caliwebman

Hi all, have a strange thing going on that is continuous with my Z. It seemingly does not want to keep charging the battery as the meter shows it charging at between 10 and 12V. Then what appears to happen is it goes into a mode whereby it will only drive at idle, without the ability to rev unless I place it into neutral then it will rev. I will pull it over and wait a moment, then all of a sudden it will rev again and drive on. Replaced the alternator twice (although be it with an oreillys alt probably not the best) and still this is going on. Whats also weird is how it can take a fully charged battery and deplete in no time. At one point during the night we could also se that the connection point at the alt was glowing. Might we have fried the power line going to the alt? The car has been a dream driving up until this point and now its been doing this on and off for more than a year. What to do? Thanks!

Scott

MicVelo

Troubleshoot-

- First thing is to check belt tension. If this isn't tight enough and/or slipping, obviously, this is an issue; however remote it may be.

- Check/clean your terminals and the quality of the cables (including the alternator-to-battery cable; especially since it's drawing too much amperage causing it to overheat. This is caused by a short, likely at the cable connect.). Also pay particular attention to the ground on the side fender. Remove, sand/clean. Tug on the cables, invisible rust breakdown can cause the terminal to separate providing bad ground and charging weirdness including a short. (Ask me how I know.) If you don't wish to lose any settings, e.g. ECU, radio tuning, clock, etc. I suggest you get a power keeper like this.

Check battery itself. Best to take the whole car to a place (like Pep Boys or Autozone or wherever batteries are sold) where they can load test the battery and charging system. I find it difficult to think that two alternators (plus original) and their regulators are all bad. Points to something else. Could be as simple as a bad cable. But if the alternator is only outputting 12v under load, you'll need to remedy this as needed.

The reason your car is behaving like this is clearly an electrical fault. The VQ35 (and most modern engines) rely heavily on stable power. Yours obviously isn't and wreaking havoc on the FBW (throttle control), ECM, and who knows whatever else.

Good luck.

caliwebman

Thanks Mic! Those are some awesome tips and are very much appreciated. And yes now that you mentioned it, there was a time in which the belt was slipping/squeaking leading me to believe the tension was wrong. Will deal with this asap! Batteries have been tested and charged as needed, I say plural because I have 2 brand new batteries, one I keep in the trunk because of the challenges currently. We'll run the lines for inspection as such and clean any dirty terminals. Think we'' replace the stock hot wires going between battery, ALT and starter, to perhaps 4 or even 0 gauge. Thanks again for the feedback. -s

icer5160

iTrader: (4)

If you saw the main positive cable to the alternator "glowing", there's a chance you have a serious short/fault somewhere. This might explain the battery drain after such a short period of time. I would check your fuses (both in IPDM and cabin), make sure some knucklehead (previous owner or shop) didn't replace a 7A or 10A fuse with a 15-25A. Essentially make sure all the fuse ratings match with each circuit as specified in the manual or fuse chart on the covers. Some crazy people have tried to resolve repeat blown fuses by slapping high amp fuses in their place, the new fuse may stop blowing, but then you risk wires melting and causing a potential fire or serious parasitic drain issues to the battery. Always trace down the root problem to blown fuses, that's why they exist! I sort of skipped ahead and say this because if you had a serious wiring fault, under normal circumstances the offending circuit would have blown a fuse by now. So w/e is causing this problem is either not over a fused circuit/link or has the incorrect rated fuse.

Late model charging systems are variable load, the alternator will work harder only when needed. If the battery is healthy, the alternator isn't stressed much, but if your battery is constantly low on charge, then the alternator will run at 100% duty cycle.

