[Howie57]

Hello all. Got a 2015 P4x 6mt with just over 15000 miles on it. I changed all fluids in the drivetrain last year. Brake/clutch fluid was also replaced last year. I will be doing a power steering flush soon mostly cuz it's cheap, it's easy, and I'm bored. I am wondering if I should be doing a coolant flush. It's 7 years old but low miles so what do you guys think? Also wondering if those heater hose fittings up at the firewall should be replaced if/ when I do the coolant flush. They seem to be a weak spot on this truck from what I've read here. No leaks there now just thinking about preventive maintenance. Serpentine belt looks great, no cracks or noises there but is it getting too old to trust? Rear diff breather has been replaced and I am keeping it clean and functional. Anything else I should consider doing? Truck has never been off-road. Cabin and engine air filters replaced regularly.
Thanks in advance for your opinions, advice and recommendations!

 

[awsXTERRA]

Sounds like you've got a good plan of action. I'd continue with that. Recommend performing the coolant flush and replacing the drive belt simply based on time/age.

 

[zanethan]

Second replacing the coolant and fittings on the firewall. Use the metal ones from Doorman and never worry about them again.

 

[Howie57]

Thanks for the quick responses guys! Sounds like I got some studying to do. Not looking forward to the coolant flush. Will replacing the fittings at the same time make it easier or harder to get all the air out of the system?

 

[RamTest]

Hello all. Got a 2015 P4x 6mt with just over 15000 miles on it.
I am wondering if I should be doing a coolant flush. It's 7 years old...

The coolant is probably the most important maintenance you could do on that particular truck.
The last thing you want is to lose a heater core due to corrosion. Coolant is a chemical bath, and those chemicals include anti-corrosion formulas which completely break down over time.
Multiple drain and fills should flush it out good, the last flush being distilled water. Be sure to flush the reservoir too.

Because its difficult to fully drain the flush water, I never use the 50/50 pre-mix coolant.
I use concentrate, the good old stuff.
2/3 coolant and 1/3 water. (2/3 coolant gives higher boil-over, lower freeze point, more corrosion protection than 50/50.)
If the cooling system capacity is 11 quarts, I'll add 7 quarts of concentrate then fill the rest with distilled water. This method will compensate for flush water which is still trapped in the system.
Distilled water is a safer bet since tap water (municipal or private well) can vary greatly in mineral content from city to city. Some tap water is fine... but is yours ??

 

[Brunnie]

Will replacing the fittings at the same time make it easier or harder to get all the air out of the system?

Yes. 😁
When I replaced those fittings the system was full, so I did the left fitting first and just took the hose and put it directly on the heater port. Little loss of fluid.
The right fitting, I replace the whole tube with the Dorman part, and I did lose some fluid. Undo the heater connection first, have the bolts off, and then do the connection on the right side. The quicker you can do that the better as you won't lose as much fluid. Then I filled the reservoir, went for a drive with the heater on, checked the reservoir after things cooled down and kept an eye on it for a few days to make sure it wasn't overheating and there was plenty of fluid.

 

[FishCannon]

Will replacing the fittings at the same time make it easier or harder to get all the air out of the system?

I replaced those fittings on my buddies truck. Come to think of it, I should probably replace them on mine too before they leave me stranded. Oh well. What's life without a little adventure, right? Anyways, when you replace them, purging the system is pretty easy. Put the nose of the truck on a hill so that the radiator cap is the highest point in the system. Fill the reservoir and radiator and let it run until bubbles stop coming up. I usually overfill the reservoir a little just in case it I don't get all the air out on the first run, then check it every 50 miles or so for the first couple hundred miles.

 

[prodragon4x]

You said you replaced and keep clean the rear diff breather....did you replace with original style or did you do the diff breather extension mod? If you haven't done the extension mod, that'd be something to consider. Other than that, your plan of action is/has been good. If you're planning to do a coolant flush, definitely replace the 2 fittings at the firewall. Z1 Offroad has a nice billet aluminum one with a bleeder valve on it if you want to spend the extra bit of money over the 2 dorman ones.

 

[Howie57]

Ok a bit of info overload.🙂
Brunnie, you said you did the fittings with the system full. I will be doing a coolant flush at the same time as I replace the fittings so I assume I will drain the coolant first, then replace the fittings with system empty (sort of) And then flush and fill. Is this the correct sequence?
Prodragon4x, I have some concerns with the breather mod so I replaced with a stock Nissan part. I like the idea of the fitting with a bleeder valve. Will look into that.
FishCannon, short of doing this whole job on some random road with a hill I don't see your plan working for me but I do think it makes a lot of sense.
Gotta research the fitting swap. I'm sure there is a how to here somewhere.

