M45 Coolant System Problems [SOLVED - TB bypass mod, hose leaking]

[M4T5]

I have had the worst luck with the cooling system on my 07' M45. Current miles: 85k. It has the third radiator in it. All previous radiators never had any road debris damages. The Nissan coolant is corrosive if you ask me. Many times the radiator hoses and such were replaced due to the signs of dried green coolant crusting up around the hose edges. This wasn't just one place, this was all over. A few months back I had to remove the upper hose and coolant tank hose to clean the corroded dried up coolant off of the aluminum coolant neck and the small aluminum tube for the coolant tank hose.
My findings discovered heavy pitting of the aluminum where the hoses slip onto.

Well, I cleaned it up really good last time and it lasted a while. Just today, the wife drives up in the car and I can smell coolant again, but cannot see any leaks. However, I'm once again seeing the dried coolant again seeping from the hose ends. I just don't get it...what the hell is going on here???

Anyone want to take a stab at this?

[EdBwoy]

Out of curiosity, what happened to the other radiators for you to have to replace them, especially if there was no road damage?

And also, any idea what percentage mix is being put in the car? 50/50 distilled water and green stuff? Just a guess here, but if your coolant is antifreeze-biased, then the solution will precipitate faster when the mixture gets hot. Heck, even in my cars with an almost perfect 50/50 mix, sometimes I see the green crusties around the hoses. I just undo the hoses and scrape that stuff off and clamp the hoses back on.

With aging rubber, plastic and clamps, the seals aren't as tight as new anymore and usually some fluid leaks out of these areas. With time the stuff dries out and cakes where they leak and this is what usually causes even bigger leaks as the system pressurizes and the sealing surfaces aren't perfectly round any more.

[EdBwoy]

Btw, I also have some aluminum corrosion. Didn't think too much of it, as it doesn't seem too bad. And I always use Prestone from auto stores or walmart. Not sure who Nissan sources their special coolant from, but it works for me.

[M4T5]

I am very particular about the fluids and maintenance on my vehicles. I use 50% of the green stuff and 50% distilled water. The distilled water is a key ingredient that a lot of people and shops look past.

The upper radiator hose is new. I cleaned that corrosion off with my pneumatic air tool with a small wire wheel. The corrosion pits were pretty bad on that upper neck that goes to the center of the engine. So bad, that when I was cleaning it, I feared the pits would go all the way through. I cleaned it up, placed a new hose on it and used two worm style clamps. I was going to replace it, but seen it was a fairly large part. No idea what it would cost. Probably expensive. I guess I will drain the system, get some green prestone and mix with 50 parts distilled water. Then replace the lower hose and whatever other hose I can find.

I have no idea what or how the radiator failed the first time. The AC condensor failed at the same time. The dealer suspected road damage, but when they pulled both units out, they didn't find any damage, just a leak on both units in the same spot. That replacement unit lasted about two years and it started leaking where the plastic top and bottom tanks meet the aluminum core. Even the original efan unit failed. However, I suspect the tech who did the repairs tightened the top bolts too tight. The plastic fan shroud top mounting tabs that bolts to the radiator broke. Dealer replaced as well.
Now that there is no more warranty, I do all the repairs and maintenance. My next projects are the cooling hoses or located leaks, trans fluid change and rear diff fluid change. Then new tires and new TPMS sensors. The batteries have began to fail in them.

[The00Dustin]

EdBwoy mentioned aging rubber. I will also point out that the maintenance schedule for our M's includes the hoses. I know it has inspections, but it may also have replacement. Regardless, as often as the Nissan belt has to be replaced compared to an aftermarket, I'd say replacing the hoses certainly couldn't hurt.

[EdBwoy]

I believe this is the part: http://infinitipartsnet.com/parts/2006/ ... am=3865090, #4 and it is more conveniently accessible with the intake manifold off the car.
The corrosion I see is more of the layer of oxide forming on the aluminum surface, I haven't really seen pits in mine. It seems you're doing the right things to maintain your cooling system including the hose inspection and replacement... plus I think the wire wheel smooths the surfaces to try and limit further pitting.

