Kush's 87 Sev6

[PURPLE_OG_KUSH]

Ok so I bought my s12 3 days ago and so far shes treating me perfectly. Running strong, nothing's falling off etc.

But there are a couple problems, and I'm hoping you guys can help me out.

First, the oil pressure gauge is almost always reading 0. sometimes it will randomly move up to under half or so, but it never stays there for more than 5 minutes before going back to 0. I have checked the oil and whatnot and everything is fine. I don't know if the gauge is bad or what but I have no idea where to begin diagnosing this issue so help would be appreciated.

Second problem is the coolant system, or, i suspect, just the thermostat. Sometimes while driving the temp gauge will shoot ALL the way up to H out of nowhere, just cruising at around 2k-2.5k rpms, not pushing it or anything. And then it will usually go right back down within a minute or two. Bad thermostat? Or more serious problem?

Also, if you haven't seen the car yet, I have a bunch of pictures in the Welcome area under my topic.

[J-man]

Ok so I bought my s12 3 days ago and so far shes treating me perfectly. Running strong, nothing's falling off etc.

But there are a couple problems, and I'm hoping you guys can help me out.

First, the oil pressure gauge is almost always reading 0. sometimes it will randomly move up to under half or so, but it never stays there for more than 5 minutes before going back to 0. I have checked the oil and whatnot and everything is fine. I don't know if the gauge is bad or what but I have no idea where to begin diagnosing this issue so help would be appreciated.

Second problem is the coolant system, or, i suspect, just the thermostat. Sometimes while driving the temp gauge will shoot ALL the way up to H out of nowhere, just cruising at around 2k-2.5k rpms, not pushing it or anything. And then it will usually go right back down within a minute or two. Bad thermostat? Or more serious problem?

Also, if you haven't seen the car yet, I have a bunch of pictures in the Welcome area under my topic.

the answer to your second problem is yes it is a sticky thermostat mainly what you should listen for to confirm this is when it hits all the way up to H listen for a click or pop noise that would be the thermostat popping open and allowing coolent flow

I had the same problem on my 240 KA unfortunately never got to replace it  

the first problem i'm not sure but it has either to do with the gauge or the oil pressure sensor IIRC Eminemrh_25 is having the same problem but he has a ca20

^like I said probably that is one of the two but let someone else chime in with thier .02 before you take my words to heart

and if you ever need a place to work on it my garage is always open to a s12 owner

[ryan206]

Ok so I bought my s12 3 days ago and so far shes treating me perfectly. Running strong, nothing's falling off etc.

But there are a couple problems, and I'm hoping you guys can help me out.

First, the oil pressure gauge is almost always reading 0. sometimes it will randomly move up to under half or so, but it never stays there for more than 5 minutes before going back to 0. I have checked the oil and whatnot and everything is fine. I don't know if the gauge is bad or what but I have no idea where to begin diagnosing this issue so help would be appreciated.

Second problem is the coolant system, or, i suspect, just the thermostat. Sometimes while driving the temp gauge will shoot ALL the way up to H out of nowhere, just cruising at around 2k-2.5k rpms, not pushing it or anything. And then it will usually go right back down within a minute or two. Bad thermostat? Or more serious problem?

Also, if you haven't seen the car yet, I have a bunch of pictures in the Welcome area under my topic.

The Oil Pressure Gauge is what I'm having problems with now.. I haven't done anything to it yet, but will soon.. I figure its either the harness on the back of the cluster is loose, bad sending unit or a bad cluster. Maybe damaged wiring, but my wiring looks mint in my car, never seen your SE's harness..

For your cooling system, some times it isn't easy to hear a thermostat "click". Its easier to remove the thermostat and throw it in a pot of boiling water.. If it pops open, its good.. It could also be an air bubble in the cooling system, which is an easy fix.. Either jack the front of the car up, or park on a steep hill with the front on the higher side.. Make sure the car is cold, and not running, remove the radiator cap and start the car. Let it run for about 10 mins, and you might see bubbles coming to the top of the radiator and pop.. Your coolant will go lower, so make sure you have some on hand..

Sorry if my post isn't readable.. Tired as fuck...

[PURPLE_OG_KUSH]

Thanks for your guy's input, I need to get down there and start working on my car with you guys eventually. I'll let you know when I get a couple days off from work and we'll see whats up..

Gonna check for air bubbles like eminem said by parking the car on a hill before work, probably gonna just replace the thermostat while I'm at it though just cuz its so cheap. But, I have a really nooby question.....is the thermostat the lid thing that just twists and then pops right off of the top radiator hose? (The one with the small hose going to the coolant tank) or do you have to actually get in there and remove some housing and such?

Eminem, let me know as soon as you figure out the oil pressure gauge, I want to take care of mine ASAP it's kinda scaring me  
Mostly just cuz I'm a pizza delivery guy so my poor baby gets driven alot more than I want her to..

[200sxkitcar]

The thermostat is the device on the engine where the upper radiator hose connects that allows coolant to go into the radiator when it reaches proper temp.  In the V6 this might be near the radiator cap (the part that twists off), I'll refer you to the V6 guys or the service manual for that one (might want to check your owner's manual if you have it).

The other thing that is common, is that there is an air pocket in the cooling system, and when the air pocket gets underneath the sending unit, the air is hotter than the coolant, and the temp gauge spikes.  I used to have this problem on another car of mine that leaked coolant, and if it did this same spike thing I would fill it back up and it would stop.  Either way, its important that you address it, either by replacing the thermostat (probably wouldn't be a bad idea) which if you do, please, for your own good, get an OEM Nissan one; and/or check the coolant level to make sure it is high enough (ONLY remove the radiator cap WHEN THE MOTOR IS COOL!).

