heat insulation suppliers Archives - Kool Wrap Heat Protection

Top Automotive Heat Shield Options for Protecting Your Engine Bay

The best automotive heat shield material depends on what you are protecting and how close it sits to the heat. A thin gold foil sheet is right for an airbox and wrong for a floor pan. A 5mm insulated sheet is right under the car and too bulky for a tight firewall gap.

This guide compares the materials first, then maps each engine bay part to the product that suits it. Every sheet and panel is in the Kool Wrap heat shield range.

Automotive heat shield materials compared

Material	Construction	Thickness	Stated performance	Best for
Gold foil on fibreglass	Gold-coloured reflective foil laminated to fibreglass, self-adhesive	0.5mm	Not published	Airboxes, intakes, tight spaces, firewalls
Aluminium foil on fibreglass	Heavy duty aluminium foil on fibreglass, self-adhesive	1.5mm	Fibreglass to 593°C, foil melting point 650°C	Firewalls, fuel tanks, composite panels, engine bays
Embossed aluminium on a fibreglass and polyester core	0.05mm embossed aluminium face, pressure-sensitive adhesive	4mm	Reflects 95% of radiant heat. Tested 30 hours at 246°C with no failure	Floor pans, tunnels, fuel tanks, body panels
Heavier embossed aluminium on the same core	0.25mm embossed aluminium face, pressure-sensitive adhesive	5mm	Reflects up to 95% of radiant heat. Tested 30 hours at 246°C with no failure	Underfloor above the exhaust, transmission tunnels
Multi-layer embossed aluminium	Single, two, four and six layer embossed aluminium, no adhesive	1.8mm to 3.3mm	Cuts radiant heat by up to 90%. Panels designed for up to 650°C	Exhaust pipes, mufflers, underbody and farm machinery

Choosing the best heat shield material for the job

Two questions settle it. Does the shield stick to the part you are protecting, or stand off the heat source? And how much room do you have?

Adhesive shields bond to the panel or part you are protecting. Thicker sheets insulate more but need more clearance. Semi-rigid panels mount near the heat source itself with brackets or hose clamps and suit places where there is no clean flat surface to stick to.

Neither goes directly onto an exhaust pipe, manifold or turbo housing. Kool Wrap does not publish a temperature rating for the adhesive, so the sheets stay on the panels around the heat. To cover the pipe itself, use exhaust heat wrap.

Source or target: where to start

There are two ways to control heat. Containing it at the source, with wrap on the headers or a blanket on the turbo, lowers radiant heat across the whole engine bay. Protecting the target, with a shield on the firewall or a sleeve on a loom, helps one part at a time. Most builds need both. Treat the hottest sources first, then fill the gaps.

Exhaust manifold and headers

On most engines the headers radiate more heat into the bay than anything else. Exhaust heat wrap keeps that heat inside the pipe. Pick the wrap by the heat it will see:

Standard fibreglass: 540°C continuous
Vermiculite coated fibreglass: 650°C continuous
Titanium basalt fibre: 980°C continuous, for the hottest jobs

Paint mild steel headers with high-temperature exhaust paint before you wrap. Leave O2 sensors and flex joints uncovered. Do not use adhesive heat shield or foil tape on the headers. Neither is made for direct exhaust contact.

Turbo

A turbo blanket keeps heat in the turbine housing instead of letting it radiate onto the intake, intercooler piping, hoses and wiring. Titanium basalt and silicone coated blankets use 12mm of internal silica insulation and a stainless steel mesh inner, and fit with stainless mounting springs. Choose titanium basalt where heat is highest, silicone coated where oil and fuel are around, or carbon fibre for an ultra-high temperature rated option. Measure your turbine housing before you order. See the turbo blanket range for sizes, and what a turbo blanket does if you are still deciding.

Dump pipe and front pipe

The dump pipe carries exhaust gas straight off the turbo and often runs close to the firewall. Wrap it with titanium basalt or vermiculite wrap and lock it down with stainless steel ties. Where the pipe runs close to a panel, add a reflective shield on the panel side as well.

Firewall

The firewall takes radiant heat from the headers and turbo and passes it into the cabin. Stick a flexible adhesive shield to the engine side. The 1.5mm silver adhesive heat shield has heavy duty aluminium foil over a fibreglass backing rated to 593°C, and cuts with scissors. Where space is tight, the thinner 0.5mm Gold Reflecta Shield gives you less bulk. Cut around wiring grommets and the steering column rather than covering them.

Intake pipe and airbox

Cooler air around the intake means the engine draws in less heat with it. A reflective face on the airbox and intake tube limits the heat the air picks up on its way to the engine. Stick Gold Reflecta Shield or 1.5mm silver sheet to the airbox. For round intake tubing, wrap fibreglass-backed aluminium tape around the tube. It reflects 95% of radiant heat and withstands up to 454°C radiant heat.

