Faster idle when hot

[southgate]

When cold, my car idles at 7-800 rpm, when hot it goes up to 900-1000.

Anyone else had this or know why it does it?

[abz]

my tuscan does this - not sure why though

[fat80b]

hmmmm.

I topped up my oil yesterday and noticed this morning that mine seemed to be doing the same - It was idling at 700 last weekend and 900 this morning .....dont know if its related or not?

[NCE 61]

Idle speed usually increases when the first cooling fan comes on.

[ec1 eex]

Mine does this too. I assumed that when cold the oil was more "gloopy" so the engine experiences more resistance. When hot as the oil more runny, less resistance.

Not exactly a scientific explanation, nor necessarily a fact! - just my thoughts.

[s6boy]

Mine did the same and also wouldn't start again when switched off from hot 90'+as though flooded and.
Coil pack and leads replaced and both problems disappeared.

[Whitey]

Depending on how it was last tuned and how long since the last tune up, it will vary from around 700 - 950rpm hot or cold idle. Aircon and/or fans on will effect it too.

You will probably experience an increase of 100rpm when the engine is hot.

Main thing in my experience, is that if it's idles lower than 700rpm after 1 minute of starting from cold, or lower than 700rpm when hot, then get it looked at asap.

Might be something simple, but also lowering revs is a sign of the valve clearances closing up.