Hello, just bought a new '13 G37X 3 days ago. I've been driving it around and testing it out for the past three days because I got it at a pretty good deal from a dealership. Its never been in an accident (as far as Carfax knows), and its at 68k miles. Service intervals looked good as well, and had a lengthy service record. However, I noticed today after a ~2 hour drive that my engine temps were at 240F and my ATF sensor 2 was reaching as high as 260F, went home immediately after noticing that. The car is throwing a pending code for the trans sensor (P0710 , ATF Sensor Circuit A DTC), so perhaps the trans sensors can not be trusted, but even the engine was reaching as high as 240F on idle (closer to 200, sometimes dipping below that when going highway speeds). There was no SES light on or anything like that, and I forgot to look at the actual temp gauge, but in recent history after ~1 hour drives, it has usually stayed around the same spot. Not sure what to make of this situation. Is it a ****ty/faulty OBD scanner, sensor, or is there a real issue here?

PS. I will update this thread tonight to see if the gauge actually mirrors the temps from the OBD scanner, gonna go on another test drive. Also, if I missed any information that would help you help me diagnose it, let me know and I can figure out whatever info you need.

Thanks in advanced.

 

Okay so some additional information: its dark out now so its hard to be 100% sure on any of this right now, however I can say a few things I noticed on my drive: first of all, I couldn't manage to get the engine temp up to 240F or get the trans temp to 260F. Or even close (only drove for ~30 mins then idled for about 20). The engine, when idling for maybe 10 minutes managed to reach 210F, and the transmission reached no more than 205F in idle or in driving. Something I did notice was that, at least for the engine, this is definitely an idle problem. Driving at any regular speed immediately cools the engine back down to between 180F-195F, and steady driving keeps it at those temps, from what I can tell. For some reason though, even when the engine was 210F at idle, neither of the two radiator fans were spinning, so that seems to be an issue that needs to be resolved.

Besides that, didn't find any leaks, no white smoke coming out of the exhaust (even on immediate start up), but I will be buying a combustion leak tester tomorrow morning and performing a test to make sure that isn't the problem.

Still have no idea why the OBD scanner was placing either temp nearly around or above 240F. Especially for the transmission which was at 260F.

 

I'm guessing its automatic. First place to look would be your fluids, make sure they are topped off.Next check the fuses for your fan. It's not a idle problem as when you drive the air coming in is cooling down your engine a bit just gets hotter with no airflow. If the fuses are blown I would replace it and wait a few minutes. If if blows again you will need a new fan motor guess that's a starting point, keep us updated

 

I had a feeling I missed some basic info in the first post. Yes, this is the 7AT. Okay so some more info from a few tests from today:

Regarding the fans, I read on another thread that you can test your radiator fans by setting your AC to max, bc the fans should immediately spin up in that situation. I tried that, and I noticed that only 1 of the fans was working. From my understanding (could be wrong), the G37 has a single unit radiator fan (with two fans), so I'd expect only one fuse, and so since one of the fans is working, I'd assume that the fuse is fine. I did also briefly check over the fuses last night, but I didn't pull up a schematic for the fuse box prior and it was dark, so I'll double check later today, but it does look like all the fuses are fine. I have yet to see the second radiator fan spin up though, which obviously brings up the possibility of one of the fans having burnt out.

Regarding the temps, I think the temps I referenced in my original post may have actually been accurate (unfortunately). I went out and drove around for about an hour in mixed stop/go/highway traffic, and the max temps I hit was about 220F on the engine and 231F on the trans, so I can image 240F and 260F respectively after another hour. Important to note that in my hour of driving last night, it didn't get anywhere near this, and its likely because its been about 90F in the day and around 65F-70F at night for the past few days. Also, as I noted before, the greatest increases in temperature were noticed at low speed driving, especially if I pull a little, and at stop lights. Highway speeds cooled the car down as they have been.

Regarding the fluids, its looking like the coolant is actually properly topped off (before I started the car, coolant was a little lower than the midline of the reservoir, after the drive coolant was at the MAX line), which is giving me a little more hope that there is no leak from a blown head gasket and thus possible cracked cylinder/compression issues. Again, doesn't seem like there are any external leaks either. Fluid looks relatively new (its blue, which if I am not mistaken, is the correct color for this trans). In terms of transmission fluids, I can't actually tell because from what I understand, these transmissions are supposed to be serviced by a dealer/approved mechanic only, so they didn't install trans dip sticks or any other method (again, as far as I know, which isn't much lol) to check fluid level or color in the transmission, besides leaking it out a bit from under the car. I'd have to crawl under the car to look for any sure signs of leaking, just got a HF jack today, looking for some good jack stands so I don't die.

