Engine fan busted blades, third time, why?

I have a 04, X-cab, Tacoma, 4x4, 5sp. ....97k+ miles

about a year & a half ago in winter, I started the truck (in garage but no door), heard a "whack" noise.. and from then the truck ran very rough. I took it to a shop and asked them to diagnose the problem and they found nothing wrong except the engine fan was missing a blade. They replaced and the problem was solved. It ran great. The culprit was a squirrel. It finally fell out after the body was shrunken enough for it to drop out. I live in a somewhat rural area so it was no surprise an animal had sought the warmth of the engine.

This happened several months later (summer this time so it seems odd an animal would seek refuge and warmth near an engine) when I was passing another car on the interstate.. this time it was about fifteen minutes after starting the truck. I down shifted to third and pushed it... heard the "whack noise again and it started to run rough. Since the noise and symptoms were the same, I checked the fan first.. and, yes, it had a blade broken off. If it was an animal, it seems odd it would lay low for this long.

I had the fan replaced again in August. Recently, I was merging onto a busy interstate and again shifted to third and pushed it to get up to speed with traffic flow pretty quick. Heard what seemed to be several whacks and the truck has been running even more rough than the other two times. In checking under the hood, there were three blades broken off completely, one half way off and another cracked and chipped.

I can't imagine this being rodent problems. Can something be happening as a result of torque? Could the first animal have bent the shaft and now the fan hits when the truck is pushed or under strain? Seems a squirrel is a pretty small animal.. I would think the truck hardware would be much more stout than that. The last two times seemed to happen upon a downshift and acceleration. Any ideas from anyone around what might be causing this re-occuring problem? At 200.00 a crack (no pun intended), I'd like to get it solved once and for all.

Last... if anyone knows of some kind of under carriage "cover" that would keep animals out, can you tell me where I can find. Seems cheaper than installing a new garage door.

Thanks in advance.. I'm new to this forum and am looking for an answer...

gla

 

Maybe check the fan shroud for damage. That is what I think the fan would hit if something was bent. Also if something was bent I doubt the truck would run with no vibration.

Welcome to TW!

 

You may have busted motor mount. Motor moves and the fan will make fan shroud contact.

 

Don't know if you have a body lift or not, but adding a body lift without dropping the fan shroud can cause the fan to hit the bottom of the shroud. If that isn't the issue, an electric fan would solve the problem for good. Sorry for your troubles. Getting stranded sucks.

 

Much appreciation for these replies... to hit each one...

The truck vibrates like a SOB when the fan is busted... not at all when it isn't.. that's what I mean "runs rough"...

Still not sure about animals the second two times... if it is critter.. the last one had a pretty f**king hard head to wipe out three and a half blades. Something in the downshift and acceleration has me wondering...

No obvious damage that I can see in the fan shroud... I'll double check this. In my astonishment around the number of fan blades missing, my focus was there.

Motor mount.. I suspect this... I saw after I posted an different post about a problem where there was a low RPM noise. Some mention of motor mounts was made there. The only noise associated here is the sound the fan blade makes when it breaks. Otherwise none...

No body lift.. completely stock TRD...

if anything drops in or you hear about similar problems... let me know...

thanks...

gla

 

Probably a motor mount, possibly drivers side, it will allow the engine to lift up and thus your fan contacts the shroud.

Put a jack under the pan with a block of wood between it and the pan (something wide to distribute the weight).

Jack up the truck a bit, shouldn't take much to shift the engine if it is an engine mount. Obviously don't try lifting the truck with the jack on the pan.

I haven't been that far under my truck so I don't know how visible the mounts are for a visual inspection.

 

to all, fwiw...

I appreciate the comments on this... and want to reply just in case something like this happens to your truck down the road... oddly enough, the problem here appeared to be a worn out fan clutch. At high rpm the fan blades would ungulate forward and make contact with, I believe, an alternator bolt thus sheering them off. The higher the rpm, the more the blades distorted. All engine mounts were intact, no animals, fan housing was not scared up... this seems to have solved the problem. I can get on it and, so far, all is well. The reoccurring problem happened upon acceleration.

The first time it happened it was an animal head that busted the blade..at least I think it was because the sound of the blade breaking happened as soon as I started the vehicle.. and there was a body count. Whether or not this had impact on the second two times, likely no one will ever know.

keep on truckin

gla