WHen I drive my 96 SE 5 speed above 75 MPH the temp guage slowly creeps past the half way mark on the guage, this is with the AC on going up a slight incline on say the freeway. Is this normal for the guage to go above half? It even goes as high as 3 quarters of the way on the guage? should l be concerned?

I opened the hood and checked when it was running warm, the fans are on high and I pulled on the throttle cable and found the lower radiator hose sucking in. like it was squeezed but doing it by itself. Anybody have this problem or is it even a problem.

I don't know if the guage is suppose to move like that, it never hit the top line though, and this car had the thermostat, water pump and both hoses replaced with nissan parts, anyone have any thoughts on this?

 

I don't think the lower hose is suppose to cavitate (collapse)... If you hadn't changed the coolant recently and replaced the hoses, this may be a good time. You can't go by the color of the coolant to check it's condition. The thermostat fails in the "Open" position so maybe it might be:

Check the condition of the radiator as well. If there is a lot of "build up" seen through the radiator cap then you may want a new radiator. Unless you use hard water I don't think this a common problem, though.

 

the fluid is clean, it was changed when the thermostat and water pump was changed along with both hoses, there is no buildup what soever, the thermostat was changed the first time, the problem occured, then I changed it again and bought another thermostat still the same thing!!!

 

Sounds like you have air in the cooling system.. you need to bleed the system to get all the air out.

 

is there a proper way to do it other than letting it idle and slowly adding coolant? I ve been driving the car like this now for almost a month now.

 

I want to know this as well my 3rd gen had a little plug you could open

 

I think what you want to do is let the car cool down completely, then open the radiator cap, and start the car... let the car warm up - i.e. reach operating temp - so that the thermostat opens up...Squeezing the hoses while doing this sometimes helps. Set the heater to max. Most of the air should escape, i.e. you'll see the fluid level drop in the radiator. Turn off the car, top it up with 50/50 coolant/distilled water mix and repeat. You may have to wait for it to cool off and repeat this a few times... but that should do it...

You might want to use this as a chance to drain/fill/flush the cooling system...

 

but I ve been driving the car for over a month and the level in the radiator has not changed and so on, shouldn't it have gone down by itself by now?

 

No - because you have not been driving with the radiator cap off - the cooling system is (supposed to be) sealed - no air in, no air out, no fluid in, no fluid out, except through the reservior, or radiator cap or drain plugs. When everything is closed, there should be no way for air to get in... thats why you have to take the cap off, and then warm up the car - so that the trapped air can bubble up and escape.

NOTE: DO NOT drive with the radiator cap OFF.... just let the car run at idle when you are doing the bleeding.

 

I ll try it and see what happens, how much air could possible be in there you think?

 

No way to guess.

 

This may or may not help...
I park the car on a steep incline (nose up) so the radiator cap is higher letting air collect near the cap. This sometimes helps as does running the Heating system for trapped air like suggested above.

 

Even better if you can do what ^^^^ he says, i.e. find an incline.

 

man its a long process, so if you see any bubble coming out, its trapped air?

I got bubbles to come out but I could not fill even a cup of water back in, and the lower hose still callapses when I pull on the throttle. I am running the ac and turning it off and running the heater and turning it off as well

 

I have the overflow bottle a little bit over the upper full line, does that matter?

 

I still dont' understand why the lower hose callapses, anyone have any idea about that? and is this a very bad thing? I just replaced both hoses as well as the thermostat and water pump

 

No the overflow bottle being higher than full does not matter.. yes - its a long process - well once your thermostat kicks in, and the coolant starts circulating you should see the level drop pretty quickly...check the upper and lower radiator hoses - do they feel hot - if they do, then that means the thermostat has opened... let the car keep running once you reach that state.

 

yea I ve done all those things and both hoses get hot, the fans kick in, so how long am I suppose to keep it running for and should the AC be fully on or the heater on full blast on the hottest position?

 

I'm kinda concerned about the collapsing lower hose...

It implies that the water pump is "starved" for coolant to pump so it's sucking the hose "dry"... are you sure you don't have a restriction at the radiator (such as "lost" rag... exaggeration)?

 

That was my next thought... since he also replaced the water pump... and the hoses... its almost like coolant is not getting from the radiator through the engine and back around - so its sucking the hose into a vaccuum.. you might want to pull the hoses and check for restrictions like Chunger implied...

And you do want the HEAT on, not the A/C.

Did you install the thermostat correctly? With the little valve at the 12 o'clock position (if I remember right).

 

I am pretty sure the thermostat only goes in 1 way, I am thinking of pulling all the hoses out and taking the radiator out and having it rodded out.

 

I am still having the problem, can't seem to figure it out, can anyone help, the last thermostat I installed was a 21200-31U03

 

anyone have any thoughts on this? I replaced my radiator cap today too, still happening.

 

It would probably be best if you take it down somewhere to really diagnose it rather than all the arm chair diagnosing here...

My best guess is a clogged radiator but you said you would have it rodded out.

 

arm chair diagnosing, that is what these forums are for! So I dont' have to pay someone a lot of money to do that, unstead to hopefully find someone that has had the same problem and discuss it.

As it turns out, when I took it to get rodded out, the guy couldn't even put the rods in because it was so clogged!!! So I just went and spent $150 for a new metal lifetime warranty radiator, solved my problem finally!!!!!

 

There you go... I am surprised that you didn't find a rag down in there... Hope you are using distilled water to minimize it happening again.