Jump to content
The mkiv Supra Owners Club

Oil temp reaching over 130 degrees on track - a bit hot?


downimpact
 Share

Recommended Posts

Has the HKS adaptor definitely got a `stat in it? You should be able to unscrew it and see if it's stuck open or not. I would remove the stock oil to water heat exchanger once you have the `stat working. 52C is far too cool, you need at least 90C running temp for good oil conditions.

Link to comment
Share on other sites

  • Replies 67
  • Created
  • Last Reply

Top Posters In This Topic

Has the HKS adaptor definitely got a `stat in it? You should be able to unscrew it and see if it's stuck open or not. I would remove the stock oil to water heat exchanger once you have the `stat working. 52C is far too cool, you need at least 90C running temp for good oil conditions.

 

Yes, either it is stuck open or it is the low temperature thermostat that HKS sells. That one opens at 75C meaning that the oil will get warmed by the stock oil/water cooler (since the water is 94 C) and then all of it passes through the 30 row cooler cooling it to 52 C.

 

I've been googling and it seems the HKS kit uses the Mitsubishi EVO stock thermostat. So I should just get a new OEM one. They open at 100 C. That way the HKS system will just take care of the excess heat that the stock system can't handle.

Link to comment
Share on other sites

Yes, either it is stuck open or it is the low temperature thermostat that HKS sells. That one opens at 75C meaning that the oil will get warmed by the stock oil/water cooler (since the water is 94 C) and then all of it passes through the 30 row cooler cooling it to 52 C.

 

I've been googling and it seems the HKS kit uses the Mitsubishi EVO stock thermostat. So I should just get a new OEM one. They open at 100 C. That way the HKS system will just take care of the excess heat that the stock system can't handle.

 

Yes, if you have a colder opening `stat that would explain things. Try and get a 100C one and hope it fits! Do make SURE that the thing is a proper fit, don't risk restricting the oil flow!!! Good luck.

Link to comment
Share on other sites

So I got a new thermostat from Mitsubishi. I exchanged it and tested the old one. It opens at 75C. So it was the low temperature thermostat.

 

But the temps at cruise are the same. 52 C.

 

But I noticed that when I slow down the temps rise quite quickly. Much quicker than you would expect possible from simple heating of the oil.

 

So I'm wondering if the way I measure the temperature is right.

 

I have a probe in the drain plug of the oil pan. And I'm thinking that the air cooling the oil pan and the drain plug might be able to cool it enough make it to 52 C. When I stop after driving it rises to 80-82 C in the oil pan.

 

Is there a better place to measure the oil temperature?

Link to comment
Share on other sites

Sump pan is a very good place to measure oil temps, it's measuring the temp the oil pump picks oil up at and sends it to the bearings. I can supply a special oil filter housing bolt drilled and tapped to take most temp probes if you want to measure it elsewhere. Is there any way the pipework can be wrongly connected? If not put thick card over the oil cooler front and rear faces and see what the temps do. If they rise the `stat is playing up and allowing cool oil to circulate through the oil to air cooler still. I have a 38 or something row cooler on my Skyline, yet it runs near 90C oil temps in daily driving, thanks to the `stat in the adaptor housing. I probe via a drilled sump plug...

Link to comment
Share on other sites

The only thing that can be wrongly connected are the hoses going from the take off plate to the remote filter/thermostat. I assume that if they are connected wrongly the filter will not allow any circulation.

 

On the take off plate the center hose flows into the engine, right? And the off center flows to the filter/thermostat?

Link to comment
Share on other sites

Oil should flow into the outside of the filter element, be filtered, then flow from the centre tapped hole of the filter to the engine oil ways. On the engine oil flows INTO the centre hole of the casting of the block, and the outer recess is fed oil from the engine oil pump. I don't like remote filters, I tend to have a sandwich type adaptor with a built in `stat with a filter on top of the sandwich plate. Most of the engines I build are race engines, so the Modine bit (oil to water heat exchanger) is removed and a different adaptor used to mount the sandwich plate direct to the block.

Link to comment
Share on other sites

I went down and checked the hoses once again and they are connected correctly.

 

I then took the opportunity to wrap som neopren from some left over A/C hoses around the temperature sensor.

 

Now it actually settled around 72-75 C and dropped to 68 when I drove quickely but without load. So wind chill could be a factor.

 

The oil senders are these:

 

http://www.efi-parts.co.uk/index.php?productID=125

 

They don't screw in very far into the drain adapter. They end quit a bit inside the drain plug and so does not go into the oil pan.

 

I have bought a new oil pan to have a bung welded on and tapped for 1/8 NPT so it will sit inside the oil and also not so low as it is now (I'm affraid to knock off and loose the oil).

