Low Oil Temperature

[Ryan.Rx_]

Hi All, My first post on FDOC UK!

I imported my 99'FD RX-7 last July and after a number of issues with the car and DVLA managed to get her on the road.

However, whenever I'm driving it the oil temperature is rather low. When cruising it hovers around 65 - 75 C and on the motorway sits right around 60 -65.
Driving very spiritedly i've seen around 85 - 90 C max which is still not the highest. I feel like its a little low, especially if I want to get on it when I've been cruising and wanted some opinions.

The car is running V mount and has the twin oil coolers. Its running the stock Twin turbo's in parallel rather than sequential with all flaps removed.

My questions are, what do other peoples FD's run at oil temperature wise when cruising and driving spiritedly etc.?
Should I worry that the oil temperature is quite low like this?

I've done some research and found that the stock FD oil thermostats open at around 60 -65 C which matches what I'm seeing.
The Rx8 supposedly has the same thermostat in the oil cooler, however this opens at around 105 C which I think is a bit excessive.
However in the states there are a few companies making thermostats which open at around 80 C. This sounds like a nice temperature.

Has anyone else looked into this or should I just stop worrying and drive the thing?

Thanks in advance
Ryan

 

[Jake_rorx7]

Hi Ryan, welcome to the forum And nice 7!

Yeah that temp sounds kinda low, but I suppose it would depend on what oil you are using the the particular viscosity at x temperature...

I have twin oil coolers on mine and no temperature sensor, but I think my oil must be a bit cold like yours, as when I don't rag it, I can get a bit of moisture buildup in the dipstick/oil cap from the oil not getting hot enough to get rid of the water.

Obviously its a different world, but for a reference point, the VAG cars I tune for a living run 0w-30 synthetic (as all modern stuff seems does) and the comfortable range of oil temperatures is anywhere from 60-140c, sitting around 100c under normal driving. So based on this information, a 100 degree thermostat sounds about right, maybe an 80 degree one if you drive hard or use it on track to get it to open a little easier and get better flow. But different oil is different oil, our mineral stuff might not tolerate as high temperatures as the synthetic stuff does. The way I see it is, the maximum oil temp will be down to your oil coolers cooling capability, and your minimum temp will be down to the thermostat.

Or we just need to drive harder!

 

[Ryan.Rx_]

Hi Ryan, welcome to the forum And nice 7!

Yeah that temp sounds kinda low, but I suppose it would depend on what oil you are using the the particular viscosity at x temperature...

I have twin oil coolers on mine and no temperature sensor, but I think my oil must be a bit cold like yours, as when I don't rag it, I can get a bit of moisture buildup in the dipstick/oil cap from the oil not getting hot enough to get rid of the water.

Obviously its a different world, but for a reference point, the VAG cars I tune for a living run 0w-30 synthetic (as all modern stuff seems does) and the comfortable range of oil temperatures is anywhere from 60-140c, sitting around 100c under normal driving. So based on this information, a 100 degree thermostat sounds about right, maybe an 80 degree one if you drive hard or use it on track to get it to open a little easier and get better flow. But different oil is different oil, our mineral stuff might not tolerate as high temperatures as the synthetic stuff does. The way I see it is, the maximum oil temp will be down to your oil coolers cooling capability, and your minimum temp will be down to the thermostat.

Or we just need to drive harder!

Thanks for the response, yeah I have also come from the VAG scene, although my Dad an FD years ago. My Golf ran at around 90 under normal conditions up to around 100 when beating on it. Generally I'd expect oil temp to be similar coolant temp which on the FD is around 85 so 60 feels a bit low for me.

Japan is obviously a much warmer climate than the UK so I'd be interested to know if UK cars got a different oil thermostat but can't find any information on it.
Mine has a Greddy gauge with warning lights, the light goes red at around 70 and goes green at around 85 from memory which I guess is what the previous owner had it set at. Sounds like a much better operating temp to me.

 

[jdmr_neil]

Oil temp should be around 85-90 usual driving iirc.

Sounds like your thermostat is stuck open, cheap part and an easy swap.

Just replace it, you'll be done in an hour

 

[Ryan.Rx_]

Oil temp should be around 85-90 usual driving iirc.

Sounds like your thermostat is stuck open, cheap part and an easy swap.

Just replace it, you'll be done in an hour

Thanks for the response, that's what I would expect for oil temp also.
As you say its probably worth getting 2 new ones and installing them and see how it goes.

I'm interested to see what temp others see when driving normally and when driving hard.