Wiring, hoses and sensors

Looms, vacuum lines and rubber hoses near the exhaust go brittle and crack. Slide a heat sleeve over them. Sleeves come in open seam and closed seam versions, so check the product pages for the one that suits your loom. For short runs and joins, the heat resistant tape range includes reinforced foil tape made for wrapping hoses and wiring. Our guide to protecting cables, hoses and sensors from engine heat goes into more detail.

Fuel lines

Hot fuel lines can cause vapour problems and hard hot starts. First, route the line as far from the exhaust as you can. Then sleeve it or wrap it with reflective tape. On a fuel tank face near the exhaust, use an adhesive shield on the tank side.

Starter motor

Starters mounted beside the exhaust suffer heat soak, which shows up as a slow crank or a no-start when the engine is hot. Fit a starter motor heat shield over the starter body.

Battery

Heat speeds up battery wear. The battery insulation kit fits batteries up to 20cm high and up to 1.0m in circumference. It suits lead acid, AGM and lithium batteries, and the material absorbs and neutralises acid.

Spark plug leads

Where plug leads pass close to the headers, heat cooks the boots and the lead ends. Spark plug boots slide over each boot to protect it.

Bonnet underside

Engine heat rises and bakes the bonnet. Under bonnet insulation comes as 10mm and 12mm foam adhesive pads and a premium compressed felt. It fixes to the bonnet underside between the bracing. Check the bonnet still closes cleanly after fitting.

Floor and transmission tunnel

The exhaust runs along the floor and tunnel and heats the cabin from below. Kool Wrap recommends the 5mm heavy duty heat shield for under-car jobs where the exhaust heats the floor. Where the pipe sits very close, an embossed semi-rigid panel mounted on brackets works better. Read how to fix a hot floor in a 4WD or ute for the full process.

Summary table

Engine bay part	Product family	Why it works
Exhaust manifold and headers	Exhaust heat wrap	Keeps heat inside the pipe
Turbo	Turbo blanket	Keeps heat in the turbine housing
Dump pipe	Titanium basalt or vermiculite wrap	Contains heat on the hottest pipe after the turbo
Firewall	1.5mm silver or 0.5mm gold adhesive shield	Reflects radiant heat away from the cabin
Intake and airbox	Adhesive shield or fibreglass-backed tape	Keeps intake air cooler
Wiring and hoses	Heat sleeves or reinforced foil tape	Slows insulation and rubber going brittle
Fuel lines and tank	Heat sleeves or adhesive shield on the tank	Limits fuel heating
Starter motor	Starter motor shield	Reduces heat soak and hot-start problems
Battery	Battery insulation kit	Slows heat-related wear
Spark plug leads	Spark plug boots	Protects boots near the headers
Bonnet underside	Under bonnet insulation	Keeps heat off the bonnet skin
Floor and tunnel	5mm heavy duty shield or semi-rigid panel	Keeps exhaust heat out of the cabin

Heat shield material FAQs

What is the best heat shield material for a car?

There is no single best. For panels you can stick to, an aluminium foil face over a fibreglass core does the most work for the least bulk, and the 1.5mm silver sheet is the general-purpose pick. Under the car above the exhaust, the 5mm heavy duty sheet with its thicker 0.25mm foil face is the one Kool Wrap recommends. Where there is nothing flat to stick to, use a semi-rigid embossed aluminium panel on brackets.

What is the best heat shield material for an engine bay?

Start at the source. Wrap on the headers and a blanket on the turbo lower the radiant heat everywhere at once, which does more than shielding parts one at a time. Then shield the firewall with a 1.5mm silver sheet, sleeve the wiring and hoses, and put a thin gold sheet on the airbox.

Does aluminium make a good heat shield?

Aluminium makes an excellent reflective face, which is why almost every shield has one. On its own it does very little, because reflecting radiant heat is only half the job. The insulating core behind the foil is what stops conducted heat, and a foil face with no core is not a heat shield.

How thick should a heat shield be?

Thick enough to insulate, thin enough to fit. Use 0.5mm where clearance is tight, 1.5mm as the general-purpose thickness on firewalls and panels, and 4mm or 5mm on floors, tunnels and fuel tanks where you have the room and the heat is worst.

What heat shield material can touch an exhaust pipe?

None of the adhesive sheets. Kool Wrap does not publish a temperature rating for the adhesive, so the sheets stay on the panels near the heat. On the pipe itself, use exhaust heat wrap, or a semi-rigid or DCI pipe shield clamped around it where the pipe measures 2 to 3 inches.

Need help choosing?

Start with the hottest part of your engine bay and work outward. If you want the basics first, read what a car heat shield does and where you need one.

