danytancou

Hi all,

[I guess my previous post with the same questions must have gotten lost somewhere; if not, a thousand apologies for double-posting!]

I looked and looked, but I couldn't find answers to my questions so I hope it is OK to ask...

Can anyone tell me at approximately what coolant temperature, as read by an Launch Technology OBD2 Tablet, the radiator fans are supposed to come on? I think it's around 97ºC / 207ºF but I'm not sure (and I can't find the info anywhere).

Following that, does anyone know the location of the sensor from which the car's computer reports the coolant temperature to the tablet?

Lastly, does the temperature gauge on the dashboard take its reading from the same sensor?


Many, many thanks in advance,

Dany

thisguyaves

The radiator fan is controlled by a switch that is essentially a plug in the bottom of the radiator. Once temperature is reached, it acts like a relay and "switches" to on.

The engine coolant temperature (ECT) sensor is what the dash gauge reads. It is just in front of the EGR valve on the engine head, left side of the bay as you look at it.

https://ww2-secure.justanswer.com/up...2_shot1311.jpg

The ECT is what reports temps. If the fans aren't coming on, it's the radiator switch. If the gauge is reading funny, it's either the cluster or the ECT sensor. Fans on my 02 EM2 activate near 190 IIRC.

ZeroSix

thisguyaves answered everything else, so I'll only answer the question about the gauge not moving past the default location even if the temp is rising:

OEM temperature gauges have a built in "dead zone"; the temperature may be fluctuating by a number of degrees, but the gauge is static. Why? For cars such as your Acura EL (Civic EX in the US), which are driven mainly by non-enthusiasts, having a linear gauge results in many owners bringing their car into the shop with complaints of a "faulty gauge that is all over the place". For cars that don't see any real performance driving, it's better to engineer a gauge that holds steady for a range of temps (say, 200-220*) than have one that shows their true coolant temperature. Really, ignorance is bliss. This is the same reason many cars have dummy lights instead of real oil pressure gauges, which fluctuate even more than coolant temperature gauges based on oil temperature, viscosity, and engine load.

If you are seeing the gauge climb past the normal spot, then the engine is overheating and you need to address this issue.

*just an example, not strictly applicable to your car

thisguyaves

^ Look at me, I'm helpful!

Aanything past 1/2 or 2/3 should be mildly concerning. Up to the red is an immediate problem. Around half is normal. I couldn't for the life of me find actual numbers on coolant temps for a D17A2...

ZeroSix

Haha! That was a good one. I admit, that was a long-winded response I wrote!

danytancou

No, no.. I don't mind long answers, especially when they go into more details, so this is all good! A big THANK YOU to you guys for the information!

A bit more from me, and more questions, if you don't mind. I believe that the individual components of the cooling system are good and in working order.. The radiator fans definitely work: when I unplug their connector from the radiator fan switch and short the connector using a paper clip they turn on when the car is on (i.e. key turned to the second position in the ignition and/or after the engine is started). Same with the radiator fan switch and the thermostat: despite having purchased them (new) from the Acura dealership, I did the boil test on both as soon as I opened the packages they came in (Honda-branded plastic bags) and before installing them, to make sure I didn't end up with bad parts; there is little chance, I believe, that the boil test damaged either, so they are likely fine. The coolant in the radiator is fresh (Honda original), poured in after I flushed the radiator, exactly described in the manual. (I don't have a means to raise the car up, so I can't flush the coolant from the engine block, but the coolant in there is only about a year old.) Finally, the radiator cap is brand new as well.

More questions: Do you guys have any idea why the radiator fans would not come on while I am driving, even if the coolant temp reaches 110ºC / 230ºF (read by the same tablet), but DO come on at around 97ºC / 207ºF when the car is idling? Does that make ANY sense at all? Should I even worry if, through all this, the temperature gauge on the dashboard doesn't move above half where it usually sits, or if it does, it comes back down soon enough as air flows over the radiator?

