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2009 Altima V6 Lower Rad Hose Replacement

13417 Views 19 Replies 4 Participants Last post by  08AltimaDriver
I am wondering if anyone has replaced the lower hose on a 4th gen V6 (mine is a manual if that makes a difference)? I just did it myself and it turned out to be a horrible job. It took me about 6 hours to do. The main issue was the bolt that mounts to the lower hose (plastic tube part) to the lower rad support. I got it off after some hardship but there was no way I was going to be able to get it back on due to no space at all to see where to bolt mounts. Could not get it back in by feel. I left it for now, thinking I will zip tie it or something. I am assuming that I ran into issues as I did not remove the fans and/or the rad itself. Seems weird that Nissan would make hose replacement so hard.

Wondering if anyone else has some insight so I know what I did wrong for next time if it arises.
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Thanks, going to have to look at that soon.

FWIW, the gen3 was a piece of cake. Just drain, disconnect coolant hoses - lower at engine, upper at rad, disconnect fan wires, remove 2 bolts for upper rad supports and pull rad out of car, fans attached. The rad is simply seated in two rubber grommeted holes. Once out re & re of the hose was trivial. I think I had to remove the battery plastic cover to get rad/fan assy out...but other than that was easy.

Would've been tricky getting the hose done without removing the rad though because of clearances.
Yeah I think I messed up by not removing the fans. I did not want to do this as I would have to remove the upper rad support which would have me removing the grill and all the bits that go with this and the hood support rod. If I had to do it again I would bit the bullet and do it though. I also had to remove the upper rad hose which is easy though as the coolant is already drained.

One other thing is that the lower hose clamps (the 3 right at the bottom) were rusted really bad and broke apart on removal (I live in Canada so I guess only a place with snow would make this an issue). I am assuming this is why it was leaking in the first place.

Curious to know what kind of leak symptoms you had (ie occasional or consistent drips). How much coolant lost over how much time? Also what kind of hose clamps were spring or gear. Did you replace the hoses or just clamps?


I noticed the reservoir was empty, filled it up a few times, then looked further and noticed that the underside had coolant was everywhere. It looked to be coming from the lower rad hose where the plastic tube joins the rubber hose. It seemed to be leaking only when hot. After I drove awhile and parked I would see a few puddles (seemed to be running along a bunch underside parts so made multiple puddles even though it was leaking from one spot). When I would park with the engine hot I would see constant drips coming down which would stop as the engine cooled. It got worse and worse and just before I fixed it I was losing about a full reservoir of coolant every two days or so. The clamps were OEM Nissan ones which are spring style. I replaced it with this from Nissan:

Nissan Parts, NISMO and Nissan Accessories -

It came with new clamps which were the same spring ones.

If you are replacing I would recommend removing the rad fans at minimum and possibly unbolting the rad to at least move it up abit to easy removing the lower hose.
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Also just to add some more information. I inspected the old hose and all looked ok except the plastic tube was an oval shape, maybe distorted from the heat? As I mentioned above the clamps were really rusted badly (while most of the car looks rust free) and as the clamps broke as soon as I put tension on them I am assuming that they are the cause of the leak and from the look I would say this would be common to all Altimas that see snow. If there is a leak I would check here first.

Looks like I'm due for this now too...bloody Canadian salt winters... Oh and I get to pay 2x as much for the part too... :crying FWIW, it was the clamp on the driver side of the pipe (ie from the rad-2-pipe section) that is leaking.

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That is exactly how mine looked before I replaced it. I was not able get that one bolt back in (the one in the second picture) so I would recommend to pull the rad and fans out of the car. I did not do that so I ended up zip tie the hose to the bracket so it would not rub against the front frame.

Good luck.
Please keep us posted. My winters are similar to Ontario's, so I might have this soon.
Please keep us posted. My winters are similar to Ontario's, so I might have this soon.
Hopefully you'll be okay, you have a single piece of rubber hose for your lower connection (unlike the V6 which has a ? shaped piece of hose, a straight bit of plastic pipe about 10" long, and then a W-shaped piece of hose). Here's the 2.5 lower hose:

versus the V6 "problem hose"

Part numbers:
W0133-1829807 or 21503-JA100 (oem 3piece assembly including clips)
GATES 23352+23351 (new rubber hoses for either end of plastic center pipe)

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Some notes on the job:

-used OEM part from dealer because I was worried the plastic middle bit was partly at fault
-used OEM long life coolant from dealer
-used distilled water (used almost exactly all of the 1USGal(3.78L) of coolant mixed 55%/45% (we do get to -40' round these parts sometimes)