Then browse the heat shield range or call 1300 44 33 34 with your engine, your exhaust setup and where the heat is showing up.

Automotive Heat Shields and Why Every Car Needs Them

A car heat shield is a barrier between a heat source and something that needs protecting. The heat source is usually the exhaust, the engine block or the turbo. The part being protected might be a fuel line, a wiring loom, the battery, the cabin floor or your feet.

Most shields do two jobs. A reflective face bounces radiant heat back towards the source. An insulating core slows down the heat that still gets through. Get both right and nearby parts run cooler and last longer. Compare every sheet and panel in our car heat shield range.

What a heat shield actually does

Heat moves in three ways. Conduction travels through solid contact, like a bracket bolted to a hot manifold. Convection moves with air, like hot air rising off the engine and pooling under the bonnet. Radiation travels as infrared energy straight across an air gap, the way you feel a campfire on your face.

In an engine bay, radiant heat from the exhaust and turbo does most of the damage. That is why most automotive heat shields have a shiny aluminium or gold foil face. The foil reflects radiant heat. The fibreglass or polyester layer behind it slows conduction into the panel or part you are protecting. For the physics, see our guide to conduction, convection and radiated heat.

Where the heat shields are on your car

Most cars leave the factory with several. The common positions are:

Over the exhaust manifold or headers, bolted to the engine or the manifold itself
Around the catalytic converter, often as a clamshell in two halves
Along the underside of the floor pan and transmission tunnel, above the exhaust
Beside or over the fuel tank
On the firewall, between the engine bay and the cabin
Under the bonnet, as a pad or liner

If you are chasing a rattle, the exhaust manifold shield and the catalytic converter shield are the two most likely culprits, because they take the most heat cycles.

Do you need a heat shield on your car?

For a standard car in normal use, keeping the factory shields in good condition is usually enough. You need extra protection when something changes the heat load. Common triggers:

Aftermarket extractors, headers or a bigger exhaust that runs closer to the floor or firewall
A turbo conversion or a tune that raises exhaust temperatures
Towing, low-range crawling or long idling with little airflow under the vehicle
A hot floor or firewall you can feel through your boots
Hoses going hard, wiring insulation cracking or a battery failing early
A fuel line, fuel filter or second battery relocated closer to the exhaust

Where your car needs automotive heat shielding

Firewall

The firewall separates the engine from the cabin. Heat soaking through it makes the footwells and pedals hot. A reflective adhesive shield on the engine side cuts the radiant heat reaching the cabin.

Floor and transmission tunnel

The exhaust and catalytic converter run directly under the floor. On 4WDs and utes this is the most common hot spot. Kool Wrap recommends the 5mm heavy duty shield, with its thicker 0.25mm foil face, for under-car jobs where the exhaust heats the floor. Our guide to fixing a hot floor in a LandCruiser or 4WD walks you through it.

Fuel tank and fuel lines

Fuel tanks and lines near the exhaust pick up heat, and hot fuel can vaporise in the line. A reflective shield on the tank or a sleeve over the line keeps radiant heat off.

Starter motor

Starters often sit beside the exhaust manifold or front pipe, and heat soak leads to slow hot starts. A starter motor heat shield covers the body of the starter.

Battery

Under-bonnet heat speeds up battery wear. A battery insulation kit wraps the battery case. It fits batteries up to 20cm high and up to 1.0m in circumference, and suits lead acid, AGM and lithium.

Intake and airbox

Your engine draws in cooler air when the air around the intake is cooler. A reflective shield on the airbox or intake pipe limits the heat the incoming air picks up.

Bonnet underside

Engine heat rises and bakes the bonnet. Under bonnet insulation comes as 10mm and 12mm foam adhesive pads and a premium compressed felt, fixed to the underside between the bracing.

How to fix a rattling heat shield

Factory shields are thin pressed steel or aluminium held on with small bolts, clips or welded tabs. Years of heat cycles, vibration, water and mud corrode the mounting points. The shield then works loose and buzzes against the exhaust.

A loose heat shield usually sounds like a metallic buzz, rattle or tinny vibration that comes and goes with revs. It is often loudest at idle or at one particular engine speed, and it can sound alarmingly like something serious. Most of the time it is a shield that has let go at one corner.

A rattling shield is a warning, not a nuisance to cut off. Fix it instead:

Let the exhaust cool completely before you touch it.
Find the loose shield. Tap along the exhaust with a rubber mallet until you hear the rattle.
Check the mounts. Where the tabs are sound, refit the shield with new bolts or clips.
Where the tabs have rusted through, hold the shield in place with a large stainless steel hose clamp, or have an exhaust shop weld on new tabs.
If the shield itself is rusted out, replace it with a new factory part or a correctly mounted aftermarket shield.

