Hi all. Started my 2003 350 today, to let it run for an hour, as I usually do once a month during the winter while in storage. I left it for an hour. When I went back, it had shut off. I restarted it, and the temp light immediately went to hot, and the car ran very rough. Shut it off, looked under, and there's a nice puddle of antifreeze underneath.

Question: What's the likely damage, if any? Why is it running rough? Does the engine auto shutoff if the temp gets too high?

Thanks for any and all help!
Newfie

 

No problem. At idle you are putting little stress on the motor. No demand. No coolant and the motor will run for hours.

Motor oil will also keep the motor cool. Unlike coolant, you can NOT run the motor with no oil.

 

im not an expert, but cars do need antifreeze to keep cool... thats why we have radiators.... when first turning the car on it could idle for a certain amount of time with no antifreeze depending on what temperature it is outside, but since you're not driving, the engine is not being cooled by wind and in your case antifreeze either... you're not putting major stress on the engine at idle, but that doesnt change the fact that its still operating at temperatures its not designed for.... i would be a little worried if this happened to my car and especially if it was running rough after the incident.... could have fudged up one of the cylinders and your piston rings and also your head gasket...... can you describe what you mean by running rough??

 

I'd say the antifreeze/coolant is absolutely necessary, since there's no way to transfer heat from the engine to the radiator without it. The engine is able to radiate a certain amount of heat, but it's going to have some serious hot spots without coolant circulating through the heads and block.

Your engine should not have overheated from idling that long.

 

^^ he said he had left it for an hour my car warms up in about 5 minutes in the winter.... without coolant id say itd b pretty much overheated in 20 minutes tops.....

 

You have a leak. It needs to be fixed. Running rough is an extremely bad sign after a car has overheated. Usually at least a head gasket. Letting a car idle for an hour is horrible on the car in other ways also. It dilutes the oil with gas. Who told you this was a good idea?

 

Sorry this is completely false on almost every car that uses antifreeze.

After swapping in an engine and getting a nasty air bubble in a jeep I almost had a bad experience, because it overheated so badly. All it was doing was idling.

 

Since the winter around here is 5 months, I start it up once a month or so and let it run to recharge the battery etc. By running rough I mean it feels as if it is running on a cylinder or two less than it should.

Does the 350 retard its timing when too hot? I have a snowmobile that does that; if there is insufficient snow to cool the antifreeze circulating up in under the track, the motor automatically retards timing until it cools. Anyone know if the 350 does that?

 

yeah defnetly killed your engine. the leak was probably a leaking hose or cracked radiator then it ran on no coolant. its warped.

 

not sure about the engine retard when hot, but i doubt it... its not a snowmobile... if it sound like its not firing on one or two cylinders or like its knocking you got problems... probably f#cked up a cylinder or two... and by f#cked up i mean sleeve, rings, could be problems in the head too.... head gasket could be burnt as i stated before.... if you're not good with a wrench i would strongly suggest visiting a mechanic aka someone who is good at fixing cars and stealing money...

as for idling your car for an hour.. who told you to do that??? Thats a terrible idea... engines are far from perfect machines and at low rpms the piston rings do let through air and fuel as stated previously... as well as poor cooling... more spark plug wear occurs... the list goes on.... idling is no good for your car...

 

when our racecar overheated the heads were warped so bad you could see the waves in them.. but yours may be slight enough to get machined out but i would defnetly not cout on it id start looking for a new long block assembly.

 

Next time get a trickle charger.

 

Refilled antifreeze this morning; started right up and ran smoothly. The ECU does retard timing and/or reduce fuel when too hot. Let it run until all the way to the H; fan didn't cut in. A new fan or switch is needed. Didn't appear to be any damage, though only a road trip will tell. That's 4 months away...

Thanks for the help!

 

there was a tsb out on the fan units themselves double check the motors.

 

yea i remember that...got that in the mail, but never got that done lol... so far so good... NEWFIE, you should look into that....

 

I thought idling wasn't even enough to recharge the battery? Needed to get up into higher RPM's to get the alternator going.

 

IIRC, the letter only tells you that there is a warranty extension on the fans. Check here...

https://my350z.com/forum/maintenance...fan-motor.html

OP is SOL since the letter indicates it's for '04-'07 cars. His probably died a natural death.

 

Thanks for a copy of the letter; I didn't receive one.

 

Itll charge it, especially if your idle for an hour. But a 5-10 minute drive would achieve the same results. Glad your engine isnt blowed up OP.