A torn engine mount makes itself known immediately: the powertrain drops on bumps, a metallic knock enters the cabin on pull-away, and vibration travels through the body on every gear change. Standard rubber mounts age from oil, heat, and constant micro-impacts, requiring repeated replacement. Polyurethane engine mounts from TIMOL factory have strength and wear resistance several times higher than rubber, are unaffected by oil leaks, and hold the engine in position for far longer. This article covers exactly how a polyurethane mount outperforms rubber, how to avoid over-specifying hardness, and how to order a mount for your vehicle.
What an Engine Mount Does and Why Rubber Fails First
An engine mount carries the static weight of the powertrain, limits its movement during acceleration and braking, and absorbs vibration before it enters the body. It is a part working under constant alternating loading: every start, every gear change, and every road irregularity passes through the mount.
As standard, manufacturers fit rubber or hydraulic mounts with a rubber spring element. Rubber damps vibration well when fresh, but ages: hardening, cracking, delamination from oil, and thermal fatigue appear within a few years. When the rubber tears, the engine gains freedom of movement, producing knocking, vibration, and load on adjacent components.
A polyurethane mount solves exactly this durability problem. The elastic polyurethane element performs the same work as the rubber one, but outlasts it through higher strength, oil resistance, and wear resistance. The range of automotive polyurethane parts is in the product catalogue.
Why Polyurethane Outlasts Rubber in Engine Mounts
Polyurethane outperforms rubber on three parameters that directly determine mount service life: wear resistance, tensile strength, and oil resistance. DIN 53516 abrasion of polyurethane is 38-39 mm³ versus 80-150 mm³ for NBR rubber and 100-200 mm³ for SBR. Tensile strength of polyurethane is 39-87 MPa versus 10-25 MPa for NBR and 20-30 MPa for natural rubber.
This numerical difference translates simply into practice: a polyurethane mount does not tear under the loads that gradually destroy rubber, and does not swell from a drop of oil that has reached it from the engine. SBR rubber and natural rubber have poor oil resistance, so an oil leak is a typical cause of rubber mount failure. Polyurethane with its excellent oil resistance removes that failure mode entirely.
There is also a downside to acknowledge honestly. Natural rubber has higher rebound elasticity (40-75 %) than polyurethane (34-61 %), so a fresh rubber mount is slightly softer and quieter. This is why polyurethane mounts are selected by hardness: not pushed to maximum stiffness, but balanced between service life and ride comfort. A correctly specified polyurethane mount gives a marginal firmness increase with a proportionally longer service life.
| Material | Abrasion DIN 53516, mm³ | Operating t, °C | Tensile strength, MPa | Rebound elasticity, % | Oil resistance |
|---|---|---|---|---|---|
| Polyurethane TIMOL | 38-39 | -60…+100 | 39-87 | 34-61 | excellent |
| NBR rubber | 80-150 | -30…+100 | 10-25 | 20-45 | good |
| SBR rubber | 100-200 | -40…+80 | 8-20 | 30-55 | poor |
| Natural rubber NR | 60-130 | -50…+70 | 20-30 | 40-75 | poor |
The table shows the core compromise: natural rubber is slightly softer and more elastic when fresh, but polyurethane outperforms any rubber several times over on wear, strength, and oil resistance — and it is precisely those three factors that kill a mount in real service.
Engineer’s tip: do not fit the stiffest mount on an everyday passenger vehicle. For daily driving, choose moderate hardness closer to the lower half of the Shore A range — this preserves acceptable ride comfort while capturing almost all of the service-life gain. Hard mounts from 90 Shore A and above are justified on commercial, tuned, or heavily loaded machinery where firm powertrain location matters more than cabin isolation.
Signs That a Mount Needs Replacement and What Switching to Polyurethane Delivers
Signs that a mount has failed include vibration and noise in the cabin at idle and during acceleration, a metallic knock on pull-away and gear changes, visible sagging or misalignment of the engine, and oil traces and rubber crumbles around the mount. When two or more of these signs coincide, the unit requires attention.
Replacing a worn rubber mount with a polyurethane one delivers several immediate benefits. Engine freedom of movement disappears, eliminating knocks and sharp shocks to the drivetrain. The mount stops being vulnerable to oil leaks that previously consumed the rubber. Service life of the unit increases, extending the replacement interval and reducing the risk of sudden mount failure on the road.
The applicable limit is important to understand. A polyurethane mount is primarily about durability and firm powertrain location, not maximum softness. For a driver for whom factory-grade compliance is critical, the difference in firmness should be discussed upfront and the appropriate hardness selected.
A separate point concerns replacement economics. A rubber mount costs less per unit but has a short service life, so over the same mileage it is replaced several times, each time requiring powertrain removal and workshop time. A polyurethane mount lasts proportionally longer, so total cost of ownership including labour and downtime is often lower. For commercial vehicles where every stop is lost revenue, this argument is frequently decisive.
Manufacturing Mounts to Sample or Drawing
The primary way to obtain a polyurethane mount for a specific vehicle is manufacturing to a sample or drawing. Supply the old mount or its dimensions together with the bracket geometry and seat hole positions, and the factory casts the part by free casting to those parameters in the required hardness.
This approach is especially valuable for rare, old, and commercial machinery for which original mounts are either no longer supplied or whose quality from the market is unpredictable. Polyurethane allows any geometry to be reproduced, including parts with embedded metal inserts and backing plates that work together with the elastic element.
Installation of a polyurethane mount is no different from the standard procedure: the part goes into the same bracket and is fastened with standard hardware. Mating surfaces are cleaned and degreased before installation. Casting technology and surface preparation are described in the reference information section.
How to Order Polyurethane Engine Mounts
To order, supply a sample of the old part or a drawing with dimensions, and describe the vehicle and operating conditions: everyday driving, loaded work, or tuning. This allows the optimal hardness between comfort and service life to be selected.
TIMOL factory manufactures both individual mounts for repairing a specific vehicle and production batches for fleets or workshops. Parts with embedded metal elements and complex bracket geometry are produced.
For a consultation, hardness selection, and ordering, contact us via TIMOL factory contacts. Engineers will reproduce the mount for your vehicle and application.