I just can't figure it out. Out of no where she starts overheating on me. But it's only when I jump on the gas or rev up the engine. If I take it easy she dosen't blow her top. As soon as I lay the hammer down you'll see the temp guage jump all the way over to the right past the 270 mark. I mean, the overflow tanks cap won't stay on tight but that really dosn't matter. Am I pinching off one of the hoses when I twist the engine or is there something else it could be? Please help anyone.

Oh and I have replaced the thermostat to a 160 hoping that would work.

 

check the obvious...have you flushed your radiator? This helps out, make sure you put in coolant and not just water. Check your fan clutch. If you grab the fan blades and spin the fan, it should barely spin. If it spins freely, or spins more than a quarter of a revolution, I would highly consider changing it out for an autozone replacement. The one for my 240Z only cost $40, and has a lifetime warranty. If those two check out, and your hoses are in good condition, consider getting either a new radiator or have your current one cleaned out and rodded. It should cost you no more than $40 to have your radiator gone through and cleaned, and that also should include soldering any holes in the radiator.

My Z would overheat like crazy, and I tried everything until I realized the fan clutch was the problem. I took the one currently on the engine off and compared it to the one at Autozone, and it was a night and day difference.

Keep in mind that there is probably a good chance that the head on your Z is probably cracked/warped by now. On my old engine, the head cracked, but would not leak until the engine was warmed up to operating temp. This caused water and oil to mix, which ended up causing me to spin a rod bearing. Pull your plugs out after you drive the car and allow it to warm up, and have someone crank over the engine. If any water shoots out, there is a good chance that you have cracked your head. At least that's what my engine did.

Good luck!

 

if the needle is "working" its way up to the red zone then I'd check the fan clutch and make sure the radiator is not plugged up inside or out (check the fins) as mentioned above ^ . Your engine creates more heat when you ride it hard so it makes sense that you would tax the cooling system a little more when you get on it. But overheating like that is not normal.

If the needle is litterally "shooting" up to the red zone as quickly as the revs are climbing then I'd suspect an electrical issue (car is not actually overheating).

Also, make sure you dont have an exhaust leak near the thermostat housing.

 

Yeah, I forgot to say that I have a brand new radiator in it and have done a complete system flush.

As for it being a 'electrical' problem...i highly doubt it b/c everytime I get out of the car when it shoots across the guage I pop the hood an there is steam spouting out.

I'm gonna check by and see about the fan clutch and new radiator cap to be on the safe side. Thanks for all the help.

P.S. I do have an exhaust leak...it's called open header.

 

I finally got some of her tore down and I found out that the lower radiator hose has a worn spot from the altinator and is about to bite the big one. The fan clutch is good...thankfully.

Now I'm just wonderin if it's my water pump. Hopefully not b/c it's kinda expencive...but I guess thats why I work at Advance Auto.

 

what brand of thermo did you get? OEM? if you didn't get OEM go get one you'll see the difference but if you want a 160 OEM order it from a first gen the second gens only list down to 170.




tbs

 

Just found out that my friend...who I had put on the upper and lower radiator hoses also thought it would be a good idea to take out my thermostat out. But I replaced it with the 160 from the 1st gen. (Lucky that the stealership...I mean dealership had one that a guy ordered but never came to pickup and pay for.) Hopefully that'll fix my overheating woes.

 

check to make sure the hoses are collapsing. Have some one get on it while you watch the hoses or vice versa.

 

Hopefully you haven't ruined anything with it overheating.

 

Everytime the temp guage shot up I would pull over, let her cool, and go again....so hopefully I didn't ruined her. Even if I did...I have a L28ET that I'm buildin in my garage that I could throw in her or just wait untill my RB25DET gets here next week (hopefully).

 

There is also another thing that is overlooked, and that is the fan shroud. Do you have one on your ZX? If not, that can cause overheating issues also. It did with my ZX too. But usually only on the freeway, and the temp guage would shoot up quick. And it was mainly because of the air going over the engine instead of on it. Because of the way the car is shaped. And without the shroud, the air doesn't hit where it is supposed to. Also I got the brass thermostat, and that helped a great deal.

As for the water pump, mine was $25 lifetime at Autozone. And it works awesome.

 

Yeah that was what I did for my Z31. I got an autozone water pump and that thing worked really well and only ran me $25.

 

The fan shroud is on...I put another thermo in (160*), new upper rad hose, and gettin a new lower rad hose tomarrow (had to order it). Hopefully don't need a waterpump and the fan clutch is good....so hopefully that'll fix the problem.

 

check whether the alt belt is rubbing on your hose while running or accelerating--my z31 was doing this--lower radiator jose holes regularly--i had to make modifications to make more clearance for the belt--it worked.

 

It is...but I'm fixin the problem tomarrow as soon as I get off work.

 

http://www.autopartsauthority.com/we...GMB+Water+Pump



go here put in the make model and choose pumps. A GMB pump for 33 bucks. That’s what I bought when I replaced mine. I went with GMB because there supply most of the Japanese OEM pumps. I'm not 100% sure that they sell to Nissan but there pumps are very high quality and look just like the OEM I pulled off my parts car. I've just had some bad luck with aftermarket junk and makes you want to buy more OEM parts, but the price sure sucks. OH BTW stay away from BlackDragon Autos front ball joints once again aftermarket parts don't fit right.




tbs

 

I think GMB was the brand I got from Advance Auto Parts for $25 for my Z31.

 

UPDATE: Finally found out what my problem is. My so-called new radiator is clogged completely...it will not flow at all. There was a defect about 1/2 way down the radiator...the metal melted together during manufacturing to basically cut off the other 1/2. I'm going to take it back to the shop I bought it from to get my money back and get a good radiator that isn't defective.

And if that dosen't work....you'll be seeing a bunch of parts and/or the car up for sale real soon b/c I have basicly redone the whole cooling system (i.e. water pump (which I got for $14 new ), upper/lower rad hoses, radiator, fan clutch, and 160* thermo). If there is anything I left off...let me know and I'll check it.