Smoke coming out of the intakes.

[Crono0001]

Sounds like you have a problem that needs to be addressed. Fans should turn on if temps rise.

[epapp]

The AC will activate the low speed fans if they are not already running. 212F will also activate the low speed fans. The temperature will dance between 201.8 and 212. How quickly the temperature swings will be determined by the ambient temperature, water pump health, airflow through radiators etc.

Crono: that picture is most likely of the post-01 cluster. The temp gauge is much more buffered than pre-01 and sits at the point shown to relax the monkey behind the wheel a bit. Pre-01 will dance up and down following the actual temp of the engine more closely.

Perfectlap: why is idling in traffic in neutral horrible in your opinion?

[Perfectlap]

I had it checked out with the Autologic, no issue was found.

Crono Your fans turn on (high) right away when you hit traffic?

Epap, enigne idling in traffic gets EXTREMELY hot. I heard Jake Raby make a similar comment about this being no good,
I think it comes up in the low t-stat threads or maybe about the importance of proactively replacing the water pump every 4 years.
That being said, I'm not sure how much running the fans on high is going to help there but I do it anyway.

[epapp]

I buy that it gets hotter than when traveling at 70mph, but the water pump and most parts are still continuously exposed to coolant temperatures (which will kind-of regulate engine temp/heat soak in traffic): the hotter engine bay/trapped heat will heat the block and because there is not much air flow when sitting still, the heat soak will conduct back into parts on the engine, most of it to eventually be dumped into the coolant, and shed off by the running fans. Sure the temps are higher but why in any would it be extremely bad?

At any rate, the fans running will help this situation I would think...

[Perfectlap]

Originally Posted by epapp

Sure the temps are higher but why in any would it be extremely bad?

Jake Raby discuses here:
http://986forum.com/forums/general-discussions/43114-yet-another-ims-solution-2.html#post327793

This engine, by design has the highest loads on the valve train at idle. Internally lubricated components that are only cooled and lubricated by the engine's oil need a constant flow of that oil to provide full film lubrication and to keep them at a sane temperature.

Low speeds have proven to kill these engines more than anything else in my research."

[epapp]

What causes the engines to have the highest load on the valve train at idle???? I don't buy that for a second. you're telling me my 5 timing chains, IMS shaft/bearing and cams/valves are under less stress and load when I'm WOT going through all gears at 5k rpm? The only thing I can think of is the chain tensioners and variocam. Still doesn't make any sense.

The second sentence of Jakes is inherently true of any moving part requiring oil, and mostly just a statement. If I'm not mistaken, the moving parts DO get a constant flow of oil, EVEN at idle...unless the oil pump just decides to take a break < 1000rpm...

I know Jake has a lot more experience than myself with these engines, but this doesn't make sense to me.

[tomonomics]

For a daily driver that sits in traffic for 60+ minutes a day, I can see how that might kill an engine over time. But I don't think that's your case, P-Lap...if I recall this isn't your DD. Turning the A/C on every time you are idling, however, could cause your condenser to fail. (I'm not saying that was the cause, but if you are constantly cycling it off/on every time the temp rises, it deserves mention).

If per Jake R. idle is the issue, why not hold the rpm at 3k when sitting in traffic? And again, if your temp is going that high, there may be another issue. I always thought that turning on the A/C had the reverse effect (I realize the fans in the 986 may be slightly different that most cars), but back in the day we used to put the HEAT when the engine ran hot to bleed off as much hot air as possible. (Insert bad flashback about being in the back of station wagon with the heat on in August).

This is yet another thread that makes it sound like these cars are fragile, and I don't think that's the case.

[jaykay]

As I recall the Vario cam solenoids actuate at 3000 rpm to phase the cam shafts into the proper position for low rpm operation. The actuators extend tensioning the chains in order to effect rotation of the cam shafts. This increased cam drive chain tension is what accelerates wear of cam drive components.

Above 3000 rpm this tension is relived as the cams change phase for high rpm operation. There are other loads associated with wot but it appears the cam drive is the most dominant point of vulerabilty. Oil film strength on cylinder walls seem to be better at higher rpm.

[epapp]

Well then let this be an experiment:

I currently sit in 2 hours of traffic each day, with another hour per day of 75+ driving and high revs. Car is running as lovely as ever, with proper pampering of course. Going through so much gas allows me to run a fuel treatment and injector cleaner almost once every two-three months, more often than normal oil changes, coolant flushes etc. The reality of it is: my car ran ********************!er when I only drove it 10 miles a week. AND, when something catastrophic happens, I certainly will not regret it saying "I wish I had driven and enjoyed my car more before having to throw it away".

I know the variocam activates at 3k rpm(along with a variety of other conditions being met), but the conclusion that anything <3000rpm is 'hurting' your engine is nonsense. In fact, I would go as far as "keeping your revs above 3000 for the sole reason to minimize engine idle related wear" is probably one of the more stupid things I've read or thought about related to my car/engine. And with the IMSB in the picture, that is saying something...

[EJ-Fresno]

Are fuel treatment and injector cleaners really efficient?
Or it's more likely a placebo, especially if you stick to "quality" gas?

Originally Posted by epapp

Well then let this be an experiment:

I currently sit in 2 hours of traffic each day, with another hour per day of 75+ driving and high revs. Car is running as lovely as ever, with proper pampering of course. Going through so much gas allows me to run a fuel treatment and injector cleaner almost once every two-three months, more often than normal oil changes, coolant flushes etc. The reality of it is: my car ran ********************!er when I only drove it 10 miles a week. AND, when something catastrophic happens, I certainly will not regret it saying "I wish I had driven and enjoyed my car more before having to throw it away".

I know the variocam activates at 3k rpm(along with a variety of other conditions being met), but the conclusion that anything <3000rpm is 'hurting' your engine is nonsense. In fact, I would go as far as "keeping your revs above 3000 for the sole reason to minimize engine idle related wear" is probably one of the more stupid things I've read or thought about related to my car/engine. And with the IMSB in the picture, that is saying something...

[epapp]

I'm sure its more of a placebo than not, especially for me because I would never touch anything less than the measly 91 octane we get here in CA...But I like to experiment. I'm sure things like throttle body cleaning and MAF cleaning are much more effective in producing noticeable results. But hey, I'm driving so damn much, a cleaner can't hurt.

[Crono0001]

My fans turn on at a certain temperature, or if I turn on AC. They turn off if there is no AC and it cools to a good amount.

[78F350]

Originally Posted by Perfectlap

AC compressor indeed....

New unit along with belt tensioner and rollers (preventative) parts are $900 and labor is about 9 hours.
:ah:

I had a very similar event last weekend with one of my SUVs. The belt popped off (burned through) a minute after I shut down. I Just finished replacing the compressor and tensioner. About $200 in parts for an 03 Ford.
Compressor bearing made noise on startup for a few days before the smoke, but it went away as soon as it warmed up.

[EJ-Fresno]

Speaking about fans: is it damaging to turn the car off while they are working? For instance, when I get home and park the car, should I wait for the fans to turn off or I can turn the car off without waiting?