You do have to remove the engine shield (plastic panel under the bumper)...about 10 poppers
You should remove the rad overflow bottle (1 x 10m bolt)
Drain the coolant (Philips head drain plug spigot on passenger side, behind the plastic rad holder)
Remove the 10mm bolt holding the plastic pipe section to the rad frame...penetrating oil recommended here...mine was pretty rusty (you will want to replace this bolt with a new one)*1
Empty your drain pan and place below the rad end of the hose. Working underneath from centre, use needle nose pliers over top of the engine subframe to loosen and move back the spring clip. Remove hose carefully, there's still quite a bit of coolant remaining in the hose! Gently drain the hose by sliding the end between rad frame and engine subframe, lower and lower until plastic part has come through and all fluid has drained.
Pop the clip holding the hose to the rad frame on the passenger side...or cut it if you bought the oem part as it comes with one
Reaching through the area where the overflow bottle was, use needle nose to loosen spring clip and slide back on to hose. Twist hose off
Feed hose the rest of the way through between rad frame and subframe...remove

Clean and wipe both coolant spigots...the rad side is plastic and will just wipe clean. The engine side will require some work with a wire brush (I used a scouring pad) or coarse steel wool to clean the corrosion off the beveled end. I jammed paper towel up the pipe to make sure no abrasive grit got inside from the clean up (I have a pic of what that looks like when done)

Feed the new part downwards past the alternator and over to the rad side spigot.
Fit end of hose onto rad (leave clip unsprung--oem part comes with a clip that is locked lever up one side and it snaps onto hose when you are ready)
Fit old engine hose clamp onto new part, then fit end of hose onto engine spigot up to stops cast in the aluminum. Adjust clamp with needle nose into position.

*1 Replacing the mounting bolt for the plastic hose:
- 10mm short socket, I used 1/4" drive parts
- reaching down from top wiggle socket onto rusty bolt head
- lower 1/4" drive ratchet from top and let handle slide between rad frame and engine frame
- working from underneath, connect ratchet to socket and begin to loosen. Bolt is about 1" long
-To Replace
- my bolt was so badly rusted I couldn't get it started again, so I used the rad overflow bottle bolt with some antiseize on it (I'll get a new one for that later)
- insert bolt into 10mm socket
- with one hand working from overtop of the subframe and the other from underneath 'feel' your way until you get the bolt through the pipe mounting flange
- you can pull the pipe back a bit to verify you are through and to help guide the bolt end to the clip on the rad frame
- once it is seated (and this was the most awkward part) hand turn the socket until it has started to thread
- again drop ratched from top down and connect to socket
- with one finger on side of socket to generate some friction and allow the ratcheting, tighten bolt
- adjust pipe for level

Now you just have to pop the plastic hose strap on the passenger side into the hold in the rad frame, and spring the rad side hose clamp into place. Easier said than done, but a minute or two of messing around blind I got the tab out of the way and clamp snapped in place

Replace rad overflow bottle (I stole a 10mm bolt from the battery to ECU holder for temporary service), connect hose

Mix coolant to water 50/50 to 60/40 depending on application (more water means better cooling, more coolant means lower freezing temp/better engine protection until 60/40)
Fill rad..will take at least 4L easy
Burp hoses, fill until coolant at top of rad neck
Start engine, set heater to max heat, continue to top up as coolant level drops
Once top hose starts to get warm, replace rad cap and shut off engine

Fill overflow bottle halfway between Max/Min for now. Let engine cool.

On next start, find a nice steep hill or parking ramp, with engine fully warmed up, top on slope and rev engine to 4000 rpm a half dozen times or so, then drive off. Let cool.
Refill bottle to MAX level.

Go for a beer!
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Great info and write-up as always. I've noticed a bit of that bright green stuff powdery residue on my car but it's at the upper hose at the rad end. I haven't seen any change in level in the overflow bottle. It's got me thinking I should pop off the bottom splash shield and at least take a look.
Great info and write-up as always. I've noticed a bit of that bright green stuff powdery residue on my car but it's at the upper hose at the rad end. I haven't seen any change in level in the overflow bottle. It's got me thinking I should pop off the bottom splash shield and at least take a look.
LOL, love your location tag :) However, you don't have to worry about the lower hose, the 2.5's have a single piece of rubber hose as shown in my post a few up.

