Cadillac Owners Forum banner

Damn! High Oil Temp and alarms? Here is a fix for it

151K views 211 replies 58 participants last post by  matt2thepoint 
#1 ·
I know that many have had problems with their Oil Temps reading incorrectly.... Mine has been acting up lately, and after the 3rd dealer visit, it still went off on me today on the freeway. It seems to stay ok until warmed up (approx 30 mins) then jumps up to around 240-250 then if I slow down/stop, or Turn on the A/C it Jumps up to 300 and Ding Ding... SOOOO ANNOYING! Its weird because it seems to be Steady, but high, until i come to a stop, or turn on A/C, The dealer has done the Ground Fix, 2 times at one dealer, and 1 time at another... I got off the phone with them and want me to bring it back on Monday. Seems like my car is at the dealer more than at my house :crybaby:
Anyone Ever Resolve this Issue?? Anyone have the same problems when turning on their A/C?? I would just ignore it, if it wasnt for that stupid Chiming Sound going off!
 
#38 ·
Yep AC is a main culprit...I have NO clue what the problem is (except its electrical).. I had the TSB done by two different dealers, and had everything replaced from the sensor back to the car, and it still does it!! I notice in traffic that when I take my foot off the brake it goes down a little - then re-apply and it goes back up, even when I press both windows up, it goes up!!

I wish I could just unplug it as well. I really dont need this info, and I see the Water Temp, and Oil Press are fine.
 
#39 ·
Unplugged mine. Didn't drive it yet, but when you start the car, you get "check oil level" on the nav. Hit OK, and it seems to go away.
I checked the oil level, and it was fine.
 
#41 ·
So have we come to the final conclusion that the sensor is wrong? I mean don't get me wrong, the dinging is annoying as hell, but sometimes I wonder if my oil is really 300+ degrees. It's not right...its the sensor thats messed up? Is there any way to make sure this is the case? My oil pressure and engine temp are usually fine so I usually assume the best. Still kind of worries me a bit though, naturally :helpless:
 
#44 ·
I'm with you... i don't want to immediately say it's the sensor. But I don't smell anything burnt on the dipstick, the water temp never goes above 212 and, if all else, the fact that the oil temp jumps from 266 to 300+ and back and forth again indicates something's wrong. Oil is more stable than to swing like that in that short a time (seconds).

I've also noticed that my sensor goes off at different temps - always goes off at 300 degrees, but sometimes it'll go off around 260.

Oh, some day i'll have a 220 oil temp
 
#45 ·
So update on this issue. Today was about 75 degrees and sunny in New Jersey. I realized when I manually turn my lights on (from auto, to down 1 notch), my oil temperature goes up approximately 25 degrees. Try this on a warm day and see if it happens to you. Damn sensors on this car :rant2:
 
#46 ·
Yea its def. electrical, and it seems to be VERY common on these cars. Most people just dont notice it (i think) - Its gotten to the point to where I almost thought about selling the V - Its drives me NUTS!!! I love my V - but one problem after the next, and the numerous trips to the dealer are making me second guess owning this car.
 
#48 ·
I was gonna try n clean up the ones on the head, and plug it back in.
 
#52 ·
Unplug that bitch. :thumbsup:
 
#56 ·
Anybody check their battery voltage? Mine seems to be a little low. Starts at 14+. Then as the car warms up, and I'm using the AC, it drops to +/- 13. I really need to get off my ass, and check those grounds before I waste $$$ on a new battery.
Keep you guys posted.
 
#57 ·
Sensor is a 3 wire connector, passenger (right) side oil pan.
If electrical loads seem to change the reading then it could be a grounding issue.
I have read a TSB on redoing the ground but have never done one.
 
#58 ·
Quick update.
I seem to be having charging issues, and a new battery didn't help. So I decided to check the grounds. Did the one on the fender first. Maggie guys should really check this (except Randy). Took off the bolt, and wire brushed everything. Did one behind the drivers side head, but could not get so much as a finger behind the other head. Then I got under the car to check the starter wires. Took one wire off. It was pretty bad, but I cleaned it up best I could.
Plugged the sensor in, and drove to work this morning. It was a cool morning, and a short ride. But I had everything on, A/C, lights etc. Oil temps moved around between 210 and low 220s.
I'll update after I've been on a longer ride.