If you're seeing 10-12V on a new battery and new alternator, I suspect you have a serious wiring fault which is causing a lot of voltage drop & draining the battery which leads to killing the new alternators. I would get this checked by a pro right away if you don't know how to trace down wiring faults, you could be facing a potential vehicle fire, melted wiring, fried electronics, etc..
Good Luck!
-Icer

caliwebman

Thanks a bunch Icer! I absolutely love your format of going after the wires via checking fuses! I am going to just that to ensure no one placed higher rated amp fuses in any of them. Should these various basic things that you folks have suggested do not get me anywhere I got a really good buddy who has worked for years in the Porsche, Audi, Benz, BMW arena and he's a whiz with electrical,.,, so I am just going to hand it all off to him and pay the bucks as I am out of attempts a bit burned out from it all, and well, ready to call UNCLE! Never the less, I thank you dearly for the great feedback and will report back regardless of the route thats taken.

You are appreciated!

Scott

caliwebman

Again, thank to all of your feedback we are making headway!

So after completing many of the items you good people here at my350 suggested I went ahead and took her into an old friends place who is an awesome mechanic. Sure enough the 1st thing he went for was a trace of the electrical which found nothing really wrong. Next, he began to take of the positive wire hooked to the ALT and found that it was loose to begin with. Once off he found that the electrical arcing has apparently malformed the lower part of the threads of that bolt that you place the positive line onto, this would not allow for the nut to be tightened down and hence was the reason for the low voltage. He then placed the hot wire on the bolt and followed with a couple of washers and then was able to get the nut tightened down. Pulled it off the rack, started 'er up, and BAM charging commenced at 14.8 or so, I have never seen it that hot!

So I get in the vehicle take off, and no more than 5 miles later she starts getting hot. Temp gauge not pegged 3but very high. I DID notice when we last started the car that there was squealing so I am fairly confident I simply must tighten the belt. on the drive home, once on the freeway the temp gauge came down to normal, then once off the freeway it again got hot. Are you guys of the same mindset as me on this? I hope so, tomorrow will tell!

Thanks again you guys, you all are awesome!

Scott

MicVelo

Lack of airflow while stationary. Check your fans. Check operation, blockage. Fairly “common” issue.

Not sure if you said so, what’s mileage on the car?

caliwebman

Well, had a look and feel of the belts and it sure seemed that the AC belt was a bit looser than it should be. Jacked 'er up and tightened that baby down, fired 'er up and let it idle for 30 mins, and Wvala! No more over heating, and not a squeal in site.

For some reason I assumed the intermittent heating I would get sometimes was in direct correlation to the overheating problem, hence I felt like if I could fix the overheating and belt squeal it would simultaneously fix the heat not getting hot. I was wrong, I think. I mean, I haven't driven it all, just tested with the 30 min. idle so we shall see if the heat comes back.

Again, thank you guys, couldn't be doing this without your help.

Scott

caliwebman

Yes Mic, thanks.

91,000 on her.

caliwebman

Damn! Took her out for a spin and she started overheating. There was still a little squeal of the belts at start up but quickly went away. Am going to check and tighten the ALT belt. Picked up two new belts just in case. You know, I noticed the heater being intermittent a few days ago. Now am beginning to think that this overheating challenge has to do with air being in the cooling system. I know that the 350 has this weird scenario when air gets in there its not only overheats but it is a ***** to get the air out. That said, does anyone have a best in class process to getting the air out?

Re tightened ALT belt. Drove it, still overheated. Reading just below the 2nd ticker below the H.
FANS WORKING!
Over flow container is slightly bubbling/boiling when I shut the car off.
They took the bleeder valve out of the car.
If I am standing at front of car looking at motor, the top left rad hose is hot, while the middle right rad hose is cool to the touch.

Thanks again Gurus of the 350!

