Anyone ever check oil temp

#1 05-22-2003, 10:30 AM

Wondering if anyone has ever checked their engine oil temperature. Where did you install a temp sender and what temps were typical?

#2 05-23-2003, 10:38 AM

The reason I ask this question is because a customer with an SVX engine in their Vanagon has installed a oil temp guage and after seeing temperatures in the 250deg range decided to install an oil cooler. I'm curious if the 3.3L when in an SVX runs high oil temps. Maybe no one has ever checked.

GreenMarine · #3 05-23-2003, 10:55 AM

That sounds kinda interesting...... Maybe I will have to check into that....

svx_commuter · #4 05-23-2003, 11:29 AM

Where is your customer measuring the oil temperature? The suction side of the oil pump is what goes to the engine and should be the coolest, as it came form the bottom of the sump. The top level of the sump would be the hotest as this is where the oil ends up after passing thru the engine.

Considering the thermostat opens at 180 deg F. At some point the radiator temperature will max out at 180F. 250 F is only a 70 difference. That seems reasonable. The oil can only loose heat through the pan when the hot air from the radiator passes over it. So a 180F air current is taking heat away from a 250F oil pan. Add fins to the pan?

What is the ambient temperature for the 250 F ? It would be nice to know if the il temperature goes up and down with the ambient.

Maybe a little duct work would fix it. In the SVX, a duct might be addable under the radiator. Look inside that SVX engine compartment. There is not much space for the air to flow around the engine.

Where would the oil cooler get connect to the engine?

mbtoloczko · #5 05-23-2003, 02:32 PM

250F seems way high for engine oil in a water cooled motor. I had an oil temp sender installed in my VW bug, and the oil in that car regularly ran at 160-180F. If I pushed it hard up a long grade, it could climb to 220F. At 250F, the oil will breakdown in less than 1000 miles and loose its "new" color. I just checked the oil in my car a few days ago, and it looks perfect, so I doubt the engine oil is running that hot, at least in my car.

Earthworm · #6 05-29-2003, 04:59 PM

Saw a 3000GT VR4 and the owner shimmed up the rear of the hood to use induction to reduce the under hood temps. I know it completely destroys the look of the car but I'm sure it works great...especially if one races.

#7 05-30-2003, 10:54 AM

Sorry about the lack of info about my customers car but the high oil temp report was second hand so I don't know about ambient temp or where the sender was located. I am getting the feeling our SVX oil temps are higher than desirable.

Paisan · #8 05-30-2003, 11:02 AM

I have a guage, but haven't installed the sender yet. I'll let you know when I finally get it connected.

-mike

svx1999 · #9 05-30-2003, 02:54 PM

I've sorta wondered this myself..

Just sorta noticed one day while changing my oil, the lil rubber grip stuff on the OIL filter was, well Crispy!... With all the tranny cooling problems it's safe to say the WHOLE thing , car, engine, and everything under the hood keeps warm ......!

I think the SVX just runs hotter then most desire to know..

I"ve yet to install in temp gauge to see if my ( wonderous thought) was correct...

Put 3 pennies down, I bet if someone check's the temps will be wamer then first thought...

happy drive'n
Svx1999

Stevebsy · #10 05-30-2003, 08:35 PM

I have a gauge on the way as part of my turbo project.

When I get it installed I'll post my results.

mbtoloczko · #11 05-30-2003, 10:48 PM

If the SVX motor oil temp does run high, would a lower temperature water thermostat reduce the motor oil temp?

immortal_suby · #12 05-31-2003, 09:40 AM

Probably won't help much going to a lower temp thermostat. Once the thermostat is open the temperature will stabilize just as before after a period of driving. A high flow thermostat will lower water temperature some but I'm not sure how much of an effect it will have on overall oil temp. I've seen many a debate on other forums regarding higher flow of coolant and whether you actually lose some actual effective cooling with how quickly the coolant passes through the engine. The water temperature may drop but the engine temperature may not. It's been quite a few years since I took thermodynamics and I barely passed it then. The answer to that lies with oil temperature change. I'm sure Trevor or Harvey or Beav could provide some info here.

I'm still surprised with the huge oil capacity for our engines that it would be running that hot. Maybe in the location of the engine in the vanagon doesn't provide as good air flow as in the svx. I bet taking off the splash guard on an svx could reduce it some with the increased air flow around the oil pan. Still, with the rarity of engine failures in the svx I bet we can't be running extremely hot.

#13 05-31-2003, 10:56 AM

The fact that all the seals and o-rings that come off a 3.3L that has many miles at all are crispy is another thing that makes me think they run hot. I thought at first that Subaru just made crummy seals but that may not be the whole reason. I was pleased when the new cam and crank seals were changed to Viton.

mbtoloczko · #14 05-31-2003, 12:15 PM

Quote:

Originally posted by immortal_suby
Probably won't help much going to a lower temp thermostat. Once the thermostat is open the temperature will stabilize just as before after a period of driving. A high flow thermostat will lower water temperature some but I'm not sure how much of an effect it will have on overall oil temp. I've seen many a debate on other forums regarding higher flow of coolant and whether you actually lose some actual effective cooling with how quickly the coolant passes through the engine. The water temperature may drop but the engine temperature may not. It's been quite a few years since I took thermodynamics and I barely passed it then. The answer to that lies with oil temperature change. I'm sure Trevor or Harvey or Beav could provide some info here.

I'm still surprised with the huge oil capacity for our engines that it would be running that hot. Maybe in the location of the engine in the vanagon doesn't provide as good air flow as in the svx. I bet taking off the splash guard on an svx could reduce it some with the increased air flow around the oil pan. Still, with the rarity of engine failures in the svx I bet we can't be running extremely hot.

I'm pretty sure that the thermostat is set to hold the water temp at a specific temperature. The thermostat speeds warm up, but after warm up, it will adjust water flow rate to keep the water at a particular temperature. That's why the needle on the water temp gauge never moves from its usual spot under normal driving conditions. If the water temp were to exceed the temperature range of the thermostat, then the water temp gauge would give varied readings depending on how hard the motor was being driven and how much air was flowing through the radiator. At any rate, I think we could get many expert opinions, but without detailed info on flow rates, radiator heat transfer effectiveness, etc, the only way we would know would be to put in a lower temp thermostat.

There is another potentially easy way to keep the motor oil cool for those who have 5 speeds. Use the ATF cooler in the radiator. You could just buy one of those adaptors that attach to the oil filter spin-on location, and voila, instant motor oil exit/entrance locations. This would also provide a means to attach a temperature sensor. Heh. I may have to do that after I put in my 5 speed. Brian, maybe you could offer this as part of your 5 speed kit?

immortal_suby · #15 05-31-2003, 01:39 PM

I'm pretty sure the thermostat stays closed until a set temperature range, then it opens and stays open fully until it cools down. It is just wax and a spring - it can't adjust for a temperature range. It can't open more to cool more once it is fully open at it's set temperature.

The needle on our temp gauges, like alot of cars, has a good buffer in the middle range where it will not move within a pretty big gap of temperatures. Put in an aftermarket coolant temp gauge and you will watch the needle jump all over as you drive. I think automakers do this to keep customers from thinking something is wrong with their car.