Jump to content
Sign in to follow this  
Macrow

A/T Oil Temp Light

Recommended Posts

So I have looked through a lot of old posts here but couldn't find one that seemed to cover exactly what my problem is I'm having on my 1992 Pathfinder SE Automatic 4wd 3.0 so hoping someone might be able to help out with this. The other day I was driving back home on the interstate when I looked down at the dash & happened to notice that my A/T oil temp light had come on. Once I noticed this I got off at the next exit & pulled into the truck stop to check things out. After opening the hood up for inspection there was some smoke coming from passenger side along with some areas that had fluid which looked as if it was leaking from somewhere around the hoses going to the firewall that I believe are going to the heater core & also saw a lot of fluid leaking onto the ground under the Pathfinder. I'm not 100% on if it was coming from the hoses or not for sure because it was certainly wet & looked to have the fluid around the brake lines as well on passenger side under the hood & also was wet from fluid on the transmission pan on passenger side of pan which I am thinking may have just been because of fluid leaking from above & thought it may have just gotten on the pan from dripping downward along with me still driving it til I pulled into truck stop.

 

I have never had my light come on before on my 92 or on my previous 2 95 Pathfinders so I am not to familiar with this happening at all. On my 92 I do have a B & M external Transmission Cooler installed on it by the PO. I didn't notice any other areas that looked bad or that were leaking other then what I mentioned above. After sitting for a good while I tried to start engine & the light was off it came on once more on me with same areas that appeared to be leaking let sit again to cool off so I could try to get back to my house since I had no phone to call a friend or anyone I knew to help tow it back so I didn't have to drive it. This time after starting the light was off & I drove it back home while heater was on this time & made it all the way home without it coming back on.

 

Not sure if having the heater back on was why it didn't come back on or not but I was thinking if that was the case that it could be pointing to the heater core as the issue from this. I have noticed that I haven't had as good as air flow coming from the vents when heater is turned on over the past few weeks & also noticed over that time that it hasn't seemed to get as hot as it normally would. Which makes me think maybe thermostat might be sticking or something. Haven't been losing any coolant or anything like that at all or any other problems either. My question is what are some things I could look for to start to diagnose this issue for the A/T oil temp light coming on? The PO has the B & M transmission cooler installed in front of radiator on the drivers side with the line ports facing downward. It appears that it is running from Transmission into cooler line on bottom of radiator coming from other cooler line bottom of radiator into B & M cooler & out from B & M cooler into other transmission line going back into transmission again. Not sure if they have it run correctly or not but that was one concern I had that I thought could be why the issue has come up possibly. If anyone may have some input I would greatly appreciate it since this is a problem I have not had to deal with before on any of my WD21's & I plan on it sitting until I know what the cause of this may be so I can get it fixed so I'm able to drive it again as it's my daily driver as well so I am without a vehicle til fixed.

Share this post


Link to post
Share on other sites

"It appears that it is running from Transmission into cooler line on bottom of radiator coming from other cooler line bottom of radiator into B & M cooler & out from B & M cooler into other transmission line going back into transmission again. Not sure if they have it run correctly"

 

That sounds like the way it is supposed to be run since there are the 2 hardlines bolted to the passenger side engine block that run from there across to the rad through reduced diameter flexible lines. I ran mine under the rad but beside the rad is fine as long as the rad itself is bypassed completely.

 

I would be doing a tour under the truck with every possible socket snugging up every nut and bolt under there as a precaution paying _careful_ attention to _anything_ that was loose or not as tight as every other identical nut / bolt. After that I would start with the radiator fluid.... is it full and flowing with the rad cap off? It should be! Throw the cap back on and let it warm up then check the trans fluid... is it red and full? It should be!

 

Other than that I would give the two hoses into the heater core back by the firewall and behind the valve cover vent a tug and wiggle with a pair of pliers (they'll be warm by now) to see if anything is loose or a clamp has come off or slipped.

 

 

That's about all I can offer from 3000 miles away! Good luck!

