kchelle

Hello All. While I have been browsing threads since I purchased my Z last September 2020, this is my first post asking for assistance. Please bare with me…and pardon the length. I just want to share whole picture.

I most recently (October 2021) had my radiator replaced on 2006 350z, 135,000 miles when my it ran hot for the first time after I ran over unavoidable road debris. To my surprise about two and half miles later, while at a stop light I noticed my temp gage had shot all the way up, smoke started to steam out and I immediately pulled over and turned off the car. Noticed what seemed to be power steering fluid everywhere when friend who came to pick me up looked under hood.

Next day car towed to local Nissan dealership who said nothing I'd ran over caused any damage; and was mere coincidence that a part on my radiator had gone bad and car had an oil pan leak. They fixed the oil pan for free because they'd just had the car months before to fix the same issue. Replaced the radiator and sent me on my way. And since the day I left their lot I've had issue after issue - after having no issues for the entire first year I owned the car. (Back story, I had a full diagnostic inspection done before buying the car, and besides oil pan gasket leak and the valve covers needing to be replaced, all looked pretty good on inspection report.)

Among other things that happened when picked up from Nissan, the immediate most concerning was the steering was all of sudden off when I picked it up. Took it back and they couldn't determine the issue. Asked if it had anything to do with what I ran over. Told no again. Got a second opinion from a steering/alignment shop and he said leak in rack and potentially could have ran over something that knocked around in there. Wouldn't do the job and referred me to Nissan service in the next closest city. Took to second Nissan dealership and ended up having the steering rack replaced. Another coincidental mechanical failure at the time of my road debris saga. This dealership also did a power steering flush. Recommended heating/cooling flush next service date.

Had car and drove a few weeks before taking a 5 hour road trip. Arrived to my destination fine and car drove without issue for the week of my vacation. Then on the day I was leaving I noticed when I went to turn on the heat, that mostly cool air was blowing. I turned it to high and drove 3 miles to nearest gas and checked all my fluids. They were all fine.

Then about another 3 miles into my trip on the highway, the car slightly jerked and gas pedal seemed to loose some power. I immediately looked at dash and saw the temperature had shot all the way up, followed immediately by the service engine light. Just as I was pulling over onto the shoulder of the highway to turn off car, it turned off on its own. A day later, after having it towed to local Nissan, they called and said that whoever had put in my radiator failed to bleed out the air properly. They said they had bled the system and I could pick up. I was relieved because I thought I'd blown my engine.

Picked it up, heat was running normal again and got on the highway for a 5 hour trip. The temp remained stable, no spikes, and everything was fine for the duration of the entire trip.

Two days later I go out to start the car and it slightly hesitated on turning over - figured it was because really cold. Let it heat up after I started it and noticed once again getting no heat. Let the car warm up to normal temp gage and drove around neighborhood and back. It didn't overheat but I decided not to drive it as I heard like water sloshing sound on driver side dash. (This was not the first time I'd heard that sound. It had done it most of last winter when I want from Summer and A/C to Winter and using the heat. Not always when I started the car, but certainly intermittently.). Waited until next day to start again - which it did without issue. Noticed though no heat unless I was pushing gas at which time then warm heat would come out. Drove it that evening about 6 miles total to and from store with heat all of a sudden. Did the same on two more occasions. And this evening drove 3 miles to my office and everything was fine.

But when I left, about a mile into my commute the temp gage shot straight up to Highest point on gage. I immediately pulled over but there wasn't any smoke or anything coming from under hood. Waited 30 minutes until my Wrangler mechanic could meet me.

By then, car had cooled down. Started to drive and after about a mile, (he said to turn heat on high) and again car started to overheat. He checked all the fluids, all seemed optimal, but kept running hot a mile or so into driving no matter how long cooled down. Driving behind me he also saw smoke coming out of back driver side exhaust.

So here we are; at first he posed that it was my radiator cap; now he thinks it's my water pump. But since he hasn't worked on my Z, I wanted to get thoughts from those with expertise on these cars.

Nissan claimed the thermostat was new when they bled the ac system because I had asked them to go ahead and change that when it was towed in. But I don't know that to be true as it's not listed on any of my recent service receipts.

So……do you think I still have air in the system, or a bad water pump or a blown head gasket. Or could it be all three? Something else?

One more thing of note - other than the water sloshing sound that has happened on and off since I've owned it, (driver side) I also noticed that my fans seem to stay on constantly - every since I've owned the car. And it was the first thing I asked Nissan to look at; they said nothing was wrong.

Thank in advance for any help you can offer. Cheers,

travlee

iTrader: (8)

to me it sounds like you still have air in the line

kchelle

I hope so. Will have that checked again today; thanks for taking the time to read and respond.

