- SHORE A
- ±5 pts against the specified hardness, solid only
- TENSILE
- Per compound datasheet, tested to ASTM D412
Pads, Stoppers & Caps · Made to order
Radiator Shroud Flaps — Sealing Out Cooling Air Bypass
Flexible flaps that close the gaps around a radiator and its shroud, so the fan pulls air through the core instead of around it. Soft enough to follow a pressed panel across a gap that varies along its length — because a strip that bridges the high spots is the same as no strip at all.
- HARDNESS
- 40–55 Shore A in solid rubber; not applicable in sponge
- TEMPERATURE
- −40 to +140 °C in solid EPDM; lower in EPDM sponge
- THICKNESS
- Flap thickness — to your drawing
- WIDTH
- Maximum blank size for die-cut flaps
- FORM
- Solid rubber or closed-cell sponge
- BACKING
- Plain, or self-adhesive with a peel liner
- SET QUANTITY
- Pieces per vehicle, to your drawing
- MADE TO ORDER
- ISO 9001:2015
- 09111526A
Product gallery
Visual Reference
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Cross section viewSection through the flap and the gap it seals — on request under NDA
- Max width
- Flap width — to your drawing
- Thickness
- Flap thickness
- Run length
- Keep — flaps are commonly supplied by the metre
- Gap range
- Smallest and largest gap the flap must close
- Fixing
- Self-adhesive, clipped, bolted or trapped under the shroud
- Pieces per vehicle
- The set that seals one shroud
- Airflow direction
- Which side the fan pulls from
Section drawing available on request. Send the gap range along the seal, the flap length and how it is fixed — or a sample and a photograph of the shroud — and we will return a dimensioned drawing with the set quantity stated.
Technical specifications
Engineering Data
- Product Family
- Pads, Stoppers & Caps
- Material
- EPDM solid or EPDM closed-cell sponge
- Hardness (Shore A)
- 40–55 Shore A in solid rubber; not applicable to sponge
- Tensile Strength
- Per compound datasheet, ASTM D412
- Elongation at Break
- Per compound datasheet, ASTM D412
- Operating Temperature
- −40 to +140 °C in solid EPDM; lower in EPDM sponge
- Compression Set
- ASTM D395 Method B on solid; ASTM D1056 on sponge
- Density
- Per grade, kg/m³ — sponge grades
- Colour Options
- Black standard, custom RAL on request
- Lead Time
- Confirmed with the quotation, from approved drawing and approved sample
- Form
- Solid rubber or closed-cell sponge
- Gap range sealed
- Smallest and largest, to your drawing
- Compression force deflection
- Per ASTM D1056 grade, on sponge flaps
- Backing
- Plain, or self-adhesive with a peel liner
- Pieces per vehicle
- Stated per part number
- Ozone and UV resistance
- Required — EPDM or neoprene
- Certifications
- ISO 9001:2015 — certificate 09111526A, valid to 21 February 2027
- Minimum Order
- 10,000 pieces per part number, per compound, or quoted against the part where geometry or tooling makes that unrealistic. Prototype and first-article lots sit outside the minimum.
Dimensional reference
- Max width
- Flap width — to your drawing
- Thickness
- Flap thickness
- Run length
- Keep — flaps are commonly supplied by the metre
- Gap range
- Smallest and largest gap the flap must close
- Fixing
- Self-adhesive, clipped, bolted or trapped under the shroud
- Pieces per vehicle
- The set that seals one shroud
- Airflow direction
- Which side the fan pulls from
Available materials
Rubber Compound Options
Select the compound best suited to your operating environment and application requirements.
| Rank | Compound or form | Temperature | Why, for a shroud flap |
|---|---|---|---|
| Recommended | EPDM closed-cell sponge | −40 to +100 °C | Fills a gap that varies along its length at almost no closing force, which is what this seal has to do. Specified on density and compression force deflection, to an ASTM D1056 grade |
| Recommended | EPDM solid, 40–55 Shore A | −40 to +140 °C | Where the gap is consistent and a tougher flap is wanted. |
| Suitable | Neoprene | −40 to +120 °C | Reasonable weathering and ozone resistance, with some oil resistance if the flap sits where oil mist reaches it |
| Suitable | Silicone | −60 to +220 °C | Where the flap runs close to a heat source. Tears more easily, which matters on a thin flexible strip |
| Not recommended | NBR | −30 to +120 °C | Cracks in ozone and UV, and this part sits in the airstream behind an open grille |
| Not recommended | SBR | −30 to +100 °C | Also poor in ozone and UV. |
| Available | Natural rubber | −20 to +90 °C | Excellent flexibility and tear strength, but it perishes in sunlight faster than any of the above |
| Not recommended | FKM · AEM | See the compound table | Expensive sealing compounds. Neither brings anything a shroud flap needs |
Not sure? Send the medium, temperature and load
SEALS A VARYING GAP
Sponge or 40–55 Shore A
not 70
Key advantages
Why Specifiers Choose Margo
A fan will always take the easy path
Air goes round the radiator rather than through it if there is a gap to go round. These flaps close those gaps, so the airflow the fan produces is airflow the core actually gets.
