Coolant Temperature Dash Gauge Showing Hot

[my12by60]

Here in the Phoenix area we were about 110 degrees today. We were out driving the Q and I noticed that the dash gauge was moving off of the usual noon position where it has always been since we bought the car last December. At one point, the gauge was moving toward the first hash mark before the letter H on the right side of the gauge. The car is showing no signs of overheating, but maybe that is in my future. I have searched the forum and see ideas such as:

change radiator cap
check coolant temp sensor wire

Do we need any special radiator cap for the Gen 2 cars?

How do I check the coolant temp sensor wire?

Any other recommendations for things to check?

[3Q Jay]

assume the level is ok? how much 'delta' do you get between the stone cold (ok, 88deg minimum PHX overnight low) bottle level and full hot when symptom?
I do not think you are on the right path, as the sensor wire if damaged would show full hot or full cold consistent. if the needle 'moves' normally that is not the issue.
yes, the correct cap is CAP, INF#21430-1P111
this is to be used at both locations. strictly speaking you could use a cap only (no spring inner seal) on the upper neck, but why bother?
more likely your issue is trapped air (incorrect coolant level), bad thermostat (THERMOSTAT- INF#21200-6P001),
bad fan clutch, no supplemental electric fan, restricted airflow thru the ac condensor or restricted flow thru the radiator itself.
also, for your climate (mild winter, hot summer) i would highly recommend a 30/70 mix of coolant to distilled water (yes--the order is listed correctly). use some redline water wetter also (surfactant)

[my12by60]

Thanks for the great feedback. I pulled the receipts from the prior owner. In September 2013 she overheated and was towed to her local shop that did all of her work. The cause of the overheat was a cracked radiator tank. The repair included new radiator, upper and lower radiator hoses, thermostat, cooling fan blade (OE blade has a cracked fin) and coolant replacement.

So based on my symptoms, you are saying that the dash gauge and wire appear to be working properly given that the gauge has been in the normal position in cooler weather and is now only climbing toward hot since we are in summer and running the ac a lot.

All of the things you list make sense. Do you have a recommended order of things for me to try one by one?

[Q451990]

Assuming everything was done correctly in 9/13, I would look at the fan clutch next. I would also get a pressure tester, so that you can pressurize the cooling system while it's cool and look for leaks. Many parts stores (like AutoZone, Advance Auto) make these available as loaner tools. Your ambient temperatures are on the ragged edge of the design for your Q's cooling system (or most any car's) so I'm guessing everything needs to be perfect.

[my12by60]

I took a look at the radiator caps this afternoon as an easy first step. Both look to be OEM Nissan parts. This does not mean they are the originals, but I guess anything is possible. The cap on the tank itself looked pretty good. It came off easily and both gaskets and the spring looked and felt good. The other cap (closer to the engine block) was gunked on the fitting but came off without too much effort. Both of the gaskets on that one looked fairly tired. I also double-checked the 2013 receipt to see if one or two radiator caps were replaced when the OEM radiator was replaced. No radiators caps are shown on that receipt. That does not mean that one or both were not replaced, but I guess it is possible that neither radiator cap was replaced as part of that coolant system repair. So my first step in trying to solve the rising coolant issue will be to replace both radiator caps. I will report back after I get the new caps on and we do some driving in high heat.

[my12by60]

June usually has the highest ambient temps of the year in Phoenix. I put on the new radiator caps an hour ago. Let's see if those make a difference. If not, then I will move on to the fan clutch as advised by Q451990.

[Q451990]

The fan clutch should offer a lot of resistance when the car is hot (just after shut down) and not as much when it's cool. There may be a more specific test in your service manual, available at www.infinitiservicemanual.com if you haven't already downloaded it.

[my12by60]

I was out doing some driving today and the temperature gauge was steady. The ambient temp was "only" 96 degrees. I will have to see how the Q does once we get back up to 110 or so. So far, so good on the new radiator caps. When I changed the caps I did notice a bit of coolant spit on the upper radiator hose near the secondary radiator cap (non-tank). Maybe that cap was bad and was allowing the system to lose full pressurization?

[my12by60]

New radiator caps did not stop the creeping temperature gauge. So I had to pop for the Mityvac MV4560 cooling system pressure test kit. This is certainly not a shop grade tool, but for $40 and occasional use I figured it would get the job done. I pressured up to about 14 psi and found each end of the upper radiator hose leaking at the hose clamp. I tightened each clamp about 1/2 to 3/4 of a socket turn and the leaking stopped. I let things set under pressure for while longer but could find any other leaks and the pressure held steady.

The radiator was replaced in 2013 and the replacement has a plastic upper. So I was afraid to tighten down too much on that plastic neck. The other end of the upper hose goes over metal so I was not worried about that end. The hose itself was also replaced in 2013 and looks to be in decent shape. Hoping this solves the problem. I will report back after I climb a few grades in the heat of the day with the ac running. Driving on flat roads has not caused the gauge the climb.

