quattrorunner

So a few weeks ago I asked about my hot oil temps. Since then, I have repaired one oil lint to the front cooler(the worst one), checked the ignition timing, adjusted the fuel mixture, blocked off the backdated heater hose allowing more air to flow over the cylinders. The car runs smoother now, but still hot (9 to 10 oclock). So now, my next thing I'll do is install my carrera oil cooler and add the mr2 turbo intercooler fan I got on ebay. I'll make a good shroud and seal it. Then I'll be repairing the other oil line. Does the oil thermostat allow oil to bypass the cooler if it has resistance like in my case of a crimped line? If so, I think I could be going in the right direction I need to get passed these issues so I can get to bigger and better projects
Any thoughts?

Edward

Hi Quattro,
AFAIK, the thermostat operates on temp only, and is not sensitive to pressure. So if you have a crimp or some other impediment restricting flow, the T-stat will not "behave" any differently, but you will (obviously) have decreased flow to you cooler.

But, I do think that you are moving in the right direction. A Carrera cooler, properly ducted, will solve your temp issue; the fan is necessary only if you get stuck in traffic, but if the car is moving air, the carrera cooler is a capable/ample heat exchanger. FWIW, we've had 100+ degree temps the past two days and I just had my SC Trackmeister out to "exercise" it ( ). With no fan but a completely sealed/ducted carrera cooler, my needle never climbed above 8:30, which is prob about 210 or so ...and that was with, uh, "spirited" driving with the RPMs up there. Hope this helps.


Edward

quattrorunner

Yeah, thanks. For a while I was wondering if I may have broken a stud but I have no sounds or other symptoms that would indicate it. I have a fresh oil change I don't want to loose the oil so I can't check the studs yet. I'll update on the repair.

theiceman

Just as an FYI

I checked my studs recently on my sc. I parked it in the garage and let the car idle for about 2 minutes, to pump the oil out of the crankcase back into the tank. I then jacked up one side at a time the next day while I checked the studs by removing the lower valve covers. I think I lost about 500ml total on both sides, hardly any came out...

ice

glenncof

Quattrorunner,

I quickly scanned the previous posts so pardon me if I missed something.

I have a 1985 911 in Norhtern Cal. Normally the temp guage is below/at the first mark. On hot days, stuck in traffic, it will creep over that but not get to the second mark.

I have had the guage approach/over the third mark when I had a bad thermostat. Hot day, stuck in traffic, it would start blowing smoke. Replacement required partial engine drop.

My understanding is the therostat diverts oil to the cooler.

I believe you replaced the sensor (which should be replaced if thermostat, or I once read).

Have you considered the therostat ?

quattrorunner

Are there two thermostats? I thought about the one on the inside of the pass rear fender. Is there another that would require a partial drop? Are we talking about the crankcase breather area?

quattrorunner

bump

Edward

Hi quattro,

AFAIK, there is the one T-stat that you have referred to. Closed, it diverts oil back to the engine; open, oil goes forward through the lines. I "think" what he's referring to is the temp sender which, IIRC, is buried in the nether regions and is best replaced when the engine's out. I could be wrong on this, but I do not believe that the 3.0/3.2s having more than one T-stat. Perhaps a real guru (Peter? ...Steve W.? )could chime in on this.

Edward

ron mcatee

The engine thermostat is on top of the engine next to the small tempsending unit. A second thermostat is in the right rear wheel of equiped cars with a front oil cooler. Usually the thermostat opens at around 180-190 F allowing oil to flow to the cooler. On the 87-89 Carrera's a fan was added to cool the oil and the cooler had a temp switch that came on at approximately 244 F.

Edward

Hi Spider,

Interesting... So what is the function of the engine Tstat? That is, where does it route the oil to when it opens? The engine-mounted oil cooler, maybe? I thought that one was always in the circuit regardless of temp?

Edward

quattrorunner

Update. I have not repaired it yet, but did find something today. As mentioned before, I have a smashed part of the line to the cooler up front. Well taday, I watched it close while idling and at the point that the thermostat opened, I noticed the line was hot till the dented part and not after it. So I feel confident that this is it. It does get hot after a while but I feel this is a major restriction. Good news.

ron mcatee

Edward, the engine T-stat opens at around 180-190 F. If the T-stat is failing, it may only open part way and not allow full flow to the engine oil cooler, thus engine temps go up. It is always in the curcuit, but it can cause temps to go up if not operating properly.

Edward

Thanks, Spider. I didn't know about this other T-stat as I had always assumed that the engine oil cooler was always "in the loop" irrespective of oil temp. On a side note, for the later cars with lines to a front cooler though (be it trombone, 28-row, or carrera type), I can only speculate that the tiny engine-mounted cooler has a modest effect on overall oil temp when the circuit beyond the fender-mounted Tstat opens up. No data behind this ...just guessing really.

Good deal, quattro. Now you're on your way to normal temps.

Edward

ron mcatee

There is still a lot of air generated by the alternator fan. Any blockage or interruption of that flow will have an effect on cooling air going across the pistons. As engines got bigger,i.e. 2.7 and up, the additional cooling from an additional oil cooler was needed. My old 2.0 liter 69 911 motor did a very good job of cooling through only the engine oil cooler. Even when I autocrossed and ran tracks like Hallet in the Tulsa area, I never got over 220 F. The harder I ran it, the better it performed. Never had to put a front or fender mounted cooler on it.

quattrorunner

I do everything in small steps. I installed the cooler, repaired the lines, and cleaned the top of the engine. I still need to install the fan. The cooler with shroud and seal around it seem to help a lot. It takes longer to get to 9 oclock. It will still get there and above in trafic. I can's seem to get it to come down much once it gets there even on the 60- 70 mph freeway. I still don't have any scoops or the fan installed so thats next I guess. My gauge is the red and hollow white type. I am still not sure it's too hot. When it was at 10:00 once, I put a thermometer between the filter and tank to see and it came to 220. I think this is OK hot temp as long as it's accurate. Any ideas or thoughts?