Good morning G Family –

Hoping you guys can help me diagnose an issue that arose this morning.

2003 G35 Coupe 6MT with approx. 77k miles.

So I’m driving to work this morning which is less than 5 miles away. Outside temp was around 75 but typical summer humidity in NC so I have the A/C running. I make a visit to Chick-Fil-A for some breakfast (cheat day) and wait in the drive-thru line for 5-10 mins. Thinking back I recall hearing the fan being audible but not to the point where I thought twice about it. As I’m pulling away towards work I notice my temp gauge needle is HIGH, past ¾ I would say which has never happened. I’m about a mile from work so I decide that I’m going to go for it. My eyes are fixated on the temperature gauge – as I get up to speed I notice that it starts to decline back towards operating temp but quickly spikes back up as I slow down at the next stop light. The fan is still noticeably audible (but not like an airplane) and I also hear what sounds like some faint belt screeching. As I’m driving I peek in my side view mirrors for any noticeable loss of fluid/coolant but wasn’t able to spot any. The remaining drive in to work is at slow speeds (2nd gear), stop/start, so my temp gauge is holding close to max. I make it to the gate, swipe my badge, and quickly pull into to the first parking spot I see and cut the engine. At that point smoke (or steam) begins to bellow out of the hood and steam begins to spray my windshield. I open the driver door and see a river of green coolant flowing that appears to be starting at the front end near the radiator. It’s about 8am so I have to get to work so did not have time to pop the hood or inspect any further. I plan to go back out and assess the situation in a few hour so hopefully then I will have some more information.

Based on the above, does anyone have any suggestions for what could be the culprit. I read the overheating thread (sticky worthy) and my symptoms seem to suggest a failing fan clutch based on the temperature decreasing at speed and climbing at slow speeds/idle. However, I suppose the overheating could also be from a slow leak to either the upper or lower radiator hose which worsened at operating.

I’ll continue to do some research on the forum but wanted to get this out there to see if anyone can help.

Thanks in advance and I’ll check back in later once the car has cooled and I can take a closer look.

 

You've either blown a hose or the radiator from what you describe! Best advice w/b to have your G towed to Nissan, have them replace what ever is causing your over heating. You don't want to drive it anywhere with the fluid loss your currently have!!
Gary

 

Thanks for the response, Gary. Any other culprits you can think of based on what I've described? Do you think the underlying issue causing the overheating was the hose/radiator? Or could the hose/radiator blowing be the result of the overheating caused by something else?

 

My fans weren't both turning on when they should have. Test the fans by putting heat on 90, max speed, and then hit the AC button. Both fans should turn on behind the radiator.

Next Time your car begins to overheat turn the heat on max as it steals some heat to heat up the car, lowering the cars Coolant temp!!!!

 

Sounds like a fan issue, since it would cool off when driving. If you have the pulley driven fan, I would say it's probably the clutch. I think there is also an electric fan as well and that could be bad as well.

I have an 06 and when my car was overheating it was due to both the motors being bad. My fans would only spin at the low setting. But, when driving it would cool off.

I'd make sure to check the hoses, thermostat, etc.. before condemning the fan(s) though.

 

Urban/Coffey - thanks for the replies. Gary may be right - I went out to the parking lot to get a look under the hood. Pics attached.

Coolant reservoir was bone dry, as expected, but otherwise all coolant hoses appear to be in decent shape with no visible cracks/splits. I didn't have a pair of pliers so wasn't able to pop off the upper to get a look at the underside. Fans were running solid during the incident this morning (noticeably audible) so I have a feeling both are fine. I have 2 theories based on the dried coolant residue spray pattern:

Theory A - the upper hose is blown. Also best-case scenario.
Theory B - the plastic neck or elsewhere on the stock radiator has cracked.

Also - I'm starting to think the Skunk2 radiator cap I've been running may have something to do with this. Perhaps the increased pressure has caused the stock radiator to give out over time and this morning was the breaking point. Or the increased pressure led to the upper (or other) hose busting.

