Is this oil temp too high? How to fix?

[Dallas56]

I bought a Superformance about four months ago, Keith Craft 351W stroked. I now have about 1,000 miles on the car. All bugs resolved save for a lingering concern about high oil temp. Running around the neighborhood on a 100 degree afternoon, stop and go, with some aggressive acceleration and rpm in low gears, water temp reaches (all temps Celsius) 100, maybe 102. Oil temp eventually reaches 120, maybe 122. On a cooler day, cruising at a steady 3,000 rpm on the freeway, temps are lower, water may reach 90 and oil 100. I never smell burnt oil or see smoke at the engine. I have an oil cooler, and it is installed, with one line running to oil filter and other to engine block. My oil temp sensor is at the oil filter, not the pan. Radiator fans are in the right direction, and both are working. Smiths oil temp guage. I have researched past threads on this topic and talked to several owners, still have these questions.

Is oil temp of 120-122 too high? If so, what should I do about it? Is there a way to check the accuracy of the temp sensor at the oil filter or the accuracy of the Smiths guage? Should I replace both to make sure I am getting accurate temp reads? If 120-22 is too high and temp reads are accurate, what next? Larry Carlson

[bobcowan]

122*C (252*F) is pretty high for what you're doing. My oil temp never gets nearly that high unless I'm on the track. Otherwise, it's usually fairly close to water temp.

My first question would be, "How accurate are your gauges, both water and oil?" Go to the local hardware store, and buy an infra red thermometer. They're inexpensive enough now that they're a valuable tool. Drive the car around and get it hot. Then let it run in the open agarage for a few minutes to let everything stabilize.

Check the temps of the metal water thermostat housing, and the bottom of the oil pan. Although not perfectly accurate, the temp readings will be pretty darn close.

[Got the Bug]

120 is getting pretty high if that temp is sustained. I think a range of 90 to 100 is good. The Roush dealer that I bought my motor from said that my oil temp could reach as high as 110, which it has on extremely hot days when I'm climbing a long uphill grade.

Could be a bad gauge. What weight oil are you running? Also, is your water temp fine (i.e. steady at 90 c)?

[vector1]

could use a laser gun and check the temps.

[Mark IV]

Test the guage using boiling water on the sender. The most common oil temp issue is too cool, not too hot.

[JBCOBRA]

Where is the timing set?

[Rick Parker]

Generally speaking the oil temps with a cooler installed will be at or below the water temps unless you are on the track and running the engine in the upper RPM band consistantly, then 30 to 40 degrees higher (F) would not be out of the norm. This is assuming no abnormal problems within the engine.

[Jerry Clayton]

We saw a SPF in our shop where the oil cooler was a dummy and wasn't hooked up---just had two hoses stuck back into the fender wells

[madmaxx]

Thankyou, it is the only way, when it boils the temp is 212F. infererd is not good for absoulte temps but relative. You get the emissivity value wrong, which you will, you will be off by 30f. you buy a cheap $40.00 and point 1 foot back and you are taking an average of about 1 foot diameter. Get a pot of water and an thermometer and be done. By the way I tested my water temp gauge (smith) it was dead on.

Your oil temps are tooooo high, you should never see above 100C unless youi are hammering it for a long long time.

Originally Posted by Mark IV

Test the guage using boiling water on the sender. The most common oil temp issue is too cool, not too hot.

[WardL]

I'm sure modern day oil can handle these temperatures. My Audi oil temp gauge shows 250 F (121 C) when it is right in the middle of the gauge temperature range. My oil temps are about 85 C when it is 70 F. If you add 30 F (17 C) to the ambient temp, my 85 C temp could easily reach 100 C. Better if some others in hot climates chime in, but I would not do anything. It responds to different operating conditions as expected.