Scott

icer5160

iTrader: (4)

Hello Scott,

1) Tightening accessory belts won't help with cooling/overheating. The 350Z water pump is run off the main timing chain, inside the timing case. The radiator + AC fan are both electric.
2) If your lower radiator hose is not getting hot, then you most likely have a stuck/failed thermostat, or large pockets of air trapped in the system (middle rad-hose is probably the crossover, and should be hot).
3) The coolant system is fairly easy to bleed when you use a spill free funnel & make sure to open up the bleeder valve when filling the System. The bleeder is located on the heater hose (while looking at the engine...back left of the engine, near battery compartment). If original, it should be a black plastic T style coupler, with a large philip's screw plug. These can crack/break easily from age when attempting to unscrew the plug, so I recommend purchasing an aluminum replacement unit.
4) The thermostat is fairly easy to replace, just follow the lower rad-hose to the engine block, that's the thermostat housing. Just replace the entire unit + gasket. Hardest part is aligning the bolts with the gasket purely by feel (no line of sight).

After parts are replaced and coolant system is as filled as you can get it with a spill free funnel and opening the bleed port. You need to run the engine through multiple hot/cold cycles, occasionally blipping/revving the engine to help purge out the air bubbles. This process can take 15-25 minutes per cycle with enough time between cycles for the engine to cool off.

You mentioned they removed the bleeder valve? This is a terrible idea, and will result in large amounts of air getting trapped in the coolant loop (usually in the heater core). As you drive, that air will move around and can get stuck in other more critical parts of the coolant loop. Unless you completely delete the heater core from the loop (Not uncommon for track cars), the bleeder valve/port is a critical must have.

You also mentioned the coolant overflow is bubbling/boiling when getting hot. Is it changing colors at all? Like turning brown or anything like that? Does the level always return back to it's previous "cold" starting point? *Some* activity in the reservoir is normal while the vehicle warms up and achieves optimum temps. You can actually watch the level rise as temps climb and fall each time the radiator fans kick on. This is normal expansion and contraction of the fluid. What would be abnormal is excessive bubbling/gurgling or color changes to the fluid. That would indicate combustion gases entering your coolant loop due to a blown head gasket (NEVER GOOD). I sincerely hope you never overheated the engine to that extent.

Good Luck!
-Icer

caliwebman

Thanks for the detailed reply and info Icer!

As far as the bleeder missing, I have been able to nix the airlock a couple times before so I dont see how you can say that without the bleeder valve its impossible to rid the air from the cooling system.

Let me ask you this...

If that right hose, that goes to the thermostat, is cold, and I cannot seem to get any cabin heat going, would that not clearly suggest that it is the thermostat being stuck closed???

Also, it cant be a blown heads gasket as the heat will come down to normal at times, then go back to hot. I thought a blown head would make it overheat constantly.

Trying really hard to get this sucker to stop over heating as I have come across a deal of a lifetime on a 2019 370z Nismo, and they are willing to take a big ch=unk off the 370 if I trade my 350 in. Only prob is I need this sucker to no longer run hot., UGh frustrating.

caliwebman

Just to update:

Jacked the front end up. Placed spill free funnel at radiator. Turned on heat in cabin. Started and and it proceeded to take a half container of fluid. Letting it cool it took more. Getting ready to fire it up again as I will also perform revs to 2500 and back to 0 3 times once hot then let her cool and try again. Still after 1 r9ound no cab heat. Hose going to TS still cool.

caliwebman

I hope, "Final" update.

Jacked the front of the car up, installed drip free funnel, filled it. Placed heater on. Start vehicle, get to operating temp, rev to 2500 for 10 seconds, repeat 3-4 times. The radiator guzzled coolant, refilled funnel 4-5 times. Noticed while running warm that the funnel would not just relieve air bubbles, but would get hot enough to come back into the funnel; one time almost over spilling from being to full but I turned the motor off in time. Let it cool and watch funnel. Refill as necessary. Refilled funnel 2 times - very little. Repeated this whole process again. It took little coolant, showed little air bubbles. Took her out for some high revs, immediately noticed heater blowing hot. Performed 2x quarter milers revving to near redline... chirping through them gears.... and the temp gauge...... did....... NOT................. BUDGE!!!

