GTT running hot...

[wrxhoon]

The main radiator fan is attached to the water pump housing and its a clutch fan , it only hooks up when the engine gets to operating temp ( DON'T try to hold it while the engine is going ). When you say it works , how do you know ? Its always going to be free spinning , you have to make sure it hooks up when the engine is hot .If you rev the engine when cold it will free spin , do it when the engine is hot and it will make a different soundand blow ( suck towards the engine ) a lot more air .

This overheating did it just apear or has it been happening for a while and it just got worse? when do you hear the belt squiek ?

It doesn't matter that you didn't remove the plug on the block to drain old coolant out .

The reason you do it is to get rid of most of the old coolant , the way you went about it you left water in the block . Next time you change coolant undo that plug , ignition on climate control to max ( hot )and either undo the bottom radiator hose or open the radiator plug , then flush with hose , leave it until most water comes out , do everything up then fill with redy mixed coolant ( buy ready mixed its easier and about the same price , i use 33% but you can use 50% if you like ).

If when you pull the thermostat out it works ok , you may want to buy a lower temp thermostat ( the temp should be on it ) .

Its normal for the coolant to come up when you are reving the engine , as long as it doesn't shoot up .

[NismoR34]

Ah, now I know what you mean about the clutch fan - I will test it next time I drive the car. So it obviously gets faster when it "hooks up". I am pretty sure I have heard the different sound in the past but will re-check it.

The overheating has only been recent and on the hottest days - not that many since summer started, but thats Melbourne! First time it ran hot was probably 2-3 weeks ago now, weather was hot and I had just driven the car for 2x short 20 minute runs. Coolant spat out of the over flow as it was bubbling over [in the overflow reservoir]. Problem is at that time I had put the standard Radiator cap on just the night before, which runs at a lower pressure to my Nismo one. I put the Nismo one back on and didnt see any problems until the next hot day I think, which was like a week later.

The belt squeak is usually around start-up time [from a cold start] and usually goes away not long after, say a couple of minutes.

I had the car in my garage when I was testing the coolant / revving and didnt want to get it everywhere!

You have been a great help so far wrxhoon, thanks a lot!

[wrxhoon]

Its hard to see the fan spinning faster but you can tell by the sound , it sounds different when its under load .

Another way of testing it , try blocking the radiator front ( cardboard will do ) , when the engine is hot if the fan operates as it should , when you rev the engine ( say 3-5000) you will see the radiator geting sucked in a little , that won't happen if the engine is cold .

To me it sounds like you have a crook thermostat ( but its only a guess ).

If you overfill the plastic coolant reservoir it will always overflow , even if everything is working well .

[NismoR34]

At the time of the first overheating / overflowing I hadn't touched the coolant or level in 12 months so I don't think it was related to the amount in the reservoir. Even now it isn't overfilled.

In a way I am hoping its the thermostat that's stuffed, otherwise it could be a much bigger problem...

[ed]

Running around 110 on the factory gauge is normal on a warm day.

I have since gotten my stock radiator re-cored ($350) + nismo thermostat + nismo radiator cap and even on the hottest days my factory oil temp sits BELOW 90 degrees.

On a normal day it will sit in the middle of 70 and 90. After consistent high-revs (over 4500) for around 5mins the oil temp sits a bit above 90.

It seems the 34's do run a little hotter. You could install oil cooler or do what I did.

[NismoR34]

I had thought about getting the Nismo Thermostat and may decide to get one if my current one is stuffed, thanks Ed! I already have the cap, but i dont have the cash to do anything with the radiator unless its rusted out or something!

[NickR33]

I wouldn't keep driving it around like that... I would get your mechanic to check the thermostat asap... mine was stuffed and I didn't know as I haven't got an oil temp guage (R33) and the factory water temp guage is not really an accurate indicator of whether the car is running hot (and it was)! a month or 2 later my car started to miss whilst cold and before I had diagnosed it as the thermostat I had wrecked my piston rings and spun a big end bearing... I should have had it at my mechanics long before that

Im not saying that it was solely to balame for the engine failure but it was a major contributor.

Good luck

[NismoR34]

Thanks for the warning NickR33. The car won't be driven much this week and I will be taking it to the mechanic on Saturday if I can't get to thermostat beforehand.

[ed]

I heard the water temp gauge stays in the same spot from around 80~100 degrees.

[NickR33]

Yeah the factory water temp guage is basically a 3 stage indicator, cold, warm, hot... I am not sure of th exact ºC though...

[Guest RedLineGTR]

I heard the water temp gauge stays in the same spot from around 80~100 degrees.

I have a aftermarket gauge in my r33, not saying the r34 and the r33 are the same but with the stock gauge the point where it sits i've seen temps from 60deg-95 deg and it hasen't moved much from one position.