Share this post


Link to post
Share on other sites

You never mentioned the color of the fluid that was leaking? That should point you in the right direction for where to began looking.

Share this post


Link to post
Share on other sites

You never mentioned the color of the fluid that was leaking? That should point you in the right direction for where to began looking.

 

It appeared to be ATF Fluid that was leaking

 

Share this post


Link to post
Share on other sites

The only thing that could be ATF in that area are those cooler lines. Make sure you don't have a pinhole in them. I had plastic wire loom rub through a metal a/c line on the 93 wd21 I had years ago.

Share this post


Link to post
Share on other sites

If the trans overheated bad enough, fluid might've boiled out around the dipstick. Apparently some of the auto trans Jeep Manglers tended to boil over right onto the exhaust manifold and catch fire. :blink:

 

I would take a scrap of hose and try blowing air through both coolers. Not 150 psi from a compressor, I doubt either cooler is designed to handle that, just blow with your mouth. If one is clogged, well, there's your problem. Of course, that gunk can only come from inside the trans, so that's still not good news. Bypass the clogged cooler and consider adding a filter to pick up whatever wear material the clog didn't pick up already. Hopefully the overheating didn't damage the trans too bad and a working cooling system + fresh fluid brings it back.

 

When I changed the fluid in mine, it still looked reddish on the stick, but came out brown and nasty into the bucket, and I even saw a little metallic shimmer when I first opened the system. I put it back together with fresh fluid, an external cooler (my rad wasn't that old so I left its cooler in the system), and a filter to catch whatever gunk didn't come out with the old fluid. No issues so far.

Share this post


Link to post
Share on other sites

The only thing that could be ATF in that area are those cooler lines. Make sure you don't have a pinhole in them. I had plastic wire loom rub through a metal a/c line on the 93 wd21 I had years ago.

 

Checked those after reading this & from what I saw after examining them very well was they checked out to be good with no sign of any pin holes,

 

Share this post


Link to post
Share on other sites

If the trans overheated bad enough, fluid might've boiled out around the dipstick. Apparently some of the auto trans Jeep Manglers tended to boil over right onto the exhaust manifold and catch fire. :blink:

 

I would take a scrap of hose and try blowing air through both coolers. Not 150 psi from a compressor, I doubt either cooler is designed to handle that, just blow with your mouth. If one is clogged, well, there's your problem. Of course, that gunk can only come from inside the trans, so that's still not good news. Bypass the clogged cooler and consider adding a filter to pick up whatever wear material the clog didn't pick up already. Hopefully the overheating didn't damage the trans too bad and a working cooling system + fresh fluid brings it back.

 

Checked them both for clogging & both were clear with no sign of clogging or partially clogged.

 

When I changed the fluid in mine, it still looked reddish on the stick, but came out brown and nasty into the bucket, and I even saw a little metallic shimmer when I first opened the system. I put it back together with fresh fluid, an external cooler (my rad wasn't that old so I left its cooler in the system), and a filter to catch whatever gunk didn't come out with the old fluid. No issues so far.

 

That's what mine ended up looking like as well once I started to drain it but was pinkish red on dipstick when I checked it. So just filled it back up with fluid today after spending any free time I had over the last couple of days to work on it. New ATF, new coolant, new belts & rubber hose on a good portion under the hood, oil change, new belts & transmission filter. Never did find the source of leak which leads me to think it may have very well boiled out from dipstick tube. Hoping with the new fluids filter & hoses that she is good to go. Had her running for a bit but haven't been able to take her out for a long enough drive yet to see if the light comes on & continues to overheat.

 

Share this post


Link to post
Share on other sites

I am having almost the same issue, as my A/T Oil light is lit up. I don't have any leaking fluid's. I replaced the radiator and thermostat, belts last December. I read through the reply's last week and just like the fore mentioned Pathy I have a automatic tranny. I had the system flushed last week after 275,000 miles and it was as clean as a whistle according to the attendant. I didn't replace the tranny filter as the gasket from O'reilly was incorrect. It drained readily and fluid looked great. I ran the ECU codes just for @!*%s and giggles and had a code of 55. Other things I have done to it recently is replace the A/C Heater fan and the Knock sensor and 1 fuel injector. Can anybody point me in the right direction as to why my oil light is displaying and how to check my oil pressure with a gauge.