Of course, not sure if I am out of the woods yet. You know how these things go.

Hopefully, with God's grace, next time I post in here I will finally be a true Nismo 370 owner. Can I get a wooohooo!

Sorta cringing thinking about giving up my 350, especially after how raw and beautiful those 2 quarter milers were. ouch!

Icer, everyone involved, thank you good people. Without you these things would not be possible.

Love, light and power.

Scott

icer5160

iTrader: (4)

The answer to your 1st question is simply "No." You should still get heat in the cabin, coolant still circulates through the engine even with a closed thermostat. The cabin heat should get insanely hot if you had a stuck thermostat and the engine temps were climbing above normal.

The answer to your second line of reasoning is correct. If you had a badly blown head gasket, then yes, the engine would not only gulp down/burn coolant, but it would also overheat due to the loss of coolant and introduction of gases/air into the coolant loop. It all depends on how badly a head gasket has failed. Sometimes you only loose coolant without oil & coolant mixing in the crankcase, other times you get chocolate milkshake in the crankcase.

Lastly, I never said it was impossible to bleed air from the engine without the heater hose bleeder port. I said it was a critical must have for non-track car usage. Nissan engineers put that bleeder port there for a reason, as you just discovered, not having & using it resulted in a massive amount of air getting trapped in your coolant loop. No cabin heat and an overheating engine. I suspect the thermostat may not have been opening at all or it was opening very late because of this.

As you just proved, bleeding most of the air out can be done without the bleeder port, but it takes much longer (more cycles, more revs, etc). I highly recommend driving the Z for at least a week and monitoring the overflow tank level after the car has completely cooled off. I just recently went through a coolant refresh on my Z and even after using the funnel and bleeder port, I think I had to come back and top off the reservoir another two times over the next few days of drive cycles. Very small pockets of air were still being purged (I made sure to check for leaks as well, none were detected). To be clear, the top offs were very minor (maybe 3/8 - 1/2" below the MAX line each time), still that's a fairly decent amount of air that was displacing the fluid. After the 2nd top off, I didn't see the level drop any further (system has stabilized).

Aside from checking the reservoir level, see if you get nice hot air from the vents while idling (no high revs). If you do get nice hot air, then that's a solid indicator that the bulk of the air has been purged. If you only get hot air after revving the engine, then you still got a large pocket of air settled/trapped in the heater core.

Congrats on sticking with it and seeing this through! I'm curious to know what kind of trade-in offer this dealer is giving you for the 350Z. Usually dealer trade-ins are a rip-off, you could probably do better selling privately. I hope the Nismo 370 is cherry. The Z34s have their own set of quirks and issues, one of them is the gallery gasket failure. So do your homework on them and make sure the common issues have already been addressed/fixed or prepare to tackle them yourself.
Cheers!
-Icer

i8acobra

iTrader: (6)

You have a stuck thermostat. If the funnel overflows, it's a stuck thermostat. Take it from a former dealer tech. It's a stuck thermostat. In case I haven't mentioned it yet... It's a stuck thermostat.

icer5160

iTrader: (4)

Hi Cobra,

Normally I would completely agree, but we don't know how much coolant was added into the funnel at cold start. It's entirely possible the engine was still warming up and the OP simply overfilled the funnel before the thermostat had a chance to open. Based on my own experiences, the funnel level will rise considerably as the coolant warms up from a cold start. Once the thermostat opens it will rapidly drop, perhaps the OP didn't wait long enough and had the funnel overfilled. On a cold engine, I only fill the funnel up about 1/4 to 1/3 since I know the heat expansion can bring the level up to 1/2-3/4.

If the OP took the car out for an Italian Tune-up and it wasn't overheating, I think that's proof enough that the thermostat is working properly and air in the system was the root cause.

If it was my car, I would replace the radiator hoses + thermostat at a minimum just for peace of mind though.
Cheers!
-Icer