Synthetic oil thermal breakdown?

[A1QSHIP]

Get yourself an infrared temperature gun & check before & after temp readings at the oil cooler after a hard run. The IR temp guns have come down in price in recent years & are worth a spot in your track tool box. Before you change the oil establish a baseline, oil pressure reading at a certain oil temperature. Compare this reading with a fresh oil change pressure reading at the same temperature. This could tell you that your oil is breaking down when it gets hot. Get a good sample of oil when you drain it & send it off for analysis. Cut the filter open & look for any obvious metal debris from the bearings.
HTH, Chris

[diesel des]

The oil your using is a easter and is very good. I would send some for analysis....

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[tomwood_uk]

Glad to hear the track day went well Alex. For your reference I'm using the same oil and oil cooler setup as you. I did a track day at Oulton around this time last year and during the 20 minute sessions I was out on track I didn't see the oil temp rise above 130deg as far as I remember. It certainly heated up rapidly on track, but seemed to recover fine and settled back to normal running temperatures (90-100deg) for the motorway journey home. May be worth noting than I'm not recirculating any crankcase pressure in my setup. Hope this helps.

[20Vcqdriver]

I use this oil in mine. Thought I had an engine issue last year as oil temps started to rise to 130deg on hard use (Like you is fun weekender so gets ragged a bit more than normal). Turned out to be the oil thermostat in the filter housing. Since then oil temps never get above 110deg max and usually stick at 100deg even on hot days

[macspring]

Turned out to be the oil thermostat in the filter housing. Since then oil temps never get above 110deg max and usually stick at 100deg even on hot days

Can I ask how you got to establish that it was the thermostat in the oem filter housing that was the culprit ?

Did you change something inside the housing or just replace the housing altogether with either a second hand one or a new one ?

Thanks.

[PRY4SNO]

Agreed on the used oil analysis.

Also, have a browse around the bobistheoilguy.com forum for more info on the technical aspects of automotive lubricants.

[20Vcqdriver]

Can I ask how you got to establish that it was the thermostat in the oem filter housing that was the culprit ?

Did you change something inside the housing or just replace the housing altogether with either a second hand one or a new one ?

Thanks.

I swapped the inards (spring and stat body). At the time the engine was fairly new (done less than 10k since rebuild) so this seemed a logical culprit. especially as I have a larger oil cooler rad. no issues since.

[macspring]

I swapped the inards (spring and stat body).

Thanks for reply, sorry to harp, but with new ones or second hand ?

Thanks again.

[varia]

hard to read, but tons of good info here:

https://540ratblog.wordpress.com/

[Error404]

Just to update this, it's actually a mechanical issue.
Started the car today, first time since last week and zero oil pressure. Gauge barely flickered and the dash pressure warning chimed after a couple of seconds so I shut it down.

So I'm guessing either oil pump drive is loose on the crank, relief valve spring is broken or the oil pickup is loose.
Good timing really as I was going to take the car to bits next week anyway. Will carry out a full inspection. Hopefully no damage to the bearings.

[diesel des]

Oh dear...

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[newsh]

Mate, I thought it had to be mechanical. I had oil go thin at the track before now and the tappets start rattling..
Thank god it didn't happen half way round a lap at the track!

[Error404]

Yeah it's all a bit lucky the timing of things.
I'm intrigued to find out what the problem is. Will get a mate to give me a hand to push it into the garage this week and start the strip down.

[SteveH]

Sorry to hear it's more than an issue with thin oil. It does sound like you may have caught it just in time. Fingers crossed the crank and shells are ok.

[diesel des]

Did you ever have noisy tappets?

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