This should be a source of alarm right?
It certainly caught my attention. However, I am pretty sure I’ve worked out what’s going on and why I’m not going to worry too much over it and I’m certainly not going to fix my thermostat. No way, no how.
That picture was taken this morning after my second track session. The first was cut very short — three hard laps and then we all got black flagged and went back to the hot pits to wait to go back out as a spec Miata lost an entire wheel, tire, rotors, calipers and all, and was sitting in a likely impact zone. I’d have just kept on driving myself, but the Miata driver felt the need to spin into the dirt. Some people just can’t handle change I guess.
While sitting there idling in the hot pit my CEL came on and I noticed that the gauge looked even a shade worse than the photo. I went back to the paddock fearing I was puking oil on the track or blew a gasket or who knows what.
Got back, checked the oil, and it was a little low. But you know how dipsticks are sometimes hard to read especially with hot, thin oil but since I ran back five sessions and did a couple dyno pulls the day before I’d walk to the pro shop and get a quart and let the engine cool and a fresh ($20!) quart and a cool engine and my pressure was fine again.
Next session I watched the gauges and all was perfect across the board. Went to the paddock and left the car running at idle to see how it would react and took the above photo.
When I bought the car I noticed the thermostat must have been stuck open as the engine and it’s oil never gets warm enough but it’s a track car so why fix a thing you really don’t care about. It’ll be plenty hot, no need to regulate it. I think this has masked how worn the bearings are in the car by keeping the oil from getting very thin. So there’s always oil pressure. There’s also oil pressure when I’m driving even when it’s hot and thin.
I’ve never driven the car hard and then stopped and sat at an idle before. I now know that it’ll read super low so hey maybe don’t do that.
I think the reason this old engine has lasted as well as it has for as long as it has (130k miles) being abused and neglected is partly due to the neglect.
Had someone bothered to fix that thermostat the engine would run roughly at the same temps as it does on the track (take another look at the photo) this thing would have been running with that low oil pressure every day. This car would have been in the boneyard long ago.
So a big shout out which of long list of previous owners who let the thermostat fail and to all the subsequent owners who never realized or cared that the gauges never pointed where they should. I think it’s what’s kept the car alive.