V6 3VZE engine - "What Everybody Should Know"

[vrocrider]

This was pulled from Toyotanation.com forum. I found this excellent for folks trying to maintain the Toyota V6 3VZE engine.   

I bought my 89 V6 4x4 X-cab in 1995 at 107k miles and now 14 years and 173k miles later, it's still going strong, so you could get a lot of years of good service out of that truck. Having said that, the 3VZE has a reputation of being a trouble-plagued motor. They aren't all like that - mine isn't (except for the headgasket replacement at 218k) - but enough of them are to give reason for caution. In addition to the head gasket problem, which every 3VZE will eventually encounter, many of them also suffer from burnt exhaust valves. A possible cause of that is valves that stretch over time, reducing clearance until they fail to fully close.

I had the valves adjusted at 125k (a year after I bought my truck) and found some of the valves had significantly less clearance than spec. I adjusted them again when I replaced my head gaskets at 218k miles. I've never had burnt exhaust valves (knocking on wood!) and I recommend you have the valves adjusted, too. The exception would be if the head gaskets were changed, in which case the valves should have been adjusted then. Perhaps checking them every 70-80k miles would be good insurance. This is a job for a well-equipped shop as it takes a special tool and is a challenging job.

Other areas of maintenance you can expect (at some point, but hard to say when) is the starter contacts wearing until it justs clicks when you turn the key (that's an inexpensive fix but getting at the starter - Oy! that's another story), needing to replace the shift bushings (very easy and cheap - should be done when you replace that clutch), having the occasional sensor fail (with the engine running roughly as a result), possibly needing to replace the distributor, and being at risk of having your catalytic converter sawed off of your truck (you'll have the dubious honor of having a truck with a converter packed with more valuable precious metals than normal - and in cities there are those who won't be able to resist). That's on top of the normal tune ups and replacing parts that periodically fail like battery, alternator etc.

Still, all of that is in the context of the legendary longevity of Toyotas. If you're lucky and take good care of the truck, you can have a reasonable expectation of getting another 200k miles out of it.

Mileage: The 3VZE is not known for either efficiency nor power, but there is something you can do to improve both by a significant margin: replace the stock muffler with a well-designed turbo style cat-back exhaust. When I installed a Borla system in 1996 (no longer available, unfortunately) my highway miles went from 20 to 24, a 20% increase. Power increased by about the same - a very significant jump in power. I think of the products available now, Flowmaster makes a decent one that is similar to the Borla.

Pinging: Mine had a really persistent pinging problem and nothing seemed to help it. It laughed at premium gas and retarding the timing, as well as all manner of fuel injector cleaners, gas additives, spark plugs and diagnostics. I finally gave up looking for the cause. Then a couple years ago I replaced my distributor because of bushing squeal when cold. Imagine my shock and delight when it completely cured the pinging problem. I guess the signal generating coil that sends crank position signals to the ecu (explained below) wasn't working properly. Speaking of gas, the 3VZE was designed to run on - and runs best on - 87 octane. Mine doesn't like Texaco or Mobil fuels very much, so I avoid them.

Clutch - when I replaced mine at about 165k miles, I bought Toyota parts. Those are still going strong at 280k miles, so that's a safe option. Many people here swear by the Marlin Crawler Heavy Duty Clutch Kit. Here's a nice thread from someone who just installed one of those:
cpmike : 1992 Pickup SR5 V6 4x4 (ext cab)

Plugs - Hands down, my engine does the best on the factory spec Denso K16R-U. They're available at Autozone for less than $1.50 each.

Plug Wires - When you need them, only get the Toyota wires. They are excellent quality and come with all the keepers, have cylinder numbering and fit perfectly. I once made the mistake of trying a fancy aftermarket brand and they sucked by comparison. I was glad to get rid of them and switch back to the Toyota ones a few years later.
 

Timing - spec is 10 degrees with a jumper attached between terminals TE1 and E1 in the gray diagnostic connector, but many people do better with a bit more advance. 12 degrees is very common and probably a better setting for the 3VZE. Some run 14 degrees and get snappier throttle response and some more low end torque but sacrifice a bit of mileage and also emissions suffer some. In fact when getting an emissions test, set it back at 10.

Oil Filter - Many opinions, but the Toyota filters have more surface area than most of the aftermarkets. It's a very good quality filter, and you can usually negotiate a good deal with the dealer if you buy a bunch of 'em.