 

[campisi]

Well, there are worse things to waste money on besides unnecessary truck maintenance. You're bored, too.

 

[Howie57]

It's about time someone chimed in from the other side of the fence. Yes I am bored but I am also cheap so go ahead and explain why my truck doesn't need my money. I will listen with open mind.

 

[xterramex]

Yes. Do the 2 plastic heater core fittings. I use 1 bottle of redline water wetter with my coolant.. helps a ton

 

[RamTest]

... I am also cheap so go ahead and explain why my truck doesn't need my money. I will listen with open mind.

Why would you change a fitting that isn't leaking. Sure, some of them leak eventually, but most don't. Swapping out just because it's plastic? Your coolant overflow tank is plastic and is known to fail... plan on changing that too?? Your radiator is half plastic....

You have very low mileage on a truck that is relatively new. Your situation is not compatible with a truck with high miles which might need those parts. But, it's your money, pee it away as you see fit.

 

[Brunnie]

It's about time someone chimed in from the other side of the fence. Yes I am bored but I am also cheap so go ahead and explain why my truck doesn't need my money. I will listen with open mind.

Since you admit that you are "cheap"... then why replace the plastic fitting on the left side of the heater core? Take it out and put the hose directly on the pipe from the heater core. You'll save a few bucks.

 

[Howie57]

Eliminating the fitting on the left side sounds like a great idea. That's 2 less joints to possibly leak.
I assume the hose is long enough to reach...

 

[maytawn]

I am in nearly the same position as you. I have a 2015 with 16,000 miles. I bought it new off of the lot in September of 2015. Besides oil changes, I haven't done much else. Well, that's not completely true; I did do the diff breather mod and replaced the cabin air filter..

Here's my list of what I plan to do:
1) Transmission drain and fill (4 quarts) -- Easy to do and will freshen up 1/3 of the fluid fluid for under $20 (I use Valvoline MaxLife ATF)
2) Coolant flush -- The blue stuff is supposed to be good for 100,000 miles or 8 years. I plan to put back the Green stuff because it's easier to control the mix since it comes in a concentrate.
3) Brake Flush -- Brake fluid is hydroscopic so it's probably absorbed a good amount of moisture in 7 years.
4) Power Steering Fluid -- Because it's cheap, easy, and fast.

Debating a few things.
1) Transfer Case -- I haven't done any hard wheeling, so this can probably go a little longer
2) Front and Rear Diff -- Same as above

This I'm not planning to do now.
1) The heater core inlet and outlet -- Yes, these are plastic and they do fail sometimes. However, I think these have more life in them and I don't want hassle with them right now. Maybe the next time I do a coolant flush I will consider it.
2) Serpentine Belt - It's in fine condition.
3) Air Filter - Checked it, also in fine condition

 

[RamTest]

Coolant flush -- The blue stuff is supposed to be good for 100,000 miles or 8 years. I plan to put back the Green stuff since it's easier to control the mix since it comes in a concentrate.

Autozone part PAB0B3
PEAK blue concentrate coolant
$24/gal plus a cut for the big guy.

 

[outback97]

1) Transmission drain and fill (4 quarts) -- Easy to do and will freshen up 1/3 of the fluid fluid for under $20 (I use Valvoline MaxLife ATF)

Just did a 2X drain and fill the other day and used the Maxlife ATF as well. I shopped around a bit and the cheapest I found it was at Walmart for around $25.

Where are you finding it for under $20?

 

[maytawn]

Autozone part PAB0B3
PEAK blue concentrate coolant
$24/gal plus a cut for the big guy.

I should have mentioned that I use the Nissan branded stuff when it comes to coolant.

Where are you finding it for under $20?

Well, Walmart used to have it for about $17 a gallon. Then inflation hit and everything is out of whack. I guess $25 is the new benchmark.

 

[RamTest]

I should have mentioned that I use the Nissan branded stuff when it comes to coolant.

Yes, Nissan is phasing out blue concentrate, Part # 999MP-L255QTP which is sold by the quart. The Nissan dealers are selling their new old stock on ebay and amazon, but it's by the quart and it's big buck. Can't see paying extra for that.

Keep in mind Nissan doesn't make any lubricants or fluids used in their cars.
They buy them from oil/chemical companies who package them in containers made in china.