308 oil cooler fan upgrade... should I?

I absolutely love driving my '85 308 GTSi into work every Friday. Often on these warm summer days if traffic grinds to a crawl I can literally watch my oil temperature needle slowly climb to the top of the gauge range. I've never had the system "overheat" but it's concerning to see it all run that hot.

Has anyone added a thermostat and small shrouded fan onto their oil radiator to kick-in independent of the water cooling system? If I do this, I plan to have the fan on a set of easily removable clamps so I can pull it off for car shows.

Any recommendations on whether this is something I should do, or tips on how best to implement the upgrade?

-Will

 

Topic regularly discussed here, and over the years.

Six weeks ago:

http://www.ferrarichat.com/forum/308-328/463595-relationship-between-oil-temperature-oil-pressure.html

On the "old forum":

FerrariChat.com: Thoughts on installing fan for oil cooler on 308

FerrariChat.com: ATTENTION 308 OWNERS: OIL COOLER FAN INSTALLED LOOK!!!

Rgds

 

Doesn't make much of a difference. That last thread above is mine and that was almost 12 years ago now so I have had a lot of use out of it.

Frankly, I bet you don't have an actual oil temp issue, If your water temp is staying normal but the oil needle is swinging right in traffic, it is an likely an electrical glitch somewhere. I am dealing with that now. It took me two years before I noticed my oil temps "dropped" back to normal when I turned on my lights (I don't drive it much at night).

Go drive your car again until the oil temps shoot up and then turn on the lights and tap the gauge and see what happens.

 

i know my oil pressure gauge levels out to normal temp when i turn the lights on, otherwise it reads a bit low...

 

Thanks, all. I'll give the lights idea a try this Fri on the way into work after it gets all warmed up. I'm not at all surprised with electrical glitches on a car this old, nor one with such a wonderfully bespoke, hand-crafted wiring harness.

 

It was warm enough today on the return drive from work yesterday that the oil temp crept up. I tried the headlight idea, as well as turning on/off the AC but it didn't swing the needles so prob not an electrical glitch. Gonna scratch my noggin some more.

 

I drove my car in the heat and traffic home yesterday as well. In stop-and-go on Lawrence I also had the oil temp heading toward the right side of the gauge. Water temp was just over 195 but the oil temp continued to climb. I finally stopped the engine at red lights as the gauge indicated around 270F. I've contemplated a fan before but I'm going to pursue it. 270F is in the high range for conventional oil and approaching bad things, and it is disconcerting to see the needle that far over on the gauge. I have a few ideas for a fan, I'm going to tinker about tomorrow and see what I can come up with.

Probably dropping the temp sender in boiling water at the next oil change to see how accurate the gauge is would be a good idea as well.

 

If it's not a sender issue, I'd say your oil cooler is probably full of junk (sludge). I'd swap the cooler out for a new one. Bet that makes a difference.

 

Hmmm, I hadn't thought of compromised exchange efficiency, but that is a possibility. The oil filter stand was super clean inside when I had it off and that's the next immediate stop after the cooler, but there was definitely a film on the heads under the cam covers. Worst part is I had the cooler out of the car for a year and I could have been soaking it in something or sent it out of cleaning during that time. Perhaps a missed opportunity.

 

It is difficult to believe that the water temps are normal but the oil temp is 270.

I'd look very hard at the oil temp sensor/gauge before changing anything else.

 

I agree but most modern syn oils do just fine to 320+.

270 was considered high for oil of a very different time.

 

Mine started doing the same thing last month. Oil at 270 and water was fine. Bringing it to Newport Beach Ferrari for Paul (308 guru) to check it out.

Will - Bert put a larger oil cooler on his 308 and is happy with it. You would have to look very hard to tell the difference. I would contact him and also ask if he received any deductions for it. He is not on FCHAT.

 

My cat is a '79 but I have never seen temps like that even on hot days. The water temp may reach 195 but the oil does not rise much above that.

If indeed the oil is rising that high, I would be concerned. How does the oil pressure respond. Is it still within the normal range at idle and 4,000 or so RPMs? If the pressure is down then the oil is thinning out too much and the temp in likely exceeding the ability of the oil to remain viscous enough.

Many good ideas have been suggested. I would start with the senor and then onto the flow of oil. On the latter, it is hard to believe the oil is not flowing properly if the pressure is normal. Could there be any obstruction in the vent to the oil cooler (sounds dumb but better to verify)?

 

Please let us know what they find.

 

Thanks for the info. I did notice that the oil pressure was low at idle. I will let you know what he finds out.

 

Oil temperature can't be much higher than coolant. At 270 oil temperature, the coolant would have boiled over before. As you advised, your water temperature is in normal range, I presume no coolant vapour being released, so most likely everything is fine just 'averageness' of oil temp sensor and gage. Am interested in your finding once you have it checked out.

 

I just don't get this at all.

I have had my car for almost twenty years and the oil temps never ever were any problem until just about two years ago. Now I will almost peg it on the highway at 70 mph on a 60 degree day. Water temps normal.

 

Have you checked the actual temp with a separate manual gauge? I agree with you, I cannot imagine what could suddenly change in the oiling system that would cause such a temp change other than if the oil cooler suddenly had no airflow due to some sort of obstruction in the airflow.

 

We are pretty sure it's an electrical problem somewhere in the maze of circuits. New temp sender and different gauge changed nothing. Those were the cheap half hour experiments that I did myself.

 

Dr. Tommy -

If it bothers you, I'd swap out the oil cooler for a new one. If your cooler is full of crap, and the oil doesn't have time to do it's "heat exchange" - you'll have higher temps.

It's not super expensive, and maybe a little messy, but relatively easy.

 

I have thought about that but if I pull mine, can't I just flush it out?

Seems like a lot of people around here have replaced theirs but I don't get doing that unless there is a hole in it. How hard would it be to soak in in a solvent, rinse it clean, dry it and put THAT one back on?

Some reason why I shouldn't do that? Just asking.

 

You won't get it all out.

You'll get some of it out, soaking with solvent, but you won't get it all out. Solvent only works if you can contact the goo. If it's so thick the stuff won't contact - you won't remove it.

That's why radiator shops take the radiator apart to clean it. Flushing it can only do so much, but not completely cure it.

Oil Coolers aren't stupidly priced. For all the work you are talking about doing, you could have the thing swapped.

 

What do they cost? Ballpark.

 

Brian A had a leaking oil cooler and wound up getting a used one because he was unhappy with what he found when trying to get a new one. The replacement part he got was not nearly identical to the old one. He said, "The original oil cooler for the car (Ferrari part number 106965) is NLA as a new part. The new black oil cooler pictured earlier in this thread IS the replacement oil cooler as supplied by Ferrari (part number 145712). It is a significantly different design, with bigger fins and larger tubes, but much less radiator surface area."

I didn't find the 308 oil cooler on Ricambi's webpage. Tom Vail has a listing for $895. TRutland doesn't have a useful webpage anymore.

If the OEM style oil cooler is cheap and available I'd love to know more.

 

I chatted with Bert about that during the FCA meet. He has a fan that he clamps onto the exchanger that he takes off for the show. The thermostat and electrical hookups are extremely well concealed.

It's easy enough to pull the exchanger off and give it a flush in the opposite of the normal flow direction to see if anything comes out.

I also really like Brian's idea of checking gauge calibration with some boiling water.

If I can swing a few dedicated hours in the garage next weekend I'll see if I can try both.