Oil Temperature Gauge

[Dannyb]

I have fitted a new Lucas Oil temperature gauge to my Spit 1500.
Problem is it does not register above 50 deg. I first has the sender unit fitted to the sump and now have it fitted to the side of the engine where the pressure  sender is fitted. I know it works as I have connected it to the water temperature sender and it registers a reading.
The oil must be getting hotter than 50 deg and the sender came with the gauge.
Any ideas ?

[piman]

Hello Danny,

no, not necessarily, oil doesn't heat up as quickly as the water in the engine, and your readings sound quite realistic.

Alec

[JohnD]

Can you remove the sender, and keep the oil in?

Set up a pan of water on a camp stove, or improvise.   Propane torches are often designed to be laid on their side while working.
Arrange to measure the water temp and put your sender on a long lead, so you can put it in the pan.
Heat the water while measuring its temp and observing the guage reading.
You have now calibrated your sender/guage, and confirmed - or proved faulty - it's functioning.

John

[Velocita Rosso]

Off topic......Alec , sent you two PM`s
Mike

[Dannyb]

Ok I have tested the sender unit in with hot water which was measured as 70 C.  and the gauge was about right.
so how long do you have to drive before oil gets to operating temperature
Does it matter on the grade of oil. mine is 20w60

[RobPearce]

It depends a lot on the driving conditions but at least twice as long as the coolant. Remember, the hot bits of the engine are all in the top, where the coolant is, but the oil is all in the bottom - only a carefully limited amount dribbles through the rocker gear. It takes especially long if you have a cooler without a stat...

[andy thompson]

At least 10 miles to see 75-80 deg on my 2000, no oil cooler - more on a cool day

[Nick Jones]

Oil temperature rate of rise is fairly revs dependent - the more revs, the more heat so if just pottering about it'll never get very hot.  In my experience, 1500s are usually pretty good at getting their oil hot but I'd not argue with Andy's figures.

Nick

[Dannyb]

Took the Spit to work this morning. 40 miles around the M25 between 60 and 80   and the oil never moved above 50C

[JohnD]

Quoted from Dannyb

Took the Spit to work this morning. 40 miles around the M25 between 60 and 80   and the oil never moved above 50C

Do you have a thermostat on the oil cooler circuit?     50C is too cold, oil not working well.
John

[Dannyb]

I do have an oil cooler and it does have a thermostat.   Maybe I should block the radiator see if it improves as I would not know how to test it.

[JohnD]

Try "temp-tabs", one-time use adhesive stickers that show the highest temp reached. If the hoses between t'stat and cooler never heat up the 'stat is seized closed.  If they warm up after a short, 5 min drive, it's seized open.
John

[Dannyb]

Thanks JohnD, I'll give it a go.

[Nick Jones]

With a 50ºC max oil temperature on a 1500 the oil-'stat is either seized open or opening way early.

The one I had on my Herald 1500 (90ºC opening IIRC) used to take about 15 fairly fast miles.  When I went back to 1300 (small crank) it hardly ever opened and I eventually took it off.

Nick

[Clive]

You could try removing the cooler, or at least bypassing it (loop one hose to join the 2 take-off plate connections) see how that affects temp. But I think Nick could be right about the thermostat, as you have already checked the calibration.

[Dannyb]

I think you are right because when stuck in traffic for awhile on my way home on the M25 which is normal on a Friday night.
The oil temp started to climb a little and then when I Started to move along 40+mph it went back down.
I'm now thinking , do I need an oil cooler at all.  The hardest drive I do it the RBRR.

[Clive]

Now you have a gauge, try it without a cooler and get some readings.

Service kits for the thermostats are available for about £12 (bottom of page)
https://www.merlinmotorsport.co.uk/s/oil-system/oil-thermostats

[Dannyb]

Thanks Clive

[Dannyb]

Update.
Checked oil cooler thermostat in hot water and it operates OK. closes when the water is cooled.
I have since added a sandwich plate that now take the oil pressure and oil temperature senders. This is fitted on top of the oil cooler sandwich plate.
I'm now getting the correct temperature readings.
I have read a few threads on this and other forums that say the sender should have oil running across it rather than in a blind hole of an adapter on the block.

[Chasj]

Hi. Not on a "proper"car but my Skoda has both water temperature gauge and, via the computer, oil temperature.

The water soon gets up to 90 and stays there however driven. I always bring up the oil temperature read out, not pulling too many revs until the oil heats up. Running temperature being 95/98 and can take 10 miles to get there. Always careful not to rev. too much until oil hot for the sake of the turbo.

On a classic I have always driven on the oil pressure gauge when starting off, keeping revs down until oil pressure doesn't go too high, ie,until it reaches running temperature. Not a believer in loosing oil pressure too much above standard.

In the late 60s to 80s use to run and race Morgans with both crossflow and Lotus twin cam engines. Instead of fitting a high pressure oil pump I used a high capacity pump but I swopped to a standard spring, result 45psi at all times, also with some 40% more flow available didn't need an oil cooler. However did run a slightly larger sump and larger spin off oil filter, prior to which, using a paper/felt filter a Wooler aluminium ribbed casing.