bre240z

So the radiator on my 2004 Z seems to be the original one but im not 100% sure. I am not having any cooling issues. Everything related to the engine on the car seems to be OE stuff. I am the 2nd owner and right now it sits at about 113K miles. Had the car about almost 2 years.

So I will be doing a coolant flush and I thought well since im doing this why not replace the water pump, thermostat, hoses and some other stuff. My question here is... is it worth upgrading to an aluminum radiator? I dont track it and I do some canyon driving once in a while. This is a daily driver and in about a year or so I will be handing this car over to my son as a high school graduation present. So I also want to do as many maintenance stuff to the car so when he gets it'll be in decent shape.

so my options are as follow:

Mishimoto Aluminum radiator $293
Mishimoto OE style radiator $140
NVA Radiator $145
Koyo $380

The Koyos are a great radiator as ive had them on my S chasis cars before but i think its over kill for my needs. Then I was really leaning towards the Mishimoto aluminum one but will that also be over kill? Im kinda stuck here and ive had all this stuff in my Z1 shopping cart but I cant seem to make my mind up in regards to the radiator. What do you guys suggest?

iideadeyeii

iTrader: (6)

Oem style

lifekenophobic

Spend the extra cash and go for the Koyo. Although I've never had one, I've heard good things about them.

I replaced my radiator with a Mishimoto and the fitment was horrible. Had to grind down several areas to get it to seat in the right places. Aside from that, I haven't had any issues with it and it's doing its job at least.

Btw, nice graduation present for your son!

icer5160

iTrader: (4)

Koyorad for the win. Excellent radiator, I installed one in my Z last year. I did need to make some relief cuts in the core support for the lower mounting tabs that hold the AC condenser. I went with the upgraded Koyo 48mm unit, other than that, it's a drop in replacement. It's a very tight fit, but it will fit without making modifications to anything else. I did need to remove the coolant reservoir bottle and bracket from the passenger side frame rail to give extra clearance for the install.

I've heard the Mishimoto unit is a cheaper clone of the Koyo, I don't think there's anything wrong with using the Mishimoto product, I just trust Japanese build quality more. I strongly recommend sticking with the OEM fan package.
Cheers!
-Icer

icer5160

iTrader: (4)

I ordered my Koyorad P/N HH021568 (6MT only) from importimageracing.com at the time they had an amazing sale and I picked it up for under $300.00. It's listed there for $332 right now. Never used this retailer before then, but it was such a good deal I figured it was worth a shot. I received a genuine part, no issues.
Cheers!
-Icer

bre240z

thank you guys for your input. Really appreciate this information

icer5160

iTrader: (4)

In terms of the other maintenance items, I would for sure tackle the hoses and thermostat, but I would consider leaving the waterpump alone (delicate + big job) unless you got signs of coolant leaking out of the weep hole which is located just under the A/C compressor (driver's side of engine block). Stick with the OE thermostat, gasket, hoses, and radiator cap. Yes the OEM radiator cap fits up to the Koyorad without issue (tight, but good fit). Nissan is using the newer Blue Coolant now, it's perfectly safe to mix their new blue coolant with the older green stuff. Since you're doing a flush, I would recommend just using the Blue Coolant since they sell it premixed. It's more expensive, but saves the time/hassle of buying the concentrate green coolant and mixing it yourself. Up to you, save a few bucks or save time in the form of additional shopping trips to get distilled water.
Cheer!
-Icer

bealljk

iTrader: (13)

+1 for the Koyo

Is it required for what you are doing with the car?? Probably not but since youre there and you will have the cooling system apart it is probably worth your time to replace it.

I love C&R Racing and both my z and g have custom radiator setups but I went with the Koyo for the g.

BORNGEARHEAD

When I bought my 04 convert a few years ago I replaced the radiator, radiator cap, upper/lower radiator hoses/clamps, and thermostat. I don't expect to have any problems or worries now.

bre240z

Icer ive thought about leaving it alone but I would hate my son to have this car and then have the water pump fail at the worst time. Im pretty sure its the original pump. Are these pumps known to last for over 100k miles? I dont see much mentioning of water pumps failing on the Zs but I feel the water pump is a crucial piece. Ive seen write ups and videos of these being replaced and doesnt seem too complicated. Im not a auto tech but i have many years of wrenching on various cars of my own so i feel confident tackling this job. I would rather not touch it if I really really dont have to.

icer5160

iTrader: (4)

I wouldn't worry about the water pump until you're close to or beyond 200k miles. These are very reliable unless the coolant system is severely neglected (contaminated coolant, very old, never changed/flushed, or severe engine overheating). I haven't seen any common reports of these units failing around 100k or even 150k. The OEM pumps are very well constructed. If a failure occurs, it's typically the O-ring seals. There are two seals, a primary and a backup. When the primary seal fails you get the warning sign by seeing coolant dripping/leaking from the weep hole under the AC compressor. The backup seal prevents the coolant from mixing with the engine oil in the timing case, thus giving you time to identify and repair the issue before risking the entire engine. This typically happens due to age and the O-rings hardening or going flat. If the engine is overheated, the O-rings could be cooked and/or the pump's shaft seal could get cooked causing failure. Obviously a serious leak elsewhere in the coolant system causing the pump to run dry or introduce major air pockets would cause the same failure mode (overheating and destroying the seals).
Hope that helps out.

