v6 1GR-FE Engine loud knocking

I recently moved to charleston SC, have a 2006 Tacoma, TRD Sport, Crew Cab, Long bed, 270k miles. 1GR-FE 5th character "U" engine. Until the other day it has run great. I used 100% syn oil regularly, slick50 every 60-70k miles. The other day I was going down the expressway running about 65, ran up on a tractor trailer and accelerated to get around, it downshifted from overdrive and all of a sudden I started hearing a loud knock. I feared I threw a rod so pulled over and shut down. I had some experience with throwing a rod before and it didn't really feel like that. while there was some slight loss in power it didn't feel like i lost a cylinder or spun a bearing. I raised the hood, cranked it back up and listen for about 30 sec then shut it back down. The sound seemed to be coming from the right (passenger) side near the front and above the exhaust manifold. I'm new to the area and didn't know where to have it taken but knew the local "dealer" would be way out of my price range. I had had my wife's AC compressor replaced at a local "tire" shop that also did repairs and they seemed to do a good job so I had it towed there after hours. they checked it the next morning, called and said "the motor is fried" and continued to tell me how to replace it with a "used" motor would cost me $8K.
I politely told them I'd have to think about it. I went down there the next day and ask to speak to the mechanic that "diagnosed" the problem. He couldn't really answer many specifics about how he arrived at his "fried" diagnoses and I definitely got the feeling that he was not a real "motor guy" and that they really didn't want to mess with it unless I was going to shower them with $8k. After I did some research and was able to find used log blocks starting at 2K and reman long blocks from $2800 I knew they were taking me for a ride. I had it towed back home. It's been a while but I have rebuilt my share of VW and small block chevy engines (back in the Holly Carburetor days), so I dug out my stethoscope. The knocking is definitely coming from the right (passenger) side above the exhaust manifold and the frequency is about half of the RPM reading which leads me to believe is not a rod. I drained the oil and ran it thru a sieve to check for metal shavings and it was clean. So... I know 270K is a lot of miles and if i fixed this issue that something else would break before long. I really can't afford to get another truck now. I really need this truck to get me to next may when i retire and will get a new truck, so i need to get another 15k out if it. I have an ok equipt shop but not to an engine swap myself. If I do a swap I would have to find a mechanic in the area that would let me have an engine shipped to him and he do the swap. Time I have lots of, money not so much, So the question is whether or not try to find/fix the problem or swap out engines. On the repair side....

1. If it's in the front (ie timing chains, oil pump etc) and the front cover has to come off can that be done without pulling the engine?

2. If its a collapsed lifter can you replace it from the top without pulling the head?

3. Looking at a diagram I assume if i have to pull the head then I will have to pull the front plate first.

4. Is this all a waste of time and should i go straight to replacing the engine ?

Sorry for the laundry list. Any suggestion or experiences would be appreciated.

thanks
Joel

 

bump I am curious on what people are thinking

 

I have thrown a rod and there really isn't any question when it happens. Maybe you busted a valve spring or have a valve Issue. Just my 2 cents. Could be a cheap fix.

 

Optimism is good.

 

Post a video of the engine knock. Generally the knock noise will get louder when your off the throttle and the rods are "floating" with no load on them. With that kind of mileage your probably better off too find a good used motor and you and your buddy swap it out on a weekend. Should be able to find a motor under 2k.

 

A compression test would be one of the first things I do.

 

This is an update. Below are pictures of my engine and VIN number.
Here is a link to a video of the knocking sound

When the video was recorded the RPMs were 1080 +-3

 

Also i need to add. When the incident first happend as described in first post, The oil light flickered some. I did not stay on but did flicker ever so often. It does not come on now at all when i start the engine. Also when I first pulled over I checked the engine codes (I have a OBD2 wifi unit that stays connected as I had been having problems with a O2 sensor I was trying to track down recently). When I checked the codes on my phone app it had just thrown a "pending" P0012 code (bank 1 cam timing). but it never set it "stored" and it is now gone.

Joel

 

BUMP... i am surprised people are not on this post lol

 

Just to answer your question 2. These motors dont have oil cushioned lifters. They are shim and bucket, direct contact, so nothing to replace there. Unless you need a different shim size for valve lash.

Definitely perform a compression test like stated above. That will give you some specific answers if the problem is in the cylinders or valve train.

 

Based on your description and video, it does sound like it's in that head. I agree with the above posts and say do a compression test. Then you can pull that valve cover, and have someone rotate the engine over by hand with a ratchet; while you watch the cams and each valve area/bucket closely to possibly locate a problem.

 

I wonder about the trouble code. That sounds to me valve related in your video. But the one variable here is the engine uses oil to control the valve timing. So that might have something to do with the flickering oil light?

