Hi guys,
I've got some issues with slow warmup on my 07 tls.
I've done most known fix and it's still not quite as warm as I think it should.
New Acura thermostat, coolant flush/burp, heater control valve, heater core reverse flush.

If I leave the car running for 20mins in the morning and the car will be barely warm. My issue is the coolant temperature never go over 182F even when engine is fully warmed. I've read that acuras should be around 190-200*F. Could someone offer some insight whether that's true?

 

You've definitely covered all of the basics. 182 is fine, especially for winter. Thermostat aren't very precise and it's normal for the temp to fluctuate. That's why the gauge is buffered. I can be going down the freeway steady state and floor it for several seconds and the heater gets hotter but obviously the gauge doesn't move.

How are you basing that it barely gets warm after 20 minutes, by the coolant temp or by the heater air?

Are you running the heater while it's warming up?

What's the starting temperature?

If you can read the coolant temp, make sure the coolant and intake air temp read close to the same when before you start it up for the first time in the morning.

Basically, if you don't live in some super cold place and you're not running the heater on full blast while it's warming up and it takes a long time for the coolant to heat up, I would dig into it more.

If it takes a long time for the heater to start blowing hot air and it never seems warm enough but the coolant is in the 180s, I would start looking at the HVAC system. You can visually make sure the heater control valve is opening all the way by having someone switch it from cold to hot and back. You can pop the cable actuator off of the valve and move it by hand to see if there's some wasted movement.

As a point of reference, when it's about freezing, I can start my car, idle for a few seconds and drive it very easy, never going over 2,000rpm and 25mph and I have a little warmth in about 1 minute and the gauge is just barely moving off of the cold. That's with the fan as low as it will go. It's a little quicker with the heater off. It takes about 2-3 minutes for the gauge to hit full temp which doesn't mean the coolant is fully hot but it's close.

 

Starts Opening:
169-176 ºF (76-80 ºC)
Fully Open:
194 ºF (90 ºC)

 

On cold days the starting temperature is around -4F or even lower. I'm talking about the overall feel of the air from the vents and the cabin temperature. I'm hoping to start the car for about 10-15 and when I enter the car the cabin temperature is close to comfortable room temperature, like all the cars I've own for the tl.

Through the hvac diagnostic I can read the coolant temp, evap outlet temp, vent temp...etc.


If I leave the car idle it'll get to around 170F and wouldn't go higher, until I drive then it'll get up to 180F or higher really quickly. I've never seen the temperature higher than 183F though. After the car has been driven for a while the vent temperature does get to an uncomfortable hot (93F at the vent) but never at idle.

I got a new radiator cap today to see if it'll help.

 

170 with the car idling in that weather is fine. You can see from the post above there's a range in which the thermostat works and they're not super precise. In weather that cold, it's possible the heater core has enough capacity to cool the engine even with the thermostat closed especially at idle.

The coldest I've had mine was around -12F and it took a looong time to warm up but I also left it with the heater blowing which is not the quickest way to warm a car up. Next time you start it, turn the heat off and the blower off and it should warm up significantly quicker. I'm assuming from your post above that you leave the car running with the heater blowing while it's warming up. It's just a little V6 making about 5hp worth of energy sitting there idling so there's just not a whole lot of energy there. You can even turn the defrost on, maybe the tiny load of the compressor will help it warm up a little quicker.

Unfortunately the radiator cap is going to be a waste of your money. Even if it were bad, you're not getting hot enough to reach the boiling point of water so the additional system pressure is not required (well it is but for other reasons).

I hate to say it but I think what you're describing is normal. I think if you let it warm up without the heater on (or blower on low) you will be satisfied with the warmup time.

 

I was affraid that would be the case. However, we've a 2011 accord 4cyl, 2002 maxima and they're both warm when we start them at the same amounts of time and temperature. I don't have another tl to see if that is by design or poor system performance, but I do agree that everything seems to be functional.

 

I don't think you can compare across different cars. For example, in my other cars, one has a heater-bypass hose, the other does not... The car with a bypass hose, the heater heats up MUCH faster.

I browsed the Honda Parts catalog... The 11' Accord 4 Cylinder, has a parts listing for a bypass hose... The same catalog for the TL does NOT have a listing for a bypass hose. Perhaps that's why your Accord's heater heats up faster. (I haven't taken a close look at our TL, so I don't know if it has a heater-bypass hose, or an integrated/molded one, and if the bypass connects through the heater core)

 

It was relatively warm day, so i decided to watch the car start.
During cold start the coolant temperature rises pretty quickly, but as the engine gets warmer, around 140F and higher the temperature rises much slower, at 160F it barely moves. Which makes me its because the thermostat is starting to open or it is because the RPM is lower because the engine is warmer. I guess i could get a higher temp thermostat, but thats probably not a good idea.

 

I think your theory is right on.

Sometimes the thermostats labeled "high performance" or something of that nature stay closed longer but go from closed to open more quickly. If you were doing it yourself, it might be worth it to try one of these aftermarket thermostats but if you're paying someone it could get expensive quickly.

 

its pretty easy to change the thermostat on the TL, i've done it before.
there isn't much out there for a higher temp thermostat though and i'm worried that it'll mess up with the system timing causing engine wear.
I did a cold start today, with temperature at HI and in 15mins, it seems to be comfortable warm, so i guess thats good enough for now.
I noticed some intermittent heat/cool moment when i'm driving in traffic today which means there might be air in the system still, so i'll try to burp it again soon.

 

Sorry I don't have much to contribute to your concerns, but I am curious about how you are accessing the HVAC Diags and getting the information.

Thanks!

 

hold the passenger side AUTO & RECIRC button then start the car.
See the chart on page 16 for the sensor selections ( TL & TSX is the same)
http://www..com/forums/content/manua...l%20System.pdf
you can scroll through the sensor by pressing the recirc button and press driver's auto to turn of diagnostic