Keep an eye on the upper hose for changes. Note, it takes quite a lot of 'seep' to drop the level in the overflow bottle.
Confirming that I had the exact same failure mode as @seanf19. The clamp (shown in post #7 above) on the driver side of the plastic hose had rotted through and was no longer springy nor round. When removed, it crumbled into a vaguely W shaped pile of rusted rot. Suspect heat/cool cycles will eventually make the plastic pipe oval shaped as noted by Sean.

In short, plan to replace all 4 clamps with new ones if you just buy the aftermarket hose pieces from RA or other vendors--and the 10mm mounting bolt for the plastic piece too!
Well it looks like it's my turn to have to deal with replacing rad hoses. I alluded to a small, unmeasurable leak at the upper hose near the filler neck. I do have powdery residue there. But decided it was too small to bother with. I wasn't seeing any real change in the reservoir bottle level, so I left it. But now I noticed the level dropping in the bottle and I have drips on the driveway. Took the bottom splash shield off to get a good look and it sure seems the lower hose is leaking at the radiator end. Dripping all over the part of the sub frame that runs across the engine bay and the splash shield. Some of it even ran back along the sub frame on the driver's side.
(in the pic, front is to the right. pic is taken looking from the passenger side looking toward driver's side)
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Your 2.5 doesn't have the plastic coupler and clamps that failed for me. Be very careful to check for cracks or stone damage to the fins in the area before investing too much time on the hose. It wasn't pleasant working on the bum end of the rad...worse now with winter upon us.

If it is just the hose, and it could just be the same POS OEM clamp failing in a different place...make sure to clean the fitting well (buff off the crud) to prevent new leaks from forming shortly after your repair.
Yeah it's a bit simpler on the 2.5, just one hose rather than the 2-piece thing the 3.5 has. No kidding about tight. It looks like I'll have to pull the rad fan assembly. That seems straightforward, manual shows it's only held in by 2 fasteners at the top. I didn't see anything obvious on the rad itself, and it is behind the condenser so I doubt it would have been hit directly. Of course, it's possible that the spout that the hose goes on is cracked/deformed, won't know until I pull the hose off. Luckily I am able to have the car stay put if I discover I need to get a new rad.
Well, finally got around to doing this. Was waiting for mild weather so that if my wife needed to keep her car outside while I worked on the car (especially if the car ended up being stranded if needing a new rad), at least she wouldn't have to scrape her windshield. Then the pandemic happened... anyway it actually went fairly smoothly. No new rad was needed. The hoses looked fine generally speaking, though I changed them anyway since I already had them and it doesn't make sense to put the old ones back in. The culprit was the clamp at the radiator end of the lower hose, it was badly corroded, and wasn't holding pressure when the thermostat opened and the radiator was seeing the pressure of the water pump. When I went to remove it it just crumbled in 2 pieces in the pliers. Every connection showed signs of slight seepage, but particularly the engine end of the upper hose. The metal spigot had a good 2 mm of crud building up between the hose the metal, over the full length of the section where the hose overlaps the spigot. Cleaned that off by gently scraping/loosening it with a utility blade, and finished up with rubbing with a fine 3m scrub pad. The plastic spigots on the radiator end were fine, just wiped them clean with a rag. I removed the overflow reservoir to clean it and found the clamp at the bottom of the reservoir had corroded badly, and I was able to break it off just using my fingers.
Put everything back in, raised the front end of the car up on stands, refilled the coolant and topped up as the air bubbled out. I have the funnel with the radiator cap adapter, so it makes this step a breeze.
Here's the before and after of the engine end of the upper hose, though I already had a lot of the crud removed at this point. Couldn't believe how thick it was!

Next is the lower hose clamp (at rad) right after trying to squeeze open the clamp. Note the small metal spigot directly above the radiator hose, this is one of the 2 CVT hoses. The lower one has to be disconnected to be able to deal with the radiator hose. Don't forget to put it back after!
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^^nice job on the cleanup!
Well, after about 4000 km of driving since the above coolant hose replacement, I noticed a small puddle near the passenger side under the radiator. Turns out there was some coolant leaking from the connection between the radiator cap fitting and the top end of the short elbow shaped hose. I wanted to make sure it wasn't cracked so I siphoned out a bit of coolant and removed the fitting. There was no crack, and which removing the fitting it sure felt that the hose clamp wasn't that tight anymore, compared to when installed. Seems like there was decreased clamping action due to the hose material flattening out a bit under the hose clamp, and the screw style hose clamp obviously doesn't self tighten, so it caused a small leak. I went over all the connections and snugged them up a bit, thankfully the only things that had to be removed to do the work were the lower splash guard and the front air duct.

Something to keep in mind for anyone else that replaces hoses...
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