser & Cooling System Flush

Changing your
antifreeze?
Flush first.

Pouring fresh antifreeze into a contaminated cooling system wastes money and accelerates corrosion. Forte Bio Degreaser & Cooling System Flush removes the sludge, oil and deposits before your new antifreeze goes in.

Order — £20 → Why flush first?
★★★★★
£20 · Free UK delivery · Safe biodegradable formula · Safe for all cooling system materials
Forte Bio Degreaser & Cooling System Flush bottle — removes sludge and contamination from cooling systems before antifreeze change
Does your cooling system need flushing?
🟤
Brown, rusty or discoloured coolant
Brown coolant indicates corrosion is already occurring inside the cooling system. The old antifreeze has broken down and is no longer protecting the metal surfaces. Flush before adding fresh antifreeze.
Flush needed before antifreeze change
📅
Coolant not changed for over 2 years
Antifreeze degrades over time regardless of appearance. After 2 years the corrosion inhibitors are depleted and the coolant becomes acidic. Always flush before replacing with fresh antifreeze.
Flush needed before antifreeze change
🌡️
Overheating or temperature fluctuations
Sludge and scale deposits in the radiator, water jacket and coolant passages reduce the cooling system's ability to transfer heat. Flushing removes the blockages that cause overheating.
Flush needed before antifreeze change
Why it matters

Why Should I Flush Before Adding New Antifreeze?

You would not pour fresh engine oil into a sludge-filled engine without flushing it first. The same logic applies to your cooling system — fresh antifreeze cannot do its job in a contaminated system.

Antifreeze breaks down over time into organic acids and mineral deposits. These acidic compounds corrode aluminium components, attack rubber hoses and deposit scale throughout the radiator and water jacket. By the time coolant appears brown and rusty the damage is already progressing.

When fresh antifreeze is mixed with old contaminated coolant the contamination immediately begins attacking the fresh fluid. The corrosion inhibitors in the new antifreeze are consumed fighting the existing deposits rather than protecting the cooling system. The fresh antifreeze is compromised from the moment it goes in.

Forte Bio Degreaser & Cooling System Flush removes the old contamination completely — so fresh antifreeze goes into a genuinely clean system and provides full protection throughout its entire service life.

Never mix fresh antifreeze with old contaminants — showing why flushing before adding fresh antifreeze is essential. Old acidic coolant immediately compromises new antifreeze and continues corroding the cooling system.
Is your cooling system compromised? Showing the warning signs of a contaminated cooling system including brown coolant, sludge deposits, scale build-up in the radiator and corrosion of aluminium components.
What it does

What Does Forte Bio Degreaser & Cooling System Flush Do?

A safe, biodegradable formula that removes oil, grease, sludge and mineral deposits from every part of the cooling system — without damaging aluminium, rubber or plastic components.

Forte Bio Degreaser & Cooling System Flush circulates through the entire cooling system with the engine running, dissolving and suspending oil contamination, sludge deposits and mineral scale so they drain out with the old coolant. It reaches everywhere the coolant flows — radiator tubes, the water jacket around the cylinders, the heater matrix and all coolant passages.

  • ✓
    Removes oil, grease and sludge contamination Particularly important if there has been a previous head gasket issue or oil contamination of the coolant
  • ✓
    Removes mineral scale and radiator deposits Scale build-up in radiator tubes reduces heat transfer — flushing restores cooling efficiency
  • ✓
    Safe biodegradable formula Will not damage aluminium, rubber hoses, plastic tanks or any cooling system components
  • ✓
    Prepares the system for fresh antifreeze Fresh antifreeze in a clean system provides full corrosion protection and maximum heat transfer efficiency from day one
What gets cleaned

Which Parts of the Cooling System Does It Clean?

Every part of the cooling system the coolant flows through — radiator, water jacket, hoses, heater matrix, water pump and all coolant passages.

Scale deposits in radiator tubes are one of the most common causes of gradual overheating. The deposits build up over years of use, progressively narrowing the tubes and reducing the radiator's ability to transfer heat to the air flowing through it. Forte Bio Degreaser & Cooling System Flush dissolves this scale and allows it to drain with the old coolant.

The water jacket around the cylinders and combustion chamber is equally important — scale deposits here reduce heat transfer from the engine to the coolant, causing hot spots and contributing to overheating under load. Flushing keeps these passages clear for effective engine cooling.

For vehicles with a history of overheating or suspected head gasket issues, flushing before adding fresh antifreeze is especially important — oil contamination in the coolant must be removed before it attacks fresh antifreeze corrosion inhibitors.

