Checking engine mount integrity

[jeremy156]

I've understand that running the engine with the transmission in gear and the brake held stationary will lift the left side of the engine in Drive. Everything I've read suggests "excessive" lift shows a bad mount... but does anyone hand an idea of what "excessive" is, exactly? An inch or so?

Jeremy

[BrianG]

DANGEROUS! Unless you have someone else in the driver's seat it is a very bad idea to have the car in drive and rely on the handbrake to hold it, just in case the handbrake slips. I had this happen to me with a Rover SD1 V8 - in reverse gear on an uphill driveway - when I wanted to adjust the idle speed in drive which was a little too low. It finally stopped when it hit the corner of the garage, smashing the fibreglass rear bumper.

[jeremy156]

I was planning to sit in the driver's seat with one foot on the brake and the other on the throttle, certainly not trust the parking brake... you can see the engine rise from there with the bonnet open

[BrianG]

Glad to hear that! I wonder if you will see enough through the gap under the bonnet? If you had a helper to look they might be able to get a measurement from a point of reference at the top of the engine which you could work back for the mount.
You don't say if your car is diesel or petrol; the diesel cars have a different engine mount which is electronically driven to reduce vibration, whereas the petrol has conventional mounts. I reckon that for a petrol car at idle revs the movement should be almost nil, maybe 1/4 inch at the most. Be careful if you rev it up - it can still lurch with your foot on the brake.
I'm curious now - I'll have to have a look at mine to see what happens!

[jeremy156]

Took a short video of mine - really not moving very much so looks as though the mounts are intact.

https://youtu.be/tJlReJnZzlc

[J44EAG]

Diesel models are prone to mount failure. You don`t hear anything about issues with petrol models. Mnnnn?

Mike