Air Filter - I replaced my intake with a K&N system, but I don't recommend you do the same. I saw no improvement in mileage or power. For air filter, I again recommend the Toyota ones. There is an alternative to the K&N known as the "ISR" mod (Intake Silencer Removal). It is documented over at the yotatech forum.

Transmission Gear Oil - very important - our transmissions do NOT do well with the current standard GL-5 gear oils. It's too slippery and the synchros don't work, making for very hard shifting. You need a GL-4 fluid, and the one nearly every Toyota techie recommends is the Red Line MT-90 which is a synthetic 75W90 GL-4 Gear Oil:
http://www.redlineoil.com/products_g...7&categoryID=7
The differentials and transfer case, however, do better with a GL-5. Red Line makes several good synthetic GL-5 oils, this is a popular one:
http://www.redlineoil.com/products_g...5&categoryID=6

Cracked dash - if yours isn't cracked yet get some Armor All on there! Otherwise it will most definitely crack.

Speedometer cable - will get dry, leading to noise and the speedo needle waving back and forth. You can usually get by with lubricating it, search the forum for info when that time comes.

Headlights - wait till you have to change one of these (sinister chuckle). You have to take off the grille, which is a lot of fun! Several of the people on the forum here swear by their Hella e-code light housings, and I have to say they do look pretty cool, not to mention making the removal of the grille unnecessary when changing out a bulb...
http://www.rallylights.com/detail.aspx?ID=744

Brakes - our trucks don't have the best brakes in the world, especially if you get oversized tires. Good pads are a must. The Hawks are very good, if a bit dusty. tirerack.com sells em at a good price. The Toyota pads are semi-metallic and work well. I bought Powerslot rotors two years ago, which are slotted Brembo rotors, and I like them a lot. A little vibration on hard stops but much better bite. Got those at tirerack too.

Timing Belt - change at about 70k miles. But if yours does break, you'll be happy to know the 3VZE is a non-interference motor - the pistons can't reach the valves if the belt breaks. Get the Toyota belts - they have timing marks on them while the aftermarket brands don't. If you pay someone to do the work, I suppose it doesn't so much matter, except that the belt on this engine is tricky to get lined up. You have to give the motor two full clockwise rotations and check it to see if the marks still line up. Often one of the cam pulleys is off a tooth. Make sure your mechanic has experience with this motor. If your idler and tensioner pulleys were not changed with the last belt change, replace 'em. The stock water pump is a very simple and VERY durable Aisin. My current one (also an Aisin) has about 160k miles on it and has seen a lot of rusty coolant! Gotta love that Japanese engineering. I will be replacing it with my next timing belt change in about 5-8k miles. I mention it here because it's behind the timing belt and so you need to figure out if you need a new pump when you change the belt.

Wheel Hub maintenance - I'm hoping your truck has the wonderful Aisin manual hubs, and if so, take care of them by periodically cleaning and greasing them. Same goes for the front wheel bearings, of course. Take care of those, and they'll last well beyond 300,000 miles. Speaking of lasting, I'm still on my original ball joints, and they're still tight. How, I have no idea. But they are.

ANTIFREEZE - VERY Important - glad I didn't forget this. Don't make the same mistake I did by using the green antifreeze. One day I looked and my coolant had turned completely rusty. The green stuff contains silicates and japanese engines hate silicates. If the coolant gets tired your block will very badly corrode. Stick with the Toyota Red coolant, which has a very different chemistry made especially for your motor. If the truck currently has green, yellow or orange coolant, you have to be very careful to thoroughly flush all traces out of it with several changes of water before filing with 50-50 Toyota Red and DISTILLED water. The different coolant types do NOT mix well. Also, tap water will cause scale and can cause corrosive byproducts to form. Stick with distilled water only. Your last flush should likewise be with distilled water, as some will remain in the heater core and various nooks and crannies. There is a draincock on the side of the motor and it helps to pull the heater hose to get a good flush.

Thermostat - make sure you have only a Toyota 180 degree thermostat in there. It should be changed when you change coolant, since you have to remove it anyway to get a good flush..

Spare tire winch - went to use mine a few years ago and it was frozen SOLID! Oh, what an enormous F-ing pain in the behind that was. I strongly recommend lowering your spare and spraying a good waxy water-repelling lube like Boeing's Boeshield T-9 in there.
http://www.amazon.com/Boeshield-T-9-...dp/B001447PEK/

Speaking of frozen, have someone work the parking brake back and forth while you look on the inside of both back wheels to make sure the parking brake levers move freely. Hit them with a little Boeshield too. I replaced a frozen one of those two years ago.

