Oil Temp Issue?
Thread Starter
Heel & Toe
Joined: Aug 2013
Posts: 16
Likes: 0
From: Smithfield Maine
Oil Temp Issue?
Recently purchased '92; put about 3k miles on it driving back to Maine from Florida. Noticed that the oil temp hardly left the lowest setting but every once in awhile it did climb up a little and then go back down as though (maybe?) the fan came on to cool it. Is this normal? If not, what might be the ave. temp? 
Should I replace the oil temp switch? I don't have a shop manual yet so I'm hoping that someone can give me some sage advice.
Should I replace the oil temp switch? I don't have a shop manual yet so I'm hoping that someone can give me some sage advice.
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
oil temp should be near the eng coolant temp. More under high stress conditions.
Oil is the primary method of heat transfer from the top end of the engine. Its slower to drop off heat because of its viscosity. Dense materials hold heat longer but they absorb more.
Your FSM will guide you thru the diagnostics and repair process for your yr model. Sensors are all same spot by filter, some may be different depending on clusters, eng type.
Good luck
Oil is the primary method of heat transfer from the top end of the engine. Its slower to drop off heat because of its viscosity. Dense materials hold heat longer but they absorb more.
Your FSM will guide you thru the diagnostics and repair process for your yr model. Sensors are all same spot by filter, some may be different depending on clusters, eng type.
Good luck
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
The oil temp is not linked to the fans so a indicated increase in oil temp was more likely linked to a increase in coolant temp
, the two are directly related , typically oil temp is slightly above the coolant temp ( w/ dino oil 15-20 above ) which would turn on the fan.
The oil temp switch is located in the oil gallery port above the oil filter
(before anyone comments , a oil pressure switch on a 3rd Gen is shown in the pic )
Last edited by vetteoz; Sep 3, 2013 at 05:48 PM.
Thread Starter
Heel & Toe
Joined: Aug 2013
Posts: 16
Likes: 0
From: Smithfield Maine
The coolant temp was just below mid scale most of the time; would get a little higher if stopped or stuck in traffic. Wasn't smart enough to check the gauge against the digital reading; guess I was too excited about driving my new toy. None the less; would the lack of a consistent gauge reading indicate the need to replace the sending unit?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Oil has to reach a temperature of 212 degrees or higher to boil off any water which is byproduct of combustion. That insures a long oil life and protects the engine from premature wear. Most cars run around 220. I'd suspect a bad Sender or Display. These Senders are thermistors meaning their resistance decreases as their temperature rises. Therefore, an open Sender or harness would read Low and a grounded harness would read Max. Test by disconnecting and checking your Gage. Then ground the harness and see what it shows. If those results are correct, replace the Sender.
