Problem:
Cruising on the freeway at a steady pace at 80mph and 3600rpm, my oil temps get up to 245 F on 90 F day. At 70mph the oil drops to 230 F. I am measuring the temperatures at the stock location oil filter with a RB oil pressure / temp adapter and an AEM analog gauge. From all my searching, it seems these temps are ok at this level, but what concerns me is that this is only under cruising conditions. If I were racing on a track or having fun going up some mountain switchbacks, I would be at much slower speeds, at much higher RPMs, and for longer durations. Is it time for me to run dual stock FC oil coolers in parallel? What are your thoughts opinions on anything I've mentioned?

Car:
87 GXL, turbo swapped with small/medium FMIC. I'm using the stock undertray (noticeably dropped oil temps) but modded it a little to fit with my FMIC. I'm still utilizing the s4 mechanical OMP. I'm using the stock turbo so its all oil cooled. The engine and turbo are s5 JDM, but with US manifolds and accessories. JDM s5 trans w/ short 5th gear. A local rotary shop did the swap, so SOME specifics I may not know.

 

An interesting post I found during my research:

Is it POSSIBLE that the shop that did my swap used my old NA oil pump and thats why I'm getting such high temperatures even while cruising?

 

If your running 6 port turbo, doubt they switched it. If your running full TII engine, your most likely running stock stuff regardless.

 

FMIC's can have a significant impact on airflow to the radiator and oil cooler. The cooler could also be fouled up and may be able to benefit from cleaning.

 

I agree with the above poster. First thing to do is to make sure the oil cooler is clean and air can flow through freely. If an oil cooler line has ever been leaking with that cooler, the dirt has much better clinging ability with that oil. Start with the small stuff first. Many people run FMICs and don't need a dual cooler setup.

 

Its a 4 port s5 turbo motor.

How would one go about cleaning an oil cooler? Should it be professionally done? I've never had a leaking line and it is the original oil cooler that came with the car new.

 

+1. the FMIC blocks the airflow to the oil cooler, so this is step 1. step 2 is to pull the thermostat out of the oil cooler and check/replace it.

 

What about the FMIC in step 1?

 

How are you still running the stock S4 pump with the S5 engine?

 

The often stated normal oil temperature range of 195-230F and maximum temperature of 250F are measured at the oil pan, which is prior to the oil cooler. Your temperature gauge measures at the oil filter pedestal, which is after the oil cooler. Racing Beat recommends a maximum of 205F at this point. As others have stated, it sounds like your oil cooler is clogged or has a stuck bypass valve. Engine damage will probably occur if the oil temperature exceeds 250F, so you may want to stop driving your car until you can fix the problem. You may also want to check to make sure your gauge is accurate.

 

as other have stated there is something not working properly with your oil cooler, I have a stock one and while Auto-X my oil temps dont go above my coolant temp (185). I have the electric fan of the mercury Villager, shimmed oil pressure regulator (about 100 psi) and the Atkins thermal pelet on the e-shaft.
Clean it and also see if you can make a duct that goes straight to the oil cooler

 

^ Holy cow I've got a serious issue here then. Time to stop driving the car until its sorted out unless I want to burn the engine up. Thanks for your help everyone.


s4 front cover

 

Fmic is a likely cuplrit..
had the problem too, even with a HUGE aftermarket oilcooiler.
Now i went V-mount with dual oil coolers, but now i have troubles getting oil up to temp. Need to add an oil thermostat.
Temps on the track never exceeded 90C

 

^ Though my FMIC is in the direct way of my oil cooler, I'm still running the undertray and should have at least a decent amount of flow to my oil cooler. I know other people have been just fine with even bigger FMICs than mine even on the racetrack.

 

http://fc3spro.com/TECH/MODS/EL/GAUGES/otemp.htm

 

Thanks guys. I ended up taking it to a local rotary shop and they stated that my FMIC was to blame. It is a custom setup situated about midway between the front grille and the AC cooler, so maybe its just the airflow due to my FMIC that just so happens to divert air around the cooler.

 

Hey guys, I'm still having problems here.