By all means, if you're willing to shell out the cash for a pump replacement, feel free to do so just for peace of mind. But if you're hiring a pro for the work, expect a large bill. If you try to tackle it yourself, read up on the process closely because it does involve messing with the timing chain and tensioner. A small mistake has the potential to throw off the timing.
Cheers!
-Icer

icer5160

iTrader: (4)

Found this from an old post (credit to user ZedFed circa 2016, probably no longer active on here):

BEFORE YOU REACH UNDER AND START REMOVING THE TENSIONER, DO THESE STEPS FIRST...
<b>Make sure you are at top dead center</b>
1. Remove the #1 spark plug (Facing engine, left side, coil closest to you).
2. Turn the crank CLOCKWISE slowly until you hear air push out of the plug hole
3. Look at your pulley and continue to turn until you line up the timing marks(You should be TDC)
4. Now you can take off the tensioner side plate and insert a small allen key in the tensioner hole to lock it in it's place.(Have a magnetic rod on hand to help prevent dropping any bolts or the allen key in the timing cover or welcome to your next 3 days of hell).

5. Remove plate from the other side for the water pump and Remove the bolts from the tensioner on the other side, then remove the tensioner.

6. Turn the crank COUNTER-CLOCKWISE only a mere 5 degrees just enough to loosen the chain on the water pump side (The other cover opposite). You don't want to turn too far because you will "pop the cams" and you will have to remove the cover and line up the cams at that point you are up s creek so turn until you see enough slack on the w/p to remove.

7. Remove the 3 bolts to the water pump
8. Clean the mating surface really well for the new pump.
9. Shoot a little PB into the weeping hole to clear any dust or other gunk.

10. Insert new pump and install the bolts.
11. Insert the tensioner(LEAVING THE ALLEN KEY IN), install the bolts.
12. Go back clockwise to tighten the chain back up
13. Verify both side are tight(A light PRESS will suffice)
14. Remove the allen key so it will lock the guide back to the chain
15. Spin slowly just for peace of mind to assure everything is in tight working order.
16. Install the plates, re-insert the belts and fire her up

If that process is within your comfort zone, have at it!
Cheers!
-Icer

bre240z

Icer thanks for the info. I was actually reading that thread yesterday when i was doing some research on replacing the water pumps. Really good points on setting the engine at TDC as mentioned above. Many write ups and vids online dont mention that. Thanks for sharing

icer5160

iTrader: (4)

Hey Bre,

While you're in there doing the cooling system maintenance, might I recommend also replacing the plastic coolant bleeder port pipe/fitting with an aluminum unit. Cheap part, gives that extra insurance cause it's not IF the OEM plastic will fail...it's WHEN.

GKtech offers a nice replacement as does Z1 and CZP. I personally have the original Z1 design (not anodized black), but I'm liking this GKtech option with the barbed fitting for a coolant swirl pot (because racecar!). But seriously, it's a nice looking unit. So far I've been very happy with all the Gktech purchases I have made.
Cheers!
-Icer

bre240z

Icer the GKtech setup is real nice. The bleeder port is one of the things on my list for sure. I think im gonna stick with Z1 anodized black.

Ive also have purchased some GKtech stuff and they are legit. I decided to leave the water pump alone for now. What do you think about that Z1 lightweight crank pulley kit?

Vitamin_B12

aluminum crank pulleys are mostly frowned upon here, due to some failures at the keyed area being just aluminum. i replaced mine with a fluidampr (there is also the ati super damper pulley and others). the fluidampr is larger in diameter than the oem, and the ati even larger than that (this matters cuz you might need a longer serpentine belt)

while not necessary, it is actually a good idea to do it at the same time as the radiator as it gives you a bit more working space freedom. also, if you intend to say for lightweight/bling get the aluminum pulley set (and toss the crank) of the idler and alternator pulley, it is much easier to remove the alternator pulley bolt with space for a gun

i also believe one of the mounting bolts are really long and will hit the radiator; so if you feel like replacing the alternator while you're at it, for high output or just preventative etc., now would also be a good time

i can't really think of anything else that would be prudent while the radiator is out. others will chime in

for removing the crank pulley, i made a little thread in the DIY section

icer5160

iTrader: (4)

I agree with Vitamin_B12, I'm actually planning to purchase a Fluidampr for my Z. It's comparable to the stock crank pulley, but the silicone filled mass damper does a much better job with cancelling out torsional vibration on the crank. Anyone who's swapped out their OEM dual mass flywheel for a lighter single mass flywheel knows about the gearbox chatter torsional vibration can cause. Even though I went with the heavier Zspeed quiet comfort clutch kit which included their iron single mass fw, I still get a little gearbox chatter at low rpm 1st gear launches.

Anyway, a Fluidampr will only be beneficial (can't hurt), helps protect your crank, rods, and bearings. Really worth reading up on the physics behind how it works.
Note: The stock pulley weighs ~6lbs and the Fluidampr weighs ~10.lbs.

So if you've gone with a light weight FW already, you're probably still having a net loss of weight even with a fluidampr crank pulley.
Cheers!
-Icer

bre240z

interesting stuff. I will assume that my Z still has the stock clutch and FW. I will definitely read more about the Fluiddampr. For now maybe just hold off on this and just replace the belts.