Although your first radiator+condenser failure issue is a mystery to me as well, I have seen many Nissan Calsonic radiators fail. You see either the plastic cracking or a loss of seal between plastic and core like you experienced.

Another curious question, double clamping the hose might not be that bad, but why are you using worm gear clamps? The original ones should be Corbin style clamps. I do not know if the OEM clamps are superior in any way when it comes to the cooling system, but it's just something I noted.

Also, before replacing the lower hoses if they are otherwise good, I'd try and see which of those connections is leaking so much coolant that you can smell it. Leave the car running after a decent drive and follow the drip, hopefully with the engine bottom cover removed so you can lay a cardboard underneath if you have to.
How's the coolant level in both the filler tube and the reservoir? What's the condition of the radiator cap?

[BlackCat81]

Infiniti has come out with a statement that some coolant seepage from the hoses is considered normal. I can't tell you how many upper radiator hoses I've replaced under warranty for the same concern your explaining. Here's a VERY easy solution to the problem; pull the hoses in question, clean the corrosion off of them, and apply a thin layer of RTV sealant either to the inside of the hose or around the radiator side. ALWAYS put the hose clamps back on in the same position you took them off, you'll easily be able to see the imprint they left when you removed them.

[M4T5]

Any idea on which type of RTV would be best to use for these hoses?

[BlackCat81]

[quote="M4T5"]Any idea on which type of RTV would be best to use for these hoses?[/quote]
I just use the gray RTV. You only need to apply a small layer. I do it on the radiator side, and once you slide the hose on, you should get a bit of the excess to kind of squirt out. Don't remove it, leave it there. As a matter of fact, I replaced the radiator in my Lexus and used RTV on all the hoses, trans cooler lines included.

[M4T5]

I'm gonna tear off the plastic upper and lower engine panels and see what's actually leaking.

[M4T5]

I found the leak. It was my throttle body bypass hose I made back in 2008. The hose had split. I decided to put it back as it is supposed to be. Replaced with new hoses and checked everything. I also replaced all the 3 or 4mm vacuum hoses. All of them were brittle and cracked. Gave the engine a bath, tested everything out and all seems to be well. All other coolant hoses looked great.

Next item will be the trans fluid and rear diff fluid changes. Anyone have ideas of what would be the best fluids to use for these? Also, should I drain and drop the pan to replace the magnet or just do two drain and fills and call it a day on the trans?

[BlackCat81]

I found the leak. It was my throttle body bypass hose I made back in 2008. The hose had split. I decided to put it back as it is supposed to be. Replaced with new hoses and checked everything. I also replaced all the 3 or 4mm vacuum hoses. All of them were brittle and cracked. Gave the engine a bath, tested everything out and all seems to be well. All other coolant hoses looked great.

Next item will be the trans fluid and rear diff fluid changes. Anyone have ideas of what would be the best fluids to use for these? Also, should I drain and drop the pan to replace the magnet or just do two drain and fills and call it a day on the trans?

I have Valvoline 80w90 in my front and rear diffs, and synthetic Valvoline ATF in my transfer case. I also have Valvoline synthetic ATF in my trans. These transmissions are pretty stout for the most part, if you don't have or don't want to pay for a full flush, do a few drain and fills. Even after I flush 15qts through some of the cars I service at work using the trans flush machine (T-Tech) through the trans cooler lines, the fluid still isn't 100% clean. So the more you can get out and replace, the better.
Edit; just realized you're RWD only, so you don't have to worry about the front diff and t-case.

[M4T5]

I just don't trust anyone to do the flush. Especially the dealer. There were more than 3 times when warranty work was performed by them, I found major issues with their repair work. As in parts damaged or just flat out missing. So...that's why I prefer to do stuff myself when possible.

[BlackCat81]

I just don't trust anyone to do the flush. Especially the dealer. There were more than 3 times when warranty work was performed by them, I found major issues with their repair work. As in parts damaged or just flat out missing. So...that's why I prefer to do stuff myself when possible.

Right on, I hear you. I'm lucky enough to be a tech at an Infiniti dealer where we're all very particular with the cars we work on. Ive worked at stores (non-Infiniti) where I couldn't believe some of the work the "techs" did. I also have a Lexus truck, which I recently got a recall notice to have the dash replaced. I'm extremely skeptical about letting somebody else work on my spotless GX470, so I certainly know how you feel.