I took it to the local rotary shop and they said it was the position of the FMIC that was blocking the stock oil cooler. So they put dual 9 rows (in parallel) in each of the factory s4 brake ducts and ducted them. They had to put them several inches backwards and a little at a sideways angle to get them to fit since s4 brake ducts are so small. However, my temps are still out of control. In 95F degree weather outside, I was cruising in 5th gear at 80mph and got my temperatures to get to 220F. I'm sure the temps will get way higher if I were to push my car and have some fun with it.

Here is some interesting info. I've done some testing and when my temps are past 180F, if I let off the throttle and coast in neutral, I can noticeably see the temps drop like a rock. After 10 seconds of coasting at freeway speeds when the oil temps were at 220F, they dropped to 210F. Whenever I am going up a steepish hill on the freeway, if I give it 40% throttle or so, I can see the temps rise.

Is this a problem with my oil coolers not being big enough or getting enough flow, or is it some mechanical issue?

 

Your using 20w/50 oil right?

 

Yep, Castrol GTX 20/50

 

this is why i hate front mounts, you lose 2 necessary major cooling components to baby the third.

mazda had the right idea when they located everything priority wise anyways. the oil cooler doesn'[t impact coolant temps via cooler location that much, air temps are NOT as critical as everyone thinks who is running a front mount.

in fact your whole engine cooking via increased coolant and oil temps usually negates the benefit from having a front mount in the first place.

v-mount or bust with rotaries.



anyways, to answer the initial question from TA, make sure your timing is not severely retarded or that your leading coil pack is dead. had a customer months back who was running his car on trailings only unknowingly and could never solve his temp issues until i went to dyno tune it, low and behold no timing induction from the leading coil(in essence running 15 degrees retarded and on inefficient firing plugs). he did make somewhere around 250 wheel horsepower like that though! lol.

 

maybe a bad pump or something or not enough pressure maybe theres tons of sludge in the block causing ur pressure to look normal but the flow is worse. idk just some ideas

 

Its a brand-spanking rebuilt engine though, so there shouldn't be sludge...

Oil pressure is perfect according to the stock gauge (yes I know its inaccurate, but it serves well as a general indicator).

I agree a v-mount would have been a much better idea, and priority-wise the oil and water coolant temp is MUCH more critical than air temps. However, all my research indicated that oil temps should be fine even when adding a front mount. And ever since I upgraded my radiator too, my coolant temps have never been better despite having a front mount now. Compared to my stock radiator on my n/a setup, the turbo setup's coolant runs much colder.

I'd have loved to have gone v-mount, but for a daily driven California street car its not feasible. I didn't want a top mount because I didn't want to have to get a non-turbo hood that didn't perfectly match the paint on the rest of my car, nor did I want to repaint the car.

I'll check my timing, thanks Karack. lol @ 250hp from only the trailing plugs.

I forgot to update this thread. I got a R-magic replica front bumper, and it has vastly larger brake duct openings than my stock s4 front bumper. Since my oil coolers are placed in the brake duct locations, the R-magic bumper let a significantly larger amount of air flow into the brake ducts. Ever since then, my oil temps are from 160-190 even on the hottest days, but I haven't driven the car hard yet.

I think I fixed the symptoms, but there has to be a main cause somewhere that still needs to be found.

 

Time to try a thinner oil? If you change to a 0W20 synthetic or a 5W20 conventional, the oil will be less than half as thick at operating temp. Your oil flow through the cooler(s) will increase and so will your heat rejection.
Throw in the improved flow at start up and you have a winner.

 

I never thought about changing my oil weight since I live in the valley of Southern California in a suburb of Los Angeles and the absolute coldest my car will ever see is in the 40s.

 

I've been using 20W50 for ever in my 90vert. I have also been using 15w40 diesel oils from time to time, based on my Porsche buddies enthusiasm.

I just changed to a 'thin' synthetic oil in my 90vert. Dino oil price has increased and Synthetic has decreased in my area. There is only $4-5 difference per oil change, so I went synthetic.

Cold engine cranking speed at 60* was noticeably faster. Not that it was a problem before...


I am not an expert, but I did stay in a Holiday Inn...