2004 350z Overheating
 

Hey guys. My son has a 2004 350z that started out with a small amount of coolant dripping and burning off/smelling. We would also see splashed/sprayed coolant remnants on the top of the radiator. After changing out the overflow hose the problem continued. We figured the radiator was cracked, so we ordered a new one. About a week ago while waiting on the new radiator, the car started to get hot. He drove it home (about 1 mile from that point) and parked it. The next day we changed the radiator and top/bottom hoses. That fixed the leak, but the car then immediately started overheating again on a short test drive. We then replaced the thermostat/housing - which still didn't resolve the overheating. That was about the extent of my mechanical abilities, so I had it towed to a local mechanic shop the next day. They did some diag on it and said that the water pump was shot - that there was no coolant flow. My question is mainly regarding that. They are saying that we should really have the timing chains and components replaced at the same time they do the water pump. It makes sense, being an interference engine, but they are quoting $2,100 to do it all (parts and labor). Does this sound like a reasonable cost? With your guy's experience here, would you recommend doing the timing chains replacement also? It's hard for me to argue the logic in having them replaced - given the age of the car and the fact that I don't know if they've ever been replaced, but daaaang - $2,100??

Hello and welcome.
A couple of things to remember -
1) This setup is famous for trapping air in the cooling system and requires "burping" with the bleed valve outside the heater core.
2) Yes, if you're pulling the timing cover to do the water pump then it makes sense to replace the chains.

It's your call, it's either a lot of $$$ if you pay to have it done, or a lot of time to do it at home. Gl!

Hi Blasty,

jhc is right. Most likely the overheating issue is related to air-pockets in the cooling loop. You really need to look into some DIY guides on burping out all the air on 350Z/G35s. There is a plastic bleed valve near the battery box/firewall on the heater core hoses. This needs to be cracked open while burping the cooling system. You also need to rev the engine during this process to break up those air pockets and get coolant circulating. This is not a quick procedure, it can easily take hours to get all the major air bubbles out.

I actually think $2100 (parts included I assume) is a pretty fair price for doing a full timing kit and water pump on one of these VQ35s. If you start reading up on the procedure (start to finish) you will understand why. I live in CA and shop labor here is typically $150-$200/hr.
Good Luck!
-Icer

Make sure both cooling fans are working. Mine and another 350z I know of had only 1 fan working. In cooler weather or driving it will stay cool. But say in hot weather at a drive thru or stop and go traffic with only 1 fan they will over heat. Funny both times it was the drivers fan.

Ever find the problem.

Got a problem that sounds the same.
How many miles on his Z? Mine has 191000 miles (305775 km). Also mine can go 2 miles (3.2 km) from cold and do OK. Park for an hour and coming home is a race against the overheating. I do live in a place that gets around 100F (37C). Did replace my thermostat at 90000 miles (144841km). Will talk to a mechanic this week and post any results. There is two things I hate in life, heights and overheating cars.

*forgot to ask: does his fans come on way too soon and the Z starts to overheat?

Make sure no coolant leak and it is full of coolant with no air pockets. Again make sure both fans are coming on without AC being on.

Rad fan failure is fairly common. Make sure those are actually turning on. I test drove a Z before I bought mine and it had this issue. It overheated on the test drive. If they do, burp the cooling system to remove air pockets and make sure you are adding distilled water or the right type of coolant. Plenty of videos on youtube describing this.

Changed my thermostat, and still overheating. There is a distinct leak on the front driver side that I have seen since before the overheating issue (right behind front bumper). Coolant level is legit. I've had cars overheat and would just blast the heater until I could pull off the road. This time the heater doesn't blast hot air. Stumped.

If it leaking 90% that equals air pockets. Sounds like the radiator is cracked.

Had same issue, first one of my fans was dead, red lined when idling or moving slowly, was okay on the highway, replaced the fan and thought I would flush the system at the same time. Took it for a ride and in a mile it red lined. It needed to be burped, been good ever since.

Ran the Z today and the temp gauge rose way to fast for a car that is stationary, had the ball and chain pour coolant in the radiator and it just sucked it up. This might be the problem. Will update once parts and repairs come in.

Pretty much all late model vehicles have plastic end caps on the radiators. These plastic caps eventually fail from the hot/cold cycles causing the plastic to become brittle. It's not a matter of IF, but WHEN it will happen. If you own a 350Z, even one that isn't high mileage, and you're still rolling on the original radiator, get it replaced as preventative maintenance. This is on my to-do list, although my Z is low mileage and spends most of it's time these days in a garage.
Cheers!
-Icer

Question, do those vacuum fill tools work on the Z? I know how to burp the system, but given its design, is it worth the $ to buy the tool or just keep doing it the way its been done?

https://www.z1motorsports.com/tools/...01dd1c6aa068f4

Link to an example, from a reputable vendor. Amazon has less expensive ones, for comparison.

Looking for something that will work on the Z, and happen to also work for my other cars...

2004 350Z VQ35DE

I don't know about the vacuum thingy I just bought the special burping funnel with the caps that fit your radiator, worked great for me. It was a learning experience for me because I'm from the old school where you just drain - fill and drive.

Just had a second radiator installed, have stored my Z in the garage except for short trips

Makes sense, they do tend to run hot, lot engine crammed in a small space, I always smell rubber when I park it, pretty sure it the radiator hoses that are way to hot to touch. Temp gauge never goes over 1/3

Had a bad thermostat, Z drank all the coolant, yes radiator was cracked. Going to look into the fans since they shouldn't come on with it cold out.

Make sure the defroster is not on or somebody has wired the fans straight.

If the Z drank the coolant, I assume it was from the cracked radiator. Fingers crossed you don't have a compromised head gasket!
-Icer