Oil Temp @ 230!

CDFARMER · 03-07-2004, 08:44 PM

I own a 74 911 with a stock 2.7S motor. Today was my first drive in temps over 80 degrees, my 911 quickly rose to 230 degrees and stayed there in all driving conditions( stop & go traffic & freeway@80mph). My 911 normally runs around 210, so I have not felt the need to upgrade to an external oil cooler yet (cost is also an issue), should I be concerned with the car running @ 230 today, is there an inexpensive alternative to the carrera style cooler? Has anyone tried the PERFORMANCE compact oil cooler with any success? Any info would be great.....thanks chris

MAS · MAS's Garage

The car should not run this hot. My 77 911S (with no external oil cooler), has never seen more than a degree or two over 100C (212F)... and that was only a couple of times last summer when the outside temp was in the 90's (F). Also I only have a 5 blade fan... but my thermal reactors have long since been removed.

One common (and it seems often overlooked) cause for overheating in any 911, can be a clogged oil screen. I'm sure others here can give you more suggestions too. But I would strongly recommend that you get the engine running cooler first before adding any external oil cooler.

-MAS

CDFARMER · 03-07-2004, 10:45 PM

MAS, thanks for the info, I am very new to the car and Porsche in general so your info is much appreciated, is access to the OIL SCREEN you refer to made by removing the sump plate......
P.S. I just returned from a trip to your beautiful city Victoria, I was on Lopez Island viewing a boat for a friend, and took a side trip by ferry to B.C..... THANKS Chris

MAS · MAS's Garage

Hi again,

I don't normally work on my car, so I'm relaying second hand info here... but, yes... to the best of my knowledge access is via the sump plate.

If it's not the oil screen, then have the oil system checked (oil return tubes, etc). Even though 911s are "advertized" as air-cooled, in truth, quite alot of cooling also comes from oil circulation problems.

-MAS

Jim Sims · 03-08-2004, 05:26 AM

There is something amiss with your car; it could be a clogged oil sump screen but I think the problem is more likely elsewhere. Clogged cooling fins or dirty engine mounted oil cooler (most likely the air side is dirty and clogged) or timing is off. There is more; see:

Oil Cooler & Oil Temp...

Jim Sims 1976 911S w/2.7 CIS

rick2 · 03-08-2004, 06:36 AM

Sounds like the oil cooler is dirty I would check that before pulling the sump plate.
I have purchased several engines and some have had a fair amount of grease/ dirt build up on the cylinder cooling fins.

dfw911 · 03-08-2004, 06:49 AM

I agree that the car is running too hot. My 74 2.7 engine rarely gets above 210 in Texas summer heat and runs at about 190 most of the time. Aside from the internal oil cooler and the cooling fins, you may want to check the oil tank. There are baffles inside that can get clogged. When I cleaned and repainted my tank I noticed about a 5 degree drop.

vash · vash's Garage

how accurate is the temp gauge anyways? mine read around 230 all day yesterday. and i have just installed the carrera cooler. i can grab the oil line under the passenger door and it can be best described a "very warm". i think 230 would hurt. and once after the install i got the car up to around 210 on the gauge and took some measurements with an infrared thermometer. i only got 180 at the hot oil line going to the tstat. i think i would like to verify the temp better before getting myself too worked up about it. just dont know how. change the sender unit? maybe a degreasing session on the motor mounting cooler is needed CDFARMER.

cliff

dfw911 · 03-08-2004, 10:28 AM

The sender unit is really easy to change out, a new one is about $20. You also may check to see if your sender type is matched to your guage. There are different senders for numeric and non-numeric guages and it is possible that the PO switched out gauges without changing the sender type.

Jim Sims · 03-08-2004, 10:34 AM

Unfixed? Do you still have your thermal reactors in place? I have to idle in traffic for an hour on a 100F day to reach those temperatures with a trombone cooler! Moving, with the A/C on, I usually don't reach 200F in my '76 911S. Jim

vash · vash's Garage

no, i have a 49 state version, so i didnt ever have them. i wish could check my gauge. i have been eyeballing my kitchen probe thermometer for the past week. but i dont think i could ever jab it into a standing rib roast ever again. for $20, maybe i will just change my sender.
my second thought is that my external tstat is bad. opps sorry CDFARMER! i hijacked.

banjomike · banjomike's Garage

Unfixed,

When the thermostat opens up and oil starts running through the lines up to the tombone, I cannot touch the lines. They get very hot. Your 'stat may not be opening completely.

