Thread: 300tdi to idle to warm or not

Excessive idling (longer than 30-60s) is bad and is not recommended by engine manufacturers. It can lead to glazed bores and other problems.

That said, your lack of short trips may have overcome any negatives.

At those km though, I would be getting a compression test done and checking blowby before deciding what to do.

Originally Posted by mudder110

hi all ive been letting my 300 tdi defender idle to warm up for about 3to 4 minutes for the last 8 years 355000ks up uses no oil leaks a drop from t seal.
rarely has short runs mainly highway ks,, was contemplating a rebuild before a trip through the northern deserts and gulf then down the west next year.
since been told that idling the engine would have damaged it is this possible? maybe I should do the rebuild any advice would be appreciated
cheers

It can cause glazing, which can cause loss of compression, excess blow by loss of power and oil consimption.


I generally advise that the head gasket is a 240ish k km maintenance item and you inspect the engine at 500k km for rebuild work.

Originally Posted by Blknight.aus

It can cause glazing, which can cause loss of compression, excess blow by loss of power and oil consimption.


I generally advise that the head gasket is a 240ish k km maintenance item and you inspect the engine at 500k km for rebuild work.

thanks blknight maybe I should redo the head gasket and inspect the bores
no oil consumption, little bit of heavy breathing form rocker cover though

As far as I know, no manufacturer in at least the last sixty years has countenanced idling to warm any engine except perhaps in extreme cold (e.g. below say -30), and then only to slightly warm the oil. Idling does not warm the engine to any extent, merely prolongs the period of cold running (cold being 'below normal operating temperature'). The practice almost certainly derives from the time when carburettor engines needed careful choke adjustment to avoid acceleration flatspots before the intake manifold hot spot warmed up.

As stated above, it can lead to multiple problems with the engine, especially in diesels, which mostly do not cope satisfactorily with prolonged idling even when warm, although it is generally a good idea to avoid shutting down turbocharged engines immediately after operation at high power setting - but about a minute of idling is usually sufficient.

John

Are you using modern multi grade oil?
Aaron

Originally Posted by Aaron IIA

Are you using modern multi grade oil?
Aaron

Yea only use penrite syn 15 40 cheers

When I do a cold start with a diesel, and I know others do this too, is start driving straight away without idling, but just take it a bit easy for the first few kms until everything gets some temperature into it. Taking it easy doesn't necessarily mean driving 'slow', just don't drive it hard.
Cheers, Murray

Best way to warm them up is driving them in my opinion.