D-4d Warm Up

[bobbarnes]

The manual for my 03 Corolla 2.0 D-4D states that the car should be driven straight from cold and not left to warm up by idling.

On heavy frost mornings like we're having at the moment I run the engine with the windscreen heaters and fans on whilst I scrape down the outside.

Does anyone know the reason why the car shouldn't stand and whether I am causing any potential problems with what I consider my normal cold weather start routine ?

[PaulT]

Does anyone know the reason why the car shouldn't stand and whether I am causing any potential problems with what I consider my normal cold weather start routine ?

←

With the petrol versions there is a risk of overheating the catalytic converter if the car is left idling for 20mins or so. I wonder if it is the same for diesels?

Presumably if the cat gets too hot it de-natures and will no longer work.

Paul.

[Black Knight]

With no load on the engine it takes longer for the engine to warm up. This means it has to run richer for longer which will be less fuel efficient. Also the oil will not be lubricating as well when it's cold.

Basic reason is to speed the warm up time up. Shouldn't be caning it from the get go though as that's worse

[Kudos+]

Basic reason is to speed the warm up time up. Shouldn't be caning it from the get go though as that's worse

←

i heard that, toyota reccomend u drive first couple of miles before reaching high rpm.

[Jones~32]

Basic reason is to speed the warm up time up. Shouldn't be caning it from the get go though as that's worse

←

i heard that, toyota reccomend u drive first couple of miles before reaching high rpm.

←

I'd reccommend that in any car, not just Toyotas

[bobbarnes]

This means it has to run richer for longer

I'm not sure if this is a diesel thing but even when it's very cold from start the revs stick at the normal 800 unless the fans are on. I'm used to petrols where the auto choke causes the higher revs. So is the mixture actually richer ?

One other point is that the D-4D takes a hell of a long time to warm up when driven from start under normal conditions. And the same to cool down. Again, not sure if this is normal for all diesels.

[selfbuild]

Diesel engines do take longer to heat up.... it's normally a good 5mins before I start feeling any heat in the car (I hit the recirc button to help clear the windscreen on frosty mornings).....

And yeah, I don't know why, but when I first start the car the revs are approx 8-900rpm.... turn the fan on and it shots up to 1100rpm without the a/c on....

Has your car got air-con as i'm wondering whether it gets confused and thinks that the a/c is on when it ain't.

[bobbarnes]

Yes the I've got a/c and it's exactly as you describe it. I was a bit surprised as

it's not on - just the fan.

Also, I couldn't quite work out the purpose of the recirc button as I presumed you'd always want fresh air from outside. So recirc keeps the air warmer and does a better job on the windscreen ?

I take it you run the engine whilst waiting for everything to clear ?

[selfbuild]

I only use the re-circ when it is frosty, with the engine running, to help clear the windscreen faster..... any heat in the car will get recirculated and it seems to boost the fan..... try it yourself... the fan noise increases so therefore must be pushing more air to the windscreen. Once the windscreen is clear I turn it off and turn the fan down.

The recirc button is also best used when using the a/c on hot days as it keeps in inside of the car nice and cool so your not drawing all that hot air in from outside.