Trying to find where i could see the water pump leak. from under the engine?.
anyone have a good picture or description?

 

Just behind your AC compressor where the upper oil pan meets the timing chain cover. I'll see if I can find a pic...

 

 

You won't be able to actually see the pump itself as it is hidden behind the timing cover. That is the location for the weep hole.

 

long story.
Car overheated the other day ,when i got home i heard coolant bubbling. oil was fine.
Let it it sit and refilled the RADIATOR and tank.

car drove fine.
2 days later driving too work. heard coolant bubbling.
let it sit all day. and filled it up. assumed i had a leak.

drove it home. let it cool of and filled it up in the morning AGAIN..
Started it in the driveway. no leak. no over heat.. ..NO LEAK

Drove it a few more days. no issues.
got home again to bubbling tank.
filled it again. tank and radiator.
Oil is fine.

drove it the next day and over heated SUPER quick on the way home from work.
stopped the car. let it sit for 10 minutes.. and could only go about 1 mile before it supper heated again.
stuck on highway. Towed it home.

Started it again in driveway with system refilled and NO OVER HEAT. No Leak.
took wife for short drive and it over heated SEVERLY in about 4 miles. stopped and let it cool and limped back to the house.
Suspected Thermostat sticking. allowing it to over heat. found lower radiator hose "cool" while upper very hot. ( ordered new thermostat)

Removed thermostat. removed thermostat guts. reinstalled and re filled coolant.

car drove fine for 3 days.

Got stuck in traffic a bit on the way home last night and it immediately went back to OVER HEAT.
filled it up again.. confused now. thought maybee it didnt like being stuck in traffic with no thermostat ( thermostat is on order)

Drove it to work today. all highway. COOLANT temp stayed fine.. lower middle area.
ENGINE got EXTREMLY hot. i could smell it. and i watched the oil pressure go down some while driving. lower than normal.
I could tell it was HOT. but the gauge readed normal.

I got off the highway and hit the clutch and pulled out of gear. oil pressure went to zero and i immediately kill the engine.

Letting it cool and coasted in to a McD's.. going to look at it again tonight. hope i can make it hope.

oil looks FINE. recent change. No obvious or noticable leaks. or coolant smell or steam when over heating.
Gutted thermstat at this time.
Severe engine over heating on highway. or in traffic.

Suspecting maybee clogged radiator? or some how the water pump blades came off shaft ? not moving coolant?

if the fans failed then crusing 65-70MPH in 6th should keep it cool. but it over heated severely.

Could use any advice or help.

 

Sounds similar to a situation I had a few years back. I had the same intermittent overheating issue and could not go more than a few miles without having to stop.

I began with checking the fans. Nissan programs them to kick on low at around 208*F and high at around 212*F (mine were 208.4* and 212.1*, respectively) If you have an OBD scanner with live data capability, connect it, let the car idle, and see if they kick on at or around those temperatures. Don't let it exceed 210* if they don't kick on. If they do turn on, they should drop the temperature back down to 190-194 * before shutting back off (mine power down at 194.1*). If they are not functioning properly, do basic troubleshooting. This may not be the problem since you mentioned temperatures not dropping when coasting in 6th (fans are useless above 30mph anyway), but may add to it.

You mentioned that you removed the T-stat and gutted it. One trick that I did was to place it in a pot of hot water. Mine opened up just fine, but I still replaced it ( better safe than sorry.)

What catches my attention is that you mention the lower radiator hose is cold. This leads me to believe that it is a clogged radiator, or much more unlikely, the water pump. Typically, this can be caused by a failing T-stat, so we will see if your new one fixes the problem, but I am leaning more toward a clogged radiator.

What year is your Z, and what is your mileage? I had to replace my radiator a few years ago (03' with 100k at that time). My OEM unit began leaking so I debated on going with the Koyo aluminum radiator and an external trans cooler (I have an auto), or an OEM-style Mishimoto radiator that was about half the price and identical to OEM. The Mishimoto unit ended up failing within weeks, so I just went with an aluminum unit. After the radiator replacement, and a proper and complete bleed, I am about 30k miles in and she runs beautifully!

I can't stress enough how important it is to FULLY and COMPLETELY bleed this system. The Z cooling system is notorious for being difficult to bleed. You really have to do a few cycles of bleeds and I can tell you that you will pretty much need a spill-free funnel to really get it worked out.

 

Last night i walked back to tthe car where i parked it.
I grabbed a large McD cup and started putting in water for the ride home.
after the 3 cup the water started coming out as fast as i could pour it with the cup.
from the ddrivers side front of the engine area near the compressor.
sounds like a leaking water pump.
I towed it home and have not started it. I know it got hot. i know it was low on oil pressure and im a little concerned with what the engine will sound like once its restarted.

I will restart it tonight and pray the engine isnt hurt. followed by a tear down on friday to get the water pump out.
I will just replace the radiator with a napa unit while im there. its only 150$.

At this point im concerned for the engine due to the over heat.
and the fact it did not want to restart after it got hot and cooled off for 20 minutes.
I am hoping i just vapour locked the fuel in the rail . and not that i hurt the rings/piston/walls with the over heat and lost compression.