57 Handyman

Engine temp gage on my son's 99 TL appears to be malfunctioning. When key is turned on, the indicator starts out at COLD (bottom of gage) but swings to HOT (top) and stays there when engine is running. This happens when engine has not run at all.

The engine coolant is full. I also noted that only one of the two electric fans was spinning...I don't know what is the usual pattern for operation.

If there is a fuse for the gage, where is it located? Also, where is the temp sensor for the gage?

I appreciate any assistance and insights. Thanks.

01tl4tl

99s, ck at the thermostat housing for fan sensor and guage sensor
the driver fan runs on and off for short periods as needed- during normal operation
and at engine shutdown it runs 1-2 minutes
If it runs 5-10 minutes after shutdown= its a bad fan sensor

passenger fan runs full time with AC on

both will run in overheat situation

01tl4tl

what you describe is often sensor unit,,if you remove the wire to it and place to ground it should do the same thing, peg the guage

57 Handyman

Ah, I was wondering that...OK, I will give that a try. Also, thanks for the location of the sensor.

I'll report what I find. All too often with online DIY sites like these, the threads don't indicate closure or resolution of the problem.

01tl4tl

aloha!
this place is the answer for your TL troubles
between us there are a few still firing brain cells~

numerous ziners in the islands too

Skirmich

1.- Wierd my Car only does that if there´s some Extreme Hot Weather (+105°F) Outside, but not All the Time.

57 Handyman

01TL4TL,

I found there appears to be two sensors...one each for water leaving the motor and the other returning from the radiator. These are located in the block close to where the radiator hoses connect. I disconnected the clip from the return side but didn't know which wire to ground so didn't proceed...or does it matter?

I also want to correct an error mentioned above regarding the indicator needle. The indicator pegs to HOT as soon as the key is turned on and stays there. Don't know if that makes a difference.

As far as the fans, the passenger fan starts running as soon as the engine starts. If the driver fan is supposed to start as soon as the AC is turned on, it doesn't.

01tl4tl

no opposite --driver fan with temp
passenger fan with ac

01tl4tl

Im betting temp sensor for guage
dont know 99s -the sensor locations are different than rest of years

57 Handyman

01tl4tl,

Where is temp sensor for rest of gen 2 TLs?

Of the two sensors I see at top of engine, would you say that the temp gage sensor would be the one closest to the hose going to rather than the coming from the radiator?

Today, I drove the car to do errands. There was an instance when the gage appeared to be working properly and registered only a third of the way up the scale...normal operating temps. However, after a short stop and restart, the indicator again pegged at HOT and remained there until I shutdown.

When I finally parked the car, no fans continued to run...both had shutdown. What do you make of that? Does that sound right? Should at least the driver's side fan continued to run or would that happen only during overheating situations?

Thanks for your help!

totaledTL

Inspect the wiring to the sensor for damage- interm. shorting to gnd?

01tl4tl

1/3 temp is not correct- has it been reading that as long as you had the car?
how long have you had the car?

If thats been the reading I would go for guage sensor
ck actual rad temp with thermometer?

correct temp reading is 1-2 lines below half- all the time,,from a few minutes after startup
anything else is wrong-something is happening~

temp sensor on lower passenger corner of rad controls driver side fan operation
dont hear mine at shutdown very often, less than a minute if it does
but sitting at a long light or intentional long idle it will cycle

AC controls pass side fan in normal conditions

guage will run off sensor where coolant exits block to thermostat, area of top hose for rad where the hot water from engine can be measured
we want engine temp , not rad temp (but that would be handy for troubleshooting!)

fsttyms1

#15 is the water temp sensor.

57 Handyman

fsttyms1,

Thanks for the graphic. That was the sensor location I was thinking I would replace if the sensor is the culprit.

I was just wondering...are both sensors the same part? Maybe I should switch them and see if the problem goes away. At least that would tell me if there is a short like totaledTL is saying.

TotaledTL raises a good point. I had messed around and moved the wire bundle a bit but no change. Maybe I should wiggle it a bit more.

57 Handyman

Update:

I just talked to Honda parts guy and he told me the temp indicator sensor is a one-pin sensor (#13). So, can't do a switcharoo.

Knowing that, I pulled the single wire and the indicator sits at bottom of scale (cold) and doesn't move when the engine is started. Earlier when I started the engine, the needle was positioned two marks below the top. I'm thinking of pulling and replacing this single-wire sensor but will check with another source at Acura dealership.

01tl4tl

put that wire to a ground point and guage should move,, iirc

57 Handyman

Update2:

OK...problem solved. Replaced coolant temp sensor; gage works.

Here is Honda Part number: 37750-PH2-014

I bought sensor from Honda dealer for $45 plus tax. Acura parts quote was about $10 more.

Thanks all for your input and assistance.

01tl4tl

wonder how much it was at autozone?
how long have you put up with this?
Now watch it for just below half and monitor constant there

57 Handyman

01tl4tl...I did a quick search online and costs ranged from $10 to $20 less. Locally, O'Reily's didn't have it, didn't check Autozone, and I wasn't too comfortable with what NAPA part person told me, so I decided to go get a Honda part.

As for putting up with temp sensor problem, not long...just a few weeks. Can't recall whether it was a problem before.

Over past 2 years, I have been enrolled as a student in Auto Body Technician Program at local community college. This car has been in auto body shop for past 9 months where I did body work and a complete tri-coat paint job. The repairs and paint job were done as a special project. Body work repairs included driver door skin replacement, removal of trunk insignia, dents and dings in body and bumper covers, and paint blemishes due to car being egged. All exterior parts, i.e., handles, mirrors, trim, bumpers, etc. were removed and painted separately. Paint color was Acura white with a mid-coat of PPG's Vibrance Silver Pearl, and 3 coast of clear.

It was a lot of work but well worth the self-satisfaction.

01tl4tl

did it sit that whole time not run?

57 Handyman

Mostly but was run when it had to be moved to paint, etc.

01tl4tl

wow- the worst of times for it!
have you run seafoam thru the gas yet,,that will clear up a lot of things
Gas gells after 6 months, good to do a system cleanout with 1 can in half a tank of gas
(in my opinion)

do the oil too- moisture forms while sitting- short engine run times make it worse,,
1/2 can in oil 30 miles/minutes or so right before next change will fix that up

57 Handyman

Thanks. I already changed oil and thinking of running Seafoam both thru gas tank and directly thru throttle body if i can find a suitable vacuum line. I've run Seafoam thru all my cars...good stuff!

I also plan to empty brake fluid in master cylinder, add new fluid, and pump fresh fluid thru brake lines and each caliper.

grahampham

Which did you end up replacing.. #13 or #15 in the diagram?

Black Tire

I have noticed my temp gauge stay just below mid point all the time. After driving and parking, I noticed the fan coming after 5 mins. It does this all the time after I park. Do I need to replace the ECT sensor like the fsttyms1 says in post # 13?

Coolant is fine and car seems to be running normal.