Started to overheat at track!!

[Blackoutz]

I had a track day yesterday at Harris Hill Road and had an absolute blast. It was my first time with the NSX on track and was amazing.

I did however on my second 25 minute session start to move the needle on the dash dam close to the red mark by the time I saw it. I didnt think these cars had heating issues. I was able to take a half lap and cool the engine back down to normal temperature then take another hot lap. I recently had teh coolant changed and new coolant put in and the 60000 mile service was done at the same time. The car now has 73,000 miles and has never gotten hot daily driving in hot weather with the A/C.

Any insight would be great and where I should start.

Thanks
Blaine

 

[CL65 Captain]

First off, daily driving isn't going to keep the rpms from 5-8k for 25 minutes straight so you are talking apples and oranges.

What was the OAT at the track? Yes NSXs do have heat issues at the track. There is a Best Motoring video of the NSX-R that started to over heat after 5 hard laps.

When it starts to get close to 90F+, my stock NSX will start to run hot after about 15 min of pushing hard. This was running 10w30, 1.3 bar Spoon radiator cap and a bottle of Redline Water Wetter.

I recently switched to 15w50 Mobil 1 and added the SOS oil cooler. I ran Sat at Mid Ohio with 87F temps and it now remains rock solid at one tick under 1/2 on the stock water temp gauge.

 

[nsxotic911]

I had a track day yesterday at Harris Hill Road and had an absolute blast. It was my first time with the NSX on track and was amazing.

I did however on my second 25 minute session start to move the needle on the dash dam close to the red mark by the time I saw it. I didnt think these cars had heating issues. I was able to take a half lap and cool the engine back down to normal temperature then take another hot lap. I recently had teh coolant changed and new coolant put in and the 60000 mile service was done at the same time. The car now has 73,000 miles and has never gotten hot daily driving in hot weather with the A/C.

Any insight would be great and where I should start.

Thanks
Blaine

Define "recent" since it's not clear whether it was at 60K miles, or > 60K.
If the coolant was > 60K, and actually recent, then it's very possible the change was performed incorrectly. It's very easy to improperly do a coolant change on the NSX...

Did you check the coolant level before going out?

 

[CL65 Captain]

Just noticed - Location: San Antonio

It was 99F yesterday there.

A stock NSX on the track, running hard for 25 minutes - I would expect it to over heat.

 

[NSXGMS]

Define "recent" since it's not clear whether it was at 60K miles, or > 60K.
If the coolant was > 60K, and actually recent, then it's very possible the change was performed incorrectly. It's very easy to improperly do a coolant change on the NSX...

Did you check the coolant level before going out?

+1

Very easy for an air bubble of sorts to be created in the coolant system after a coolant change if it's not done properly and I've seen it happen many times. An indicator of this is if the air blower won't blow hot during or after the overheating event.

 

[Blackoutz]

The coolant and the 60k was done with in the past 6 months by a former NSX tech at Acura.

It sounds like this might be normal over a 25 min session from what you all are saying.

Switching from 10w 30 to 15w 50 will help?? If so I need a oil change this week and can do that pretty easily. And as far as the oil cooler that will help with cooling issues too??

Am I going to have to upgrade the radiator ultimatley to fix this problem??

Thanks for all the responses and yes it was almost 100 degrees this past sunday.

thanks
Blaine Waddell

 

[Larry Bastanza]

Switching from 10w 30 to 15w 50 will help??

Not really, maybe the oil cooler, but not the oil.

Regards,
LarryB

 

[Blackoutz]

I would be willing to bet if it was only about 85 degrees out I would not of had a problem. I need to change something though before the next track day.

Thanks
Blaine

 

[Hrant]

I would be willing to bet if it was only about 85 degrees out I would not of had a problem. I need to change something though before the next track day.

Thanks
Blaine

Even at 85F if you are driving mostly in the 6000+ RPM range it will "overheat" over 25 minutes - that is the needle will move above the middle; how much above depends on other variables too but probably not as close to the red line.

Depending on your driving needs (daily driver/track mix), you may consider going with mostly water in the radiator rather than 50/50 with water wetter. The nest step with be clearing the front scoop for better air flow (ie, rotate the horns up, move the AC temp sensor), add an oil cooler, and then it gets more involved .......... aftermarket radiator (I am informed there will be a new option with dual fans), lower operating thermostat, vented hood .....