Share this post


Link to post
Share on other sites
Posted (edited)

The A/T temp warning light is run by a thermometer switch in the trans valve body. When the temperature is high enough, it will turn on the light. The original coolers were a poor design that was prone to clogging. I believe starting with the 94 model year the cooler was changed to a different design to address the clogging issue. When the cooler would get restricted or clogged, the only solution was/is to either replace the radiator and or use a large external cooler and bypass the original. 

If the engine temp was normal but the trans was hot, the problem is likely in the trans. If the torque converter clutch is not locking up when in cruise, it will cause elevated temps. If you simply shut off the engine when the trans is over temp, then it will take a while for it to cool down again because the fluid is not circulating. Best thing if it goes hot is to let it sit at idle either in park or neutral for a while to cool down. If a sprinkler is handy, can always spray the trans pan with cold water to help speed the cooling. 

 

As far as the fluid everywhere, if there are no leaks, likely it was getting pushed out of the breather. How big is your external cooler, and what style is it? Is it the tube and fin type or the plate type. The plate type is more efficient at heat transfer. Are you running stock size tires or over size? That will have an effect on the load the trans is dealing with. 

 

Finally, you won't find any trans codes with the ECU. The WD21 is a primitive truck and the engine control unit doesn't have much interaction with the transmission control module like the OBDII systems. You have to go to the TCM to get information for the trans, and without a scan tool that can interface, it is very limited in the information you can get. I don't recall the process for getting codes from the TCM, but I think I still have it squirreled away somewhere in my computer. It is a lot more involved than the ECU, but it does give flash codes like the ECU using the trans temp light. 

 

Oh, forgot to mention. Unless you are replacing a leaking pan or gasket, replacing the "filter" is a waste of time and money. It is simply a fine mesh screen that essentially cleans itself when the engine is shut off. As the fluid flows back out the filter, it carries the debris with it. Regular drain and fills do a good job of keeping it clean. I do mine about every 15k miles, because ATF is relatively cheap and my truck is used as a trail ride more than a daily driver. Also she is a bit over weight and turning 33x12.50 MT's. 

Edited by Mr_Reverse

Share this post


Link to post
Share on other sites

The trans codes aren't too bad, there's a procedure in the AT section of the service manual (use the '94 or '95 manual). It'll automatically spit codes on startup if it thinks something is wrong, or you can check them whenever (IIRC you ground one of the pins in a connector under the dash). The light in the E-AT switch (or possibly the "power" light on the dash) will flicker, and the long flickers indicate problems. Kind of a hokey way of doing it but that's OBD1 for you.

 

Is the light coming on after driving a while or as soon as you start the truck?

Share this post


Link to post
Share on other sites

Thanks for getting back to me on this problem. I gotta figure it out. And wet had my oil change the other day and I figured I just have them replaced the oil temperature sensor. While they were underneath the vehicle changing my oil. The Jack that plugs into the oil temperature sensor is missing. Somehow it broke off and then the wiring broke so I have to rewire of Jack to plug into the sensor. I know my oil pump is working properly. They dented the end of the oil filter slightly. And when they fired the vehicle back up the pressure from the oil pump Poped out the dent in the end of the oil filter.

Share this post


Link to post
Share on other sites

Are you still talking about the transmission temp sensor? The engine's got an oil pressure sensor (switch really) next to the oil filter, which is what it sounds like the wire's broken off of (which is not uncommon).

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

Welcome to NPORA Forums

 

Please REGISTER to gain full access to the forum.

Make sure you read the Forum Guidelines and don't forget to post a new intro in the New People Start Here! section, to say hi too everyone.

 

-NPORA

×
×
  • Create New...