This could be a good excuse to buy an aluminum Koyo radiator from Z1..

 

As others have said have it towed.

Call AAA if you have it as they provide a free tow.
If it overheats and you warp the heads you'll have bigger problems.
With a almost fifteen year old vehicle when was the last time the water pump, thermostat, hoses, belts, radiator cap, and coolant were replaced?
After a complete inspection, have it pressure tested.
If your radiator is clogged that may need to be replaced also.

Telcoman

 

Thanks for the replies. I've elected to purchase a new radiator and coolant hoses. Luckily I'm close to Z1 so parts should arrive by tomorrow. Will try to do the install in the parking lot and hope for the best. I do have AAA so will have her towed to a shop if it comes to it. I'll post again tomorrow once I have an update.

 

Looks like maybe the radiator had a seepage leak along the bottom of it also. Mine was the same way and I replaced it as well. I think over the years the gasket and plastic get brittle and just end up failing. I'd try to pressure test the system first though, so you can find all the leaks first.

You might as well do the thermostat as well, since you'll have the system drained.

I think the cap has a pressure valve that will allow the coolant to bypass if the pressure gets to high. You can also pressure test the cap if you rent a pressure tester.

Be prepared to spend a lot of time bleeding air out of the system if you've never done it before. Buy a spill free funnel from Lisle. You want to use Nissan/Infiniti coolant or something without silicates like Valvolie Zerex for Asian vehicles (comes in red and blue). Usually, takes me about 1-2 hours to remove the air from the system.

This is how I bleed the system:

Fill up slowly
Leave coolant in the spill free funnel
Start car with heat on
Rev engine to about 2-2.5K for a few seconds until coolant raises in funnel
Stop car
Squeeze both radiator hoses
Do the following for about an hour.

Car still usually has cold air in the cabin.
I verify both hoses are hot.
Drive it out down the parkway fast to flush out other air bubbles
Top of system as needed

I've done this at lest 4-5 times without any issues.

 

Good morning -

Thanks again to those of you who replied and provided input. Just wanted to follow up on how things played out. I was too exhausted after Saturday to post. Spent the morning working on my brother's 300zx TT - we installed the HICAS elimination kit from Powertrix. By 2pm FedEx had arrived with my parts from Z1. Removal and installation were pretty straightforward. Getting some of the clamps and stock hoses off were a challenge but overall went pretty smoothly considering we did this all in my work parking lot. Fitment of the Koyo was just about perfect (about 98%) - the mounting points for the cooling fan assembly was slightly off and the passenger side upper radiator bracket is loose compared to drivers side. Otherwise it is a beautiful radiator and a shame it hides between the fans and AC condenser. This was my first radiator install so burping the system was terrifying and a mess without a spill free funnel (looked for one Coffey but couldn't find it). Anyways, so far so good. No leaks since the overfill mess has burned off. Car is running a bit cooler if anything. If anyone comes across this in the future and has any questions about the install, feel free to PM me.

 

im having the same issue my car was squeeling evertime id press the throddle the smoke started coming from under the power steering resivoir so i shut the car off again the coolant resivior is full but the radiator itself it empty the fluid hasnt dried but i saw it spray from either the cap or jus below the cap or a hose but i cant find any cracks or leaks but everything on the engine was soaked

 

Rent. A. Pressure. Tester...

 

I suspect the squealing is from coolant getting on the belts. I’d say you have a crack in your radiator. After the coolant has dried you should be able to find the source. Look for the spot where the most coolant is and I’m sure you can locate it.

 

im having this same exact problem and was curious on to whether you were about to determine what the issue was. I seen you did the hose and radiator replacement but wanted to know if you found for sure if it was one or the other. My engine bay looks the same as the pictures you provided.

 

It was a crack in the radiator for me. May or may not have been because of the aftermarket radiator cap is was using with the OEM rad. Take a close look once it has all dried and you should be able to find the source of the leak. It will be the area where the most coolant is.