96 Tacoma 2.7L squeaking noise and puttering noise from engine

Hello everyone,

I've been having some problems with my 1996 Toyota Tacoma 2.7L truck. The first problem is sometimes when I start the truck I get an extremely high pitch squeaking noise from the belts. It's as if the belts are soaked, and completely worn. The strange part is I replaced the belts with new ones this past winter. Even stranger is it squeaks really bad (you can hear it down the street) for about 30 seconds than just COMPLETELY stops. You can also hear it if the steering wheel is turned all the way like when parking. This happens regardless of weather or temperature. It doesn't happen all the time, maybe 50/50 chance of it doing this. I think it has to do with the tensioner not being correct, but I'm open to other suggestions.

My next problem, is the past couple days, I've been hearing a knocking or putting noise from the engine. I attached a sound video clip of it doing it. I have no idea what it could be? Maybe it needs a valve adjustment is what I'm thinking? I'm not sure when or if that was ever done.

Other issues I've had was at times it could be hard to start, especially after loading the bed up with heavy items. I'm not really sure why. I do know my sister had a car that would have problems starting like this, and it turned out all it needed was a new fuel filter. I bought a new fuel filter for the Tacoma when I tuned it up last winter, but I never was able to install due to the difficult position.

I'm thinking about taking it to to a mechanic to install the fuel filter, but any insight into the other problems would be greatly appreciated.

Thanks!

 

I cant really help for the knocking sound but maybe I can for the belts squealing.

First, like you stated you might have a problem with the tensioner. Just check how tight the belts are. You can check them by hand and they need to feel pretty tight or theres a tool used specially for tightening belts.

Second, Belts might sqeal if what they are supposed to make turn (PS pump, alternator, fan,etc) are harder to turn than normal. I have the same squealing sound when I crank the wheel full lock and I know, in my case, its causes by my PS pump going bad (loose bearing, whining during winter). It has a hard time building pressure to overcome the pressure relief valve.

Third, your alternator might be going bad also. When you start the engine, it sucks voltage from the battery which the alternator has to work harder to recharge it. If your alternator output is weak, it will create more resistance on the pulley to make it turn. Stops after the battery has recharged.

Just giving you some ideas on what to look for. Hope it helped!

 

Honestly sounds like a rod knock. I'd start saving for a replacement engine.

 

Check your spark plugs. A loose spark plug can make a knocking noise.

 

From what I read about rod knock it's usually caused from lack of lubrication. I've owned the truck for the past 10 months, and already changed the oil twice, not to mention check the level of it once a week. The oil level has always been fine. I also do all highway driving with it, and rarely have a large load maybe 5-6 different times I've had heavy loads, so it's not being beaten on by any means.

I will check to make sure they are in the head tight, I really hope it's something stupid like that.

Thanks for the help thus far!

 

For the hard start I'd change the filter first since you already have it.

But if the knock if coming from the mis adjusted valves and the valves are truly mis adjusted then that could also be causeing the hard starts.

But don't jump to conclusions. Check the spark plugs first. Maybe regap them or just buy new ones.

Also you might have to check/replace the knock sensor if I'm not mistaken

 

Sounds a lot like a rod knock to me.

 

Can you make another sound clip while revving the engine a few times?

 

Since the sound is even more pronounced after the ignition is turned off, I have to vote rod knock as well. I know you have said the oil has been kept up during the 10 months you've had it, but it may be impossible to know what maintenance or lack thereof was done by the previous owner(s).

 

OP: "I've been hearing a knocking or putting noise from the engine"

I'm hearing putting noise not rod knock. Sounds more like a major exhaust leak to me.

As I posted before a sound clip with the engine revving would make it easier to confirm a rod knock vs other noise.

 

Here is another clip. My Fuji camera really isn't so great at doing videos apparently. Hopefully you can guys can hear the noise.

The tapping definitely increases as I rev the engine up. I think either the valves need to be adjusted, or as most of you guys are saying it's rod knock. The spark plugs and wires we're replaced this past fall. I used brand new OEM Densos and bought the ones the owner's manual calls for. They we're pre-gapped, and I checked them too. The spark plugs are NGK. One thing I noticed was after a few revs the puttering noise kinda quiets down a little. It's still obviously there, but not as loud as when it's first started.