[M4T5]

Yeah, I too at first thought I bought into superior service, but instead I found that I bought more into to complimentary cookies, muffins and a variety of drinks. The first time I received my car back with the radiator sitting lower than the upper mounts and more than an inch of back and forth movement, I knew something wasn't right. I printed out a schematic with the lower radiator grommets and a foam insert missing with the items highlighted that were missing. The tech was like, "Where did you get these print outs from?" I told him the internet.... Anyways, so I get it back and the upper center engine cover was scratched really bad. As if they threw it upside down somewhere and let it get kicked around. They replaced it.

Moving on, I get one of my headlight assemblies replaced due to a faulty servo motor. When I got it back, I took it home to do an oil change. I discover that the lower engine cover wasn't going to come off due to them striping the screws when tightening them down. Upon further inspection, I find several screws missing and sheet metal screws in place of the machine screws...... I was like, "WTF, seriously...." I bring it back and they began tearing up the plastics and clips in an attempt to remove the engine cover to replace with the correct hardware. I stood right in front of the car while it was on the lift....yeah, I know it is wrong, but I was fed up with the poor service repair work. I observed some of the side plastics ripped up and damaged where the clips slid onto. The tech was going to just put the cover on, and I stop him. I said, there isn't anything going back together until those plastic parts are replaced that were damaged. Anyways, the dealer replaced what I asked for. They even asked me if the parts and screws they replaced were correct. I said, "you guys are the experts, but from my research, everything looks to be correct now."

That was the last time I took it to the dealer. I have done multiple oil changes and replaced many serviceable items on the car, and have yet to ruin or strip one lower engine cover screw or retainer clip.

So far, nothing else has leaked, but I'm keeping the upper engine covers off for a while to be certain. I still smell heavy odors of coolant, but I'm not finding any additional leaks. The coolant reservoir tank has drop down a little in coolant level, but I believe the air has worked its way out of the system finally and it has hopefully leveled off. I also replaced a lot of the weak spring style clamps for worm style clamps. Crossing my fingers I have fixed the leaks for a while.

James

[BlackCat81]

Yeah, I too at first thought I bought into superior service, but instead I found that I bought more into to complimentary cookies, muffins and a variety of drinks. The first time I received my car back with the radiator sitting lower than the upper mounts and more than an inch of back and forth movement, I knew something wasn't right. I printed out a schematic with the lower radiator grommets and a foam insert missing with the items highlighted that were missing. The tech was like, "Where did you get these print outs from?" I told him the internet.... Anyways, so I get it back and the upper center engine cover was scratched really bad. As if they threw it upside down somewhere and let it get kicked around. They replaced it.

Moving on, I get one of my headlight assemblies replaced due to a faulty servo motor. When I got it back, I took it home to do an oil change. I discover that the lower engine cover wasn't going to come off due to them striping the screws when tightening them down. Upon further inspection, I find several screws missing and sheet metal screws in place of the machine screws...... I was like, "WTF, seriously...." I bring it back and they began tearing up the plastics and clips in an attempt to remove the engine cover to replace with the correct hardware. I stood right in front of the car while it was on the lift....yeah, I know it is wrong, but I was fed up with the poor service repair work. I observed some of the side plastics ripped up and damaged where the clips slid onto. The tech was going to just put the cover on, and I stop him. I said, there isn't anything going back together until those plastic parts are replaced that were damaged. Anyways, the dealer replaced what I asked for. They even asked me if the parts and screws they replaced were correct. I said, "you guys are the experts, but from my research, everything looks to be correct now."

That was the last time I took it to the dealer. I have done multiple oil changes and replaced many serviceable items on the car, and have yet to ruin or strip one lower engine cover screw or retainer clip.

So far, nothing else has leaked, but I'm keeping the upper engine covers off for a while to be certain. I still smell heavy odors of coolant, but I'm not finding any additional leaks. The coolant reservoir tank has drop down a little in coolant level, but I believe the air has worked its way out of the system finally and it has hopefully leveled off. I also replaced a lot of the weak spring style clamps for worm style clamps. Crossing my fingers I have fixed the leaks for a while.

