86 4RUN- 22RE, Recently purchased.

When the truck,is run cold, there is a "growling" noise when the gas is pressed, not really audible when idle.
I can compare the noise to a diesel type sound. The sound softens as it warms up, but is still present slightly.

I am unfamilliar with a knocking rod sound as well as worn timing chain guides.
I am guessing it is the later. thats what it sounds most like.

ANY GUESSES or suggestions?

And..
If it is the timing chain, Do I HAVE TO remove the head to replace the guides and damper?????

On my truck I get alot of the diesel noise. Its mostly caused by a exhaust header gasket leak. Its worse when cold, untill things start warming up and expanding, but it never goes away completely. For me its not worth braving the rusted manifold bolts to change the gasket. I spent a lot of time trying to trace the noise, I probably checked and adjusted the valves two dozen times thinking it was valve noise.
But, both of those things are worth checking into before you do more drastic repairs.

I've had "that diesel noise too on my last truck too. It was a crack in my header. this sounds different, or from a different area,
I think.
I'm going to record the sound see if it comes out decent,
maybe thatll spark some ideas.

I saw an engine stethescope at harbor freight, that may be worth picking up.

BUT
Do I have to take the head off if Im going to get to the chain gides and damper????

I wouldnt think so, but I have never messed with mine. I would pick up a good work manuel on the truck, their nice to have. Maybe someone who has done this will chime in.

Think I'll just tough it out also with the diesel noise.
Will do a complete tune up this spring and replace
the complete exhaust with the 2" into 2.250" upgrade.
Working 6 days a week I need to keep thing simple for now.
The header leak will have to wait a long time.
Will post up soon, just got the truck painted
utility grey with 2 coats clear.
Was a complete tear down. Looks factory fresh <img src="/forums/images/graemlins/smile.gif" alt="" />

It is rather easy to tell if the t-chain is loose, pull the valve cover and grab the chain, if there is any movement at all it needs to be replaced.

You don't haveto remove the head to get to the guides, though you will have remove the fan, t-chain cover, the front 2 bolts from the oil pan, the hidden bolt from the head to the t-chain cover, and I believe the crankshaft pulley as well. If the t-chain breaks and you are unlucky it will likely cost you more than a new t-chain and guides, i.e. broken/bent valves, punctured piston head, bend piston rod or crank shaft, etc.

The '93 FSM at the top of the forum will work for the '86 runner.

If it is the knocking type diesel sound the valves probably need to be adjusted. A rod knock on start up would be constant low knock-knock at idle, not the higher pich deisel knock. Picking up the stethescope from HF wouldn't be a bad idea, it is nice to have around from time to time.

With any used vehicle it is always wise to do a complete tune-up yourself before putting many miles on it.

The original engine in my 94 pickup 22RE sounded very much like a diesel. I was sure it was the timing chain but it actually turned out to be a spun bearing. The original owner didn't believe in routine maintenance and when they finally did change the timing chain they did not bother to clean any of the debris out of the oil pan. Therefore the oil pickup was blocked and starved the bottom end of oil.

4crawler.com has a really good tutorial of changing the timing chain without removing the head if you find that is the problem. I'll be using it later this year (when it gets warmer) to do the T chain on my 88 runner.

Good Luck!! Jim

If I had a garage this decision would be much easier.
Its cold and rainy here.
I'm starting to lean back towards the exhaust leak idea.
When i bought it, it didnt make the noise, (go figure)
But after a three hour drive home, I could smell a familiar chemical burning smell.

I think the seller plugged the leak w/ jb weld and it burned off during the drive.

I recall when i fixed the manifold crack in my last truck, i was really suprised thats what caused that noise.

I have no problem tearing the upper half off. Plan on doing it to do a thorough cleaning and revacuum hosing, EGR scraping and what not.
Its a process, since i like to have everything I need.
PBlaster for the manifold bolts, the complete gasket kit, shopping for a good complete kit, etc etc

Guess Ill go post up in my local craigs list for a garage to rent.

I have a similar noise in my 86 runner. Still does it with new exhaust and full tuneup. It's done it as long as i've owned it (about 7 years) and so far it doesn't seem to be bad, still has good power and great mileage. I guess I just always assumed it was normal.

X2 re exhaust leak. Mine was making diesel-type noises that went away with cat-back replacement. I was utterly convinced the source was somewhere in the engine compartment, but turned out it wasn't.

Also, check the crank pulley bolt. A loose crank pulley can make quite a knock.