As for the starting problem, I'm not sure what to think. Last weekend I had the battery/starter/alternator tested for free at Advance Auto Parts than Autozone. Advance Auto Parts said I need a new battery, but everything else was good. Autozone said everything was good. This all based on the electrical test hookup they have. Since I had an older battery from Costco from another Toyota, I just returned it and got a brand new battery and put it in. So far so good, no hesitation at all, but time will tell. It also has been cooler this past week, so that may also help.

 

That's another bad sign for rod knock I'd say ... It's louder when it's not getting lubricated/ the oil probably physically muffles it too once it's circulating.

 

Thanks for the replies, from what I've been reading up on rod knock it's not looking good.

It's just a shame, and I feel really bad for my bro who bought the truck. The thing wasn't cheap by any means, and is totally no frills. No clock, no AC no cassette, etc. but my bro was content with it thinking it would last him a long time, and reading up on the reviews and reliability of this particular model.

I guess we'll take it to a mechanic and get the official word and some estimates. We've spent a decent amount on the truck, new Yoko tires, new battery, full tune up, bedliner, so we're not ready to part with it just yet. But at the same time I'm not to keen on doing a new engine considering theres defin rust on the truck. So I dunno, I'll let you guys know what happens with it though.

Any ideas on cost of rebuild/new engine for these trucks? I'm talking ballpark estimates.

 

This is why I think it is absolutely retarded that they crush all the frame recall trucks. They would be plentiful in scrap yards now for those of us who wanna keep ours running longer and you could pick up a used engine for probably pretty cheap.

On the other hand... sounds like a perfect excuse for a V8 or diesel swap

 

Ya it is kind of retarded. I guess maybe we should look into the frame recall from Toyota lol. As for a swap, my bro got it because he liked the idea of a 4 cylinder good on gas, a V8 kinda defeats the purpose, but a diesel maybe something looking into.

At that rate, it may as well be sold for parts. The engine itself is that cost, than through in the labor and misc. parts and your talking almost what we paid for the truck itself.

 

I spoke with my future bro-in-law. I respect his opinion with cars and mechanics, I know he has a lot of experience with tuner cars, and building them up and what not. He was thinking it may be salvageable with over sized bearings. As I explained to him the noise more though, he was thinking it may be a lifter issue. The truck has no loose of power, and the knock noise isn't that loud.

What he suggested, which I think I'll do either tomorrow or Sunday is to drain the oil and check for metal shavings. If there are metal shavings than a bearing was spun. But if there are no shavings, to try a thicker oil, I'm thinking 10w-40 or a diesel 15w-40 oil? and see if that quiets it down. He said pray it's a lifter noise because thats easier to deal with than rod knocking.

So who knows, I'll mess around with it tomorrow.

 

Pull all the belts off and run it. If the noise is still there pull the valve cover and check for any weirdness.

With the valve cover off either crank the engine without starting or maybe run the engine with the valve cover off if the oil doesn,t spray around too much.

You don't have anything to lose doing these things to hopefully avoid a lower end problem.

 

One last final update, at least in regard to the knocking

I just drained the oil (no shavings at all), put 10w-40 and some risilone engine treatment. Same exact results. At this point, with it running, I start to pull spark plug wires 1 at a time. Same noise for all, except for the third one. I pull the 3rd and it's quiet and no knocking at all. So I know the problem is from this cylinder. Turn it off, and check the plug. The plug was tight, as checked before, but when I took the actual plug out and check the gap, I notice the plug is broken. The actual plug is rotating freely within the nut. I have no idea how this happened considering this is an OEM Denso plug that was put it in brand new this past fall. So I take one of the extra plugs that the truck had in it, check the gap, put it in, and just like magic the knock is completely gone.

I'm really not sure how the plug got messed up, but I'm VERY VERY happy and relieved that I found the problem, and it was a cheap spark plug.

So long live the 2.7! lol

Thank you all that replied to this thread!

I'll still bring it to the mechanic to adjust the belt tensioner, install the fuel filter and put a new lug nut stud on it.