Hello! I have an '04 Coupe 6MT, and I'm at Mid-America Motorplex this weekend with NASA. I'm having an overheating issue today and am hoping for some ideas. The engine is mostly stock, it's around 85 today, I've added a fairly large oil cooler and am running 30% coolant/70% H2O, along with waterwetter. When I push the car hard, the water and oil temps creep up until I have to back off and let it cool (which it quickly does but is very frustrating). Any ideas what I could do to keep the engine a little cooler? Thanks in advance!!!



-6MT4me

 

oil cooler with a bigger radiator...more air you can get to the radiator the better...you could get an open grill like the gialla

 

Good suggestions! I'm hoping for something to do for tomorrow, though. The engine is pretty close to stock. 350Z intake, 5/16" plenum spacer and Ebay y-pipe on the exhaust. Other than that the engine is bone stock. I'm not sure why it's overheating, especially w/ the oil cooler added...

 

i noticed you listed % of the contents...

did you recently drain/flush the radiator?

you might have air pockets!


where do you live?

normally water & water wetter is mor than enough & actually will cool better
than the mixture with antifreeze.

In the summer i run straight water & 1 bottle of water wetter

 

The air pockets are a very good thought-- I did use the air escape hole in the rear heater line when refilling, and have refilled it a number of times to "top it off" Now it won't take any more coolant, so I think I have the air pockets out. I tried just 15% coolant, but I found it would start to overheat when stopped for a long time with the A/C on and dump coolant into the overflow, so I think it was boiling the mixture. My underdrive pulley is probably responsible for that... I do have a NISMO radiator cap so I don't think pressure is the problem.

 

you could get a nismo thermostat along with a oil pan spacer as well

 

Your car should not be over-heating like that. I have run many track days in 90F heat, and 25 minute sessions with no heating problems from the engine. I have a stock G coupe as well.

Before you go out buying aftermarket coolers etc, I'd check your radiator hoses, thermostat, coolant etc. Basically do the regular maintenance checks first.

Your car should not overheat in its stock form.

 

yes i agree with others, there is another issue at stake here. I ran plenty of track days myself even some in 100 degree days and never had any overheating issues on a stock car with just simple bolt ons.

I am planing to do what you did and run 25% coolant 75% water and Purple ice (royal purple). THat alone should cool the engine plenty. But i might even consider going for the APS radiator as well. Although that may be a bit too mich cooling.

 

follow the service manual procedure for getting rid of air pockets. A sure sign is you have no heat.

 

also many track days, lots of time near limiter and no overheating . . .

Although I just shredded my second A/C compressor belt at 30K - I will start another thread for that.

 

Hey Bryce,
Given the level of mods, or the lack of, your overheating issue is most likely "air pocket" related. It is especially suspect, seeing as you have attempted to flush the coolant at least once in the past. 4 out of 5 VQer experiencing overheating issue have tried to flush their own coolant or had incompetent mechanics attempted the same.

It would be unfortunate if you or anyone else attempted to perform manual air bleeding via the procedures outlined in the service manual. It is an extremely poor and inefficient method and simply NOT capable of purging ALL air trapped inside the labyrinths and cavities of the engine block. Just about the surest way is by means of a coolant flushing machine (attached to the cooling system), which allows the egine running to actively carry out ALL the trapped air. All dealers and most shops would have access to such a beast.

A good friend of mine actually came up with an ingenious DIY contraption which mimics the flushing machine, which I have been using with great success. The concept is not complex, but trying to describe using 2D text on the net is more work than I'd like to go into right now. If you're interested and is *especially* handy, PM me about it (the operating procedure is quite involved).

I should also point out, unless you were using the "recirculation method", you have not flushed out the old coolant in its entirety. Simply draining the radiator accounts for only 50% of the entire content at best.

Finally, one other suspect is your radiator thermostat. Have you checked it out?

Good Luck,

 

You may very well be right THX723-- I've noticed that when I suck out coolant to test it's % antifreeze, it can never get it all back in. Therefore, air just got trapped... I did install a new 350Z Koyo 1 9/16" radiator in the hopes that it will cool better than the OEM unit, although the filler neck is in the wrong place... I'll PM you about the air-removal unit you mentioned. Thanks!

--Bryce

 

The new larger radiator certainly can't hurt, but your overheating problem would persist if air pockets remain. I'll try to put something together for you regarding the contraption.