Spike100

Was the smoke your mechanic noticed coming from the exhaust white? If so, you have a warped head gasket that is allowing coolant to enter the engine. That also causes overheating. If that is the case, there is likely other engine damage.

kchelle

just met up; he thought it looked more like steam. Just picked up combustion leak detector kit and gonna test.

sucks if hg is blown or other engine damage. Would the car overheating have been enough to blow/warp the gasket? And why would it have allowed me to drive five hours after picking it up when Nissan bled it before running hot again?

Thx for your help

Spike100

Intermittent engine overheating can be a symptom of a failing head gasket (a head gasket that is no longer sealing completely). The seal can improve or worsen as the engine temperature fluctuates. That is why the overheating problem is intermittent, and why the engine temperature can change so drastically so quickly.

The "power steering fluid" you noticed under the hood wasn’t hydraulic fluid. It was probably oil mixed with antifreeze that was escaping at a point where the head gasket’s seal was inadequate.

The “steam” your mechanic noticed was antifreeze leaking into the engine and escaping through your exhaust.

There are reliable diagnostic tests you can run. Your mechanic should have that done right away. If the gasket is bad, it can result in a warped head, a damaged camshaft, or some other really bad things.

kchelle

Well that all makes sense and sucks at the same time. It’s frustrating that between 3 Nissan dealerships nobody could check for and determine this - ESPECIALLY the fluid you remark was likely antifreeze and oil mixed. So I may have gotten a radiator replaced when unnecessary?!

“They” insisted I had a lower oil pan leak and a failed radiator. I should mention this was after the first service manager called and said it was my upper oil pan gasket and that they had to redo their original sealing of oil pan job + radiator.

When I called back to speak to supervisor, I was told the info about the upper oil pan gasket was incorrect and had been diagnosed by a Junior mechanic. I despise this dealership. They messed up The factory wheels with some kind of solution that ate right through them; kept the car to re-furbish/paint them, and then reinstalled the wheels backwards with one almost falling off while I was driving.

At any rate all of what you say sounds logical I just don’t understand while I would not have seen any leaks on driveway and why all of this started after the radiator was replaced. To me it just seems so ironic that all of these mechanical failures happened when I ran over whatever was in the road.

Will run test for gasket tomorrow as it was getting too late in the evening by the time I had gone back to AutoZone to purchase something to pull the fluid out of the radiator before running the compression test.

urgh!

kchelle

Also, i’m curious to you or anyone who reads this if indeed it is a gasket do you recommend just selling the car??

or is it worth it to buy a refurbished or used engine?

Spike100

You might be getting ahead of yourself. Before making any decision, have a qualified mechanic check the engine and its head gasket. They have instruments and equipment to do an accurate diagnosis. If the gasket was leaking and there is engine damage, and you own an old car that has covered over 100,000 miles that holds little value over the repair cost; it's probably wise to dump it on a scrapyard. It’s hard to let go, but it may be a better option.

kchelle

Thanks for replying. We did the combustion test today and the fluid remained blue rather than yellow. So my personal mechanic friend felt it affirmed his theory that it is not my head gasket.

He thinks its the water pump and recommends that I replace that. I honestly don’t want to spend another dime if there is engine trouble because I have already between two Nissan dealerships just spent three grand on a steering rack, radiator and valve covers.

he suggested I drive the car around and within 2 miles it went from regular temperature and shot right up - not all the way to the H, but steadily getting close. Turned it off. No smoke coming from exhaust. There was nothing going on under the hood either.

So although he thinks it’s the water pump, I’m at a loss and frustrated that all I know is 1) I no longer have heat in the car unless I’m driving for a while, 2) My fans which sounded like they were always on in the year that I’ve owned it now seem to be not coming on as quickly as they used to and they also seem to me to tirnMy fans which sounded like they were always on in the year that I’ve owned it now seem to be not coming on as quickly as they used to and they also seem to turn off when I turn the engine off. Which might be normal but they used to stay on even after the car was off and I remember taking it in to Nissan about that last year and they said it was fine. 3) the car has been supposedly bled for air twice, and no matter what if I’m idling temperature is fine but when I drive it shoots up, and 4) there is still the sound of water sloshing on the driver side intermittently and that has been happening since I’ve owned the car.

it’s a 2006, and I just hit 140,000 miles. My problem is I live in a small town where there’s only one Nissan Dealership and they have messed things up every time so I don’t have access to great Z mechanic. I’ve owned Z’s before, a 240, 280 and a 300 - the last which I used to take to Z1 motors in Georgia because I couldn’t find anyone local. I should’ve remembered that before buying another one.

thanks for all your advice and help I’m trying not to jump ahead of myself but I went from thinking I had purchased a really reliable car that gave me no trouble for a year straight until I ran over road debris and started dealing with my local Nissan Dealership who after changing the radiator has catapulted me into this land of strange overheating. Urgh.

