3.4L V6 Engine Flaw

[4Running Daily]

Does the 3.4L V6 have some kind of flaw in cylinder #3?

My Headgasket blew in Cylinder #3.
Recently had only #3 injector changed.

Brianemc2_42 had a cracked head on #3.

Something is up?

 

[hondafmx1000]

Mine was cylinder 4, changed the injectors twice plugs wires, everything i could think of, still gives me a mystery misfire every once in a while no code anymore though, and luckily enough for me no head gaskets have gone out. Idk could be a toyota equivalent of a mopar mystery

 

[tbst]

When did you HG blow? After the whole being stuck on the road or a long time ago?

 

[4Running Daily]

When did you HG blow? After the whole being stuck on the road or a long time ago?

About 10,000 miles ago. Stuck on the side of a road was fuel injector.

 

[BrianSD_42]

Sucks dude.

175k is actually a "long life" for a automobile engine. Some Toyotas go a lot longer but for the most part 175k and the engine is tired. This applies for most domestic and foriegn.

So I guess IMO it isn't a flaw.

I will say that when my mechanic found out it was a 97 V6 with over 150k and CYL #3 he told me he strongly suspected it would be a cracked head but couldnt know for sure until it was apart. That shop claims to redo 5-6 Toyota top ends a month.

 

[troy_279]

My 02 Limited recently hit 175k and runs like new. I would say its far from wore out and still gets consistent 20 mpgs. Oil change every 3k and the oil still looks pretty fresh after that. I figure i have 175k more!

 

[jonwilly2]

its a strong engine and from what i can tell they are hard to break. The bock may be a heavy chunk of cast iron but its internals are all good for power and to last. The rings go out from careless flogging and bad oil. Other then that its mostly sensors belts and wires the lead to problems. TRD had a drag program for the engine but was scrapped in 2002 im guessing when they came out with the 4th gen. I got 160,000 miles on mine and i still put down some good numbers and rubber on the 1/8th mile drag strip. So for only hearing about 2 broken cranks and one throwing a rod I think there were just the weak part out of the bunch. Not every part is perfect. I have never had a problem and I was a dumb kid with a first car.

 

[BFEATHER2008]

The 3.4 liter motor is one the strongest motors toyota has. I am a toyota mechanic and ive seen nothing that has gone wrong with engines except for when jiffy lube and all those other places level things loose like the oil filter and drain plug. I would have to say to find out your misfire find which coil pack runs cylinder 3 and change it with another one then check your codes again. The computer in the truck keeps all data wethere the check engine light is on or not. It may not be enough of a misfire to set the check engine light. If the cylinder misfire changes replace coil pack thats what i had to do to mine cause i had the same problem. It runs like new now. Also check and make sure your plugs are dual electrode plugs. That also can make them run bad. I only replace my engine parts suchs as plugs and all that with oem. I dont like alot of aftermarket things if you go with anything aftermarket get denso or ngk those work best. Because they oem. Ngk plugs come from factory in them and denso are the oem replacements. Let me know what you find out.

 

[BrianSD_42]

I am a toyota mechanic and ive seen nothing that has gone wrong with engines except for when jiffy lube and all those other places level things loose like the oil filter and drain plug

Just to be fair here, you must have seen some top end failures.

If you are a basic Toyota mechanic does that mean that when the top end (head) fails, you dont see it because it is out of your scope to do that type of work?

It doesn't mean they don't fail because mine did

 

[BFEATHER2008]

Me personally im a master tech at work i have never seen a top end failure on the 3.4's now i have seen them in the 2nd gen cause they had a big problem with head gaskets failing. It could be a possiblity but i highly doubt it. My dad has been a toyota mechanic for 32 years and i asked him just now about it and he said most likely those plugs. And he alos said he hasnt seen a top end failure on these engines.

 

[BFEATHER2008]

Just to be fair here, you must have seen some top end failures.

If you are a basic Toyota mechanic does that mean that when the top end (head) fails, you dont see it because it is out of your scope to do that type of work?

It doesn't mean they don't fail.

Im not trying to start a fight or anything im just saying from my experience being a master tech. Ive never seen a top end failure in these engines but it could be likely but i doubt it. Im just saying start with replacing those plugs thats it.

 

[BrianSD_42]

I totally understand but I'm sure they can and do fail between 175k and above. I am not a tech or mechanic but my engine suffered a cracked head at 199k and I'm not alone. We see threads head gasket / head failures about every 2-3 weeks on T4R. Usually: CEL & misfiring, blowing smoke, loosing coolant.

So I was just theorizing, no offense that when someone comes to a dealer (agree it is rare) with a top end failure, they speak with the service manager he tells them it will be $5,000 for repair and they decide to take it elsewhere. In general, most of the time dealerships don't repair cracked heads.

That was my though process anyways.

 

[BFEATHER2008]

I totally understand but I'm sure they can and do fail between 175k and above. I am not a tech or mechanic but my engine suffered a cracked head at 199k and I'm not alone. We see threads head gasket / head failures about every 2-3 weeks on T4R. Usually: CEL & misfiring, blowing smoke, loosing coolant.

So I was just theorizing, no offense that when someone comes to a dealer (agree it is rare) with a top end failure, they speak with the service manager he tells them it will be $5,000 for repair and they decide to take it elsewhere. In general, most of the time dealerships don't repair cracked heads.