Also, can you guys think of a reason why the coolant doesn't get sucked back into the radiator from the reserve/overflow tank? I cleaned it thoroughly when I did the "half-flush" the other day, and it flowed back properly after I finished idling the engine after the flush (i.e. when the engine was off, as I was waiting for it to cool down, so I could open the radiator cap to add more coolant); during this idling, as per the manual, the radiator cap was only tightened to the first stop.

Thank you again,
Dany

NDNV

Welcome to the site Dany.
I have the same vehicle as yours with 185k kms (115K miles) on it. Shoot me any questions you might have.
Notable repairs over the years has been: head gasket replacement, front lower ball joints, alternator, By-Pass (Canister) Shut Valve (CVS)/Canister P1457 and driver's seatbelt buckle which are all common issues for our vehicles.

thisguyaves

Dany,

You have to realize the ECT sensor is on the head of the engine as the coolant flows out to the radiator. This means the ECT sees the absolute hottest coolant temps. When it flows into the radiator at the top, the water begins to cool. Cooler fluids have more density, so they sink. This means that the bottom of your radiator is the coolest part of your cooling system. Your fan switch is in this coolest area. As you drive, airflow will naturally cool your radiator to the point where you shouldn't need fans as you drive. And since that airflow is cooling your radiator fluids, by the time the cooled fluid gets to the fan switch at the bottom it's not hot enough to turn on. That much is normal. Don't sweat it if your gauge doesn't pass half.

danytancou

Thanks again guys! Sorry I haven't been able to post since last week. I think my car is beyond repair though.. yesterday I drove about 15Km in 20ºC weather, and I had to stop three times as the temp gauge went up above 3/4. The head gasket was already replaced twice (second time at around 180K) and either it's gone again (now I'm at around 211K) or, as my mechanic said, the cylinder head block became warped (in time, after the second head gasket replacement, due to being re-machined). He said the only thing he can think of is to get another engine, but I can't imagine where he could find one, as these engines stopped being manufactured in 2005.

I'll be happy to post all the details of what's going on in case you guys have any other ideas, but I don't know if any of you would want to take the time to read it.. I'd probably need at least a full page to write it all up.


Totally bummed,

Dany

ZeroSix

Sorry to hear how this turned out. It's upsetting that the D series engines are so prone to head gasket problems, so I hope it's somewhat comforting to know your frustration has been shared among many owners.

Your mechanic is correct; your most economical choice is to do an engine swap, or part ways with the car. The good news is that D17s are readily available for decent prices. If you decide to go the replacement route, do thorough research on the shop before you make your purchase. A lot of chop shops will give you a deal on an engine that will burn you in the long run.

danytancou

Hi again,

(There's no point starting a new thread, since this about is the same problem.) I haven't had time to deal with the car anymore--and now that the weather is nice, walking is my preferred mode of transportation. Anyway, something still doesn't make sense to me about this stupid problem: when I turn on the blower and the air conditioner, both radiator fans come on; my understanding is that this is normal. How is it possible though, with the fans on, for the coolant temperature to go UP--even when the car is idling??

Last wekeend, I ensured that there is enough antifreeze in the radiator & reserve tank, and I drove around the block (literally) for about 20 minutes last weekend until the coolant temperature reading on my ODB Book was up about 95ºC. When it did, I came back to my parking spot in the garage, left the engine on and opened the hood. The fans weren't on but the coolant temp was 98º already, so I turned the AC on and the fans started up as expected. I let it run like that for about 2-3 minutes, and the temp kept climbing. When it got to 118ºC, I figured no point doing even more damage, so I turned the engine off and haven't touched it since. As I said, this makes absolutely no sense to me, but perhaps there IS an explanation?

I simply want to understand what's going on not because I don't want to do the engine replacement, but because I want to make sure that I do everything I can, from then on, to ensure that this doesn't happen again.


Thanks,

Dany