You may already know, but don't run your gas too low in the tank - as with most fuel injected vehicles, the fuel pump is in the tank and uses fuel for cooling. I try to keep mine over 1/4 full.

Brake fluid - as you may already know, you can get the most life out of your calipers, wheel cylinders, clutch slave cylinder and master cylinders by flushing your fluid with fresh good quality DOT 4 fluid every 2-3 years. Bleeding is turned into a very easy, almost fun job with a set of speed bleeders - replacement bleed fittings that have check valves in them that prevent air from getting sucked in. They enable you to bleed the brakes by yourself. Again, if you won't be doing this work they're unnecessary, but if you want to get them, I finally found good ones after two sets of lousy ones:
http://www.raceshopper.com/speed_bleeders.shtml The same vendor sells excellent fluids at very good prices, and carries excellent pads and rotors too.

Keeping the 3VZE running at in top form may require you to learn a little about how the computerized engine control systems work. Here is a very brief run-down:

The ecu (called the ecm in toyota literature) receives a bunch of information about engine conditions from a variety of sensors, then sends out pulses to control spark and fuel injection. The most important sensors are the following, and the motor won't run right unless they are all functioning properly:

ECT - Engine Coolant Temp sensor, located on the top of the motor in the back, just in front of the firewall and half under the plenum (along with 3-4 other sensors) It changes resistance when the motor reaches operating temp. When the motor is cold, the ecu operates in "Open Loop" mode which means it uses mainly preset values for mixture and it ignores the Oxygen sensor. When the ECT signals operating temp, the ecu goes into "Closed Loop" mode and uses all the sensors' input to calibrate the fuel and timing.

VAFM - Volume Air Flow Meter - what the 3VZE has instead of a mass air sensor. It's the big metal thing attached to the air filter housing. It contains a trap door-like vane that measures the air flow into the motor. It has to open some to close a ground for the relay that controls the fuel pump. No air flow, no fuel pressure. It also measures intake air temperature.
 

TPS - Throttle position sensor - measures throttle position (duh) but also has an idle signal when the throttle is closed that wasn't working on my truck and it ran rough at idle. Took two years to find the pesky tps and when replaced the truck began to purr at idle and still does now 12 years later.

Oxygen Sensor - in the exhaust pipe just in front of the cat. Must be replaced at least every 90k miles, or sooner if it has been gunked up by something evil. Gives the ecu the info needed to set the mixture right.

Crankshaft Position Sensor - is actually part of the distributor. There are a series of cam-like projections on two metal rotors (called signal rotors) under the distributor's rotor (the one you replace at tune-up). There are three coils called signal coils or signal generating coils that send signals to the ecu as the signal rotors rotate past. These signals provide the signals used by the ecu to control spark timing and advance.

There are other sensors, such as EGR gas temp sensor, knock sensor, vehicle speed sensor etc., but the above are the main ones and problems with any of them will cause the motor to not run right. There are procedures and specs for testing all of them in the factory manual. If you don't have an fsm, google 1993 toyota pickup service manual That will give you 98% correct info. There were a few changes between 91 and 93 including the timing belt idler arrangement, slightly different throttle body and slightly different distributor, but almost everything else is identically the same.

There is a great Automotive Training and Resource Site that has technical articles explaining the operation of most systems in Toyota engines. It includes info on newer and more advanced motors, but there's a lot of good info on the 3VZE type motor controls, too. Follow the link for Technical Articles: http://autoshop101.com/

PARTS SUPPLIERS:
You usually can't beat the OEM Toyota parts for quality and longevity. Fortunately, there's a dealer in Washington State that sells online at a huge discount:
http://www.1sttoyotaparts.com/

Sometimes you can get the OEM brand of part (Denso, Aisin etc) from other sources for less even than the very discounted 1sttoyota prices. A very good source is http://www.autohausaz.com, another is http://www.rockauto.com. Rockauto also carries Beck/Arnley parts, which come from a variety of OEMs, many of them japanese. Sometimes a junkyard part is just what the doctor ordered, and there is a great portal for hundreds of salvage yards: http://car-part.com/

 

 

[Hoonah]

Great info!

Edited June 5, 2017 by Hoonah
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