hey im not sure where to turn to but here it goes......So my engine overheated for maybe 1-2 seconds passed by until i turned it off. it ALMOST reached the H mark. i had coolant everywhere and it sprayed from the cap. At first i thought it was the cap so i replaced it. i topped the coolant off and it idled fine. (my car is parked on the street at this point). I notice that coolant is not circulating through the hose...so i give it a good squeeze to force coolant to circulate and my engine temperature needle immediately drops to cold (it was at normal operating temperature and it dropped to almost cold...i assume in result of finally getting coolant to circulate) i also notice that hot air is not coming from the vents, just cold. At this point i turn the car off, i start it again with no problems a few times. im like alright car hasn't overheated at all besides that one time for 1-2 seconds. I decide to move the car inside my driveway which is like 30 seconds away, as im going up my driveway im carefully making sure my car doesnt overheat and then out of nowhere the needle starts shooting up to hot. i immediately put the car on park and as im going to turn the car off i see that the needle reaching the H mark, this happened maybe between half a second to a full second but turn it off really fast. i have coolant everywhere again (came out from the new cap i had just installed on the radiator) and im just scared out of my mind since i dont have money to fix this, even if a headgasket blew i cant afford it at the moment. anyways, i proceed to top it off and let it sit for almost 10 minutes. i go to turn it on and it cranks but wont turn on....at this point im scared as hell that my engine is gone since its my only way of transportation. i crank it a few more times and it feels like it wants to start like it only needs a little bit more but wont turn on. I finally gas it and and it turns on..... once its on im watching the temperature to keep going up the driveway, i check for any white smoke coming from the tailpipe but it feels fine. car didnt shake or rattle or make any funny noises. i go up the driveway like nothing is wrong. i reverse into my parking spot cars temp is fine and i proceed to turn it off.
Things that i have checked for:
-radiator fans spin
-waterpump was apperantly changed by previous owner (ive only owned this car for like 2 weeks)
-cannot find a collant leak anywhere else besides the cap
-no white smoke from tailpipe and when i gassed the car to turn on it felt fine.
-also oil looks fine, no milky like substance
.......i have ruled that it might be the thermostat so any opinions would help. I am really scared to try to turn on my car again in case it doesn't want to turn on and in case of messing something up. Has anyone had a similar experience? do you think i warped some heads despite the really short time that the engine overheated....its not like i kept driving minutes or miles like some people do. i was on an uphill when the car cranked but didn't start....not sure if that has anything to do with it.....this is urgent so i really would like to hear your guys experiences.

 

The reason for the initial over heating is to be determined but your issue right now may just be the difficulty in removing air from the coolant system which is a known problem with the G35. Do a search on the correct procedure for removing air. There is a vent in the blumbing that must be purged in the process of evacuating air. After you have all of the air out and the coolant temp is stable you can focus on why it overheated in the first place.

 

I really wish i had researched about this cars overheating problems prior to trying to move it up my driveway. Im gonna bleed the system tomorrow and hopefully it helps it. since coolant is not circulating and its only overheating when driving it makes me think its the thermostat which is like 20 dollars. Do you think i caused some severe damage since it had a really rough time starting after the second time? Its just insane since it literally overheated for no more than a few seconds. If my car keeps having a hard time to start should i stop trying to make it start? at worst case scenario im hoping for it to be only a headgasket without warping of the heads.

 

There is a good chance it is not your head gasket. Could be the thermostat, and its almost guaranteed that there is air in the system now. Don't believe I saw it in you post, does your heater blow out hot air?

 

heater only blows out cold air. no hot air

 

Definitely air in the the cooling system.

 

If your heater core isn't blowing hot air at idle, there's still air in your system and that'll cause overheating under load for sure. Bleeding the system is a massive PITA to get right, lots on here recommend a Lilse style spill free funnel which makes it a 15 minute job as opposed to hours of idling, pouring, revving, and cursing, Cleric has another recent post on here pretty much summing up the process.

Your overheat may have fried your coolant temperature sensor which caused hard starting in my car due to sending the wrong temperature data to the computer to set correct fuel to start the engine. I replaced mine with a $6 Beck-Arnly part and it fired right up. I was terrified at the time posting on here wondering if I blew my head gasket just like you.

 

i really hope that is all....but why did my car refuse to start after the second time it overheated? after a few failed attempts it finally started by giving it a little bit of gas....thats what worries me the most

 

wow really??? after reading your reply i feel a little bit better. This whole day i have been feeling kinda depressed since i just spent a good portion of my money to get this car and now its broken without having the funds to fix it... i really hope my case is like yours, im going to see if i go out tomorrow to replace that sensor. Is the sensor hard to replace?

 

See my above post, my guess is the coolant temperature sensor. Cheap fix, you might need to go buy a tool to install it though, take a look, it's the sensor attached to a hardline underneath the passenger side camshaft sensor. Not hard just tight space. Glad to make your day better! The G will just keep breaking on you though, for me at least it's one thing after another. It's "reliable" in that it doesn't break down if maintained half decently, but all the little things to keep it driving and riding properly really add up.

 

Thanks man! im gonna head to the autoparts store tomorrow and see if they have one available since im going to be changing the thermostat anyways. I really hope its something like this instead of the headgasket (which would be crazy since it overheated for only a few seconds at max) i am praying that its just a simple fix like this. I will update tomorrow.

 

There's almost no way you harmed the engine to any serious degree. That's the good news. The bad news is you bought an older car with a lot of wear and tear already on it and repairs are to be expected. It sounds like you have no money put aside to make these repairs and it'll suck when something else goes out and needs to be replaced. Being able to do a lot of DIY repairs will help with expenses but you still have to buy the parts to get the job done. I hate to preach but anyone who buys a first gen G should have money saved for insurance, gas and R&M. If not it wasn't a responsible purchase.....

 

The CTS on some cars can cause a no start if it thinks the engine is too hot; I'm not sure if the G has that feature built-in though.

Since, you said it came out of the same spot after you replaced the cap, I would check the neck to make sure there are no holes/cracks. It's plastic and can become brittle overtime as well and I'd squeeze both hoses to see if there is a drastic temperature difference.

Do you know when the original owner changed the water pump? It could just be he didn't bleed it out properly. You could test the thermostat by taking it out and putting it in boiling water to see if it works. You can rent a block tester from the auto parts store as well. You take some coolant out of the radiator and put a tube over the top with some fluid that will change colors as you press the squeege thing. It's like a 20 dollar rental at AutoZone if I remember right and if the color doesn't change your head gasket is fine. I used it the other day on my Audi to rule out a possible HG issue.

Buy a Lisle funnel as well if you need to bleed the system again.

 

Coffey my bad CTS on my 04 G caused an intermittent no start/hard start.

OP, Don't get us wrong, the G is a great car. But on your average 15 year old Craigslist car so many of the original parts (rubber parts especially) are at or past end-of-life. Unless they've been recently replaced with QUALITY PARTS at high expense, they aren't going to hold up to much abuse. (don't be doing pulls everyday or corner carving unless you plan to be upgrading parts often).

I've probably got at least 1500 into my Craigslist G not including expensive tires (doing literally everything myself) over the course of a year, although I have autocrossed it and tend to drive like a reckless idiot when there's nobody else around.

 

Yea, that's weird I wonder if it only cares about a signal then? There was a time on my 06 where the cheapo fans I bought seized unable to move. I would have to drive fast, heat on full blast, take long way home, and pay 1000% attention the gauge. Until, I got the time to replace them again....but, the car would start again when hot.

I'm pretty sure my rear caliper seized again and this is like the 3rd or 4th time replacing it. So, I have to deal with that now.