 

I'll also recheck the calibrations. I have calibrated them with a digital thermometer from ebay (chinese stuff) submerged into heated oil, so I'm going to get a proper mercury thermometer to recheck.

 

How do you calibrate temperature sensors?

Link to comment
Share on other sites

Did some more testing. At night it drops to 58 C at cruise. I disassembled the thermotat and everything looks fine. Tested the new thermostat from the EVO and it opens at 100C the old one opens at 75 C. Checked all oil passages in the remote thermostat/filter housing and nothing is blocked. The spring on the Mitsubishi thermostat is slightly softer than the HKS 75 C thermostat so it should allow more circulation out side the cooler (more bypass).

 

So I guess the conclusion is that the HKS thermostat/filter housing allows too much oil to circulate to the cooler at closed condition allowing it to overcool when combined with a larger than standard cooler.

 

Chris, Which thermostat are you using to get 90 C with a 36 row cooler?

Link to comment
Share on other sites

Ok. How did you mount your oil cooler? Mine is behind the intercooler getting all the air that is filtered through that and I have the JZA70 hydrofan setup pulling air through at 4100 CFM (I think).

 

The strange thing is that my automatic transmission is also very cold. Around 55 C to 75 C depending of the load measures in the sump. I also have a temperatur sensor at the outlet and it varies between 95C and 105-110 C depending on the load. It is cooled through two 25 row setrab coolers and they are also controlled by a thermostat. So even with a thermostat it removes 40 C or more.

Link to comment
Share on other sites

That is like I have mounted mine.

 

I have now ordered a new temperature sensor (1/8 NPT) like the ones I have installed along with a temperature sensor that I have a calibration for (I have this dash logger: http://www.powertraincontrolsolutions.com/product/D200/ and it supports a GM 3/4 NPT sensor) and I going to double check that the temperatures read the same.

 

If they do there must be something wrong with the HKS thermostat although I have no clue what. Could the fact that I have retained the original water/oil cooler have anything to do with it?. I assume as it is now it actually adds heat to the oil.

 

How much damage am I doing to my engíne driving around with temperatures between 58 and 75 C in the sump?

Edited by Kristian_Wraae (see edit history)
Link to comment
Share on other sites

I would try what I suggested the other day. Blank off the cooler with thick card, front and rear and see if the temps rise around town. If they do then for whatever reason the `stat is sending too much oil through the cooler when it is "shut", see following! I think all `stats bleed some oil as a by pass even when they are supposedly "shut". This is to make sure the cooler itself, and oil lines are permanently purged of air, and the engine is always going to get air free oil from the cooler circuit when the `stat opens fully. Maybe yours bleeds too much oil...

 

 

Short term, if the sump temps you are citing are right (and I suspect they may not be an accurate indication of the actual sump OIL temperature), you won't do much harm. Long term the oil is not getting hot enough to drive condensed water from the oil, and it will deteriorate far faster than oil run at the correct temp. You will lose some small amount of power, as the too cold oil is more viscous. You will lose some amount of MPG.

 

I see between 100 and 130 degrees Centigrade on track dependent on ambient temperature. Temperature is measured at the sump, it actually has the thermocouple in the sump casting, in a drilled and tapped hole, not in the sump plug, although the result should be similar. Only caveat might be if the walls of the sump or the sump plug draw too much heat from the tip of the sensor. You can get long reach sensors, but I think you may struggle to find a supplier. Cooler fittings and lines are -12.

Link to comment
Share on other sites

I will try the card trick tomorrow. I have calibrated the sensors with this: http://www.ebay.co.uk/itm/K-Type-Digital-LCD-Thermometer-Thermodetector-Thermocouple-Probe-50-1300-/271179330295?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item3f238c32f7

 

When I turn the ignition on but do not start the car all temperatures read the same (EGT, transmission sump, engine sump, ambient and the stock temperature sensor for the transmission outlet as well as water sensor). But I guess I might have calibrated wrong at high temperatures. I used a can filled with transmission oil and three candles underneeth and the above thermometer.

Link to comment
Share on other sites

I tried the cardboard. Today is a hot day so the temperatures rose to around 72-73 and then I stopped with the engine running (after 10 kms driving - water temp around 89C measured by the Apexi Power FC). Removed the cardboard and when I got back into the car the temperature was 78C. Then I drove off without the cardboard and the temps were hovering around 78 to 80 C. This is just around town.

 

I think the sensors are not making enough contact with the oil and are probably just heat soaked by the drainplug/sump-metal and then air-cooled if the speed is high enough.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.