This is my first post. I am a relatively new G35 sedan owner. I own a 2007 G35 Sport sedan and most recently purchased a 2004 G35 sedan with 143,000 miles on the odometer for $5,000

Although $5,000 seems like a great deal I may end up having to put more into the car than it is worth. I thought I would ask a few questions here and get some opinions.

The car has new tires and brakes all the way around. The two accessory belts are brand new. The door seals show some age but I do not see any leaks during heavy rain. The interior is pretty good for its age. Everything inside the car is functional. The auto transmission shifts smoothly.

I have no idea what has or hasn't been done to this car over the years. I have the feeling that the original owners just drove it and didn't do much to it as far as maintaining it. The car starts and runs fairly well but I do notice that the car has a slight skip when idling but it idles at a normal RPM on the tach. I plan on changing the spark plugs and PCV valve in the next few weeks and maybe that will cure the slight engine skip sensation I feel at idle. Any other thoughts? I am using a Techron additive over the next several fuel fill-ups.

The larger radiator cooling fan comes on as soon as you start the car and never shuts off until you turn the ignition off. I don't think this is normal but the operating temperature is right at half way on the gauge. Should I be worried about the fact that the cooling fan runs constantly?

When driving the vehicle over small bumps in the road I notice somewhat of a pronounced "thud" under the car. It's like running over railroad tracks. I don't really feel a jolt it just sounds like you are taking a heavy object and striking underneath the car when you hit a bump in the road. Almost like a hard object is hitting the floor pan. This is only when going over bumps and the bumps don't have to be very large. Could this be the control arm bushings that I have read so much about causing this? If so, can the bushings be changed with after-market bushings without having to replace the entire control arm?

My fiance is currently in school and is driving a tremendous amount of miles weekly and I purchased this car for her to hopefully drive for the next year so she doesn't continue to rack up miles on my other vehicles. It would be nice if I could keep this running reliably but the above mentioned items are on my list of questionable repairs that need to be done soon.

Any thoughts on these items and other suggestions for keeping this car running would be appreciated.

 

RE: the cooling fan

Watch out that the previous owner hasn't shorted some wires together... I had an old bimmer that had the coolant temp sensor intentionally shorted so the gauge read acceptable... the fan was also wired to be always on... you never know what kind of games people play to get their POS sold...

 

Honestly, it sounds like your issues are pretty minor. Spark plugs, changing the fluids (all of them) and just general maintenance would be a great place to start. My 2004 sedan has 123k miles on it and still runs brand new. You'll get lots of mileage out of your new sedan, probably well over an additional 200k more with proper love and care.

The sound you are hearing is most likely your shocks or control arms.

 

Seafom in engine Oil, Gas tank and through vacuum line.

 

Test your thermostat to see if its still opening and closing as it should before you start having overheating problems. As far as the clunking goes, its most likely the compression rod bushings, but If the previous owner modded the car, its possible that he installed a coupe mid pipe which could also cause that clunk while going over bumps. I've been meaning to wrap mine with something but havent had the time...

 

That's dirt cheap... 5k? it COULD be compression rod bushings, but at the same time it can be bad ball joints too. Might be both.

 

Yes. It was a young guy who paid $8,400 for the G35 earlier this year. He needed money and I told him I would not pay over $5,000 because I was sure it would need some work and almost anything could go wrong at any time. He accepted!

I have to drive it from TN to FL as soon as I get everything repaired that we have been discussing here. I don't want to leave my fiance with an unreliable car. I have been driving it every day to work with no issues other than what I mentioned in my original post but it is not more than a 10-12 minute drive to work one way.

If I have to sink quite a bit of money into repairs it would be better for me to sell it. So.....I'm hoping that it doesn't need anything too costly.

 

No modifications have been done to the car. It's all original. Just an old car that spent most of its life in the heat of Arizona from the Car Fax report details.

 

I also notice that when I first start the engine there is a quick but somewhat loud thud right as the engine turns over but then all seems normal. It's like one loud knock on the engine firewall as the engine starts. Any explanation for this? Starter?

 

143k is young for a G. I'm going on 233k, and still going strong on my coupe. The PO took good care of the car, and keep everything decently maintained. The only serious issue it had was VERY bad spark plugs, which I replaced about 15,000 miles ago.

That "thud" you hear at startup may be from bad or worn motor mounts. I know my car does it every now and then.

Honestly, the issues you have sound like they won't be too costly to fix. I'd sink some money into and drive it. You'll get your money's worth out of it in no time if you do.

 

Be careful with this. If the car has been run on conventional oil for 143k miles, you risk opening up some leaks possibly. If it's been run on conventional oil for it's life, continue using conventional.

Putting the seafoam in the tank and vaccuum line is ok though. You have to change the fuel filter after running it through the tank as it cleans up the crud in the tank and lines and then all that gets stuck in the fuel filter.

My 05 X sedan has 148k miles on it and runs strong. I paid $6700 about a month ago. Sounds like you got a good deal. These are strong engines from the miles I have put on mine. I haven't checked the plugs yet.

When you replace the plugs, get OEMs. DO NOT get those bosch twin tip ones or whatever they are that can apparently defy the laws of physics. Because actually, they can't defy the laws of physics, no matter what bosch tells you.

 

The thud you hear at start up most likely is a bad engine mount drivers side it also will do that over bumps because the engine is jumping around on bumps and another sign of bad engine mounts is when driving down the highway when you speed up its theres no vibration and when you coast you start to feel some vibration and it goes away when you speed up again, but the best thing to do would be for you to take it to the dealer and get it checked out then you will know everything that it needs and go from there instead of guessing what problems it has and then fix them yourself.

 

The two problems you listed are:

Cooling fan runs constantly. You need to change the themostat that controls the fan. It should not be expensive.

Suspension noise. You need to change both compression rods. I recently repalced both rods after some research. Foget about replacing just the bushings, it's not worth it. When replacing these rods, make sure the ball joints are replaced also. They are one piece, bushing and the ball joints.

 

Motor mounts symptoms. A simple way to check is to gun the gas and let go a few times when in Park, if the engine vibrates/shakes a lot, the mounts are bad.

 

Thanks for all of the advice so far.