99 TL with 150K miles. A year ago dealer had a list of recommended fixes -- one was to replace the coolant temp sensor (at total cost of about $200.) He suggested that the fan would continue running for a long time and drain battery. Fan was not running for long after shutdown. I had noticed no cooling issues at all. In past two months, either when running at high speed or when stuck in traffic, temp climbs to about 3/4 point on gage. I turn off AC and temp drops in less than a minute to below half on gage where it usually is. This has happened about 5 times in past month. It has been 100+ in Dallas. Of course, I have no idea what the fans are doing while I am driving.

No radiator boilover. Coolant is bright green and at top of radiator. Driver side fan and sometimes passenger side fan run after shutdown, sometimes for 5 minutes, maybe a bit more. I don't recall water pump or other components being replaced though could have been done 5 years ago after rear-ending truck and getting $6K body repairs done.

Is it likely to be coolant temp sensor? How would dealer have known? Might it be thermostat?

Other threads have pointed out location of coolant temp sensor at lower radiator corner on passenger side. The acuraautomotiveparts.org parts list shows temp sensor at front of thermostat housing and no part associated with lower radiator. Are there two temp sensors? Perhaps location differs by year?

Thanks,
Hot in Dallas

 

yes it differs in location by year-
So a year has gone by and now you have put the car in the danger zone on the temp- anything past 1/2 is not OK!
The tech either tested the thermostat resistance reading or saw corrosion or whatever and said replace it last year
When the fan sensor fails it does not run when its supposed to and it runs long after the car is shut off- more than a few minutes is too long
Replace it yourself and hope the engine is ok
Color means very little on coolant- there is a 2 dollar tester that will say what conition its really in
Anything over 5 years old and your on borrowed time
PH changes and aluminum does not care for acidic environment
Water pump replaced at crash damage? not usually- maybe a radiator replacement and hoses if they were destroyed- but more than that---- body shops fix body panels- they are not mechanics in any way~

The right-passenger side fan is controlled by the AC and cones on with it- and when there is some serious overheating (guage indicated or not) and its trying to help
The left-driver side fan is temp sensor controlled and may run on and off as the car sits at idle and in traffic- and when you shut the engine off.
The engine heat rises before it cools, so the sensor make pick that up and pull some cool air thru the radiator- lowering its temp.

 

Why not try bleeding any trapped air out per recommended proced.? Free, & might cure your problem.

 

thats always worth a try if you had any work done recently- who knows what really happened at the body shop if they replaced it- and dint open the heater for example
Check the owner manual for the procedure specific to your year- my 01 has a series of steps and takes about 20 minutes to complete

 

Wow, what a coincidence.

I also have a 99 TL. With 147k miles
I live in Dallas as well.. with a similar problem as you.

After some research here and on aw.com ~ seems like it is the coolant temp sensor for me. Recently, after driving, the car doesn't start unless I let it sit and cool down a bit.

My symptoms:
The primary (drivers side) fan doesn't kick on.
Car only overheats after 15+ mins of driving/in the hot sun/traffic (as of recent)
Car refuses to start after some driving around in the city, until it cools down

Autozone has the part in stock for roughly $26.
I'll let you know the results once I get a chance to install this weekend

 

Its death warning for your engine when it wont start when hot

if the temp on a tl exceeds halfway- its bad news needing fix today
If its been temp redlined- or close- a few times,,, in 6 monthes it blows a head gasket

 

I understand about the headgasket.. but why about a car not starting when its hot?

I've seen a faulty coil pack cause a car not to start until it cools down.
How would that be a "death" warning?

