Running in the Engine

[squiretolley]

Hi Guys,

just wondering what your thoughts are on how you should run in a new engine? I've always had VAG diesels and on both occasions the salesman has told me to drive normally and the engine will be fine. In fact they said that the harder I drove it in the first few thousand miles it would actually improve performance! Not sure how true this is but I've put 106k miles on my 2004 A3 and 147k on my current Golf and I've never had any mechanical issues (touch wood!!)

 

[Vertigo1]

The generally accepted advice these days is not to rev it too high for the first thousand miles or so. That said, you shouldn't take it too easy either. The first few hundred miles are critical in allowing the piston rings to bed in properly with the cylinders and, to do this, the engine needs a bit of loading.

So, don't rev it too much and don't load it when cold. Once the engine is fully up to temperature though, do subject it to some decent loadings now and then as you drive, to help it bed in. Providing you don't do this when it's cold you'll be fine and it should help economy and performance in the long term. That's the theory at least

 

[squiretolley]

Thanks Vertigo, looks like I'll be able to have a bit of fun with it when it arrives!

 

[NHN]

500-1000 miles take it very easy, then do as you see fit, was what I've always been advised/done, but letting oil get upto temps always helps & the dis can advise you of the temps anyway.

 

[dieseldoug]

Nail it when it gets hot and let it idle before switching off. These engines are all tested at full power before being installed in your car so don't worry. The days of running in ate finished unless you have very close fitting parts like F1 cars.

 

[Rom]

My first advice, is spend an hour reading up, and making your own decision.

There are 2 main camps of bedding in.

Break them in gently. Not being too high revving, dont labour engine etc.

Break them hard. Will be hitting full throttle runs almost straight away.

I'm in the hard camp. I've rebuilt countless engines for my job. As well as replacing blocks etc.
Also rebuilt my own engines, and ran them in hard. Never had issues, always had good power. My last personal engine, after initial start up and leak check, I hit full throttle with in 20-30 mins, and took it to 7k rpm.

Rings do not take hundreds of miles to bed in. The honing on the bores is what your being in with the rings. That initial honing soon wears to a point it no longer 'beds'. After that, there will be no more bedding in of the rings.
Rings need pressure to expand them against the bore. This comes from high rpm runs, and letting off.

Conversely, cams need bedding in completely differently. They generally need to be held at 2-3k (manufactures have their own specs) for quite a while, last set I did was around 20mins.

Engines are generally bench tested before installed. Thought I can't be sure every manufacturer does that. Plus it's already been driven around by factory staff, dock workers, transport drivers, valeters, salesmen, techs.

 

[hittchy]

I've tried both approaches on various VAG engines over the years. Never had any reliability issues with either approach. However, breaking in gently seemed to improve oil consumption - I barely used 1ltr between services. Breaking in hard seemed to produce better power but had a tendency to drink oil more.

 

[viperfire]

In my experience bedding in on new cars is ********. Had three new cars now and I've treat them no different to how i do when they have ten thousand miles and no issues whatsoever. Modern engines are designed to require as little as bedding in as possible

 

[squiretolley]

Thanks for the replies, can't bear the thought of driving around like an 80yr old!!

 

[Ben (T25) Ruz]

I think it depends on the car/manufacturer. I have not bedded in my previous diesels (Honda/BMW) and will not be with the new A3. On the opposite end of the scale, with my Lotus they void the warranty if you red line in the first 600 miles!