When these fail, something else gets blamed
A perished flap leaks nothing and makes no noise — the machine just runs hotter. The thermostat, the fan clutch and often the radiator get replaced first, and the strip that caused it costs almost nothing.
The gap is never the same twice
The distance between shroud and panel varies along the seal and between vehicles. A hard strip bridges the high spots and leaves the low ones open — we specify soft solid or closed-cell sponge so it follows the panel.
It lives behind an open grille
Sunlight, road spray, ozone and radiator heat, for the life of the machine. EPDM is our default here for that reason — and nitrile and SBR, the cheaper options, crack in exactly those conditions.
Industries served
Global Applications
Agriculture
tractors and harvesters working at full load in dust and heat, where a blocked or bypassed radiator stops the day
Automotive and commercial vehicles
cars, vans, trucks and buses, front-end cooling packs
Construction plant
excavators and loaders idling in high ambient temperatures
Generator sets and compressors
stationary engines in enclosures, where recirculating hot air is the whole cooling problem
Manufacturing process
From Compound to Certification
Material compounding
Polymer blending, additive integration and batch QC in our in-house lab. The compound is built for ozone and UV resistance, since the flap sits behind an open grille for the life of the machine.
Tool or die design
Cutting dies for die-cut flaps, moulds for shaped ones, made in-house and held as a controlled record.
Compression Moulding
Sheet or bun cure for die-cut flaps, or compression moulding where the flap is shaped. Sponge grades are expanded during cure to the specified density.
Post-Cure & Trimming
Die-cutting and trimming, with self-adhesive backing applied where specified.
Quality inspection
Thickness and cut dimensions checked against the drawing, plus hardness on solid grades and density on sponge.
Export packaging
Industrial packing with documentation, packed flat and uncompressed so the flaps do not take a set before fitting. ISPM-15 treated pallets where timber packaging is used.
Quality assurance
Certified to International Standards
Every product leaves our facility with a documentation package — material test reports, dimensional inspection sheets and a certificate of conformance — giving traceability from raw material to finished part.
ISO 9001:2015 · Certificate 09111526A
Integral Certification Ltd · Valid to 21 February 2027
Scope: rubber moulded components — quality management, not a product approval
IATF 16949 — upgrade in progress, certification targeted by end 2026
ISO 14001 and ISO 45001 — targeted 2027
Die-cut flaps fall outside the certificate scope.
Certification detailProduction metrics
- Since 2005
- In operation
- 60+
- Active clients
- 3–4 weeks from approved sample
- Avg. lead time
Downloads
Technical Documentation
Sealing profiles and grade data are issued on request, under NDA where required. Send the smallest and largest gap the flap must close, the length and how it is fixed, and we will recommend solid or sponge and return a cut drawing.
Request a cut drawingFAQ
Technical & Commercial Questions
Answers to the most common questions from engineering teams and procurement managers worldwide.
What is the minimum order quantity for this part?
We supply in bulk. The minimum run is 10,000 pieces per part number, per compound, or quoted per metre where the flap is a cut strip. Prototype and first-article lots sit outside the minimum.
Can you match a competitor specification or reverse-engineer an existing part?
Yes — and measure the gap, not only the old flap. A flap that has hardened has usually stopped touching the panel, and one that was too hard when new never touched it properly. The gap is the specification; the old part may never have met it.
What file formats do you accept for drawings?
PDF, DWG and DXF. A flat outline with the thickness marked is enough — add the smallest and largest gap the flap must close, and whether you want self-adhesive backing. A 3D model is not required for a cut flap.
Do you provide material test reports with each shipment?
Yes. Material test reports, dimensional inspection sheets and a certificate of conformance ship with every consignment. Hardness and tensile to ASTM D412 on solid grades, density and compression force deflection to ASTM D1056 on sponge grades, tested in-house.
What are your payment and delivery terms for international orders?
TT and LC accepted, discussed per order. Ex-works Nashik or FOB Nhava Sheva. Commercial invoice, packing list and certificate of origin are issued with every consignment. Flaps ship flat and uncompressed.
Same compound
Other parts we mould in the same compounds
- EPDM Gaskets — Weather, Steam and Water Service · EPDM
- Silicone Rotary Shaft Seals — High-Temperature, Low-Speed Service · Silicone
- Flat Packing Pad — Moulded to Your Load and Gap · EPDM
- EPDM Rotary Shaft Seals — Water, Coolant and Steam · EPDM
- Rubber Oil Filler Cap — Push-In, Sealed or Vented · Neoprene
- Glove Box Stopper — Damped Interior Closure Bumper · EPDM, Neoprene, Silicone
Need this part quoted?
Send the smallest and largest gap the flap must close, the length and how it is fixed — a flat outline if you have one, a sample and a photograph of the shroud if you do not. We recommend solid or sponge before quoting, then price against your annual quantity. We respond within 48 hours.