grottoman

I didn't find a direct thread on this, sorry if I missed it.

2003 with about 140k miles, radiator was replaced a couple years back, recently replaced timing belt (#2) and some valve cover gaskets in advance of a road trip.

On the road trip, used no cooling air, occasionally used heat at night with the roof down.
At one point, I thought I heard my engine louder than normal, but decided it was actually machinery nearby.

The next morning, after only about 1 hour of leisurely driving through a civil war park for about an hour, I confirmed that in fact it was my vehicle making the noise.

It was fairly frequent, and basically sounds and feels (hand on air filter) like the blower kicking on, as if to cool the car off.

But the air temp was cool, the car temp was solid and cool, so there wasn't a good reason for this to be happening.

Because I had just had the timing belt & such done, I stopped at a dealer. The engine light came on as I pulled in.

They indicated that they saw a MAF sensor failure, and that while it needed to be replaced, it wasn't a problem to finish my road trip. They indicated the check engine light was related and also ok to drive with. They then lost a lot of credibility when they tried to ask me if perhaps the AM radio was the noise I was hearing...

Despite that, I continued on (had to be somewhere and they said it was ok to drive). The engine light actually went off the next time I filled up, so I decided perhaps that was actually a gas cap pressure issue (saw that once before in my ~6 years of driving the car).

Back at my home Toyota shop, they confirmed the MAF replacement need, and have also suggested spark plugs (fair enough).

But re: the air, they don't believe it sounds 'wrong'. I agree with that- it sounds 'right', as in when the blower kicks on, and I vaguely recall that it was something I heard back when my radiator actually rusted out / failed.

My issue is that it seems to be happening MUCH more frequently than normal.

So while I don't recall hearing it at all over the past couple years or only on very rare occasions under load, or when the radiator failed, it seems to be almost routine now, where at a given stop light (even in just a few miles of driving in town at low speeds), I'll hear the extra noise.

Any bright ideas? The Toyota shop didn't argue with my assessment, but really could only offer that it's an old vehicle, which is true...

I've not tried to put it under load with the A/C to see what it does, but that may be next, as I'm about ready to need it here in the South, as it warms up.

Thanks for any feedback.

bb430

iTrader: (1)

When the timing belt was replaced, did you have new anti freeze put in? Maybe the anti freeze was mixed where the OEM anti freeze don't require mixing.
Just a thought.

grottoman

Hmm. Thanks for the thought, but didnt ask for that and didn't gear anything about it, so I wouldn't think so, but can check...

Definitely still happening, and also, my check engine light is back on, they said it came on while they had it...

Hmm.

Bgw70

Just to clarify, when you say blower, are you referring to the electric cooling fans in front of the radiator or the HVAC blower?
-Have you checked the coolant level?
-has the water pump ever been replaced?
-- if not, they should have and 140k miles on a water pump is a tremendous amount.
-is the engine temp in the normal range?
--if so, you could have a temp sensor going bad and it may be turining the cooling fans on too early.
-did they change the thermostat, is it original?
--if original, it could be staying partially closed which would elevate the engine temperature and cause the cooling fans to turn on more often.

If you can think of more information, we might be able to help you narrow it down...
BTW, just because you have an old car does not mean the cooling fans should run more often...did a service guy say that to you?

grottoman

Thank you for your feedback.

Just to clarify, when you say blower, are you referring to the electric cooling fans in front of the radiator or the HVAC blower?

I'm not entirely sure- but I think I mean the electric cooling fans. The interior hvac is not running.

-Have you checked the coolant level?
Yes, looks ok.
-has the water pump ever been replaced?
-- if not, they should have and 140k miles on a water pump is a tremendous amount.
Yes, twice now (~70k and now again)
-is the engine temp in the normal range?
Yes, rock steady.
--if so, you could have a temp sensor going bad and it may be turining the cooling fans on too early.
Makes sense- didn't show up in the engine check diagnostics.
-did they change the thermostat, is it original?
Don't know about that.
--if original, it could be staying partially closed which would elevate the engine temperature and cause the cooling fans to turn on more often.

And yes, they truly did say 'it's an old car, it might just be because of that.'

I'm not a mechanic, but yeah, I found that pretty silly myself...

I'm hoping that perhaps somehow, the air flow sensor which is diagnosed as bad (waiting on the part) is triggering more air intake or something, but that's a desperate straw grab.

grottoman

Mystery solved. The original dealer (that I took it to for timing belt / preventive maintenance), and who first advised me it was just 'an old car', on 2nd review found a 'control module' that was unplugged.

I don't know precisely what was unplugged, but it has been back to its rock solid flawless self since they apparently plugged it back in. I would note that this same dealer left my 4runner cruise control unplugged once before doing unrelated service. Odd.

Comically, they speculated that the out of state dealer had forgot to replug it- but the only reason I stopped at that out of state dealer was because the fan was operating oddly.

So all is back to normal and well- apparently there is some sort of control module (not the main ECU, I figure) that the fans pays attention to - without it, it was just doing its thing sporadically...

Thanks for the feedback!