Oil Temp 120??? Need help trouble shooting

[surflvr911sc]

I’ve read past threads on backdating the oil temp but I didn’t see my problem addressed.

I did the backdate, gauge and sender, but after an hour on the freeway, cruising at 65-75mph the max temp was 120. I also drove for two hours in traffic, max speed 35 & only rarely, (got to love CA Fwys) and the same thing, max temp 120. Ambient temp was about 65. The sender is working, as ohms drop as the car warms up.

The only thing that I did other than just R&R the old gauge and sender was extend the wire to the sender a couple inches. The orientation of the new sender would not allow the connector to reach and it had a couple bad spots in the insulation anyway so I soldered a new piece of wire on the connector and spliced it to the old wire, using of course, a splice and heat shrink around it. My connections are good but this is the only place where things changed.

Could the length of wire add that much resistance that the gauge is now always low? Should I redo the extension and does anyone have any tips that I should look out for? I do have experience with electrical and electronic so I’m not doing this blind, but I’m not a pro either. Any suggested reading I should take to verify the signal to the gauge

[surflvr911sc]

I replaced the repair I did and it had no effect on the gauge. I’m stumped. I what kind of resistance should I be seeing from the sender wire to ground? That would at least eliminate the system and I could look at replacing the brand new sender.

Just for record, I’m sure my temps are over 120. I could hear oil going to the front cooler so I know the thermostat in the wheel well is opening. My temps before backdating were usually at 7-8 o’clock on the gauge.

[Chuck Moreland]

I see you replaced both sender and guage. Are you sure you have a properly matched set?

If yes, it is possible (though not likely) that one of the new parts is defective.

I've heard people say they hear oil going to the front cooler before. I'm not sure what that sounds like, I sure can't hear the oil in the tubes. Put your hand on the tubes and see if they are hot to be sure the oil is flowing.

[makaio]

I have a numerical gauge and sender in my 78. I noticed that when the ambient temps are belwo 70 F., it takes lots of spirited driving for the gauge to get up off 120. IN the winter, I can go months without seing 180-190 on the gauge.

Take your car out for a good spirited drive, never letting the revs drop below 3,500 rpms. And report back.

[surflvr911sc]

OK, you wont believe what happened. I changed senders (I had two) and went it go for a spirited drive. As a started going up the mountain, this POS Toyota truck got if front of me. I figured that I would see if he will pull over for me and if not I’d pass him or pull off and wait a while. As soon as we started climbing the hill his truck started spewing smoke. Then it started sprinkling. Wait a minute, that’s not water, that’s oil from the SOB’s truck!!! They whole front of the car was covered in oil and I had to be a least five-car lengths behind him. Damn I was mad! At least I can feel good about the fact that his motor probably blew up before he ever got to the top of the mountain.

I brought the car home a washed it and tried again. I got the temp to 120 but it never climbed over that. The front cooler is warm so the thermostat opened. I’ve replaced the wire repair and sender. Is it possible that everything is working fine, the thermostat is working and the oil really isn’t getting over 120? The cooler felt like it was more than 120, not that I really know by feeling.

[marcesq]

I thought the external thermostat opened at about 190 which would further support your assesment.

When I was messing around with senders during the convertsion, and getting high readings, I took the car to my local wrench who dropped a wire in the oil tank and gave me a reading of temp. He said it would be a little lower than than the block, but at least I knew whether I had the right sender.

[Rouxzy]

Is is possible that the thermostat stuck open?

[Chuck Moreland]

The external tstat opens a bit over 180. So I think you are correct in suspecting the guage is misreporting.

I go back to my earlier comment. Are the guage and sender matched properly?


Matt, I promise your new car will always go to 180 even on a cold day. Of course cold is a relative term, I probably never had the car in temps under 50F.

[makaio]

Not to steal the thread, but Chuck I know the new car goes to 180 on cold mornings. I was driving the other day in 52 F. with the top and windows down. Heater cranked and my sock hat on .

Gosh I love having a cab .

[surflvr911sc]

Chuck, that’s pretty much where I’m at. I will call Pelican Monday to see if they have any insight. I bought the gauge and sender as a kit that Pelican sells. They sent me a sender in the box w/ the gauge and another one in it’s own package that I was going to send back. I tried both with the same results.

[rattlsnak]

Interesting you bring up matched sets. When I put the C2T engine in my SC, I was using the stock gauge and the sender that came with the engine. Long story short as some of you remember, I chased a "hot" condition for months, going through an array of different coolers, etc. I finally updated the gauge and sender as a pair, and now I dont even get to 180. ! DOH !!

[surflvr911sc]

I talked to Thomas at Pelican, he told me that when you ground the wire to the sender the gauge should max out. I tried it and the gauge would only go to 270, instead of 300+ like it should. Well, there you go, new gauge is on the way.

Have I told you guys how much I love Pelican?