Besides all this, I purchased a combustion leak detector just to be 100% on the head gasket/cylinder head, will update with those results when I test it. Also, found a nearby JDM auto shop that looks good and won't rob me, so I'll be taking it down there regardless on Monday. Until then I'm going to try to trouble shoot as much as possible on my own to reduce possible costs at the mechanic. Any more suggestions are absolutely welcome.

 

There is more than one relay. High and low speed you can use a test light to see if you rea getting power to the fanwires

 

The easiest way to test the fans (yes, both of them) is to perform the IPDM/er self-test procedure:



As the test cycles through, you should see/hear both of the fans come on and cycle speeds.

 

Okay so a little more info:

Regarding the fans, I performed the Auto Active Test and I think at this point it is definitely a fan problem. So I watched the test cycle through 3 times I believe, and I noticed two things: at no point in the entire test did the left fan come on, and also I never saw or heard the right fan go into HI mode. Seems like it was the same speed the entire time, and I am assuming it was on LO since it really wasn't going all that fast/hard/loud.

Regarding the fuses, I had no idea the main fuse box was at the driver seat, I was only aware of the one right next to the battery. In either case, I checked through the blower fuses (from my understanding those are the radiator blower fans) and both fuses were completely fine. So its looking like its a case of bad fans. Hopefully the pain ends at $90 and doesn't require the engine to be opened up...

Regarding combustion leak, I ****ed the test up (lol), not sure if I just didn't wait long enough, or if this is part of the problem, but it seemed like fluid kept on coming up the rad neck even after the car had sat there long enough to reach operating temps, so I never had the chance to pull just gasses off the top. The fluid changed colors, but that is because I took in a whole lot of rad fluid. Im gonna go back to YouTube, make sure I got the directions down, and then try it again later today, and maybe refill the fluid just in case. However, I know I noted this in my first post but I've had the car for about 250 miles since I got it off the dealer, and the rad fluid is looking fine, the oil cap is looking fine, and the oil dipstick doesn't seem like it has been changed to hide anything (looks old) and it doesn't have any rust on it, not sure if 250 miles would be enough to notice any of this. No white smoke coming from the tail pipe. I just hope it ends at the radiator fans. And again, like I said in my last post, tomorrow I will be taking it to a mechanic, as long as they have the time slot for me to bring it in.

Again, any more suggestions are welcome, especially in helping me make sure there is not head gasket leak causing the heat. For the time being, I'm keeping my drives short and turning back once I break ~210F on trans or engine.

 

To clarify, BLOWER refers to your cabin fan (AC/heat/defrost) whereas FAN refers to your radiator/ condenser fans.

If you are adventurous, you can always try jumping the "dead" fan directly to a 12V source and see if it powers up to full speed. Repeat the test for the other fan that seems to run at "low" speed. Anything less than full speed indicates a dead/dying fan motor. If one or both fans come on full speed then you have to move up the diagnostic chain.

In my case, I had both fans crap out at nearly the same time due to beach sand. Replaced the entire fan assembly for ≈$150 (eBay) and 30-45min. of time.

Being you just bought the car, is there any warranty in place or was this "As Is?"

 

Ahh... I'll check once again and update accordingly. Not super adventurous, but I also live out of an apartment right now (going to college), so I don't have my own garage. I could take it to my buddies place and do the work there, but not super stressed to try jumping it myself just yet, I'm gonna try a few more things (including checking the correct fuses) and in either case, if I've gotten this far into the fan diagnosis, I think the mechanic can take it from there.

Do you think that just having bad fans could get me to temps like these? I just have an odd feeling that I'm probably going to find out I have a crack somewhere in my engine in the next few days lol.

And yes, sold as is, from a Subaru dealership (stayed away from the shady ones, but it may have not made a difference). In my defense, this car doesn't overheat if its not hot out for one, and two as long as you don't drive it for longer than around 30 minutes, so test drives weren't very telling, and the car pulled and performed as I'd expected it to (and still does). Also, got the car for 11.3 where as KBB had a range for this car (loaded options, 68k, black exterior) at 15.4 on the upper end, so until I spend more than 3k getting this car to 100%, I'll be happy. Kinda wish it was the XS though .

 

Yes having a bad fan can even give you higher temp. The more you drive it thr higher chance you take of warping something. Just use a test light to see if you are getting power .if the last comes on it's your fan motor .