The next Nissan dealership is an hour away I can’t think of how to get it there without overheating unless I tow it.

I did ask my personal mechanic friend who works on my jeep if he would be willing to use the kit I see everyone in these forums talking about to try and burp the air out of the system again…. Do you think that’s worth a try?

TatsuyaToujou

Hi, I have the same problem too. I just recently bought a 2004 350z and as I was driving home, I noticed that there was no heat when I blast the heater at high also. I’ve done a lot of refurbishing to the engine and see what was happening. Most of the “leaks” or “drips” was coming from the oil pan below but I replaced the oil pan gasket it was still continuing to drip. The z’s temperature gauge has also shot up just like what u have stated too. I took apart the radiator and everything and what ur friend had said was the water pump. I believe it’s the water pump that’s broken cause when I took it to the shop cause there was a bolt snapped and I couldn’t get it out, we found out that the water pump was really corroded and breaking apart. I just bought a new water pump and will be installing it soon. I will let you know if it’s the water pump that’s broken and that it can be fixed by just replacing it. Hope that can ease you up a bit.

kchelle

how kind of a note; really appreciated! Def looking for the ease. So yeah what you’re talking about with your oil pan has been an ongoing issue since I purchased mine. Only because the first time they sealed it they messed up and the first time it ever ran hot when it was towed in they took responsibility for messing it up the first time with the junior mechanic and assured me that they were fixing it with a senior mechanic this time.

I don’t even know if they really did or not. Although I don’t really see any leaks under the car but they explain that I wouldn’t necessarily see them when it’s a slow leak.

so I’m assuming you already had bled all of the air out of your system and don’t think that that’s what’s going on with yours?

and yes I would totally appreciate it if you let me know about your water pump after you replace it because I’ve decided to just do nothing for a few days so that I can wrap my head around all of what’s going on. Also the guy at O’Riley‘s said that if I did change the water pump I would have to change all of the timing change belts etc. is that true?

Thx

jhc

Since you have a sloshing sound in your cabin, yes-you have air trapped in your heater core. Here's the hack-
Find the bleeder valve on passenger side rear engine bay, remove and set aside. Get a funnel into the tube and slowly fill with 50/50 coolant until ALL air is gone. Put bleeder cap on, top off radiator and overflow. Run engine/drive until temp is reached. Let cool. Repeat all steps as many times as necessary.

Once you've gotten the air out the easy way to diagnose a head gasket is to watch for coolant consumption. Also smell the exhaust - it will smell "sweet." Gl!

TatsuyaToujou

I believe so. The time you usually change the timing belt is when u change the water pump or the other way around. Being on a budget and trying to not spend as much money, I’ve decided to keep the original belts but they also look fairly new. I think the old owners has changed them but not the water pump I’ll keep you posted.👍🏻

TatsuyaToujou

i believe so. The time when u change your timing belt is probably the time u change the water pump. I may be wrong but I’m on a budget and not wanting to spend too much money at one time I’ve decided to change just the water pump cause the belt looks fairly new and I think the previous owner has changed it without the water pump cause it was corroded. I’ll keep you posted.

kchelle

Hello! Thanks for this helpful info. I will share with my friend and hopefully get somewhere with the process. One question, the repeat all steps as necessary is based on…. driving to see/or until car runs hot, or something else. And is it not damaging to drive until car gets hot? Trying to figure out how to get around that; as when it does in fact run hot, it tends to shoot up from normal to high super quickly. Never when idling; once driving.

jhc

Good question. This cooling setup has vexxed folks for a minute.
My best answer is you will see on your temp gauge whether it's going to stay normal operating temperature after a few minutes of running. Monitor your coolant volume and temps.
Check for leaks. If you'd like to see if both your water pump and thermostat are working correctly start with a cold engine, take the radiator cap off. When the dash temp guage gets to "normal" you should see the cooolant level drop quickly and then refill as the thermostat opens and the water pump does it's job.

kchelle

very helpful info! Thank you. Happy new year! Between distraction with the holidays and then a snowstorm I haven’t had time to even deal with the Z. I did crank it yesterday after snow had melted to move it and noticed that when I went to accelerate as though I was warming the car up I could hear water moving with acceleration; the heavier i pressed . the pedal the louder the water moving around. And again it “sounds” to be on the driver side. I’m going to try the suggestions you made this week, but was just wondering if that points any further in a particular diagnostic direction. Thx!

kchelle

hey there! happy new year. I was wondering if you had an opportunity to change out your water pump and if that fixed your problem? Thx

TatsuyaToujou

Hi, sorry I completely forgot cause I was busy but yes, my coolant leaking problem was the water pump, there was a lot of corrosion and one of the bolts was snapped, she runs fine and strong now I recommend on giving it a try if that helps