[NismoR34]

I am leaning even more towards the problem being the thermostat now, will try and get it out tonight [weds]...

edit: Radiator was hot after the mrs took it for a short trip yesterday, top hose was pretty hot "couldnt leave your hand on it" hot. The bottom return hose was not even warm it felt about the same as the ambient temperature. Engine was too warm to do it last night, will remove thermostat tonight and test.

Any advice on whether using a Standard replacement or a Colder Nismo thermostat is better? I am leaning towards just a std replacement at this stage, nismo ones are probably better suited to track cars rather than daily-driven, like mine.

Opinions? Thanks.

[NismoR34]

I am leaning even more towards the problem being the thermostat now, will try and get it out tonight [weds]...

edit: Radiator was hot after the mrs took it for a short trip yesterday, top hose was pretty hot "couldnt leave your hand on it" hot. The bottom return hose was not even warm it felt about the same as the ambient temperature. Engine was too warm to do it last night, will remove thermostat tonight and test.

Any advice on whether using a Standard replacement or a Colder Nismo thermostat is better? I am leaning towards just a std replacement at this stage, nismo ones are probably better suited to track cars rather than daily-driven, like mine.

Opinions? Thanks.

[ed]

maybe your radiator is blocked?

I'm using nismo thermo and on cold days it takes awhile for water temp to come up to norm operating temp.

[igor]

maybe your radiator is blocked?

I'm using nismo thermo and on cold days it takes awhile for water temp to come up to norm operating temp.

That sounds more like it. Normally if a thermostat is broken it lets all the water through the radiator, so the car takes longer to warm up. This is also the case with the nismo thermostat, except it opens earlier.

[NismoR34]

The car doesn't take long to warm up though. There really is no issue with how long or how hot it gets except that it gets too hot AND probably quicker than it should.

What if the thermostat does not open? then radiator runs hotter than normal, less fluid in it, return hose doesn't get warm because the warm water that should be flowing through it isn't because the thermo isn't opening to let it through [at all]...

Igor there isn't much logic to your comment? But I am trying

Sounds like you understood it backwards perhaps?

[wrxhoon]

Nismo , igor has a point when he says that when thermostats play up they usualy stay open all the time , not closed . Thats not always the case ( obviously not in your car if its stuffed ) some times they wont open up or they open at much higher temp . Of course the radiator could be blocked , the fan not working and a lot of other things but you have to eliminate the possible causes one by one and the thermostat is easy for you check so do that first .

You cant tell by puting your hand on the hose how hot it is , the bottom hose is always going to be cooler than the top .

[NismoR34]

OK, I pulled out the thermostat last night and it's pretty much stuffed. After 3 attempts I finally managed to get it to open with boiling water straight out of the kettle. I also tried slightly cooler temps ie. mixing 400ml 60 degree tap water with 1600ml 100 degree boiling water and it didnt budge.

Also after having it open [just] in the boiling water only, I removed it for 20 seconds and put it back in, at this stage I was assuming the water was still at least 90-95 degree and it did not open back up.

The temperature stamp on it says 82 C - so I think it has grown tolerant of that temp.

I have a mate [RedlineGTR] going to Nissan to try get me a replacement today!

I lost about 4-5 litres of coolant mix whilst removing the thermo and also managed to snap the air release bolt [on top of the plenum] in the process ARGH!!!!

I may do another flush or just top up with more of the same coolant... hopefully after replacing the thermo, things start to run normal again. Still need to test the Clutch Fan activity though... thanks!

[NismoR34]

I agree that igor has a point [a good point] in general I just didn't think it related to my situation.

I also didn't think my radiator was blocked [and still don't] because when I flushed it 2 weeks ago I witnessed coolant coming out of ALL orifices...is that enough to be convinced of it not being blocked? I guess a partly blocked radiator will still let coolant flow at a lower rate.

[wrxhoon]

You know you dont have to go to nissan for a thermostat don't you ? You can buy them at any auto shop , just buy one with a temp the same as yours or if you like slightly lower , say 80deg .

The correct way of testing would be to have a thermometer in the water so you know at what temp it opens . When you say it opened at boiling water temp , how much did it open ? fullly open it should be around 10 mm , not just cracked open .

Anyway they are cheap so just replaced since yoy have it out .

As for the bolt you snapped you will need to drill in the centre of the bolt and use an easyout to remove it , next time dont be so agro with bolts , the snap !!!

If you are not experienced doing bolts up use this rule : do it normaly with whatever , socket spanner ... then get a ringy open end spanner ( have you noticed how they are small for the small sizes and they get bigger as the size goes up ? ) now if you use that spanner do it fairly tight , without busting your finger !!!