Deep cleaning the arteries of your engine — showing how Forte Bio Degreaser & Cooling System Flush circulates through the entire cooling system removing scale deposits from radiator tubes, sludge from the water jacket and oil contamination from all coolant passages
TBIO wet belt engines

TBIO Engines — Where Cooling System Cleanliness Is Critical

TBIO wet belt engines use a timing belt that runs submerged in the engine oil. But correct coolant temperature management is equally important — and contaminated coolant can affect the thermostat and temperature management that the engine relies on.

Ford EcoBoost, VW Group TSI/TDI small capacity engines and PSA PureTech engines all use TBIO (Timing Belt In Oil) wet belt systems. The timing belt life in these engines depends on using the correct, clean oil — but coolant cleanliness is also important for correct engine temperature management.

The thermostat, water pump and coolant temperature sensor must all function correctly for the engine management system to maintain the precise temperature range these engines require. Scale deposits on sensors and restricted coolant flow from deposit build-up can affect temperature management and indirectly affect belt life.

Forte Bio Degreaser & Cooling System Flush is safe for all TBIO cooling system materials and is recommended before every coolant change on these engines.

TBIO engines where cleanliness is critical — showing why TBIO wet belt engines including Ford EcoBoost, VW Group TSI and TDI and PSA PureTech require especially clean cooling systems and why flushing before antifreeze change is particularly important
Instructions

4 Steps to a Restored Cooling System

1
Add Forte Bio Degreaser
Add to the existing cooling system via the expansion tank or radiator filler. Do not drain first — the product needs to mix with the existing coolant to work effectively.
2
Run to temperature
Start the engine and run to normal operating temperature with the heater set to hot. This circulates the product through all cooling system components including the heater matrix.
3
Drain and flush
Drain the cooling system and flush with clean water. If the drained coolant is heavily contaminated, refill with clean water and repeat steps 2-3 before adding fresh antifreeze.
4
Add fresh antifreeze
Refill with fresh antifreeze mixed to the correct concentration for your climate. If treating a minor leak at the same time, add Forte Radiator Stop Leak to the fresh antifreeze.
Best practice — 4 steps to a restored cooling system. Add Forte Bio Degreaser to existing coolant, run engine to operating temperature, drain and flush with clean water, refill with fresh antifreeze.
Common questions

Every question about
Forte Bio Degreaser & Cooling System Flush, answered.

Can I flush my coolant myself?
Yes — Forte Bio Degreaser & Cooling System Flush is designed for DIY use. Add it to the existing coolant, run the engine up to operating temperature, then drain and refill with fresh antifreeze. No special tools needed — it's the simplest way to clean years of scale and contamination out before new antifreeze goes in.
Are coolant flushes actually good for your car?
Done at the right time, yes. Antifreeze loses its corrosion inhibitors and turns acidic over time, and old contaminated coolant left in place causes scale, sludge and corrosion that block the radiator and wear the water pump. Flushing with Forte Bio Degreaser before fresh antifreeze removes that contamination so the new coolant protects properly. What you shouldn't do is keep topping up old, degraded coolant indefinitely.
There's oil in my coolant — can this clean it out?
Forte Bio Degreaser will clean oil, grease and sludge out of the cooling system — but only after the cause is fixed. Oil in the coolant usually means a failed oil cooler or head gasket, and that mechanical fault has to be repaired first or the contamination simply returns. Once the source is sorted, flushing with Forte Bio Degreaser removes the oily residue before you refill with clean coolant.
Can I use it if different antifreeze types have been mixed?
Yes — this is one of the most important times to use Forte Bio Degreaser & Cooling System Flush. Different antifreeze types use incompatible corrosion inhibitor chemistry. When mixed they can react and form a sludge that blocks the cooling system. Flushing thoroughly before adding a fresh unified antifreeze type is essential in this situation.
Is it safe for aluminium radiators and engine components?
Yes. Forte Bio Degreaser & Cooling System Flush is specifically formulated to be safe for all cooling system materials including aluminium radiators and engine blocks, rubber hoses, plastic expansion tanks and water pump seals. The biodegradable formula is gentle on materials while effective at removing contamination.
My car has been overheating — will this help?
If overheating is caused by scale deposits in the radiator or water jacket restricting coolant flow and heat transfer, Forte Bio Degreaser & Cooling System Flush can significantly improve it. If overheating is caused by a head gasket failure, a broken water pump, a stuck thermostat or a physically damaged radiator, those mechanical issues will need to be repaired. Flushing and fitting fresh antifreeze is a good first step before committing to more expensive diagnosis.
Should I use it before Forte Radiator Stop Leak?
Yes — always flush first. Forte Radiator Stop Leak works most effectively in a clean system. Contamination can interfere with the sealing chemistry and reduce its effectiveness. Flush with Forte Bio Degreaser first, add fresh antifreeze, then add Forte Radiator Stop Leak.
How often should I use it?
Use it every time you change your antifreeze — which should be every 2 years for standard antifreeze or every 5 years for long-life antifreeze. Never add fresh antifreeze to old contaminated coolant without flushing first.
My coolant looks fine — do I still need to flush?
Clear coolant can still be acidic and depleted of corrosion inhibitors. The colour change to brown happens as corrosion products accumulate — but the protective properties of antifreeze begin degrading long before the colour changes. If the coolant is more than 2 years old, flush and replace regardless of colour.

