Chipsndukes

Hi y'all, title says everything.

Thought I had confronted everything as far as cars go, this one has me stumped.

Bought a 1996 Tacoma 2RZ-FE about a year and a half ago, had 63000 miles, has 76000 miles now, was not well taken care of but was not driven a lot either.

Began to notice a diesel-like rattle sound at idle, thought the worst, rod bearing, crank bearing, blah, blah, have never rebuilt an engine, was worried...until a mechanic pointed out "timing chain".

Sounded logical, did not sound like a knock but a rattle, pulled head off, replaced timing chain and VOILA, noise was gone...BUT!!!!

In two days the noise was back.
Here is the run down:

1. noise does not happen when cold (oil pressure > 40PSI)
2. oil pressure is 100% OK measured at the sender port (15 PSI idle hot, 85 PSI revved)
3. noise loudest at bottom of timing cover front and on the front of the oil pan (motor contact stethoscope)
4. sounds like a diesel "chuckles", is not bang, bang, bang but somewhat inconsistent, random--sounds like a diesel...
5. old timing chain checked to spec., gears OK, guides barely worn (0.5mm), tensioner only 1/2 extended, threw it all away anyways (should have kept for evidence)
6. problem did go away for about 2 days after replacing the chain, then came back

THEORY: tensioner not receiving enough oil pressure, not pressuring the chain enough at idle (<2000RPM)

ACTION: flushed engine with 1/2 kerosene PLEASE, NO DISCUSSIONS ON ENGINE FLUSHING, engine apparently none the worse for wear, valves louder and the noise apparently slightly louder, otherwise truck runs beautifully, oil a clear golden color, like beer.

Do I take it to the dealership?
Is there a known issue with oil pressure at the tensioner?

I have two ideas now:
1. trash the tensioner by boring a hole and putting a screw through it to manually pressure the plunger and see if the noise really comes from not enough tension
2. equally trash the tensioner by putting a port on it to measure oil pressure behind the plunger, is it starved for pressure as maybe the case--remember: old and new chain made the same sound and both appear to be in A1 OK shape

Neither idea seems real appetizing...

I came over from TN to see if you guys could help, not getting many hits there, THANKS hope someone has a magic bullet HAVE DONE EVERYTHING I KNOW!!!

Thanks again guys, hope to hear from someone.

Peace,
Chipsndukes

colsoncj

wow... well I dont have your answer, but I do wish you the best of luck.

However, i would say with some certainty that the oil pressure at the tensioner is roughly similar to that found at the sender, blockage seems unlikely. Is it anyway rpm or load specific?

Hopefully someone can correct me if wrong, but the oil pump might be a vane style pump driven off the crank near the timing chain. When you changed the chain, it could have disturbed the oil pump enough to negate the noise, but upon resettling, revived the noise. Maybe a vane to housing or rotor to housing contact inside the oil pump which is counteracted by high oil pressure at cold temps? Just a thought.....

Chipsndukes

Thanks Corey,
yes, problem only at idle or ~<2000RPM, sound really disappears after this, NOT just hidden by engine noise, it actually ceases.

I couldn't tell you what a vane pump is, only that there are there are two gears that rotate within each other, an outer ring with inner gears/lobes and an inner gear with outer lobes. If I rem. correctly, this is a gear pump. Did have it apart just to look, repacked it w/vaseline and closed it back up.

The problem does sound just like a timing chain rattle. Was tempted to run the motor with the tensioner out and put a big ole' 1/2" socket extension in the hole and "be my own tensioner" but chicken out cuz' I figured it would spray oil all over the place and also didn't have a buddy to shut the engine down when I released tension/didn't want to damage anything.

THX, Peace, Chipsndukes

Chipsndukes

M' OFF to bed, am thankful for any and all replies.

I know I am a guest here and prob. don't know SQT compared to the rest of you here, hope I can help someone else if they have a prob., am usually good at tracking stuff down--GULP--not this time.

Thanks again, will answer all in the morn., have a day off, am debating go dealership and pay $65 for them to tell me what I already knew, but am getting desperate...

NUF said, good night!!!

Peace,
CND

Chipsndukes

Searching forums, another poster had the same prob:

https://www.yotatech.com/forums/show...ghlight=2rz-fe

https://www.yotatech.com/forums/show...ghlight=2rz-fe

BUT...it's not lifter clatter like he keeps saying, the dealer manager said "hydraulic tensioner", which can only mean timing chain. 2RZ-FE has mechanical lifters with shim adjusters.

I'm sure now, problem is tensioning of timing chain at lower oil pressures. Just don't understand why only I and this other person have the problem, even after changing my tensioner.

Why are our engines different than the others with no probs.?

I realize I'm talking to myself a little here, I hope someone with good exp. with the 2RZ-FE can shed more light on what the SOLUTION is.
If not, I'll have to figure it out myself, next try is straight SAE 30 and see what happens. Other possibility is 'yota filter, should increase oil pressure.

THANKS TO ALL!
Chipsndukes

colsoncj

I wish I could offer more help. Nonetheless, if you do find a solution to your query, please post up for others in the future!

Chipsndukes

'course I will, thanks for the encouragement.

Maybe there is one other person out there that could be helped by this (like me!).

Will certaintly write to help.

next steps: Toyota filter, then heavier oil, then even heavier oil, then "don't know" but "will find".

Thx,
chipsndukes

Madtaco04

Did you ever fix the issue. My 2004 Tacoma with the 2rz has the same problem. 105,000miles