 

[davidf]

I was in SanAntonio this past week and it dipped into the 100's almost daily, so yes outside temp was likely a big factor.

 

[davidf]

Not to start up a debate here but you track guys should consider Evans NGP+ coolant. It worked wonders on my boosted MR2. The lifespan is probably 4/5 times of the Honda coolant. Just my .02.

 

[nsxotic911]

I would be willing to bet if it was only about 85 degrees out I would not of had a problem. I need to change something though before the next track day.

Thanks
Blaine

Take it back to the dealer, tell them what happened. Look @ the coolant level, is it below the line at all? That would an indiciation that everything was not A-ok.

A few other things you can do...
Turn on the car and let it idle for 30 minutes and see what happens. If it nudges slightly up, you for sure have a problem that is not track related.

Create a higher water concentration with the coolant. Nothing wrong with that. Racers do it all the time. No risk the coolant freezing as even 100% water under 1.3 bars of pressure will resist freezing up to something like -10 - -30C's. 50/50 coolant is for Siberia and North Pole driving. The only downside is that your boiling point decreases (again, much higher than 100 because of the lower "antifreeze=anti-overheating solution" but it's something you monitor. I usually run around with 65% water/35% af or so..Still, this is only after you determined the cause of the overheating, and you should monitor very carefuly. If you're loosing/boiling water, top it off with the Honda coolant until it stops.

Bottom line..I wouldn't drive the car outside of my driveway an inche if there was any evidence that it overheated until I FIGURED OUT what the problem was. Otherwise you're flying blindly on "hope and change" which could very likely result in a disaster, and 10K-20K out of pocket expense. This is coming from a guy with two non-NSX overheated engines...

 

[CL65 Captain]

This is coming from a guy with two non-NSX overheated engines...

Really? Have you tracked the car hard in 100F temps?

 

[nsxotic911]

Not to start up a debate here but you track guys should consider Evans NGP+ coolant. It worked wonders on my boosted MR2. The lifespan is probably 4/5 times of the Honda coolant. Just my .02.

Tell us about it.. I've used Water Wetter and RMI before.. but without scientific tests, I can't say whether they helped or not.

My concern with RL is that it sometimes gunks up the coolant, just doesn't feel right. When people see this, they often freak out thinking they have a headgasket feailrue or something. Redline should fix this...

With RMI, it was well regarded years ago.. but little data on it now. I have a sample that I'm supposed to send to a coolant analysis place, but too lazy.

 

[goldNSX]

Just another hint: You've a 94. Did you change the coolant hoses recently? The small little o-rings of the radiator and around the engine too? :wink:
It has been some while ago (years actually) but GerardvanSanten here on prime talked about overheating at the track which was diminished by changing a $0.01 o-rings of the radiator. You actually don't loose coolant visually but the system can't build up the needed pressure. The pressure cap is useless in this scenario.

I've changed those two little babies et voilà I had from near to none pressure a full amount of pressure.

Another hint: There has been a stuck radiator-story here recently.

After all: Listen to the track guys.

 

[jtower]

i'm posting this from the summit point paddock and can tell you that 15-20 of full tilt driving in mid-80s weather can push the cooling system of a nsx to the limit. not to the point of damaging anything mind you, but the gauge starts creeping up past the halfway point and the ecu might drop the rev limit to 7000. still, i was able to catch that damn sn95 mustang race car with a 415hp motor

 

[davidf]

Tell us about it.. I've used Water Wetter and RMI before.. but without scientific tests, I can't say whether they helped or not.

My concern with RL is that it sometimes gunks up the coolant, just doesn't feel right. When people see this, they often freak out thinking they have a headgasket feailrue or something. Redline should fix this...

With RMI, it was well regarded years ago.. but little data on it now. I have a sample that I'm supposed to send to a coolant analysis place, but too lazy.

Better details than I can explain.

http://www.evanscooling.com/html/npgPls.htm

 

[Blackoutz]

thanks for all the great advice guys!! Im going to do all the hoses in the next month and buy that kit from SOS. Is that the kit to buy?

Im also going to go ahead and swap out the thermostat since I don't know the last time it was done.