Clean first.
Then add
fresh antifreeze.

Forte Bio Degreaser & Cooling System Flush removes the contamination that undermines fresh antifreeze — safe biodegradable formula, compatible with all cooling system materials. Free UK delivery.

£20free UK delivery
Order Forte Bio Degreaser — £20 →
Use alongside
  • →
    Forte Radiator Stop Leak If there is also a minor coolant leak — flush first with Forte Bio Degreaser, then add fresh antifreeze with Forte Radiator Stop Leak
  • →
    Forte Advanced Formula Motor Flush For complete engine maintenance — flush both the oil system and cooling system at every service
Use alongside these products

Complete cooling system care.

After flushing — if a leak is present
Forte Radiator Stop Leak
Minor coolant leaks from radiators, hoses or gaskets can be sealed with Forte Radiator Stop Leak. Always flush with Forte Bio Degreaser first for best results — a clean system allows the sealing chemistry to work most effectively.
View Forte Radiator Stop Leak →
At every oil change
Forte Advanced Formula Motor Flush
Just as the cooling system needs flushing before fresh antifreeze, the oil system benefits from flushing before fresh oil. Use Forte Advanced Formula Motor Flush at every oil change alongside Forte Bio Degreaser at every coolant change.
View Forte Advanced Formula Motor Flush →
If oil is in the coolant
Forte Seal Conditioner
Oil contamination in the coolant can indicate a leaking head gasket, oil cooler or valve cover. If valve stem seals are also leaking — causing blue exhaust smoke — Forte Seal Conditioner may help restore them.
View Forte Seal Conditioner →

Take A Look At Our 5 Star Reviews For Forte Seal Conditioner

At BMW Tool Rental, we pride ourselves on providing excellent customer service and offering honest and reliable advice to our customers. We understand that when it comes to your car, you want to ensure that you are using the right products and getting the right advice. That's why we take the time to listen to our customers, understand their concerns, and provide the best possible solution.

Our forte seal conditioner has received numerous 5-star reviews from our satisfied customers, who have found our product to be effective in reducing engine oil leaks and stopping blue smoke caused by worn valve seals. However, we don't just rely on product reviews to show our commitment to customer satisfaction. We offer a personal touch that sets us apart from other retailers.

If you have any questions about our products or services, we encourage you to reach out to us. We're always happy to help and provide you with the information you need to make the right decision. Whether you're looking to rent our AGA valve seal tool or purchase our forte seal conditioner, we're here to help.

Take A Look At Our 5 Star Reviews For Forte Seal Conditioner

At BMW Tool Rental, we pride ourselves on providing excellent customer service and offering honest and reliable advice to our customers. We understand that when it comes to your car, you want to ensure that you are using the right products and getting the right advice. That's why we take the time to listen to our customers, understand their concerns, and provide the best possible solution.

Our forte seal conditioner has received numerous 5-star reviews from our satisfied customers, who have found our product to be effective in reducing engine oil leaks and stopping blue smoke caused by worn valve seals. However, we don't just rely on product reviews to show our commitment to customer satisfaction. We offer a personal touch that sets us apart from other retailers.

If you have any questions about our products or services, we encourage you to reach out to us. We're always happy to help and provide you with the information you need to make the right decision. Whether you're looking to rent our AGA valve seal tool or purchase our forte seal conditioner, we're here to help.

Registered office
Clements Trading Ltd
82a James Carter Road
Mildenhall, Bury St Edmunds
Suffolk, IP28 7DE
Lichfield
BMW Tool Rental
63 Purcell Avenue
Lichfield
Staffordshire, WS13 7PH

Clements Trading Ltd trading as BMW Tool Rental. Registered in England & Wales, company no. 10629836. Registered office: 82a James Carter Road, Mildenhall, Bury St Edmunds, Suffolk, IP28 7DE.

BMW Tool Rental is an independent specialist supplying tool hire and Forte automotive additives. We are not affiliated with, authorised by, or endorsed by BMW AG. "BMW" is a trademark of BMW AG and is used here for descriptive/compatibility purposes only.

© Clements Trading Ltd. All rights reserved.