Never remove a factory heat shield and leave it off. It is there because something nearby, often the floor, the fuel tank or a fuel line, needs protecting from exhaust heat.

What heat shields are made of

Reflective aluminium foil. The most common face, and it shrugs off moisture. The foil on our 1.5mm silver shield has a melting point of 650°C.
Gold foil. Gold Reflecta Shield uses a gold-coloured reflective foil laminated to fibreglass. It suits airboxes and tight spots where you want a thin sheet.
Fibreglass cores. Fibreglass sits behind the foil as the insulating layer. The fibreglass backing on the 1.5mm silver shield is rated to 593°C.
Fibreglass and polyester cores. The 4mm and 5mm Aluma Shield II sheets put an embossed aluminium face over a fibreglass and polyester core. They reflect up to 95% of radiant heat and passed a 30-hour oven test at 246°C with no failure.
Embossed multi-layer aluminium. Semi-rigid panels stack layers of embossed aluminium with no adhesive, in single layer at 1.8mm and in two, four and six layer builds up to 3.3mm. They cut radiant heat by up to 90% and are designed for up to 650°C.

Flexible adhesive or semi-rigid?

Choose a flexible adhesive shield to cover a panel, such as a firewall, floor pan, tunnel, airbox or fuel tank. You cut it with scissors, peel the liner and stick it on. Our adhesive heat shield installation guide covers prep, cutting and sealing the edges.

Choose an embossed semi-rigid heat shield when the shield needs to stand off a very hot part, or when there is no clean, flat surface to stick to. You fold and form the panel by hand, then mount it with brackets or hose clamps.

Never stick an adhesive shield directly onto an exhaust pipe, manifold or turbo housing. Kool Wrap does not publish a temperature rating for the adhesive, so keep adhesive sheets on the panels and parts near the heat, not on the heat source. To cover the pipe itself, use exhaust heat wrap.

For a part-by-part breakdown, see the best heat shield material for each engine bay part.

Car heat shield FAQs

What is a heat shield on a car?

It is a barrier between a heat source and something that needs protecting. Most car heat shields have a reflective metal face that bounces radiant heat back towards the source, and an insulating layer behind it that slows the heat that still gets through. Cars carry them over the exhaust, around the catalytic converter, under the floor and near the fuel tank.

Where is the heat shield on a car?

Most cars have several. Look over the exhaust manifold, around the catalytic converter, along the underside of the floor pan above the exhaust, beside the fuel tank, on the firewall between the engine and the cabin, and under the bonnet. A rattle usually comes from the manifold shield or the catalytic converter shield.

What does a loose heat shield sound like?

A metallic buzz, rattle or tinny vibration that changes with engine speed and often disappears above a certain rev range. It is loudest at idle on many cars. It sounds worse than it is, and it is usually one corner of a shield that has rusted off its mount.

Can you drive with a loose heat shield?

You can drive a short distance to get it looked at, but it is not something to leave. A shield that comes fully loose can drag on the road or fall off, and the part it was protecting then sits in direct exhaust heat. Get it refitted or replaced rather than removed.

How long can you drive without a heat shield?

There is no safe number of kilometres. Removing a shield leaves whatever it was protecting exposed to exhaust heat, which on the floor pan or near a fuel line is a real risk rather than a theoretical one. Refit it, replace it, or fit a correctly mounted aftermarket shield in its place.

Do you need a heat shield to pass inspection?

Requirements vary between states and between inspection types, so check with your inspector or your state authority rather than relying on a general answer. What is consistent is that a shield hanging loose, dragging or missing over the exhaust is the kind of defect an inspector notices.

Do you need a heat shield on your exhaust?

If your car came with one, yes. Factory shields sit where the manufacturer found a heat problem. On a modified exhaust, the question is whether the new pipe runs closer to the floor, the fuel tank or the firewall than the old one did. If it does, it needs shielding even if nothing rattles.

What are heat shields made of?

Factory shields are thin pressed steel or aluminium. Aftermarket shields use a reflective aluminium or gold foil face over an insulating core of fibreglass, or fibreglass and polyester. Semi-rigid shields are multiple layers of embossed aluminium formed into a panel, with no adhesive backing.

Can you make a heat shield out of aluminium foil?

Kitchen foil is not a heat shield. It has no insulating layer, it tears, and it does nothing about conducted heat. What makes a shield work is the reflective face and the insulating core together. If you want a thin sheet for a tight space, the 0.5mm gold shield is the product that does that job properly.

Need help choosing?

Compare every sheet thickness and panel style in the Kool Wrap heat shield range. Not sure which shield suits your car? Call 1300 44 33 34 with the make, model and where the heat is coming from. Kool Wrap has supplied heat protection in Australia since 1995.