On your oil pressure sending unit (the sensor for the gauge) its very likely either the sending unit itself is going bad, OR, which is more likely, the connection to it- the single wire- is loose or soaked in oil to the point where it isn't connected all the time.  This would explain why it works occasionally and then stops- mine has done that, as well as a number of S12s that I've worked on over the years.  Check it, clean it real good with brakecleaner or other similar product, and reconnect to see if you have better results, if not, consider changing the sending unit (like $25 or so from most parts stores, I think most Nissans use the same one).  If you still have problems, I think what I've done, was simply removed the original connector and put on a new one (usu. just a flat spade type connection) which worked fine.

gl, and ask any more ?s you've got.  Go ahead and post some of your pics in this thread too

[vg30e_x2_200sx]

BTW that sending unit is on the side of the block just above the oil filter housing and just below the passenger side exhaust manifold. It's a real BIATCH to get at. I ended up removing the oil filter to get at it. You need a BIG wrench, but I can't remember the size. It's been a few years since I did it. It takes patience to replace it. Just take your time and all will go well. Use teflon tape on the threads. You don't want an oil leak there.......trust me.

As far as the temp gauge goes my gut says it's an air bubble. Check the coolant level and see where it is.

[PURPLE_OG_KUSH]

I have been working every single say since I bought the car so I haven't had much time to tinker, but today is my day off so I plan to get in there and see what I can..
The coolant level in the actual tank by the wiper fluid tank is about 2-2.5 inches ABOVE the MAX line. Would an air bubble cause that by 'pushing' the coolant level higher than it really is?

I just woke up but I'll take some fresh pics soon as I get out there and start fuckin' around with it.

[PURPLE_OG_KUSH]

Ok so I just tried to purge the air bubbles out of my radiator.. Not really sure if it worked.

Parked my car on a hill facing up, removed radiator cap and started her up. No fluid was visible through the cap hole until the temp got to about 2/3, and then white foam filled the hose. The foam started rising up through the neck and almost out of the cap opening before I shut the car off. The foam level went back down, so I started her up again. This time nothing happened at all until the temp got to halfway to H; normal level. When this happened, fumes began coming out of the radiator opening, but no fluid was running through the hose. The temp gauge continued to climb like it always does and I shut off the engine just before it reached the 3/4 mark. Fumes continued to come out for another minute or so.

Not really sure what to do next.. new thermostat?

[200sxkitcar]

there should be fluid in there when you take the cap off.  fill it up.

Might want to replace the radiator cap, it appears the system is not pulling in the coolant from the overflow like its supposed to.

Probably also a really good idea to drain out the coolant and put in all new fresh stuff, seeing as its probably been quite awhile.

If you haven't taken the time yet, please download the FSM from the general tech section stickies, it will help you on many things.  That fsm doesn't have the v6 car in it, you can reference z31 books if you like, but most everything chassis wise is basically the same.

[J-man]

there should be fluid in there when you take the cap off.  fill it up.

Might want to replace the radiator cap, it appears the system is not pulling in the coolant from the overflow like its supposed to.

Probably also a really good idea to drain out the coolant and put in all new fresh stuff, seeing as its probably been quite awhile.

I agree with the whole replace the radiator cap it sounds like your coolant system isn't getting sealed off to get to a high enough psi to where the coolant wont boil over plus it's cheep

so do that before you change the thermostat

and depending on the color of your coolant you probably should change it your actually supposed to like every 3 years up here IIRC because it gets soo cold here in the winter

[S-NationS12]

This brings up a problem I'm having..Oil Pressure Gauge, but mine is totally fine till I hit freeway speeds, then itll drop to 0 unless I baby it...I dont drive freeway hardly ever, but is it supposed to drop like that?

[J-man]

This brings up a problem I'm having..Oil Pressure Gauge, but mine is totally fine till I hit freeway speeds, then itll drop to 0 unless I baby it...I dont drive freeway hardly ever, but is it supposed to drop like that?

IDK why it should but first thing i would check is how much oil you actually have in the motor....if your good idk that is a weird problem maybe bad sensor?

[ryan206]

This brings up a problem I'm having..Oil Pressure Gauge, but mine is totally fine till I hit freeway speeds, then itll drop to 0 unless I baby it...I dont drive freeway hardly ever, but is it supposed to drop like that?

Mine does the same thing.. I drive 30+ miles on the freeway a week with no problem.. I think something is loose and hitting all the bumps will do that..

[200sxkitcar]

On your oil pressure sending unit (the sensor for the gauge) its very likely either the sending unit itself is going bad, OR, which is more likely, the connection to it- the single wire- is loose or soaked in oil to the point where it isn't connected all the time.  This would explain why it works occasionally and then stops- mine has done that, as well as a number of S12s that I've worked on over the years.  Check it, clean it real good with brakecleaner or other similar product, and reconnect to see if you have better results, if not, consider changing the sending unit (like $25 or so from most parts stores, I think most Nissans use the same one).  If you still have problems, I think what I've done, was simply removed the original connector and put on a new one (usu. just a flat spade type connection) which worked fine.
 

 

[nismologist]

87 se......the bottom line fastest in all stock s12s in the us of a.se power.