 

If the engine internals are getting so hot the expand to the pointn of engine doesnt like to crank over when warm- and you must wait until the rings cool and shrink, or whatever, but its not good
Yes it could be just the engine hot is causing fuel to boil in the line when you shut down, that will cause a vapor lock and wont want to start
You would have to get it realllllly hot for those type things to occur
Check your oil level- it used to help cool and will use some in cases like this

 

run
did you replace the water pump and timing belt at 100k miles?
If not- the pump could be weak and or leaking from its seal-
is your coolant level ok?
Burbing the system only helps if there is air suddenly for some reason- its worth a try if you find a bad cap or hose. See owner manual for exact way for your year- my 01 is freaky lengthy procedure- like no other car I have worked on

In this case of no driver side fan- that is probably the temp sensor in raditor lower corner
Driving without it is VERY dangerous- like I said, over half on the guage is danger-
peg it a few times and say goodbye to the heads as well as the gaskets

 

Well, it went about 3/4 one time and I turned the ac off... went back to normal. The car's been sitting in the garage since (about 4 days ago)

Anyhow.. update
It was not the coolant temp sensor. (although I replaced it earlier tonight)

I checked the fuses, checked the relays.. and all were fine.
So, I got my test light and checked the primary fan at the connector. Sure enough, there was power going to the fan... but fan was dead. Looks like its time to replace the fan

 

Did you connect power to the fan to see if the fan worked?

 

i've been having similar problems to those of PaulTX.

you guys know what the resistance reading of a properly functioning coolant temp sensor should be? i hope to test mine tomorrow.

 

UPDATE:

Picked up a radiator fan assembly from a local junkyard. $40 + tax.
(the part was from a 94 accord with a 60 day warranty)

Literally took me about 6 minutes to replace.
(2) 10mm bolts, moved the coolant relief hose out of the way... disconnected the power plug to fan... pulled right out.

The accord fan went right in. EXACT match down to the connecting plug and bolt locations. Jumped in the car and started it... beautiful. Both fans turned on.

 

Both fans arent supposed to run. Only one. one is for the radiator, one is for the AC

 

correct.. but when the car is cold, neither fan will turn on.
solution?

Turn on the a/c
That will turn both fans on

Didn't think all that detail was needed... but the a/c was on

 

with AC on, the passenger side fan will run
At idle after temp warms to normal - the left fan will come on anf off just sitting in the driveway

Congrats on the auto recycler yard find! 40 bucks is a score

 

Only ONE fan comes on for the A/C. So if you turn A/C on it shouldnt turn both fans on.

 

AFAIK, I believe they both turn on with AC on (with one cycling)
Why would only the condensor fan turn on.. that's only going to put more stress on the radiator.

 

thanks... car-part.com rocks!

 

I think you're asking the question wrong. The question should be - "Why would both fans come on if only the condenser fan is required?"

It's my understanding that they run independent of each other. So for example if you're on the freeway with a/c on the condensor fan comes on if needed, not both. Now if your car is getting really hot, the condenser fan can be triggered independent of the requirement of the A/C to provide additional cooling for the radiator.

 

Does anybody know what the coolant temperature sensor wire is and the path it takes to get to gauge cluster? Problem: I bought a 99TL with a Type-S cluster in it and bought the original cluster. When I installed it to see if the temp gauge would work it still doesn't. So with the knowledge I have about vehicle wiring, I was wondering if anyone could give me some wire colors to track down either from the ECU or from the sensor itself. Pretty much any way I can rewire the temperature sensor myself. Please help, temp sensor is kind of a crucial thing to have!

 

Im having the same problem as well but a little different.

I have a 99TL as well with 89,500 miles.

The temp would rise if I'm driving in slow traffic, idling for a while, or climbing hills at a constant speed. The only way to lower the temp would be to run the A/C or turn on the heater which would instantly drop the temp to normal running temperature (little bit below the half mark). Earlier I noticed that the fans would run for a while after I turn off the engine and now I they dont turn on at all unless I turn on the A/C. When I run the A/C the engine stays at normal temp during traffic driving and what not. I noticed both fans turn on when I use the A/C so I know its not the cooling fan itself. Im guessing its the radiator fan switch or coolant temp sensor. Could it be anything else?

 

I'd say something to do with the control of that one fan. if its not the relay then check the coolant temp sending unit.