[GoadQ45T95]

The gauge is notoriously inaccurate, I wouldn't necessarily use that as a a guide, more of a terrible estimation on how hot the car is running. I recently overhauled the entire cooling system (all OEM except rad) on my Q and the gauge still reads at about 2 30. Consult shows temp ranges between 182-187 depending on the ambient temp outside and how hard I'm pushing the car. In short, what I'm saying is to hook it up to consult and monitor it in real time. I decided not to troubleshoot and replaced everything.

[my12by60]

What is "consult"? All through the winter my dash gauge sat a just slightly left of dead center. It only started to flare higher when we hit our hot summer days here in Phoenix. Not saying the dash gauge is so accurate, but it is probably showing increased temps accurately.

[3Q Jay]

he's saying use the OBD-ii interface to see what the ECU is seeing as the temperature (recall that the ECU temp sensor is down in the valley by the y-pipe, so it does not read from exactly the same place as the dashboard gauge). This ECU reading should be accurate within 2deg F.

[my12by60]

Ok, I get it now. Do I need a tool/scanner to connect to a port ("OBD-ii interface") to get the temperature readings? If yes, is there an inexpensive scanner that is recommended here? Or can I get these temperature readings by pushing some buttons on the dash?

[Q451990]

You can buy a Bluetooth enabled OBDII scanner on eBay for a few bucks, which will interface with an app on an Android device. I like Torque Lite - which is available free of charge. I assume they have something similar on iPhone, and there's something for Windows Phone if you're in the 3% of the population that uses it (like me) - but it doesn't have the features of Torque Lite.

http://www.ebay.com/itm/Super-Mini-OBD2 ... 88&vxp=mtr

[my12by60]

I am still a flip phone dinosaur, so the devices that talk to a smart phone via Bluetooth are out for me. Will a device like this give me the real time coolant temp readings similar to the device linked by Q451990? Or does this device just spit out check engine codes?

[3Q Jay]

i looked at the ebay item linked, and it would appear that coolant temp is supported. you can also buy a dongle to interface with your laptop (may still need 3rd party GUI to ride on your laptop) or a hardwired tool (not just a code reader) that will display primary functions.

[GoadQ45T95]

Must have missed that you have a second gen, Consult is basically a diagnostic tool for OBD1. Starting in 96 you'll have OBD2 that you can read with any generic code scanner. You'll have to find one that supports coolant temp like jay said. Id splurge on a good one since It will be used multiple times for various issues.

[ArmedAviator]

I've used ScanXL by Palmer Performance and an ElmScan device for years for OBDII diagnostics on a laptop. Worked great albeit it a bit slow. More modern Elm devices are much faster with the same software.

Reason I like these programs on a laptop is the ability to easily data log many parameters. That way it becomes easier to diagnose with more data, such as "ECT rises when below 30MPH" or "ECT rises when RPM are below 1300.". You can use this information to identify a bad fan/clutch/radiator or a weak water pump, for example.

[Q451990]

You can pick up cheap Android tablet devices for $40 these days... probably less used. Places like Family Dollar have Android Phones for $10... you probably don't need to activate them to use them as a wi-fi device, which would allow you to download the Torque Lite app.

[my12by60]

Each of my kids has a chromebook. Is that device any help in using some of the computer tools and apps you guys are mentioning?

In the meantime, I have been continuing with low-tech attempts to solve the cooling system problem. 3Q Jay mentioned earlier in this thread to check for air in the cooling system. Our driveway has a good slope, so I parked with the nose up hill and let the car idle while squeezing the upper radiator hose. That did not cure the flaring temp gauge. So I bought one of these:

https://www.amazon.com/Lisle-24680-Spil ... B00A6AS6LY

Parked uphill again and filled this with water/coolant then let it idle for 20 minutes or so. I revved the engine enough to get the cooling fans to kick on. I was keeping an eye on the action in the funnel and I definitely saw some air bubbles escaping over the 20 minute period -- some at the start of the process and some more when the cooling fans kicked on. I have put on about 100 miles since then and the temp gauge has not moved past the halfway point. So I think that a bit of air was trapped in the system and that was the source of the problem. I won't declare full victory until we have another 110 degree day and I climb a few hills. But so far, so good.

[3Q Jay]

i have that same lisle tool. use it often, it is great!
fingers crossed, keep us posted. is the rack/starter all sorted out now?

[my12by60]

The rack warranty work and the starter rebuild are scheduled for December, which is the slow season for the shop that is doing the warranty work on the rack. The starter rebuild shop is also slow at that time. Between now and then I just have to keep topping off the power steering fluid.

