problem solved


 

Are the fans working? Common issue for them to fail.

 

Yea fans are working. I also forgot to mention radiator is cool to the touch all around except for cap.

 

I've never seen a water pump on a VQ crapastrophically fail and not pump water at all. Not saying it can't happen but I strongly suspect you have other issues, usually impeller blades in the pump will erode over time and you have less flow than usually but you still DO have flow, however this only happens by putting stuff other than coolant into the system (tap water is notorious for impeller erosion).

I think you still have a little air in the system, probably trapped right behind the thermostat, how far down did you vacuum the system? I usually go to like -20 to -25 psi before shutting off the venturi, the hoses will all be completely flat collapsed at that point.

Did you make sure to run the heater on max heat max fan when you started the vehicle back up?

Have you pressure tested the system? I suspect this is the actual culprit, that it isn't building pressure and thus coming to a rapid boil before heat soaks through to the thermostat.

I've been temped to drill a very VERY small hole in the thermostat for an air relief just to help get air out from behind thermostats but I've had great luck with the coolant vac the last few VQ's I've tried it on so I haven't done one yet. 1/64th bit would be ok, lets air through but very little coolant. You would need a micro bit holder to drill it by hand.

 

My typical method for burping the system is to airvac the coolant, turn the heater to max heat/fan, get the car up to normal temp at idle with a spill free funnel, then when it's up to temp drive down the road with the throttle on the floor, then back (basically rip through 1st and 2nd gear, then turn around and do it back to the shop), make sure to slam the brakes hard at the end of each pull because it will slosh hot coolant forward up against the back of the thermostat (water has more weight than air so it displaces the air when you're standing on the brakes hard like that).

Verify there is hot air blowing from the heater, usually it's blowing hot after the first rip down the road. Shut the engine down at the shop, put a fan in front of the radiator for 5min to cool it down enough to get the cap off without belching coolant. Then top it off, go for a normal drive to verify all the air is out.

 

That is kind of what I read. I had a 350z at one point and it was your typical leaking from the water pump. What I have read is that these pretty much don't go bad, but will leak or make noise. I do know that this was a junkyard motor that got swapped in about 9k miles ago. I don't know it's history so I wouldn't be able to speak for the impeller blades getting deteriorated.

I ran it down to -23, it didn't seem like it wanted to go any further down, all hoses were collapsed, I shut off the valve, then pulled the air out of the line before I started letting it into the system. I do have the heater on high.

I did pressure test the system and It held 23psi for about 20 minutes. I have had good luck drilling an 1/8 hole in some other vehicles thermostat's to let air by, and thought about it when I did this one, but I didn't figure it would be necessary...I've been temped to pull the damn thermostat out and see what happens.


I will admit that I have not tried to drive it at all since I replaced the thermostat and bled the system as it would get hot just idling. I will give that a whirl when I get off and see if I can make any more progress on it.

I will say that when it gets pretty warm (about 3/4 up the heat gauge) and I turn it off, you can hear what sounds to be water boiling or pushing on the passenger side...I agree, I mean if I watch the temp gauge, then it really kind of acts like air, but I have tried 3 different ways of bleeding it, and the vacuum way should be a for sure way of not getting any air in the system.

 

Little update. Today after work I decided to drive it as mentioned accelerating hard and braking hard. Came back and topped fluid off. Went for a drive around the block, let it warm up a bit no heat nothing. Drove it around the block again and this time it started getting hot as I pulled in my driveway.

Overflow tank was filled to the top with coolant and going out the overflow. As it cooled down it sucked it all back down while you could hear bubbling.

radiator was cold, lower hose was warm, upper hose blistering hot.

which got me to thinking. Could this possibly be a radiator cap issue, perhaps it is opening too soon and letting air in?

or could this potentially be a clogged up radiator?

 

I think your next step is to get a coolant pressure tester from your local auto parts house and see if the system is holding pressure. They usually "rent" these things for free, you just have to pay a deposit fee that you get back when you return it.

 

I have one and it held 20 psi for 20 minutes without any loss. Just put new radiator cap on and it’s a mo go. Figured I’d try it since they are cheap.


I took the hoses off for the radiator and sprayed water both ways to make sure there wasn’t a big restriction and that was a pass as well.

I pulled the hoses off when it was pretty warm so I could see if the thermostat was working for sure and it was. Sprayed water from the hose on the passenger side and it came out of the thermostat housing until it was cool enough then it closed and wouldn’t allow water past it.

 

Do your fans turn on to both low and high speed? If so you may have gotten a defective thermostat, I always try to test them on the stove to make sure they actually work before installing.

When adding coolant make sure you pour it in SUPER slowly, no faster than 1 gal per minute. You might have a very massive bubble that you can't push water through if you added it quickly.

 

problem solved


 

Ok don't try to turn the motor over AT ALL, you can easily skip a tooth and impact the piston to the valves.

It's not nearly as hard to replace the timing chain as you're thinking, it's just a lot of steps and things to remove. There are match marks on the chains and the sprockets so it's REALLY hard to screw things up, just follow the steps/pictures in the FSM.

I've never even heard of the guide above the water pump breaking.

Yes those broken components are down in the oil pan, not a big deal just remove the lower oil pan and fish them out.

There's only one option for fixing that engine, you MUST remove the crank pulley and front timing cover, that guide you pulled out is supposed to be bolted up above the water pump and you can't reach those bolts with the timing cover on. Then fish the chunks out of the oil pan and clean the screen on the oil pickup because there might be some larger pieces stuck on it.

I suspect someone had replaced the timing chain in the past and didn't properly torque down components thus why the guide bracket came loose.

 

Once you have the timing chain cover off then pull the spark plugs, put the crank pulley back on (spray some WD40 on the shaft and it easily slides on by hand) then turn the crank pull BY HAND (no compression with the spark plugs removed so it turns pretty easily by turning the crank pulley with your hands)) to get it set back at TDC, then you can make the fine tune adjustments to everything to get the match marks on the timing chains set.

 

problem solved.


 

https://www.nicoclub.com/infiniti-service-manuals

Section EM - Engine Mechanical
When looking up other stuff in the FSM the document normally starts at FWD - Forward.