[CWizard]

Dallas-
What does your engine builder say about the oil temp?
If you haven't confirmed that the oil cooler is plumbed properly, then that would be worth checking. If you elect to check the accuracy of your gauge, handle it with care. The small metal tube that goes from the sensor to the back of the housing in the dash is rather delicate, so avoid sharp bends or kinks. It contains the working fluid (ether) and a small hole will cause the thing to fail. You should be able to set up some kind of portable heat source so you only have to remove the sensor from the oil filter adapter, and dunk it into the water bath. Be sure the sensor doesn't touch the sides or bottom of the boiling water container.
Good luck.

[Tom Kirkham]

http://clubcobra.com/forums/showthread.php?t=101134

[Goopie 18]

My SPF (Roush427R) runs at 80C both oil and water. 95-100 outside temp in hot southern Fla. Use Valvoline 10-40 fossil oil. Fans should both be turning counter clockwise

[Excaliber]

I've seen and personally talked to several owners of small block based engines that mention high oil temps. I don't know, but I'm getting a hunch that small blocks run hotter oil temps, generally speaking, than big blocks do?

Is it possibly because of smaller oil pan capacities? The cases that I'm specifically aware of were not large capacity pans. My pan, with filter, holds about 11 quarts, most of the time it's all I can do to get the oil temp up to a reasonable amount. I don't run a cooler, nor would I want too! Even running the engine HARD on a track it might get up to 100 c, on a hot day, thats as high as I've ever seen it.

"Rule of thumb" seems to be 250 F is about as high as you want to go with oil temp, by the way. Over 300 F and it's bad news for sure.

[Got the Bug]

90c is probably going to be sweet spot for engine life and contaminent burn off.

[Dallas56]

Very helpful, all. Thank you. It sounds like I may have a problem.

In response to some of the questions, oil (recently changed) is Valvoline 10W-30, oil cooler is connected (one line to oil filter, other to engine block), fans are both working, and both correctly turn counterclockwise, pulling air through radiator and oil cooler.

I bought an infrared thermometer (accuracy +/- 3%) today, ran the car up to water 100C/212F and oil 120C/248F by guages. Using the infrared thermometer, I shot the oil temp sensor housing at the oil filter (without pulling it) and surrounding oil filter hardware. Highest temp was 102.2C/216F (compared to guage reading of 120C/248F). That suggests my oil temp sensor may read a little high, but I don't know what temp loss is from inside oil and sensor to hardware outside and so, don't know. I then shot the oil pan, highest reading was 115.5C/240F.

I took some oil pressure readings today at different temps and different rpms, am giving those to one of the SPF experts, who will talk to me about viscosity recommendations.

Given comments of CWizard and others, I am a little nervous about pulling the oil temp sensor to test it myself.

I may have car taken in to the guy here in the Dallas area who is best for Cobras, have him check accuracy of oil temp sensor and guage and plumbing of oil cooler. If reads are accurate and oil cooler is plumbed correctly, then we can have a discussion about next steps.

Again, thank you all. Enjoy remaining weekend.

[bobcowan]

It does sound like you have a problem. More like a concern, actually. A good synthetic oil will handle those temps just fine, but the temps are kinda high. it also sounds like your gauge is fairly accurate. Not perfect, but few of them are.

Another question is, does the cooler work? Maybe your thermostat isn not opening. But even not working/connected, temps should be lower.

What's the pressure? That's another thing that will increase the temp.

[madmaxx]

+/_ 3% if you are shooting with an emissivity of 1. To get a emissivity of 1 paint a black circle where you are taking your temp and hold as close as possible.

It is sooooo easy to test. Remove sensor let it hang. Boil water in kitchen, take pan to car and put probe in, you will not loose but a couple degrees of temp in your pan, then monitor temp on the way down. I hate to tell, gauges are painfully accurate or at least mine is.

[vector1]

if it was mine i wouldn't worry about it after the readings from the laser gun. i would use the gauge as a relative indicator and fix it sometime in the future. but worry, no. your pan should be the hottest reading.