hosrom_951

Now, i know that after hard driving or if you use the turbocharger, you should let the car idle for a few minutes to cool down the turbocharger.

Now, does this apply when you do NOT use the turbocharger? basically i cruise to work and college, never getting over 3,000rpm and never even hit 1bar (factory gauge). Should i also let it idle? i do that anyway, but i am just curious.

Secondly, when replacing the expansion valve for the climate control, does it require any special tools or proceedures? or is just 'remove old expantion valve, place new expantion valve' mojo?

Mike Murcia

You'll get mixed replies, but you don't really need to let your car idle at all. We have waperpumps for the turbochargers that run for at least 30 sec after you shut the car off, cooling the turbo. If it's still hot, the thermostat will keep the pump running.

I've never replaced the expansion valve on my 951, but I've done it on my '84 and it only requires simple tools and patience.

azmi951

Look for the post about ac retrofit, very recent. a fellow rennlister did a great job explaining this.

hosrom_951

Hmm....who else does/doesn't leave their cars idle for cooling?

NZ951

Only after hard driving, if I am off boost the turbo does not get hot enough to warrant it. Its a function of revs...

hosrom_951

So it would be alright to turn off the engine after a cruise and a/c was on all the time? ONLY leave it after high reving and/or hard driving right?

NZ951

Yup, if you look at the logic based timers like the greddy unit, they add time to the cool down period based on rpm... meaning a hotter turbo etc. I dont even have water cooling on my turbo... weight saving and cleans up the bay.

hosrom_951

Hmm.........well.....its VERY hot here, and i am running 0w~40 oil grade (very thin). SO, i guess i would rather leave it idle just a little bit to help in cooling.

Does anyone know if the Mobil 1 15w~50 is out of production and replaced by the new 0w~40?

NeedPorscheSpeed

Here in the states, I purchased some 15W-50 just the other day.

On topic, until I read this thread, especially Mike's and NZ's logical responses, I have always let the car idle for a couple minutes after driving, whether I drove hard or not. From now on, I think I'll just let it idle after hard driving.

hosrom_951

Well...........i would let it idle for a bit if the water temp is high or if the fans are on.

poormans9fitty1

Let it idle. Yes the cooling still goes through the system, but the oil is not moving. It is the buring of the oil on the turbo that reduces turbo life. Now I am talking like 1 min of idle at the most. Even after hard driving you really only need to let it idle for no more than 2 min. But in your heat, let it idle for a little, 30 sec, even after you are nice to it.

theedge

After hard driving I let mine idle. Easy driving ill usually give it 30 seconds or so, just as I put faceplate away, put sunroof on, things like that.

Tom M'Guinn

I only let it idle if I've really been boosting hard. I tend to drive it easy for a while before shut down, rather than sitting at idle. Beside, worst case, you need to change your tubro a bit sooner...and of course that is just an opportunity in the making....

For all the hype, how many people --who change oil regularly -- have actually coked-up the bearings in the turbo ?

hosrom_951

Well, if the fans are on, i wait (on idle) till they switch off (at normal driving).

If i was driving hard (using the turbo) i cruise for 5~10mins letting it cool down. Then at idle, leave it for 1min or so.

Even when the fans are not on, i leave it for 1min to just cool itself (normal driving).