what the heck is going on?!!

[pixelhaus]

i have been having overheating problems for the last 6months. the dealer first thought it was an air pocket in the system. bled it. everything seemed fine. until...a few weeks later, it started overheating again. dealer found more air in the system. bled it. seemed like it was fixed. 2 weeks later...you get the idea. the mechanic then came up with the idea that the radiator (being that it was a little bent from a previous accident i guess) was causing the problem. $500 later, i have a new radiator installed and everything seems great. 4 weeks later, overheating again.
a couple of key points to make.
1. when it overheats, it climbs fast. always after i have been idling for a few minutes. when i rev the motor, the temp drops like a sack of bricks. this is why the mechanic thought the radiator was the problem. an air pocket gets stuck in the radiator because it was bent, reving pushes it through... seemed like a logical solution.

needless to say. the radiator was not the issue. he did mention that it appears someone did some head work on the car since the head gaskets look misaligned (sticking out a little on one side is guess) he did say it is a slim possibility that may be the problem.

i need HELP!! i hope it's not a major repair. i was ripped off (and/or stupid) when i bought the car and now it's draining my wallet.

sorry for the rant. can anyone offer any possible solution? or what to check for?

thanks

 

[NSX TT]

Originally posted by pixelhaus:
i have been having overheating problems for the last 6months. the dealer first thought it was an air pocket in the system. bled it. everything seemed fine. until...a few weeks later, it started overheating again. dealer found more air in the system. bled it. seemed like it was fixed. 2 weeks later...you get the idea. the mechanic then came up with the idea that the radiator (being that it was a little bent from a previous accident i guess) was causing the problem. $500 later, i have a new radiator installed and everything seems great. 4 weeks later, overheating again.
a couple of key points to make.
1. when it overheats, it climbs fast. always after i have been idling for a few minutes. when i rev the motor, the temp drops like a sack of bricks. this is why the mechanic thought the radiator was the problem. an air pocket gets stuck in the radiator because it was bent, reving pushes it through... seemed like a logical solution.

needless to say. the radiator was not the issue. he did mention that it appears someone did some head work on the car since the head gaskets look misaligned (sticking out a little on one side is guess) he did say it is a slim possibility that may be the problem.

i need HELP!! i hope it's not a major repair. i was ripped off (and/or stupid) when i bought the car and now it's draining my wallet.

sorry for the rant. can anyone offer any possible solution? or what to check for?

thanks

Well.All I can think off, if the car overheat when is in idle,you might wana check the water pump impeller, just in case the impeller is loose in the back of the water pump.this might be the problem.sounds stupid,but might be possible.the only problem is that you gona have to remove the water pump.if I were you,I will check other options, before get to the water pump job.but that is the only thing I can think off.loose impeller is very rare case.but you never know.
I hope it will help.

 

[MAJOR STONER]

I am not familar with the NSX cooling system. Sounds like the water is not circulating, is there a solenoid that isn't opening?

 

[NSXTech]

Originally posted by pixelhaus:
sorry for the rant. can anyone offer any possible solution? or what to check for?

thanks[/B]

pixelhuas- You fail to mention what would be the most important piece of info- is the cooling system low on coolant evey time it starts to overheat, or have you checked? Most common reason for what you describe is a bad coolant cap- I see it quite often. bad cap will loose a small amount of coolant each heat cycle untill you loose enough to make the car SEEM to be overheating. I say "seem to be" because of the way you describe the needles rapid reaction to revving the motor. When the coolant is a little low, not enough circulates up high where the temp sensor is, and its only hot up top. If I were you, I would top up the cooling system and makes sure its bled once. Then as soon as you notice the temp getting hot again, check the coolant again. Do both checks on a COLD motor, level ground. Another test is to lift the coolant overflow tube out of its clip and look to see if the end is wet. If the cap was recently bypassing (spilling coolant) it will be evident by the prsance of coolant at the end of the hose.
DO NOT REPLACE YOUR "MISALIGNED" HEAD GASKETS.

Good Luck,
Mark Basch

 

[pixelhaus]

thanks mark!
it's funny, i just returned from the garage checking the fluid level. exactly to your point, the level was a bit low. i did fill it up, now i would guess a bleed is necessary. in addition, the smell of coolant is ALWAYS present, which would support your theory of a bad cap. i hope this is the case! maybe i'll purchase a new cap and see what happens.
unfortunately, i do not know how to bleed the system and hear it is pretty complicated. i guess i'll take it in once again.

thanks for the help!

 

[hk4site]

To bleed the system you can put it on a incline over 30 deg's and open up the front bleeding screws. This is a half assed way but it works well

 

[pixelhaus]

had the cap pressure tested. the results came in at 13lbs. is this too low? is the cap bad?

 

[nsxtasy]

Is it also possible that the coolant reservoir tank has a slight crack in it that is causing the leak? I know this is a fairly common problem, don't know if it could account for the symptoms noted here.

P.S. Mark, it's nice to have you and your expertise back with us.

 

[NoClgDeg]

How about replacing your therostat?

------------------
91 Red/Ivory #2061

 

[robr]

pixel, you got screwed, its definitely the thermostat. i had the 100% exact same symptoms, emailed mark basch about it, he said he'd stake his life that it was the thermostat (along with a very in depth explanation), so i ordered a thermostat, had it replaced, no more problems.

 

[robr]

i just noticed mark responded to this thread, mark, it sounds like exactly what i wrote to you about back in january.

marks explanation:

Rob, I'm sure it is a bad t-stat- you have ALL the symptoms. The t-stat has a small hole in it to let it bleed when the cooling system is drained and filled, so if it is stuck closed, you won't get enough hot water at the heater core at idle, but at speed the small amount that bleeds thru the bleed hole will warm the core some. Slow down, or idle, and you don't have enough hot water again. (the heater core cools very quickly with th blower motor blowing air past it) the overheating at idle is for all the same reasons- At idle, not enough water gets past the t-stat to the radiator to cool the motor, but at speed, it gets at least some and that keeps the overheating at bay.

Buy yourself a FACTORY t-stat, 2 gallons of coolant (to be mixed 50/50- no more no less) and I would also reccomend a bottle of Redline Waterwetter. I use it in all my customers cars, its great stuff.

Cheers,
Mark