Your crankshaft seals keep all of your precious oil in the engine and all the nasty contaminants out. The rear main seal is what protects your main bearings and crankshaft from moisture and dirt that can harm them. 

What is a crankshaft rear main seal?

The crankshaft rear main seal is made out of synthetic rubber and contained with a steel casing to keep it in place. It also makes sure the crankshaft can keep rotating and doing its job. The difficulty in accessing the rear seal is compounded by the flywheel and transmission that connect to the crankshaft. 

Why do you need a crankshaft rear main seal?

If dirt or moisture were to get into the crankshaft it could lead to the bearings failing and the engine seizing. This is the most expensive thing to replace, so the crankshaft seal is something that is worth replacing if needs be.

How to tell if you need a new crankshaft rear main seal

If you notice oil leaking from the back of your engine, it usually means the rear seal is leaking. If your oil level is getting progressively lower that can also mean that the rear seal may need to be replaced.

What’s involved in getting a crankshaft rear main seal replaced?

The mechanic will hoist the car up and unbolt the transmission from the engine and driveshaft and remove it. The oil will then be drained and the rear seal will be able to be removed. The mounting surface will be cleaned and the new rear seal installed. The oil will be refilled and the transmission will be reconnected. The car will be test driven and be good to go.

How much does a crankshaft rear main seal cost near Marlborough?

The difficulty in accessing the rear seal is where the majority of the cost comes from. Prices generally range widely from $450 to well over $1250 depending on the make and model.

How often do I need a crankshaft rear main seal replaced?

Typically not that often, they shouldn’t fail under 125,000km but they can fail under 100,000km and can go over 150,000km.

Is a broken crankshaft rear main seal unsafe?

It can lead to catastrophic engine failure, so while it isn’t unsafe to drive, it is extremely unsafe for your wallet.

You can find a mechanic near Marlborough with My Auto Shop