jscott82

When the car is "hot" can you feel hot a air being exhausted in front of the RF wheel? I'm wondering if the thermostat in the oil tank is opening...

Do you have an IR thermometer to gauge the input and output temps on the cooler?

If you the IR, I would check each cylinder temp and see if you have one oddball that is Lean/hoter than the others... is, check the distributor belt.

Or maybe the gauge is just off... IR will you that too.

fast_freddy

RS spoiler

I'll check when I drive it next, likely tomorrow.

earossi

I'm not certain that you have a problem. Normal operation is that the engine thermostat prevents flow of oil to the oil cooler until the oil has reached a temp that generally corresponds to about the 7:30 position on the temp gauge at which point the thermostat opens releasing oil to the oil cooler located in the right front fender. With oil coming to it, the fan will be on low speed. On a warm to hot day, low speed fan operation will usually not be sufficient to stabilize oil temps particularly if you are stuck in low speed traffic. So, oil temps will continue to slowly rise. When your temp gauge sees a temp at or very slightly above the 9:00 position, the oil cooler fan speed will be increased to high speed. At this point you should see oil temps stabilize at the 9:00 position. High speed fan operation will not lower oil temp enough to get back to the 7:30 position until you are able to get car speed up to a point where air flow across the engine begins to affect oil temps.

You should see oil temps in the 7:30 range on a hot day when you are at highway speeds and the tranny is in the 6th speed....with engine taching around 3000 rpm.

Sorry for long reply, but your engine temps may be fine.

As an afterthought, what oil are you running?

jscott82

Well Said...

earossi

Thanks for the compliment. Went to your profile and noted that your engine is all original at 124k miles. That's quite a record! These motors are usually good for 250k miles.....except for valve guides. I've never made it much past 100k without having to do a top end driven by the need to replace the exhaust valve guides. What is your secret?

NYC993

Actually the fan on high setting will lower temps almost all the way to the 8 o'clock mark if you have fan override in an idling car. Otherwise it shuts off a bit higher than 9 o'olock temp.

jscott82

Dumb luck, i guess...

I treat it like an abused spouse... Take her to the track, beat the hell out of it for a couple of hours.. Then take it home give her a warm bath, change her oil, apologize and tell her it will never happen again....

Its up to 128 now.. Its probably time, but I cant find any physical sign of a problem, and I keep looking for one...

I do an oil analysis every year and they all come up clean.. The motor is stock other than a chip and custom exhaust... and it still pulls 289hp at the wheels...

fast_freddy

The reason for the concern is simply that it is running a bit higher than before. I used to be able to drive it around Manhattan in traffic and the temp would not go above "7:30", now this....

Anyway, I mostly run 15/50 Mobil 1. I have run 0/40 too.

vincer77

Your car seems to behave as mine. I am usually between 8 and 9 o'clock. Heck, I don't get the oil level gage to work until 9.

71-3.0-911

Seems fine. I just replaced a bad ballast resistor. Low speed doesn't engage until about 930 position. High speed at 1000. I use the fan override in idle/high temp zones and not moving. Pcarworkshop had a DIY tutorial on how to check this resistor. Sounds like all is well.

JB 911

+1

Fastfreddy, your car sounds like it is behaving normally to me, except,,,, that you mentioned you unpluged the wire behind the passenger headlight to force the fan to always on. If I force my fan on in 95 degree weather, it will maintain the temp to barely above 8 (as NYC993 noted), no where near 9. Perhaps (1) someone plugged back in your sensor or (2) your fan failed. I would do more investigation. I'm not sure I like the unplug the sensor to force fan on as a permanent solution. In fact I don't like that. It has uses, like for autocross, de, maybe, but for a street car, the overide mod is the better option, imo.

earossi

It is possible that your car was not operating "normally" in the past. You have not provided any data to lead one to believe it was operating correctly in the past. But, I have several comments.

First, in your original post you mentioned seeing the engine fan "free wheeling" after an engine shut down. This is not possible since that fan is driven ou directly off the crankshaft. So, when the engine stops rotating....so will that fan. Unless the fan belt is broken. Can you rethink what you observed and clarify it for those of us trying to help you work through this issue?

Second, have you made any changes to any of your temperature sensors? If so, it could be that your original sensor was malfunctioning. I say this since I believe your car is behaving normally now.

Third, I agree with the comment suggesting that you reactivate the two speed cooling fan. You should not have to run the fan on high speed all the time.

Fourth. Did you retain the OEM cover on the bottom of your engine? If so, consider removing it permanently. The cover was designed to reduce engine noise to comply with European laws. Though the cover does reduce noise, it does so at the expense of a hotter running engine.

Last, I suggest staying with the 15/50 oil during the warmer time of year. But, I suggest you run an oil that hasen't been reformulated to lower the zinc. I run either Joe Gibbs racing oil or Mobil 1 for motorcycles which is available in the 15/50 and still has the elevated zinc.

pp000830

I wonder of the guage is really that accurate that any conclusions can be drawn from it beyond a very large change in its position as in pinning or near the top. If you have an OBDC reader such as Durametric one of the variables that the software graphs is running engine temperature. Even in this case a failing or switching out of the sender could conceivably display a change at the gauge? Was the sender changed at rebuild? Another alternative would be to buy a non-contact thermal meter and reference different points on the engine case and head for measurement and then do the same on another 993 for reference.

NC TRACKRAT

"The reason for the concern is simply that it is running a bit higher than before. I used to be able to drive it around Manhattan in traffic and the temp would not go above "7:30", now this..." Global Warming!

fast_freddy

A few new wrinkles...

I've developed a whine from the engine bay. Clutch in, nothing. In first and second gear or idling in neutral, I get the whine. Also, I'm getting highly intermittent warning lights for the belt.

Could the whine be the bearing in the cooling fan which of course puts extra drag on the engine which makes it run a bit hotter?