Unfortunately, car is still showing low to mid 13v :mad:

Tony
 
#60 ·
If you remove the windshield wiper facia (very easy) you can get at the rear of the heads much easier.

The passenger side is less of a problem if you remove the battery.
Battery was out. With the wire harness, and some extra Maggie stuff back there, it was too tight.
I'll see if I fixed the oil temp. Not too worried about that now. Trying to figure out why my voltage doesn't stay at 14 when the car warms up.
 
#61 ·
#62 ·
what is the most up to date TSB number on this issue that I should tell my dealer to reference?

Mine's a 2005... the info here seems to indicate this only happens on 2004 models??? http://www.cadillacfaq.com/faq/answers/oilguage.html
I subscirbe to the Technical Service Bulletins from Alldata for the 2005 V. I have reviewed those and find none for the 2005. The 2004 TSB behind your link was specific to a certain VIN series so it appear that particular cause is non-recurring. Thus, the problem in a 2005 is presumably from the causes covered in the Service Manual which includes the ususal suspects - sensor, the grounding, or the wiring.
 
#63 ·
Went on a longer ride today (about 30 mins), had the AC off most of the time. Coolant temp was a little under 200, and the oil temp was around 220.
The last few miles, I hit traffic. Turned on the AC, voltage dropped from 13.6 to 13.3. The oil temp jumped up about 15. For the last 10-15 mins of the trip the oil temp was high 220s to mid 230s, but pretty steady. Jumping up and down a few degrees. I'll probably have the AC on the whole way home, so that'll give us a pretty good test.

Guys, check your voltage, if you have this problem or not. I'm trying to figure out if they are related. At startup mine charges up to 14.3. But after a while drops down to mid 13s. AC on, it goes to low 13s.

Tony
 
#64 ·
I agree it sounds like a grounding issue but I also thing an oil cooler is good insurance regardless.

I picked one up from TPIS with stainless lines and the oil filter boss adapter. It was an easy install, looks factory, and dropped my oil temp ~35 degrees. It usually hangs at 195 degrees now.
 
#65 ·
I went to Brogan Cadillac on 46 in Totowa - described the problem, told them that I thought it was a grounding issue. I told them that, after running for 10 minutes, the oil temp swung drastically rather than generally complaining that it was "running hot".

It's fixed. Yea! The service order says "Poor Ground As Per P.I. #2034644, Run Wire From Low Oil Sender to G200 as Per P.I."

Since they performed this service, my oil temp hasn't gone over 212.

Hope this helps someone!
 
#66 ·
I went to Brogan Cadillac on 46 in Totowa - described the problem, told them that I thought it was a grounding issue. I told them that, after running for 10 minutes, the oil temp swung drastically rather than generally complaining that it was "running hot".

It's fixed. Yea! The service order says "Poor Ground As Per P.I. #2034644, Run Wire From Low Oil Sender to G200 as Per P.I."

Since they performed this service, my oil temp hasn't gone over 212.

Hope this helps someone!
The low oil sender is not related to the temp sender??

If one of the three wires is a ground going to the sensor maybe that lead should be rewired directly to the block or negative terminal on battery?

And if one more person recommends a cooler:bighead: , were trying to solve an electrical issue here!
 
#68 ·
JUst to confirm. They added a ground to the sensor on the oil pan?

I agree with NOT running an oil cooler. I don't want my oil too cold. You might go from an annoying electrical issue to a big mechanical problem.
 
#74 ·
I agree with NOT running an oil cooler. I don't want my oil too cold. You might go from an annoying electrical issue to a big mechanical problem.
A proper oil cooler setup has a oil-stat to keep oil temps up where they should be.

And I really need to get off my ass and see about properly grounding my sensor, as I still get some unusual/incorrect high readings, despite having the dealer TSB "fix" done a year or two ago.
 
#69 ·
They performed this service on Friday, July 10th.

I haven't gotten up under the car to look around at what they did yet, so I don't know the answer to the question "They added a ground to the sensor on the oil pan?" All I know so far is what's written on the service slip they gave me.

FYI - saw a silver V from NY there the same day I was picking mine up
 
#72 ·
I was wondering when this thread was gonna pop up again lol
Been lazy, but I'm gonna run another ground to the sensor. Let you guys know how it works.

Tony
 
This post has been deleted
#75 ·
If you have a DVM you can measure the resistance from the black ground wire to the battery negative.

