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Oil temperatures
rodgling - 4/8/13 at 04:08 PM

These have been a bit high lately (not just the hot weather, they're a lot higher than they used to be on hot days). Seeing 120 on track where it used to be 100, so need to figure out why.

Took the oil cooler off today and flushed it out with petrol, then replaced. Made no difference. I did notice when filling it with oil prior to refitting that after pouring oil in one side, it took a fair while to come through to the other side. Is this normal? Wondering if it's blocked up & I should replace the cooler?

Could also be the oil stat not fully opening? Think this very rarely breaks though?


britishtrident - 4/8/13 at 05:39 PM

120c isn't that high with modern synthetic oil, synthetic oils are fine at that temperature range, remember more engines are killed by cold oil than hot oil.



How long the oil takes to fill the cooler depends on the oil viscosity grade at the low end of the range, if you are running an oil with a treacle like cold viscosity it will take a long time to run through.


rodgling - 4/8/13 at 06:05 PM

Yeah, 120 is not a big concern, it's the fact that it used to be 100 that worries me. Also that was with backing off on long straights and doing short stints as the oil temperature was still rising at 120 and I didn't want to go higher.

Oil was 5w40 btw, not particularly thick at ambient today.


bi22le - 4/8/13 at 06:38 PM

Did you see my post the other day? I was dealing with 150+.

I have made some additions to cooling that may help cool the oil although the change may not register on the temp gage, just take tge edge off. Ill be fitting an oil cooler this winter. Just need to get through the rest of the track days for this year.

I used slightly thinner and cheaper (commar) oil when I went to the ring last year. The temp went over 120 and the engine did start to sound a little loose so I backed off straight away and got to the pits. Changes the oil for a thicker grade fuchs pro R and have not looked back.

On sat with temp 150 my keen ear could not hear any concerning noises like before and sounded very tight and healthy when in the pits so I have no concerns with damage being caused at the higher temps.

If your new to your car or have improved its handling at all this makes a big difference. 18 months ago I was supprised and concerned to see 120. Now due to harder driving and more time spent on the gas I work the engine far harder. This is a combination of improved driving skills, a better set up car and just more guts due to feeling comfortable with the car. My friend who was driving my car last weekend on track did not see 120 and he is no slouch, just not used to se7ens. I woild go out out 10mins later and it would bo off of the gage!

May be this is the same for you?


rodgling - 4/8/13 at 08:30 PM

Yeah, I did see your post - 150+ would really worry me! Can't see the rest of this year being as hot as Bedford though, so you should make it through to winter to fit a cooler.

Don't think it's down to my driving - I was lifting off quite a bit on the straights to try and give the car a bit of a break. It's a nice idea though :-)

Anyway going to try changing the stat and take it from there.


bigfoot4616 - 4/8/13 at 08:37 PM

what are your coolant temps like? they have a big affect on oil temps.

last year i was seeing oil temps of 120+ and rising after 10 mins on track, fitted bigger oil cooler, ducted rad and cut out some cooling vents which all helped to prolong the temp rises a little but 15 mins was generally my max time i could stay out for.

over winter i fitted an alloy rad(same as the radtec) in place of the standard polo one i was using and it made a big difference.
the highest oil temp i've seen this year has been 102 after a 25 minute session at knockhill on a very hot day recently.


rodgling - 4/8/13 at 08:54 PM

Coolant temps are bang in the middle as always, massive alloy radiator makes sure of that. So pretty sure it's not that.


bi22le - 4/8/13 at 10:00 PM

My water temps are also always good.

I have an oil to water sandwich pkate ti aid cooling, dont think it's man enough though.


DH2 - 5/8/13 at 08:16 AM

quote:
Originally posted by bi22le
My water temps are also always good.

I have an oil to water sandwich pkate ti aid cooling, dont think it's man enough though.


If you have a heat exchanger, and your oil is 150 (which is when synthetic oil starts to break down, generally), then how is your water temp not getting dragged up by the oil?

DH2


bigfoot4616 - 5/8/13 at 07:09 PM

you would think it should do. when i've had high oil temps the water has always been within about 10/15 degrees below the oil temp.

even without the heat exchanger you would expect water temps to rise as the oil temps do due to heat soak through the engine.