 

[Spendyrx]

Awesome name! Are you a son-uva digger?

 

[marco]

where are you measuring the temp?

 

[jdmr_neil]

Thanks for the response, that's what I would expect for oil temp also.
As you say its probably worth getting 2 new ones and installing them and see how it goes.

I'm interested to see what temp others see when driving normally and when driving hard.

I recall i used to get well above 100 on track.

I had this very same problem 6-8 months before i sold my fd and it was exactly a you described. A running warmed engine was only only reading 60-65 oil temp and dropping a low as 40s if cold and on the motorway.

Thermostat was around £30 new and the 3 or 4 bolts on the filler neck and it just pulls out behind that.

There is only 1 by the way.

 

[Ryan.Rx_]

I recall i used to get well above 100 on track.

I had this very same problem 6-8 months before i sold my fd and it was exactly a you described. A running warmed engine was only only reading 60-65 oil temp and dropping a low as 40s if cold and on the motorway.

Thermostat was around £30 new and the 3 or 4 bolts on the filler neck and it just pulls out behind that.

There is only 1 by the way.

Thanks for the response again. So there is an oil thermostat on the engine also? I was referring to the oil bypass thermostats in the oil cooler/s. What does the oil thermostat on the engine do? Have you got a part number for it?
Thanks

 

[Ryan.Rx_]

where are you measuring the temp?

Good question. I'm not sure where the giage is plumbed in. I went to check but it's super windy and I've nobody to hold the bonnet I'll try to check later

 

[Ryan.Rx_]

Thanks for the response again. So there is an oil thermostat on the engine also? I was referring to the oil bypass thermostats in the oil cooler/s. What does the oil thermostat on the engine do? Have you got a part number for it?
Thanks

As far as I'm aware there is no Oil thermostat on the engine, on a diagram I see a pressure reg but no mention of a thermostat. As far as I'm aware the oil stat is only on the coolers which make the oil bypass when not up to temp

 

[jdmr_neil]

I'm talking about the coolant thermostat. It's behind the water filler neck. Its closed until your water gets about 60-70 degrees then opens to flow water around the channels inside your engine to cool it. If this thermostat is stuck open which yours sounds like it is then water is always flowing and your engine oil can't get hot enough because the coolant water is cooling the engine down.

If i remember the heater blower won't be very hot either of this is the case

 

[Ryan.Rx_]

I'm talking about the coolant thermostat. It's behind the water filler neck. Its closed until your water gets about 60-70 degrees then opens to flow water around the channels inside your engine to cool it. If this thermostat is stuck open which yours sounds like it is then water is always flowing and your engine oil can't get hot enough because the coolant water is cooling the engine down.

If i remember the heater blower won't be very hot either of this is the case

Coolant temp isn't the issue mate. I have an analog gauge and readout from the link which both read around 80-85 which is fine, just the oil which runs cool

 

[jdmr_neil]

Ok mate, sorry i must have missed something. Not to worry, brainfart day, don't mind me!

 

[JoeLanger]

As far as I'm aware there is no Oil thermostat on the engine, on a diagram I see a pressure reg but no mention of a thermostat. As far as I'm aware the oil stat is only on the coolers which make the oil bypass when not up to temp

The oil thermostats are built into the coolers AFAIK

TBH I don't see 65-75 being low, although I've never took too much note of mine, like Marco is hinting at depends where it's being measured

 

[Ryan.Rx_]

Ok mate, sorry i must have missed something. Not to worry, brainfart day, don't mind me!

No worries, it's a valid point, if the coolant temp was low then it would probably pull the oil temp down

 

[Ryan.Rx_]

The oil thermostats are built into the coolers AFAIK

TBH I don't see 65-75 being low, although I've never took too much note of mine, like Marco is hinting at depends where it's being measured

Yeah they are built into the cooler, they open up flow to the radiator once they reach temperature.

I'll find out where the temperature is being measured and feedback.

 

[jdmr_neil]

My running temp was about 90 and up to 130 on track, that was temp taken from the sump which is the hottest part of the path.

I think if your taking the temp after the coolers then 65/70 is probably right and proves your coolers are working well.

 

[Ryan.Rx_]

So the oil temperature is being read at the oil filter.
The sensor goes into the head of the banjo bolt. Looking at the diagram I found it seems this is the return from the oil coolers. Can anyone chip in?
If it is the return oil flow then I'm happy with the temps I'm seeing as it shows they are doing their job!

 

[marco]

Yeah, pretty sure that is post oilcooler from memory.