James

The level dropping down is pretty normal, and you're exactly correct, it's more than likely worked an air bubble out of the heater core. Also, even though you probably fixed all your leaks, the smell will linger for quite some time. The coolant smell is very hard to get rid of. Being in IL, those lower splash shield bolts are a bear sometimes due to road salt corrosion. AWD models have an access flap in the cover so the whole thing doesn't need to come down, but I ALWAYS Remove the cover when doing oil changes simply to avoid accidentally getting oil on someone's cover. My philosophy is pretty simple, if the car isn't right the owner isn't getting it back. Occasionally, it'll upset someone, but really, how upset can you be when a tech is making sure your vehicle is 100% correct before it being returned? I'm actually more careful with client cars than I am with my own Infiniti, haha. Some of the guys at work make fun of me because when replacing air filters on the new Q50, you have to pull 8 little push pin clips to pull the upper cover off. I always have to make sure the little notches are all perfectly aligned on them when I put them back on, it'll drive me crazy if they're not aligned. I'm a bit OCD, lol.

[EdBwoy]

I found the leak. It was my throttle body bypass hose I made back in 2008...

Glad you got the issue sorted out, and thanks for reporting back with the solution

[M4T5]

The level dropping down is pretty normal, and you're exactly correct, it's more than likely worked an air bubble out of the heater core. Also, even though you probably fixed all your leaks, the smell will linger for quite some time. The coolant smell is very hard to get rid of. Being in IL, those lower splash shield bolts are a bear sometimes due to road salt corrosion. AWD models have an access flap in the cover so the whole thing doesn't need to come down, but I ALWAYS Remove the cover when doing oil changes simply to avoid accidentally getting oil on someone's cover. My philosophy is pretty simple, if the car isn't right the owner isn't getting it back. Occasionally, it'll upset someone, but really, how upset can you be when a tech is making sure your vehicle is 100% correct before it being returned? I'm actually more careful with client cars than I am with my own Infiniti, haha. Some of the guys at work make fun of me because when replacing air filters on the new Q50, you have to pull 8 little push pin clips to pull the upper cover off. I always have to make sure the little notches are all perfectly aligned on them when I put them back on, it'll drive me crazy if they're not aligned. I'm a bit OCD, lol.

Yeah, I have to say one thing about Infiniti and push pins....they suck!! The quality of the push pins they use are cheap and not designed to take on under hood engine temps. They get brittle and crumble when you remove them. I don't know how many of those things I have replaced throughout the years. I hope they changed the quality of them on the newer Infiniti's.

[BlackCat81]

The level dropping down is pretty normal, and you're exactly correct, it's more than likely worked an air bubble out of the heater core. Also, even though you probably fixed all your leaks, the smell will linger for quite some time. The coolant smell is very hard to get rid of. Being in IL, those lower splash shield bolts are a bear sometimes due to road salt corrosion. AWD models have an access flap in the cover so the whole thing doesn't need to come down, but I ALWAYS Remove the cover when doing oil changes simply to avoid accidentally getting oil on someone's cover. My philosophy is pretty simple, if the car isn't right the owner isn't getting it back. Occasionally, it'll upset someone, but really, how upset can you be when a tech is making sure your vehicle is 100% correct before it being returned? I'm actually more careful with client cars than I am with my own Infiniti, haha. Some of the guys at work make fun of me because when replacing air filters on the new Q50, you have to pull 8 little push pin clips to pull the upper cover off. I always have to make sure the little notches are all perfectly aligned on them when I put them back on, it'll drive me crazy if they're not aligned. I'm a bit OCD, lol.

Yeah, I have to say one thing about Infiniti and push pins....they suck!! The quality of the push pins they use are cheap and not designed to take on under hood engine temps. They get brittle and crumble when you remove them. I don't know how many of those things I have replaced throughout the years. I hope they changed the quality of them on the newer Infiniti's.

Nope, same cheap push pins. As a matter of fact, they use more of them now than they used to.

[jiggersplat]

Yeah, I too at first thought I bought into superior service, but instead I found that I bought more into to complimentary cookies, muffins and a variety of drinks.

Totally. My dealer has a latte machine.