Coolant loss

[The Silent Genius]

Hey everyone, just signed up here (made an intro post in the General section)

This past saturday I was cruising down the interstate, headed to my buddy's dyno shop and I look at my water temp gauge and it was almost to the top. I immediatly shut the engine off and coasted to the side of the highway. Top of the motor was cool to the touch and I could see coolant all over the bottom of the car. Towed the car home and today I go out to find out the problem. I poured 2 liters of water into the radiator, and nothing leaked out. So, I started the car up to pressurize the cooling system in hopes of the problem revealing itself. No leaks anywhere around the radiator or motor, there is, however, water spitting out of the exhaust. I'm guessing turbo seals since everything in the car is pretty much original. Any other ideas?



edit: is there a coolant system pressure tester available for these cars? I have one but it seems to be only for domestics.

[NissanFairladyZ32]

Water coming out exhaust ?

You could have blown a headgasket .. check ur oil it should be a light brown, not milky

if not its prob one of the million coolant lines the z has, hose may have torn or came off

is the car idleing and running fine except the overheating ?

[NissanFairladyZ32]

and yes there is a pressure tester for nissans, you need one

[skypad]

Yeah like Fairlady said, there is alot of coolant hoses running throughout the engine, including several under the plenum... could be possible that your thermostat is stuck/shot as well..temp sensor connector could be loose or corroded, but sounds more like a hose leak BUT keep in mind that could be due to a build up of pressure from a faulty thermostat..

[The Silent Genius]

I did the throttle body coolant bypass last spring, so that rules those lines out. I'm liking the possibility of the thermostat being stuck though, maybe all that mess of coolant under the car came from boiling over. The oil looks fine by dipstick check, i will drain some from the pan and see.

[skypad]

On my 93' NA you have a TT but should be relatively the same, the inlet/outlet pipe had cracked and was leaking there, but in this case it was actually shooting out from the hood several feet so if it is that pipe it's a small crack but i hope for you that its not. Easy fix and all, but more costly than a thermostat I believe beings it's aluminum, although I replaced both at the time..eh keep us updated I'm curious as to what it is! Good luck!

[vitaminZ]

top up your rad..and leave the cap open..start your car to get rid of all the bubbles..IF you see its bubbling a lot= head gasket goooooooone

[es.biggs]

It's probably not a head gasket, but don't rule that out. I would just jack the car up, start it, and find the leak. VitaminZ has a good idea to test your head gasket. If you are really worried about it, the best way to test it is a compression test.

[The Silent Genius]

well, i already have everything pulled to replace the t-stat, short of one last allen head bolt that I need to get a socket for. Once replaced I will check compression and also running with the cap off to make sure the head gaskets are ok.

[The Silent Genius]

got the thermostat out today and boiled it in a pot of water on the stove. it didn't open up, so there is the culprit. Thank you for pointing out the thermostat for me. I was getting ready to pull the turbos thinking the internal seals were done. For some reason, whenever something goes wrong with this car, I overlook the simple routine things and think the worst and most complicated things.

[The Silent Genius]

spoke too soon. just put everything back together and started to refill the radiator, and it started leaking somewhere on the front of the motor. Have to take it all back out and try to find where. There aren't any freeze plugs in the front are there?

[es.biggs]

I don't think there's any freeze plugs in the front.

Are you sure you made a good seal when you re-installed the hard pipes over the thermostat? It might be that, the water pump, or the radiator hoses. When is the last time either of those two were changed?

edit - wait did it start to leak before you started the car, just when you were pouring the coolant in? I would look at the lower hose or the bottom of the radiator if that is the case.

[The Silent Genius]

I don't think there's any freeze plugs in the front.

Are you sure you made a good seal when you re-installed the hard pipes over the thermostat? It might be that, the water pump, or the radiator hoses. When is the last time either of those two were changed?

edit - wait did it start to leak before you started the car, just when you were pouring the coolant in? I would look at the lower hose or the bottom of the radiator if that is the case.

That's the thing, I didn't start the car at all, i was pouring coolant back into the radiator and started hearing drips, I crawled underneath and I could see it dripping from the front-center of the engine. Both hoses were dry. I think maybe I didn't get a good seal on that thermostat pipe, because before I even took anything apart I topped off the radiator and ran the car, and nothing was leaking anywhere by the motor.

[es.biggs]

That's probably what it is. Sorry if you have to take it all apart again man, that just sucks

[The Silent Genius]

I think it's the water pump leaking. I took everything apart and poured water into the thermostat pipe while it was still attached and couldn't see anything leaking from it, but the leaking still showed up from behind the crank pulley.

[The Silent Genius]

just wanted to say that the water pump has been replaced now along with the tstat and all is well again...for now at least.

I think my old water pump was actually fine. I think what happened is that the tstat slid down a bit as I was bolting the water neck back on over it, thus sitting between the neck flange and block preventing a seal and causing the leak.

[es.biggs]

good to know you fixed it, also I checked my block the other day and I was wrong, there are one or two freeze plugs on the front!