erndog

I am at my wit’s end regarding an overheating issue with my son’s 2010 Civic DX VP.

Initially, it was losing water and overheating. We could not determine where it was losing it from. There were no puddles anywhere or wet areas noticeable. A cracked head or blown head gasket came to mind, but there is no water in the oil, and the engine runs great. Realizing that it may be a leak that only occurs when the engine is warm, we started looking elsewhere and found a faulty lower seam on the radiator. At the same time we found the radiator fan to be broken. We replaced both the fan and the radiator, as well as the hoses and cap. The issue seemed to be fixed, although it may have just been short drives masking the problem. After about a week, the overheating returned. We then replaced the thermostat. Still overheating. The radiator fan would only come on with the A/C fan when the engine was quite hot. My son took it to AAA and they said they thought it was a faulty ECM. Before doing that I tested and verified that all the relays were good (not just the fan related ones), as well as the fan control switch in the fuse box and all the fuses. Then I replaced the ECM and had it reprogrammed. The car continued to overheat. At this point about the only thing left that I could think of was the #2 ECT sensor, so I replaced that, too. I took the car on an extended drive (two trips of ~90 minutes each) with my Innova unit hooked up monitoring live ECT data. The ECT ran at about 217-232 most of the time, but would run up to 244 on occasion and once hit 250, at which time I had to take evasive action.

The fan comes on religiously at high temperature with the A/C fan, but never by itself.




I don’t know where to go from here. I know the fan supposedly has a low and high speed and evidently is not running in low speed. Is this a fan issue or a circuit issue? Any other ideas or thoughts??



Thanks in advance.

erndog

I don't know if there is any connection, but in the wacky world of modern car electronics there may be.
The fuel gauge sometimes disappears and sometimes it reverses, i.e. blocks light up from full to some point toward empty.
Also, as an added note:
Yesterday I recharged the freon in the A/C system (was at zero). Now both fans come on when the engine gets warm (earlier than prior); however the radiator fan still never comes on solo.

erndog

The car still overheats. The radiator fan NEVER comes on by itself. It should, shouldn't it?? However, it does come on in conjunction with the other fan when the engine gets too warm or the A/C is on, as it should. The only thing I haven't replaced is the temperature sensor on the head itself. I don't think that one has anything to do with the radiator fan.
Since rtd's resistance goes up as temperature goes up, shouldn't disconnecting the lower sensor on the radiator make the fan run? I tried thaat and it doesn't. Also tried jumpering the wires; also no go.
I am looking for ideas, please. Especially as to why the fan doesn't run solo. I think that is the root of the overheating issue.

hondaslave1342

What about a bubble on the cooling system..

erndog

I've done the burping process with funnel a couple of times. The only thing I haven't done is remove the ECT1, but it doesn't appear to be a high point anyway.

erndog

I disconnected the radiator sensor, ECT2, thinking that should start the radiator fan anytime the key is on. However, the fan does not start. I know the fan is good, as it runs when the A/C is on. Could it be a short in the wiring giving a permanent cold reading?
Another possibility is that maybe the fan doesn't have a low speed?

erndog

Update-
I changed out the coolant with straight 50/50. Previous coolant was pretty diluted, due to emergency refills. Bled bubbles for about 30 minutes. Runs in the 2/3 range of gauge unless you step on it or are doing 70+ on interstate. Then it goes right up to the top and stays there until you intervene with the heater on full blast.
Could this be a head gasket issue? I am kinda leaning that way now. does it make sense that high rpms would be an issue, but not at other times? If it is not that, then the ONLY thing we haven't done is replace the water pump. Would that fit the symptoms?

tech8

Generally, both cooling fans (radiator fan and A/C condenser fan) should be running at the same time; high coolant temperature or A/C is on.

When coolant temperature is above 206_F (97_C), both cooling fans should run. (High speed)

When A/C is on, both cooling fans should run. (Low speed)
When A/C is on and if the refrigerant pressure rises above 1520 kPa(221 psi), both cooling fans should run. (high speed)

************************************************** ************************************************** ******
Get a compression test to see if the head gasket is blown.

erndog

Wow. Wish I new that a long time ago! Thanks!!
Now I need to solve the issue.

Ryanthegreat1

Going the highway should provide WAY more than enough air to keep things cool. Can your scan tool read ECT2 sensor and ECT1 and the same time? Or even read them individually? Should be 50 degree delta between them on a good radiator on a 80-90 degree day running down the highway at 70mph.

I sort of suspect water pump is missing vanes or is missing a belt. This generation I believe has the water pump on the accessory belt. Maybe the belt is routed incorrectly and is spinning the wrong direction? Smooth pulley goes on the smooth side of the belt, ribbed pulley goes on the ribbed side of the belt.

erndog

Good thinking. The belt is routed correctly; I was hoping that was it. However, I suppose the vanes could have degraded. I am a little nervous about replacing the water pump, due to that one killer allen head bolt on the bracket that gets everyone. I guess I need to do it, though. Wish me luck.

Ryanthegreat1

Just to check, the condenser is not packed with debris right? Air is able to pass through to the radiator?

erndog

Yes, it is clear.

erndog

Replaced water pump. Old one was fine. Next stop, head gasket.

erndog

So, I replaced the head gasket and got everything all buttoned up again. Engine started right up. Topped off fluids. Turned off engine. Checked tire pressures.

The "D" for Drive was blinking and the service engine light was on. Not knowing what the blinking D was all about, I read the codes and cleared them. I expected codes, due to all the disconnecting and reconnecting, so I didn't really pay much attention to them. One was the camshaft position sensor, and the other may have been the some, or maybe crankshaft sensor. Anyway, now the engine won't start at all. It cranks for a while and then one little putt and then cranks some more. D still blinks.

Any ideas??

tech8

Check that Ground G101 bolt was properly reinstalled and tightened.

erndog

Well, that little interruption has been solved. Found the camshaft position sensor disconnected. Plugged it in and the blinking went away, engine purrs, and car still runs hot. Not a warped head, because I just installed a fresh resurfaced pressure tested head.
Just put in a 170 thermostat to see if it makes any difference. Maybe the old one went bad?