When I bought my Z form the small dealer (not nissan) the carfax said the previous owner had taken the Z to a local dealer and they had swapped out the motor. I thought that this meant literally removing the old and getting a new or rebuilt engine, yet I notice some of the components on my engine are worn ( engine harness, the old spark plugs, connectors etc). Contacting the dealer yielded no answers to why they swapped it or what they swapped, they told me they weren't allowed to discuss previous owner car history ( prob BS on their part) so here is my question to you guys who work or have worked at dealers.

Exactly what do they replace when they "replace the engine"?

Thank you

 

Depends on what the original problem was. If it was a warranty issue with the shortblock, the techs would only replace that part of the engine. The top end of the engine, including the heads, intake and all ancillary parts would be used over again. Even if they had to replace a longblock, they typically reuse the engine harness, plugs and other items.

 

^I question that. I called Nissan when I was pricing out my engine rebuild, just to see what laughable figure they would tell me. They actually told me they don't rebuild engines, they just replace the whole long block (which includes the heads).

It may vary from dealership to dealership, but either way if they replace your engine, that doesn't include the wire harness or any connectors. At most it might include some engine sensors, but probably not even IMO.

 

The dealer will get a pretty bare engine. No harness, engine covers or coils. I think the pulleys get swapped over as well. Spark plugs would come with it, how do you know their old?

 

I have no Idea, its an 05, 6 speed DE Z. At around 45K it was taken in to a dealer for "engine change". All the plugs look like they are aged since 05 ( like you stated)

Well I was asking because I recently swapped out my cam PO sensors (code) and the harness connector for those two was so old and brittle part of the connector snapped, so they sit zip tied to the sensor now( they are on really tight). So I began to question exactly how much they changed out.


The spark plugs were HORRIBLE when I swapped then over. I bought the car with 50K on the odo and the engine swap was done at 45k ish. Look at the pics





The values indicate the gap of the spark plug /cyl



This was before I fixed the seal on cyl #6 because it was leaking. I also put in new plugs and the engine started behaving normally, before it was misfiring like crazy.

 

Whoops, double post.

 

Yeah, that doesn't look like 5000 mile old plugs. There could have been some warranty the shop manager made with the previous customer. In that case, they would put in a used motor. So who knows on how many miles.

 

So what should I do to find out more info on how old this motor is?

 

You could call nissan corporate and they might force them to give you the correct info

I had a lady denied a tranny warranty because her altima was too old but she had around 18000 miles on the clock. I told her to call corporate, they called the owner and it was fixed under warranty.
She also owned three other nissans and has a bunch of family members with them....

 

I don't think the Nissan dealer or Nissan Corporate owes you an explanation for the replaced engine. You bought the car from a third party dealer and knew the engine had been replaced. You should probably have tried to get more information before buying the car. I suspect the dealer you bought the car from could have contacted the Nissan dealer to get the information for you. But since you bought the car, they now have no interest either. It seems to me that you are just out of luck getting any information unless you can find out who the previous owner is and contact them.

 

Those spark plugs were definitely ****, maybe a combination of things making them look like that (since it looks like they have different problems happening in each cylinder), oil leaking into the cylinder, a bad tune, dirty injectors, incorrectly gapped spark plugs?

Maybe your cam pos sensor was fine, and spark plugs were just gapped so terribly it was giving you that code even?

How many miles is on the car now? If you're really concerned, just get a leak down test, and compression test. If all is well, then you can stop worrying.

Welcome to the VQ35DE

 

I will try this, thanks.

I knew the engine had been replaced by a dealer. I also knew the previous owner had taken the car to the dealer for everything! and I mean everything, the damn carfax was like 8 pages long. Its not a big deal to me to find out about the motor, when I changed the valve cover gaskets, I saw the liquid gasket on the corners was still fresh looking so that and how clean the cams looked made me happy.

Those were deff bad. The spark plug issue happened like 4-5 months ago. The cam sensors gave the code, but when I saw that the harness connector for the sensors was a bit brittle and falling apart it could have been that with the engine moving it moved out of place for a second. I replaced them anyway just in case and I zip tied the connectors to their sensors tight. So far no issues, I am trying to source out a upper half of the harness to replace it.

When I did the spark plug fix I did a compression test and it was great on all cylinders, I cant recall at the moment what the exact psi was but I remember it being withing spec per the FSM. The issue back then was that the car started behaving erratically with misfires and low idle. A scan revealed it was cyl 6 misfire. To isolate the coil packs I swapped em and the issue persisted. I bought new plugs, valve cover gasket, and I sealed the spark plug seal for all cylinders. Did all the relearn procedures and so far she runs great!

Honestly so far the VQ has been behaving rather well. She gets Amsoil every 5K, just did a trans and diff fluid change, new plugs, and overall as soon as anything breaks, I replace it or fix it.

Trust me its gold compared to the pontiac grand am my parents had when we first came to the US. I was introduced into mechanics with a very bad starter car LOL

 

Well at least you're not using Mobil 1, like I did for 115k miles. I think oil is partially responsible for the death of my piston rings, that and the fact that '03 piston rings were **** from the factory.

 

LoL yeah I read up on the oil before I did the first change. Amsoil and shell t6 got overall A+ so yeah

 

Called the dealer again today, they still dont feel like telling me what was changed on the car, or the reason why it was swapped from the previous owner.

I guess I will try a local nissan dealer in person to see if they can shed some light.