DTC P0012 is Camshaft Position "A" - Timing Over-Retarded (Bank 1)

DTC No.
P0012 P0022

DTC Detection Conditions
Retarded cam timing:
With warm engine and engine speed of between 500 rpm and 4,000 rpm, all conditions (a), (b) and (c) met (2 trip detection logic)
(a) Difference between target and actual intake valve timings more than 5°CA (Crankshaft Angle) for 4.5 seconds
(b) Current intake valve timing fixed (timing changes less than 5°CA in 5 seconds)
(c) Variations in VVT controller timing 19°CA or less of maximum delayed timing (retarded)

Trouble Areas
• Valve timing
• Oil control valve (OCV)
• OCV filter
• Camshaft timing gear assembly
• ECM

The FSM goes through several troubleshooting steps, including checking sensors, timing chain for jumped tooth, camshaft oil control valve (OCV, it controls the VVT), OCV filter, camshaft gears, etc.

I'm only guessing, but a compression check would be first to do but it might not be conclusive by itself. You'll probably need to pull the valve covers for an inspection, too.

Then before I tore into rebuilding or replacing an engine or doing head work I might have someone who can really diagnose what the ECU is doing with the VVT control look at it. The fix could be a cheap broken connector, clogged OCV filter or relatively cheap sensor.

I'm used to old junk, too. So this VVT is new and interesting to me. This video shows how it works and I could see the actuator tapping if the valve isn't working. Or perhaps the VVT itself is failed?

https://www.youtube.com/watch?v=YjIKUrre4FQ

 

Thanks to all,
I have a compression tester someplace in deep storage and will pull the plugs in the AM and post back results
Thanks to all that have responded.

 

If you are sure it isn't coming from the rod/crank area it could be a wrist pin but I doubt it. It almost sounds like a valve hitting the piston to me, but that is coming from audio from the video. Have you pulled the spark plug/coil pack wire off of the cylinder? If it is a rod or wrist pin, it will quiet down significantly. If you get a chance try that, just don't get shocked,it hurts... Keep us updated

 

Good info here, this is what I was thinking when he mentioned oil light flickering too. I wish I could help OP, but good luck!!

 

UPDATE....
Pulled plugs to do a compression check. Other than needing to be replaced cause they been in there for 270k miles they looked OK, no signs of oil burning/rich burning etc. Ran compression test
Bank 1
1 - 176
3 - 185
5 - 150

Bank 2
2 - 183
4 - 180
6 - 173

So the 150 in cyl 5 was suspicious.
Did a poor mans rod check


ie, rotate each cylinder thru TDC then a little passed. Insert small rod (i use a 18" 3/8 steel rod) until it contacts the piston, then push down hard. There should be NO movement.
#5 had at least 1/8"+ slop, all other cyl were OK. So it's definitely #5 cylinder rod spun a bearing. . BUMMER

So....
Back in the days of my youth a relatively temp fix was to drop the oil pan and change out the rods bearings without removing the engine. Granted this is not any where close to the best solution but if you caught it soon enough and the journals on the crank were still in good shape it would get to back on the road. That said engines have changed a lot since those days and i don't know if you could even get the oil pan off this engine without taking it out of the truck ??? Does anyone know ??

Like I mentioned in my original post I need to find some way to keep this truck on the road for another 9 mo. for the least amount of cash out lay. While I've done 5 or 6 engine swaps in my day, I haven't done one in 30 years. There's a lot more stuff in there these days. I think I could do it if I could find a good DIY guide to follow ??? I can rent a lift and get a couple of buddies to help if I supply the beer ;>) .

SO if I could change the bearings without removing the engine I might try that (est $100 parts, lots of labor), but then you don't know what shape the journals or rod ends are in till you get it apart. OR add hoist rental, a lot more labor, pull engine but just change rod bearings. OR I could just go for the engine swap with a medium mileage (80-125k) used engine (est $2000+ plus hoist rental, gaskets and things) and be done with it assuming i get a good engine, OR get a reman long block for $2800 plus shipping put on my other stuff and go with that ???

thoughts / suggestions / experiences anyone ???

Joel

 

That's a real bummer.

I'll be interested to hear if it's possible to do bearings in place like you once could. You don't hear about it that much anymore.

If that's not possible I'd probably try to find a used engine, maybe someone parting out a 4Runner/FJC/Tacoma on Craigslist. Seems like it shouldn't be $2K but if it is that much I'd be harder pressed not to buy a reman with a warranty.

 

That sucks. Maybe time for the tundra 5.7 V8?

If it were me, I think I would go for a used lower mileage motor. It would suck to fix that problem only to have another part failure.

 

Call around to local scrapyards and see what they charge for an engine. I personally agree with moondeath, no sense in fixing one rod bearing and not tearing the engine down for a complete overhaul. Especially if your oil light is flickering occasionally.