So I recently had my mechanic do a coolant flush in my 04 g35 sedan because it looked orangish brownish and gunk and disgusting. Ever since, I have been encountering overheating problems! I thought doing the flush would help the car but it seems to only have hurt it. Water(not coolant) is leaking from under the car from what appears the be the front of the engine block. I was able to drive home from the mechanic(10 miles) with no problem and just all of a sudden it's over heating!!! I put an entire gallon of Asian car antifreeze/ coolant into the system and then topped it off with water but I could see the level slowly dropping. Before I did the coolant flush I had no overheating problems at all. Please help!!!
Edit: I live in sunny Florida, if that makes any effect on your answers

 

Bring it back to the mechanic if you weren't having problems before. You're supposed to leave there without problems, not with problems. Most likely didn't get all the air out of the system. If you're leaking water, you're leaking coolant. The water you see could be condensation from the ac running. Clean up the leak and try to track it down. Can you hear water running when you start your car? You shouldn't. Make sure your oil isn't milky. Most likely air in the system though. You hear about it at least once a week on here

 

Take it to a mechanic that knows how to bleed the air from a VQ engine because it sounds like your mechanic doesn't know how.

 

I agree. My mechanic is a lamborghini ferrari audi porsche expert and admittedly not into japanese cars but he fixed my misfire for cheap so I'm trying to go through him. My intuition says that the gunky liquid was preventin the leak from happening and after the flush it allowed it to leak again. I think I need to get the leak fixed before I can worry about bleeding the car because leaks let liquids out and suck air in. I just need to figure out where the leak is before I can move forward and I am mechanically retarded so I won't be of any help to myself. I'm also on a bit of a budget constraint so I'm trying to go through the cheapest routes....

 

Also, I don't run the ac. I recently noticed the coolant on the ground as well, so it is definitely leaking coolant

 

With a fourteen year old vehicle I would first suspect a failing thermostat?
Did your so called mechanic ever test it?
Replace the thermostat, radiator cap, and use the proper coolant as specified in your owners manual. Properly bleed your cooling system. Follow the troubleshooting steps in the FSM. Are your fans running properly? You may also have a clogged radiator if the coolant was never flushed in your vehicle?

I'm on my third Infiniti and do not trust any of those so called mechanics.I only use my local dealer and have never had any issues with the work that they have done.
You get what you pay for and using poorly trained so called mechanics that are unable to follow the FSM for your vehicle while charging you for their substandard work just leaves you with aggravation, wasted time, and money.
Just my $.02

Telcoman

 

First thing is find the leak, start with the radiator cap, get an inspection mirror and a flashlight and look around until you find it.

Bleeding, firstly while filling the vehicle with coolant open the air purge screw and fill coolant till it pours out the purge then put the screw back in. Top off coolant, turn on the car, turn the heater on high and max fan speed, when the engine warms up rev it up quite a few times while repeatedly checking coolant level with the cap off and refill as needed and manually squeeze radiator hoses until the thermostat opens and you feel hot water cycle through. When engine is fully warmed up shut it off, put the coolant cap on and fill the reservoir.

Next, test drive the customers vehicle, ensure hot air blows from the heater, ensure there's no leaks, ensure it's not over heating.

Done.

These are basic steps for shop work, coolant flushes are simple work for your new hire trainees, yes the VQ is a little more of a pain because of the coolant purge valve and they like to trap air but it's not rocket science. You NEVER let the customer drive away with a vehicle that's leaking coolant and overheating.

Definitely not a Lambo or Porsche mechanic, doesn't sound like he knows **** about cars in general and I would definitely find a new mechanic.

The dealership might charge a little more but you get the job done right, by trained technicians.

As for any physical debris or "gunk" in the coolant, that's what happens when you use tap water in an engines coolant system. It's designed for GLYCOL ANTIFREEZE and DISTILLED WATER, only those two items, nothing else, and in the proper ratio depending on your climate but usually a 50/50 mix. You can play it safe and buy pre-mixed glycol, don't mix red/green glycol.

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Whenever your in los Angeles can you do my coolant flush?

 

I blame the problem on the design of the VQ thermostat with the weird integrated housing, there's no jiggle valve / air check valve on them. They NEED an air bypass of some kind and then this issue wouldn't happen.

 

I hesitate to think that any of the parts of the cooling system have failed because they all worked fine until the flush. Now there is like a 0.000001% chance that the happened to break the same day I got the flush but I'm going to lean away from that idea until further inspection is done. I will attempt the bleed off myself although I could not find the bleed of valve (after watching a couple videos on the coolant flush, and they pointed it out) but I will give it another go tomorrow. And I don' think my mechanic doesnt know **** about cars. He was able to diagnose and fix my misfire for 200 when the infiniti dealership was not able even corretly diagnose it and gave me a 3000$ list of parts(not including labor) to waste my money on, suggested I get another car, and tried to sell me one on their lot. There' a reason theyre called stealerships. He says the bleed off is super simple if not automatic (don' remember his words) on German cars. I can understand from what limited information you have received why you would come to that conclusion, but I just don't think it's accurate.

 

Two other bits of info: I drove it home 10+ miles with no heating issues, and I used zerex asian car antifreeze/coolant. Not sure if that's glycol or not. He didn' just let me drive off with a ****ed up car, the issues began a while after we departed (couple days)

 

Clogged radiator is a distinct possibility. I purchased it used and the transmission fluid was basically black when I had that changed the same day so I wouldn' be surprised if nothing else had been taken care of properly. And sorry for all the replies lol, I have to post and go back and reread what was said to reply. Oopsy

 

No worries, the coolant bleed valve is on the passenger side near the firewall. Look for a green cap with a tag on it, that's not the coolant bleed valve but it's almost directly BELOW that piece. It's a black plastic "coupling" on the coolant hose going to the heater core with a screw cap that can be removed. Be aware that coolant will come pouring out of it and it's slightly fragile so make sure the engine is cold if you try it.

Do you have hot air blowing from the heater when you crank it up to 90° with the fan on high?

 

Zerex Asian is fine it's silicate free and I've used it for awhile. Feel both of your radiator hoses on the top and bottom. See if one is still cold and the other is hot. Check the radiator hose clamps to see if they are tight enough. I don't mess with that bleeder valve anymore; I was doing a coolant change a few years ago and it broke in half. I then got sprayed with luke warm coolant all over my body and face. Several other people have had that experience as well here.

Does it over heat when driving or idling? If it's during an idle your fan(s) could also be the problem. Sign of that would be fine when driving at high speeds, but overheating when idle.

 

When I was driving it back home after I first noticed it overheating I threw it on max fan and 90° and it took quite a while for it to blow hot air out.