[my12by60]

Temp gauge is still flaring up. When I park the car hot, I usually hear a single drip then sizzle. So I knew something was leaking somewhere. I also had to add a bit of coolant since I used the Lisle funnel to remove any air from the cooling system a few weeks ago. What I found today was some crust under the bottom hose on the passenger side of the heater hose connection fixture that is attached to the firewall (four hose sections attach to the fixture). I looked below that hose and saw some white crust on the transmission bell housing. So I think I had a small coolant leak from that hose. I wiggled the hose, re-positioned the clamp and snugged it down tight. That is a tough area to work in because you can't get much leverage on those hoses. I will report back once again if this latest fix cures the flaring temp gauge.

[my12by60]

Temp gauge was up again today when I was out driving. I ordered this OBDII scan tool from Amazon:

https://smile.amazon.com/gp/product/B01 ... UTF8&psc=1

My daughter does have an android phone on hand, so I should have some feedback from this new tool in a few days.

[my12by60]

I also just did a search and read some more on the fan clutch. When the car was hot, right after shutdown, I tried to spin the plastic fan blade. The blade would only spin a quarter to a half turn. I just went back to check again now that the car is cooler and I can get a more free spin from the fan blade. That all seems to be normal based on what I read in the search. However, when I grabbed the fan blades to check for wobble, I felt what seemed like quite a bit of movement. I then grabbed the fan clutch itself and tried to get some movement there to eliminate the flex from the plastic fan blades. That fan clutch also has some play in it.

Does this mean that my fan clutch might be bad and be the source of my high coolant temps? I don't have enough experience with fan clutches to know how much play is indicative of a fan clutch that is failing.

[my12by60]

I am talking to myself here for the benefit of anybody else that visits this forum with a similar problem to what I am trying to solve. Today I went to O'Reilly and had a former mechanic that works behind the counter take a look at the play in my fan clutch. He thought the play was too much and that the fan blades were spinning too freely. So I bought a new fan clutch and put it in on this afternoon. My wife will be out driving quite a bit tomorrow and it will be hot, so we shall see if a failing fan clutch was the source of my climbing temp gauge.

I know this board has a running debate about using OEM parts vs. auto parts store products. I can tell you that in the case of the fan clutch at least, the OEM unit that came off was a good bit more substantial than the replacement. The cooling fins were taller and the overall unit just felt more substantial. Of course, the OEM price is $181 through Infiniti of Scottsdale and I paid $60. Only time will tell how the replacement performs and lasts.

It would have been nice to have a 10mm gear wrench on hand for those four nuts holding on the fan clutch. However, the threads were pretty clean on mine. So once I broke the nuts loose, I was able to spin off three of the four nuts with my fingers. Once I broke loose the two nuts that were easily accessible from on top, I started and stopped the engine to re-position the pulley so that I had better access to the other two nuts. I had to do the stop/start gimmick twice to get all four nuts in position for breaking loose.

Is there a better way to move the pully?

Anyway, the job would be very simple if the you did not have to partially lift the radiator shroud. I only had to lift the shroud about halfway up the radiator to enable me to get the fan blade/fan clutch assembly out. However, this required taking loose the upper radiator hose which makes a bit of a mess.

[3Q Jay]

yeah there's a few things on the fgy33 that are not as graceful. one nice feature i liked was that the radiator shroud lower section could be removed from the bottom with two finger clips.
I use a long 10mm flat combo wrench on the 4 nuts you mention. break the 4 loose, then undo the drive belt so the waterpump pulley turns freely and you can access all 4 easy once loose. plus, you want the belt loose as you reinstall the 4 nuts at least until you get them snug or else you won't tighten them evenly due to the belt torsional load.

did you ever get measured coolant temp in degrees F or C vs. the needle sweep?

[my12by60]

No measured coolant temp yet. My OBDII device should arrive tomorrow (ordered from Amazon). Then I will get my daughter to download the Torque Lite app so that I can see if the coolant is in fact too hot or not.

My wife was out driving quite a bit today and she says the temp needle was still showing coolant as being too hot. Climbing any sort of grade is when the needle really starts to move to the right.

I am anxious to see what sort of information the Torque Lite app produces.

[GoadQ45T95]

Think you may be on the right track with the clutch fan. From my experience, it shouldn't really have any play. I don't think the slightly loose hose is the reason for the flare up in temp. Could it be letting air into the system and increasing the temp? Plausible, but not probable unless the hose is literally dumping coolant. The cooling system is relatively simple by design so hopefully you can finally put the issue to rest.

[my12by60]

If the dash temp gauge does prove to be accurate after I receive real-time data from the scan tool and Torque Lite, then I am running out of things to try. The only things left to do are:

flush coolant
replace thermostat
replace water pump

Scan tool arrives tomorrow according to Amazon package tracking.