CDfarmer,

If your take off the strap that hold the fan housing you can tip the fan back and get a flashlight in there to look at the tops of your cylinders. If they are clean then you oil cooler is also probably clean. But if there is gunk that you can see then you may have found your problem, Some people have reported finding rats nests in there. This is important to check because if the cooling fins on some cylinders are blocked with gunk then those cylinders would be running much hotter.

I have never checked my oil sump screen, I guess I will at next oil change.

Does you fan have 5 or eleven blades? If it still has the 5 blade fan on it that could be your problem. Most 5 blade fans have been replaced by now.

Installing an external oil cooler can be REAlly expensive or if you do the work yourself it is only expensive and lots of work. If you call EASY or Parts Heaven (both in the bay area) they will often have used lines, trombones, and thermostats for $650-800. All the little mounting bits and the two new lines which you can get new will cost another ~$200. and if I did it anyone should be able to! Then next summer you can upgrade the trombone to a carrera cooler.

If you don't go over 240 you should be okay, but if you see these temps in commuting and the take it autox'ing you'll have trouble.

rfix'n · 03-08-2004, 03:28 PM

It would be great if someone who knows their external t-Stat is working properly would take some readings with an IR thermometer.

Maybe with 190 on the dash gage take a reading before the external t-stat and before the fender oil cooler. A couple more readings on the return line would help as well.

My car runs a steady 210 when cold outside (<60) but quickly rises to 230 when sitting in traffic. Yet I only get a reading of 180 at the t-stat.

banjomike · banjomike's Garage

I've only used my digital temperature sensor (that is the 5 digits on my hand ;-). There is a difference between the two lines but contact with either when the car is well warmed up hurts.

Adam · Adam's Garage

Ditto on the hot lines.

When my car is running around 90ºC (190ºF), the lines can get very hot. Even in heavy traffic now, I barely get to 195ºF. I have only used my switchable cooling fan once since the cooler was installed.

Even in heavy traffic on a 37ºC / 98ºF day, my car only just reached 200ºF and didn't get breathless and wheezy like it used to in hot weather before the oil cooler upgrade. When I hit the freeway, the temps dropped like a stone.

azasadny · azasadny's Garage

My '74 911 with CIS and Carrera-style oil cooler runs 180-210 degrees F in the Michigan summers (80-high 90's), only on the hottest day, sitting in traffic does it get to 220 or 230...

vash · vash's Garage

mmmm. thanks for the heads up banjo. i may need to get a new tstat. my lines are definately "grab-able". i will take my IR therm next time i hook up with a bunch of bay area guys, and take some notes. the thought of changing out my tstat makes me ill. it was messy enough with a dry system. i am going to valdez my garage!

cliff

CDFARMER · 03-08-2004, 06:20 PM

Thanks guys for the info. I drove the car early today and it did not exceed 210 untill the outside temp went over 90, then once again it hit 230 and even 240+ on a long grade (no traffic). I returned home and read your replies, both the top of the motor and oil cooler @ S-hose look clean and free of any gunk.....I will try to remove the fan to get a better look next......I'm starting to become suspicious of the gauge or the T-stat( which I'm told is not accessible with the motor in place)MORE INFO PLEASE! P.S. the car has the 11 blade fan, I use kendall motor oil and at the last oil change had the valves adj., timing and mixture appear to correct. Thanks Again guys Chris

jjrowe · 03-09-2004, 03:20 PM

I did see some temps like yours when I was stuck in traffic at idle in LA in my 76 911S. The car would creep up to 250F or so. I then installed the front mounted aftermarket lemke cooler from performance products (tried pelican, but they didn't have a full kit for a car that never had a cooler). The kit came with everything that I needed to install the cooler. It runs around $900 I think. Now the car rarely gets above 180F, it made a huge difference. My car has always had the 11 blade fan and does not have the thermoreactors installed. I don't think your temp is that unusual for that car. I was skeptical about the front cooler at first but believe me it works. Definitely check the screen as well, but plan on installing a cooler.

Jesse