 

Think positive and don't stress too much on numbers. These are very reliable cars with reputable, robust engines. As long as there is coolant in the radiator your engine should be fine for the short term.

If you do a lot of city "stop-and-go" traffic than having a bad fan will make a big difference in coolant/engine temperature management. Especially if the second fan is not pulling it's own weight. In my case I only ran hot at red lights and at my bank's notoriously slow ATM. That and the AC did not blow cold. At highway/interstate speed all was normal as there was sufficient airflow through the radiator and condenser to reject heat.

Best advice. Relax. Take things one step at a time. If you must drive it, keep a eye on your temp gauge. Just don't let the mechanic take you for a ride, financially.

 

Alright so the FAN fuse is in the box next to the battery, that was the one I checked before and just checked again, its intact, so looks like its a motor problem. I'm gonna take a voltometer out tonight (have some work that needs to be done before it gets too late) and pull up a schematic for the fan and check if the wiring is a possible issue.

And yeah you're right, part of the reason I bought this car was bc these engines are solid, but its hard not to stress lol. Little low on funds since I just bought it, and about to go on a long drive across state lines, so just want to make sure everything is ready to go before I leave. And yes, the engine and trans only heat up when I stop, though it does take a while for the air to passively cool the rad, so the trans and engine can keep getting hotter if I am driving in stop and go. Problem is, pretty much every highway in this state have stoplights every half mile :/. I am watching the temps basically every time I get in my car, and I go back home/stop driving when it reaches 210F usually.

Thanks for all the advice thus far, and of course to you as well @Birdie , its very much appreciated.

 

No problem. I was a college kid once. Not that I did much studying, but.... this will get you started:

 

Hey so just a few updates:

Regarding the rad fans, haven't gotten around the checking the fans just yet (had something that needed to be finished last night, took way more time than I ever wanted to invest in it...) but I'll do that today and update here for certain results that the fans or the fan circuit is dead. Called up the mechanic, unfortunately they're booked until Wednesday, but I have an appointment for that day, and they'll probably replace my rad fan, unless I take my car to my parents house and just do the work there, I'll see how much they quote me.

Regarding the combustion leak, so I finally tried the test again after how badly it went last time, and I can say with around 80% certainty that I probably don't have a blown head gasket/cracked cylinder head/cracked block. In addition to lacking any of the other symptoms that I have listed in my other posts, I ran the combustion leak test 3 times today after draining down my radiator to MIN (while the vehicle was running), the first test I was still trying to keep the seal between the nozzle of the tester and the rad neck, so I got like 1 squeeze in and then it just pulled in a bunch of rad fluid. Then second test, probably the best one so far and the one I'm most confident in, I gave up on having that perfect seal, and instead, I just put the nozzle as deep in the rad neck as I could before it would seal and then end up pulling rad fluid up (I think this is a design issue on the product I bought, doesn't seem like anyone else was getting this type of problem, or maybe I had to drain the reservoir even more?), and then I got in about 5-10 pumps, and absolutely nothing happened, fluid stayed blue. Third test I gave the seal one last chance, got 2 pumps in (nothing happened), third pump I pulled up some rad fluid. Kept pumping without the seal after that and the fluid stayed the slightly bluish-green that it gets when I pull rad fluid up. I'll see what the mechanic has to say, but to an untrained eye, I'm pretty hopeful that this will JUST be a rad fan. I might get a cylinder compression tester in the future to test certainly myself, but for now, this doesn't seem to be the cause of the heat and that is what I am most worried about.

Thanks again to @ILM-NC G37S and @Birdie , your help has been great. And again, if you feel like I missed something in any of my testing, or if you think theres a quick test I can run to check any other possible faults that may be causing the heat, let me know.

 

Alright so last update before I take it into the shop to get a mechanics opinion. I took my car out today to my friends place (more space to work), and I looked through the wiring for the radiator. I tested the relay box and the fuses for continuity and voltage (everything looking good in that regard), and I took a peek at the wiring to see if I could directly test the fan wiring or the fans themselves. Unfortunately, there is a plastic shroud covering any access to the radiator fans, and I dont think its worth it to take that off to check the fans, I think we have a culprit. I did the auto active test one more time to confirm everything, and its looking like the same results as before: right fan is weak, left fan doesn't spin up at all.

I'll post (hopefully) the final update tomorrow, on how everything goes. Though I will probably need to wait for the fan to come in, so perhaps longer. In either case, the problem will hopefully be getting solved in the next few days and I'll update the thread accordingly.