Hi guys,

My oil temp during normal driving is around 56°C (133°F). I initially thought my oil thermostat was stuck open, but after replacing it there's no change at all. I suspect this thermostat might simply just can't keep it warm.

- SakeBomb Garage Dual 25-Row Setrab Oil Coolers
- Mocal 80°C (176°F) Oil Thermostat
- 99-Spec Front Bumper
- 3D Printed Oil Cooler Ducts
- Electric Water Pump
- GReddy VMIC
- A/C deleted

Would really appreciate getting your opinion and advice on this. Thanks a lot!

(Now I just tape my bumper openings up...)

 

Twin 25 row coolers on a street car are giving you exactly what they were designed to do. Block one of the coolers with a cardboard and drive again. Downsize to 19 row and you'll be fine

 

I have the Sakebomb dual 19 row kit, and the highest temperature I have ever seen was around 210 while driving The Tail stuck in 2nd gear uphill in a little traffic during DGRR.
I don't log, but track days are usually around that temperature or less because of the speed. I have a 93 bumper cover oil cooler openings, and no ducts. Running the typical 10W-30 Valvoline VR-1.
25 row oil coolers are probably better for endurance track activity than the common street driven applications or occasional track days.

 

Whats the temp where you live outside?

 

Thanks all for your kind reply!

Right now it's around 15°C or 60°F where I live. If I leave the car stationary and idling the oil temp will eventually warm up, but once I start driving, it cools down very quickly even at very low speeds.

For a short 15-min driving between work and home, I almost need to tape up both my bumper openings completely to warm up to normal temperature.

 

Thanks all for your insight!

Right now it is around 15°C, 60°F where I live. If I leave my car stationary and idling the oil temp will eventually warm up, but once I start driving it goes down immediately, even at low speeds.

For a short 15-min drive between work and home, I have to tape up both my bumper openings completely for the oil temp to reach normal temps. A car with tape or cardboard slapped on will never look right. So right now I am revising my 3D printed duct to feature a screw-on cover.

 

I'd be happy to arrange shipping if you want to print an extra one for me!

 

Curious, what are your coolant temps? Super cold coolant temps can affect your oil temps to a degree as well.

Also, if your oil thermostat is working, the low temps should be spikes not sustained low temps. Still not good but you should be seeing is a sudden drop from something close to your target oil thermostat temp to a low temp when your oil coolers are actually being used. Temps would go back up then drop again over and over with the single thermostat. There is no way you would get a sustained low temp if you oil thermostat is actually bypassing the oil coolers! If it is sustained, something is wrong. Your oil coolers should not be doing anything until the oil is hot enough, no matter how large they are. Switching from the single thermostat to the newer SakeBomb Smart thermostats on each cooler should get rid of the cold temp spikes.

 

Oil thermostats allow a certain amount of bypass even in the 'closed' position. The mocal minimum bypass seems to be quite large. See this post from another member who resolved his temp issues by switching to the Improved Racing thermostat.
https://www.rx7club.com/3rd-generati.../#post12573819

 

Interesting!

 

If running a single Mocal thermostat you can get a ~$20 rebuild kit with a 200F open temp. I did this with my custom dual 25 row kit.

Make sure you get the right one for your Mocal thermostat model

 

I was thinking about this too about the oil thermostat but I didnt want to comment on something I wasn't 100% on

 

I was thinking about this too about the oil thermostat but I didnt want to comment on something I wasn't 100% on

 

have you tested your thermostat? you should be able to see exactly whats going on if you chuck the thermostat and a thermometre in a pot of cold water and warm it up on the stove.

 

I did, but I probably wasn't doing it right. I put both old and new ones in almost boiling hot water and did not observe any notable movement.

The SakeBomb cooler kit came with 95C (203F) thermostats, which I suspect might be stuck open, so I replaced it with an off-the-shelf 80C (176F) one. Honestly, I don't intend to test it again, at least not for now. To take it out, I had to remove intake, intercooler, radiator, electric water pump just to get to the two 10 AN fitting on the back, and of course, drain oil/coolant before all that. Then bleeding, making sure there's no leak... etc.

Though it's never great to make any assumption, considering the probability of having two oil thermostat both stuck open pretty low, hmmmm... Yeah.

Anyway, I almost finished up my new cooler duct design (now featuring a cover). Let's see if this works.

 

The way to do it is bring cold or warm water to the boil and observe what temp they start to open. The OEM one was supposed to crack at about 80 something C iirc
but yeah, they should be pretty fool proof. It might be something else.

 

Years ago I warned that even with the stock R1 twin oil coolers you need to block the second one because the oil does not heat up in winter.
The second cooler acts like a large heat sink even when bypassing.
I block off the opening with a towel.

 

UPDATE:

I took my old oil thermostat completely apart and put it in hot water. It turned out, it was indeed working properly.

I actually measured the shaft extension just to be sure, but here is a funny video of the thermostat just kicking itself against the bowl.

 

UPDATE:

I took my old oil thermostat completely apart today and tested it. It turned out, it was indeed working properly.

I actually measured the change in shaft length, but that's nerdy, so here's a funny video of it kicking against the bowl.

 

Really appreciate all the help. Well, now I know this little thermostat is not enough to regulate temperature, at least now when driving in winter with two big *** oil coolers...

Here's what I plan to do about it. And yes, for competition use only. Don't even ask. Because racecar lol.

 

Are you all referring to the thermostats that are actually in the oil coolers themselves?

 

just swap it for the 200F one and test drive it. It could be a simple cheap solution.

 

No, mine has aftermarket dual oil coolers with a remote thermostat located at the bottom of the engine. Not an onboard unit.

 

I drive all winter here and my oil sits at between 135~145 F when warmed up, It will drop below 100 F at pace on the freeway with the coolant at 85 C..

What is the concern with the cool oil?

BTW the turbo love the cold air. Maybe that offsets the ticker oil (15W40 all year around)?

 

Condensation build-up in the oil, engine is designed to operate in a specific operating temp so will lose some efficiency with cold oil but hot coolant.