That was my though process anyways.

We do head work all the time ive never seen a 3.4 4 runner hae any kinda of head work done though.

 

[BrianSD_42]

I guess I'm just really unlucky

Good news for everyone else though

 

[BFEATHER2008]

I mean im not trying to say your unlucky. How long have you owned your truck how was the maintence and everything before you bought it? If its not maintianed it will happen more likely im not saying you dont take care of your truck cause your truck looks awesome and in great shape.

 

[BrianSD_42]

Its been really well maintained with oil changes consistantly every 3k.

It ran perfectly until it instantly didn't anymore.

I'm the second owner and have had it since 2002 @ 67k miles. Now I'm at 211k.

4Running Daily's rig: still the ogininal owner. I assume he took good care as well.

Brian2Sun had the same failure and he is a truck person and I'm sure he did maintenance.

Btw, on a better note, I like your truck as well, especially the red!

 

[BFEATHER2008]

Its been really well maintained with oil changes consistantly every 3k.

It ran perfectly until it instantly didn't anymore.

I'm the second owner and have had it since 2002 @ 67k miles. Now I'm at 211k.

4Running Daily's rig: still the ogininal owner. I assume he took good care as well.

Brian2Sun had the same failure and he is a truck person and I'm sure he did maintenance.

Btw, on a better note, I like your truck as well, especially the red!

yea i guess there are flaws then i personally just have not seen any of them. i hope i dont have a problem later im at 186k right now. i change my oil ever 1500 miles lol. just cause i can and have access to free oil lol. i like my red just wish it was cleared when it was new. its really chalky when i dont wash it every other day lol. and i guess you guys were just the unlucky ones sorry to say that.

 

[MySons4Runner]

The 3.4 liter motor is one the strongest motors toyota has. I am a toyota mechanic and ive seen nothing that has gone wrong with engines except for when jiffy lube and all those other places level things loose like the oil filter and drain plug. I would have to say to find out your misfire find which coil pack runs cylinder 3 and change it with another one then check your codes again. The computer in the truck keeps all data wethere the check engine light is on or not. It may not be enough of a misfire to set the check engine light. If the cylinder misfire changes replace coil pack thats what i had to do to mine cause i had the same problem. It runs like new now. Also check and make sure your plugs are dual electrode plugs. That also can make them run bad. I only replace my engine parts suchs as plugs and all that with oem. I dont like alot of aftermarket things if you go with anything aftermarket get denso or ngk those work best. Because they oem. Ngk plugs come from factory in them and denso are the oem replacements. Let me know what you find out.

I'm new to all this but you seem knowledgeable. I inherited a 1997 SR5 3.4 manual 5spd 4Runner with 240k miles. It has a blown gasket head and my mechanic is telling me $2300 to rebuild the top end. We also discussed replacing the whole motor with a low milage used or rebuilt. Is it worth it or should I just let the truck go. It's in great shape otherwise (well not the oxidized paint) everything works well. The truck actually belongs to my son and he loves it but it went south just before he left to go overseas. I'd love to make it run for him but I'm thinking it might be smarter to just start looking for another good used 4runner. I'd appreciate your thoughts if you have the time.

 

[Brad_solo]

I'm new to all this but you seem knowledgeable. I inherited a 1997 SR5 3.4 manual 5spd 4Runner with 240k miles. It has a blown gasket head and my mechanic is telling me $2300 to rebuild the top end. We also discussed replacing the whole motor with a low milage used or rebuilt. Is it worth it or should I just let the truck go. It's in great shape otherwise (well not the oxidized paint) everything works well. The truck actually belongs to my son and he loves it but it went south just before he left to go overseas. I'd love to make it run for him but I'm thinking it might be smarter to just start looking for another good used 4runner. I'd appreciate your thoughts if you have the time.

You can find low mileage JDM 5VZ-FE for pretty cheap, around $1000 I think. They generally have around 50-75k miles. You would want to replace the timing belt, water pump and spark plugs at minimum to be safe before putting it in. If your 4Runner is 4x4 I believe it's about a 20 hour job according to the factory service manual. Around here average shop rate is about $100/hr for somebody that knows and cares about what they're doing. I think doing a JDM engine will be better in the long run. I worked at a shop where we did many JDM engine swaps on all types of vehicles with great success. Good luck!

 

[Scramble]

I'm new to all this but you seem knowledgeable. I inherited a 1997 SR5 3.4 manual 5spd 4Runner with 240k miles. It has a blown gasket head and my mechanic is telling me $2300 to rebuild the top end. We also discussed replacing the whole motor with a low milage used or rebuilt. Is it worth it or should I just let the truck go. It's in great shape otherwise (well not the oxidized paint) everything works well. The truck actually belongs to my son and he loves it but it went south just before he left to go overseas. I'd love to make it run for him but I'm thinking it might be smarter to just start looking for another good used 4runner. I'd appreciate your thoughts if you have the time.

2300 is about right, I had mine done for 1600 but I have the 3RZ. A used motor is a good way to go too but you dont know the history of the motor. Either way is a gamble.

Head gasket failures are rare on the 5VZ. They're more prevalent on the 3RZ but nothing like the POS 3.0.