totally not worth it unless you plan installing cams. the front cover is full of oil passages and other essentials that require that you must replace o-rings and seals. All which come up to around 1,200. Mind you I have a discount on OEM parts at my local infiniti dealer. Has 1 large timing chain and 2 smaller that go from each camshaft. I wrote up a DIY a while ago very time consumptive. Not worth it. Slap a 2005-6 non revup motor in it. You'll use your knock sensor and fuel injectors/rail. Call it a day.

 

These cars are notoriously hard to bleed out the air bubbles properly, especially if the mechanic isn't used to working on this type of car (350Z & G35). There's an air purge valve behind the engine next to the battery area to help get the air out.

If the new waterpump fixed overheating for a minute, then it really sounds like there just still air in the system. Also, check the condition of the radiator cap (when engine is cool of course) a worn or damaged one will also cause the coolant to boil over into the overflow tank.

 

Hey Eric thanks for all of the info on the Radiator. I might consider it a little later, but at the moment I am gonna keep looking. A 4 core would be awesome at cooling, but you did mention that the electric fan didn't pull enough CFM to cool the massive amount of coolant.. Have you found a "Hi-Flow" water pump for this engine or heard anything about the extra thermostat for the block that is on the pathfinder with the 35DE?

 

Not that it didn't pull enough just it takes longer having a larger amount of coolant to bring the heat down opposed to a smaller radiator.

The oem water pump is sufficient.

Problem with the pathfinder mod and my particular car is the ECU. The early model g35s cannot be throughly tuned as the ecu is an older style and has no aftermarket support. You'd have to custom make a standalone in conjuction with your oem ecu to handle other functions in the car.

Although that mod is very effective for temp spikes.

 

I am kinda confused with your statement about the ecu. From my understanding the thermostat runs of pressure and temperature to open so it would not have connection to the ecu. The water pump maybe; however, I was under the impression the water pump was mechanical so it got mechanical energy from the motor to power the pump. If it is electric it would make since with the ecu, but that hi flow design could be from a larger blade pushing the coolant or just a larger intake/outlet.. I don't see why the ecu would be affected by either component.

 

Going with a bigger means your fan regardless of type electric or mechanical will have to work harder when temperatures reach the point where the fan is engaged.

Remember just because the mechanical fan is spinning all the time it does not mean that it is spinning at the same rpm as your tachometer reads. Mechanical fans vary in speed depending on temperature set by the manufacturer and with wear and tear it slowly breaks down internally providing less intended cfm.

 

Lets not get out of the scope, what I was mentioning is the drawback of the pathfinder mod.

Yes its all thermal and mechanical. Problem is Nissan programmed the ecu based on our OEM setups. By doing the pathfinder mod although it is a good mod it creates one small problem. It makes the engine colder at a certain spot whivh is a good thing if you can go into the ecu and tap into the timing, fuel, and ignition because when you cannot control that then the ecu detects too cold, dumps more fuel at times it'll retard timing and instead of helping your engine all you did was create an underlying problem.

 

OK. I get it now. I didn't know there are sensors there. So I would have to either by pass the sensors or I would have to have infinity reprogram the ecu. So off topic of the bypass, but what kind of fans are you running and which ones can I get that pull the same current as OEM?

 

I think you're still a bit confused...

There are no sensors there per say... What the ECU does is read temperature, air flow, load, oxygen sensors, and it adds or removes fuel along with timing based on these readings.

 

Kinda. The way I understood what you types was that the mod would trip a sensor for being too cold somewhere and make the motor run harder to get the temp up to the need temp. The picture I looked at shows a pipe on the back k side of the block with a thermostat that should open with the main one and that would allow coolant to flow more freely which would make that motor run cooler. I'm not sure which sensor you are talking about that would make the motor run rich or retard the rimeing.

 

Ok without trying to complicate things:


In the mornings when you turn on your car ever wondered why it rev's past 1k RPM but within a few minutes it gradually drops down to 900 then lower and lower eventually to 600's?

It wont do it in random or because the engine knows it's a certain time. It does so based on sensor readings.

Air Intake Temp
Coolant Temp
Mass Air Flow

These 3 readings give the ECU raw data to which it should direct more or less fuel/air into a given circumstance. The ECU is pre-programmed by Nissan for "target values" in other words ecu won't know you changed a setup outside of the mathematical computations already given to that ecu. So if the data that is being read is different than that of what it's been programmed to do it'll do things to try and come back to where it was designed to be.

Give you a scenario for better perspective:

Say you remove the thermostat all together, the engine will run cooler as there is nothing controlling the temperature from being consistent. So as you come to a stop the temp will eventually come to standard operating levels because the cooling factors are limited to your fan's output meanwhile the engine is still producing heat from all of the moving parts. As you begin to move the air flowing will eventually cool down the fluid PAST the Manufacturers standard operating level. So the ECU will be like HEY WTF I need to fix the problem. So automatically the ECU begins to change fuel pressure, injector pulse, timing, etc... What does that mean?

It'll attempt to run richer with more timing as this will increase temperature within the combustion chamber. Is this good or bad? Bad for engine reliability as you are dumping more fuel creating a overly rich environment within the combustion chamber, which means the rings will have blow-by much more introducing fuel into the oil and eventually wearing down the cylinder walls prematurely. This is also caused by the metallic expansion rates. at 188 degree's the cylinder wall will be XYZ millionth of an inch and at 120 degree's it'll be at ABC millionth of an inch but the Piston/Rings will be at full operating temp which is at QRS millionth of an inch and you are creating more friction by being colder more friction = more wear and tear.

No special sensors just what the engine already has. Just the ECU programming comes into play because you've changed it's standard operating ranges. This is why it's so important to tune your ECU or "car" after mods. So that you can recalibrate the ECU to perform in unison with the new parts on your vehicle thus extracting more power and/or increasing reliability by again staying within the scope of your engines capabilities.

Hope I've cleared some of your doubts with this post.

 

Eric Again thank you very much.. I knew why the motor does the high idle and slowly goes down in the morning, but honestly I didn't know it was from sensors.. I kinda thought it was from programming in the ECU. Anyway, I won't take my thermostat out now and I still don't want to get a 4 core at the moment. I am thinking that the common koyo, mishimoto, or whatever I come up with will do the trick.. I talked to a buddy of mine and he hooked me up with a shop. So I am going to go check them out and maybe they will have something for me. If not then I suppose I will have to just settle. I am curious though, FlexAlite has alot of universal fans.. Is there one you would say is good? I am hoping to be able to use the stock harness with the new fans and not draw too many amps or too much voltage.

 

3053002984

Give me a buzz...

I see you're still a bit lost with this issue. Getting a bigger radiator will not fix your problem if anything youll just toss money away and be more aggravated.

 

Alright thanks!! I will hit you up pretty soon.

 

I think a valve grind kit at the dealer retails for $350 or so. In that kit, you'll have each and every gasket you need to replaced the headgaskets including the headgaskets themselves. According the manual, you don't have to replace the bolts if they haven't stretched beyond spec.