It may be higher then what it is supposed to be indicating a funky ground.
Yeah, that's the plan. Gonna have to grow some longer arms to do it, I think. :p

I also want to see how the ground changes (or if it changes) when I turn on the A/C. I still get a temperature spike as soon as I turn on the A/C, and an instantaneous drop when I turn it back off.
 
#76 ·
Quick update:
Not a solution but it helps a bit. The first thing, I got from Jesse. When the oil temp is going nuts, turn down the dimmer (overhead). That was good for 20-30* on my car.
The second worked much better for me. Ground on the driver side rear of the head. It's a 15mm bolt. The contact didn't look bad at all, but I cleaned it, the bolt, and the head with a wire brush. Went for a long drive Sunday. It was warm and humid. Had A/C lights, wipers and fog lights on. Temp did not go over 255, usually around 240 or lower. On my car, when I have more accessories on the voltage drops. This is when I get the oil temp gong. It happened two weeks ago in similar conditions to Sunday. But after cleaning that ground, I couldn't make it go near 300 if I tried.
Just an FYI

Tony
 
#78 ·
Quick update:
Not a solution but it helps a bit. The first thing, I got from Jesse. When the oil temp is going nuts, turn down the dimmer (overhead). That was good for 20-30* on my car.
Wow, I don't think I would've ever thought to try that one! I'll have to give that a shot next time I'm out, particularly on track. At this weekend's track event, with a new, freshly routed ground (done by Lindsay per the IPC that is supposed to fix the issue) + a new sensor (installed by me), my oil temps would still peg high at 329F during every session.

I did have a Vette guy at my last track event suggest I should remove the FRCs. Unfortunately, he recommended that after I had already done my last run for that event, so I wasn't able to get a back-to-back comparison. However, it seemed that oil temp was slower to rise to 329F and quicker to come back down at this weekend's event, despite the ambient temps being about 10F higher.

I'll have to do some more ground checking on mine. Thanks to both of you for some good places to start looking.
 
#77 ·
I helped Reed with the same problem(s) as the hot weather is starting to return (and so are the alarms).

The culprit in his case turned out to be the ground right under the hood support and very easy to get at.

Reading a DVM from the bolt head to battery negative showed almost 1/2 volt! (450 mv).

We removed the 15 mm bolt, added a 3/8" "star" washer (between lug and frame) and the voltage dropped to less then 50 mv.

All the problems vanished.:highfive:
 
#80 ·
:bouncy: props to all those who never gave up on electricals.

This bracket [mod edit since old image is gone: "this bracket" refers to the hood prop rod bracket on the passenger fender / strut tower] is painted and is the batt ground. I guess it works OK just passing voltage through the bolt... for awhile. I removed the bolt (15mm), scraped the paint off the bracket in the area of the ring connector, cleaned the ring connector, added a star washer and bolted it back up. (Hint: Have your key fob handy. Reconnecting the bolt will cause the theft alarm to go off.) Haven't done a full test drive yet but I'll bet this cures my problem.

I had abnormally high oil temps way back when and my '04 got the instrument cluster reflash in Aug '04 when the bulletin first came out. No oil temp probs since until recently. I moved to AZ in 2009 and no oil temp problems until several weeks ago. On the first day of hot weather this year, started getting temps > 299 and lots of bongs. I was a little puzzled given no problems the prior year. I attributed the behavior to lots of stop & go driving on that particular day. This Friday I noticed the guage reading erratically, jumping up and down several degrees, though never hitting the alarm level. Given this is AZ, thought an oil cooler would be prudent. In researching the cooler in the forum, came across this string.

Just got in from making the repair and wanted to give my thanks. Still going to get an oil cooler, this is Arizona after all, but now at least the guage should be accurate!

P.S. Did the power steering cooler beef-up per FAQ last year. Works like a champ. 👍


I helped Reed with the same problem(s) as the hot weather is starting to return (and so are the alarms).

The culprit in his case turned out to be the ground right under the hood support and very easy to get at.

Reading a DVM from the bolt head to battery negative showed almost 1/2 volt! (450 mv).

We removed the 15 mm bolt, added a 3/8" "star" washer (between lug and frame) and the voltage dropped to less then 50 mv.

All the problems vanished.:highfive:
 
#79 ·
Went out last night. It was a cool night with A/C on. Oil temps were in the 220s.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top