danytancou

As I wrote in my other thread, I will most likely (have to) replace the engine in my 2003 Acura EL 1.7 (once my mechanic is back from his vacation). Meanwhile though, I keep poking around, trying to find out if I REALLY need to do this; it's not that I don't trust my mechanic (he's a long-time friend of the family) but it's possible he didn't think of EVERYTHING, right? Anyway, here is something I didn't bring up before..

In the winter (I live in Toronto, Canada), I only got heat in the car when it was moving (after about 20 minutes of driving--ie. once the thermostat opened): with the heat at full blast, the air from the vents would start to cool once I stopped at a red light, and by the time it turned green, the air was cold; it would then warm up again within a minute after I'd start rolling. Now that summer is kinda here, again after the thermostat opens, my temperature gauge starts to go up within a few seconds of stopping at a red light, but then comes down to normal soon after I start driving again; similarly, the gauge goes UP while I'm driving DOWN a long slope (without my foot on the gas), and then goes DOWN when I drive UP the other side of the valley. (This makes no sense, right? The engine gets hotter under load, as it pulls the car uphill--and therefore, if anything, the gauge should go up when the engine is revved, not when it's idling, right?) Another thing: once I get home and park the car, if I leave the engine on and open the hood, the radiator fans are on (I turned them on with the AC)... but instead of the temp gauge going down (because, presumably, the coolant is being cooled as it flows through the radiator) it continues to go up. (I confirmed all of the above with my ODB Book streaming the Coolant Temperature data.)

... All of which is a looooong way to get to my question here: does it not stand to reason that what I described above is what would happen if the water pump is broken in such a way that it only turns when the engine is revved? I've read a bit about water pumps, and it doesn't seem like they can break that way, but... OR, could it be that for some reason, the water pump simply doesn't have the power to move the coolant EXCEPT when it's turning faster (i.e. again, when the engine is revved)? Maybe that's the same question, worded a different way, I don't know. (The water pump was replaced about twenty five thousand Km ago, back in 2015.)

If there's even a remote chance of this, I would ask my mechanic to check the water pump first and replace it if necessary. (Obviously, I would rather spend $300 on that repair, than $1,500 for the new engine.)


Thanks,

Dany

thisguyaves

I mean...

Yeah.

The water pump is on the timing belt. It's directly connected to the speed of the engine. The faster the engine goes, the faster the pump works, and the better the system cools, but it the pump has broken impellers, you wouldn't get enough flow for anything at idle.

holmesnmanny

the water pump fins can corrode away but that would probably be the opposite of what you are experiencing

however it wouldn't hurt to replace it for $40 for the cost of just the wp if you do the work

i would think you either got the wrong thermostat or the maybe the radiator is internally clogged

you can also run a compression test just to rule out head warpage

danytancou

Thanks for replying guys.. sorry I haven't had a chance to come back until now.

OK, so not that I "want to believe" @thisguyavesbecause he seems to be confirming my theory so it's easier for me to accept the answer as a result, but, @holmesnmanny, can you explain how a clogged radiator would lead to such symptoms? I mean, if that was the problem, from what I understand about these things, the cooling system would either not work at all or nor well... all the time. And by the same token, revving the engine wouldn't make a difference to the coolant temp, no? Please let me know if I am wrong here.

I am 100% sure the thermostat is fine: I bought it from Acura myself, took it to my mechanic, we tested it to make sure I didn't buy a lemon, was fine, so he installed it; this was back in January, but and there's nothing wrong with it now: streaming coolant temperature data from my ODB Book shows that once the coolant reaches 84-85ºC, it stays at that temp for at least five minutes before it starts going up again. If the thermostat was stuck (either closed OR open) the temperature would just keep going up, would nit no? Based on my understanding & observations, and, again, simple logic, I believe that when the thermostat opens, the coolant from the water jacket takes some time to mix with the coolant from the radiator, so until it's fully mixed, the temp remains the same.

Finally, if the head was warped, or if the head gasket was gone (again), wouldn't I see dried coolant on the engine block, just below where the head & block meet, since that's where it would be spewing out? Wouldn't I get cylinder misfires from having coolant in there?


Oh, one last thing: in another thread someone wrote that the ECT sensor on this car is in the bottom part of the cooling system.. can you guys confirm that, please? Somehow it doesn't make sense to me.. and this picture says different: https://ww2.justanswer.com/uploads/a...2_shot1311.jpg. Is the picture right?


Thanks so much again for all your help!

Dany

thisguyaves

The ECT is on top of the thermostat housing on the block... just in front of the EGR valve if you have one, left side of the engine as you look at it in the bay. The fan switch is in the bottom of the radiator on Si models (SiR in canada) but on D17 powered vehicles it's in the bottom of the thermostat housing

If the head was warped, it could simply pop the gasket into one of the cylinders allowing coolant to boil quicker and/or leak. Take the spark plugs out and see if one looks clean, or just buy the $25 compression tester.

s0hayat

Hi there what you have explained it seems that you might have a head gasket leak I have the exact same symptoms before I did mine on a 2001 Honda civic 2003 Acura el has the D17A2 motor vtec and those engines are notorious for head gasket failure. One of the main thing that you will notice if you back up your car from your driveway and than put it in drive you will hear a gush of liquid either louder or may be minimal that means there is air in your coolant system. which means a leaking head gasket the only remedy for that to put a new head gasket. Hope this helps.

holmesnmanny

a clogged radiator will cause a restriction which will be more apparent at idle and less when driving