Thanks alot

Blaine Waddell

 

[R13]

Better details than I can explain.

http://www.evanscooling.com/html/npgPls.htm

If I can find a jug or two of this stuff I may give it a try in my MR2. I had some issues with it overheating after along session on a hot day, and that was a pretty interesting read. Even if it's $30/gallon that's still a sight less than a racing radiator.

 

[Bigglezworth]

It's a possibility that you have a small air pocket in the coolant system that created a temperature spike when the steam hit your temperature sensor. I find it hard to believe the car would cool down after one lap permitting you to do more hot laps. Hot is hot. You would need a decent amount of time to cool down prior to more hot laps. I run 20 minutes straight at 6000-8000 RPM contantly and have never experienced anything close to high temperature levels.

Something to try. Prior to your next cold start-up, crack the cooltant tank cap, but don't take the cap off. The coolant system will not be able to build up pressure. Let the car warm-up to operating temperature. Ensure your overflow tank is full to the 'hot' level. Take car out for a 5-10 minute normal drive. This will purge any rogue bubbles out of the system. When you get back, double check the coolant tank to make sure it is filled to the hot level. Close pressure cap and let the system suck in reserve fluid to replace the expanded hot fluid. Prior to next cold start-up, check coolant reserve and ensure it is filled to 'cold' level. Ensure cap is tight. Voila, you've purged the airlock out of your system.

 

[Blackoutz]

Thanks for the advice bigglesworth. I will look in to that. Has anyone ever tried his method??

thanks
BLaine

 

[goldNSX]

Something to try.

The NSX coolant system is self 'de-airing' (what a word! :tongue:) for small amount of air in the system which you still have right after a coolant change for example. No need to complicate things.

One more test (very, very simple one): Go for a drive for >15 minutes. Open the cap only half a turn (AND PROTECT YOUR HANDS AND SKIN!), don't take it off. There should be a loud and pronounced whooosh/relief of the coolant system. If you don't have one your system is not building up enough pressure.

Yes, I think SOS has the things you're looking for. Make sure it contains those two o-rings at the radiator.

 

[Blackoutz]

What would you all think about putting a mishimoto radiator in replacment of the stock one? Would I get any gains on the track or wouldI have the same problems.

I found one on ebay for 380 dollars and was wondering if anybody has ever used it for track duty?

thanks
Blaine

 

[Bigglezworth]

The NSX coolant system is self 'de-airing' (what a word! :tongue:) for small amount of air in the system which you still have right after a coolant change for example. No need to complicate things.

i.e. Expansion Tank vs. Overflow Tank?

http://www.custompistols.com/cars/articles/overflow.htm

 

[john@johnhudakracing]

I had a track day yesterday at Harris Hill Road and had an absolute blast. It was my first time with the NSX on track and was amazing.

Sweet.

I did however on my second 25 minute session start to move the needle on the dash dam close to the red mark by the time I saw it. I didnt think these cars had heating issues.

Generally they don't. Due to the ME design, the stock cooling system on the NSX is adequate for what most people are doing. Sounds like it was a hot one, but given what you have stated, I think you should still have been ok.

I was able to take a half lap and cool the engine back down to normal temperature then take another hot lap.

Next time I would just come in to the pits and shut it down.

Any insight would be great and where I should start.

Given the symptom you described- the number one thing you can do: I would suggest you take the time and bleed the system through really, really, good. You can do it track-side. Fire it up. Remove the pressure cap on the expansion tank, on throttle to get it good and hot all the way up to a rolling boil, one by one go through and crack the bleeders in sequence, and work any air pockets out until you have a nice steady flow.

You might also just use water plus a bottle of redline water wetter. You can probably due without the anti-freeze in 100F Texas Summer weather for the time being.

What would you all think about putting a mishimoto radiator in replacement of the stock one? Would I get any gains on the track or would have the same problems. I found one on ebay for 380 dollars and was wondering if anybody has ever used it for track duty?

Yeah, I wouldn't just drop anything in there and assume it is going to be an improvement- even if someone tells you it will be.

If you want to install a higher capacity radiator that isn't an overall regression from stock all things considered, I'd take a little more time on that one before forking over your hard earned money. If you want something quick and drop-in Dali has an offering that isn't much more, and much beyond that you are in the range you could put something together custom.

Frankly, the stock single pass, matched to the stock water pump, coupled with the ME layout is very good, and I think you could get it to work for the time being.