Coolant trouble.

[DutchBlackNsx]

On me trip to Monza i had my Honda coolant tank go leaking (the common leak), so i decided it was a good thing, and ordered a aftermarket coolanttank, coz the Honda one looked crap anyway.

Installed the new tank, and eversince i have trouble.

I bled the system a couple of times, refilled the tank a few times, but it seems that everytime again, the coolant gets thrown out again, resulting in hot engines in trafficjams, coz the system sucks air in everytime (i think).
Everytime when i fill the thing i bleed the system at 4 points, so the air should be out.

Possible trouble:

1. I don't know what i'm doing.
2. Cap on the coolant bottle not in spec.
3. Leaky headgasket.


Anyone?

Thankx,

Michel
Holland


[This message has been edited by DutchBlackNsx (edited 26 August 2002).]

 

[Larry Bastanza]

HI Michel,

A few things to try:

1. Before you bleed it, make sure the heat valve is open (Turn the heat on full)

2. Get the car up on jack stands in the rear only. You want the nose lower then the rest of the car.

When I did this Mark Basch rcommended this to make is easy to bleed. He said it can take a very long time if the car is level, but if you lower the nose it takes twenty minutes. I did as he suggested and it worked very well. I topped the coolant up about 150 miles later (it took about 1 liter more.

If you do suspect a head gasket, I recommend you perform a compression check, also check you oil level. If it is too high, you may be getting coolant in the oil.

I understand there also is a kit which contains a special chemical(fluid) you can add to the coolant and check to color to see if you have combustion by-products are in the coolant. (sign of head gasket failure)

I do not recall exactly what that is, but someone here will know.

HTH,
LarryB

 

[DutchBlackNsx]

Thankx Larry,

Was waiting for your answer

What you think about a faulty cap? i.e. the relief-pressure is to low ?

thankx,

Mich

 

[Larry Bastanza]

This could be a possibility, do you have coolant leaking from it?? I am thinking it would be pretty easy to see?? Also, if this is a case, then you have excess pressure on the cooling system. So it does kind of make you ask about a head gasket!?

Are you saying that coolant is getting lost somehow?? It just seems odd, that you changed the coolant bottle and all of a sudden you may have a bad head gasket??

So I am clear about it, all was fine, then the coolant bollte leaks, and you just replaced it, then things are not right now??

Also, to change to coolant bottle you really did not have to drain the coolant in the system, just the bottle. Did you do a coolant flush on the whole drivetrain at this time, since it was due??

Let me know.

LarryB

 

[nsxtasy]

Why not just replace the cap? It's easy, it's inexpensive...

 

[DutchBlackNsx]

Spoke to the vendor and he told me there was a problem with some of the caps.

It seems that all the coolant is being thrown out of the overflow tube, and also through the top of the cap itself (easy to see indeed, i.e. white spots).
As Larry pointed out, it would be rather a coincidence (oops, wrong spelling) if a blown headgasket shows up at the same time the coolant tank goes...

I have only 120K kilomters (75K miles).

I might try to find another one locally, so i know what the problem is.

Is the standard one 1.1 bar?

Thankx,


Mich


[This message has been edited by DutchBlackNsx (edited 26 August 2002).]

 

[ACR_Motorsports]

If it is one of those aftermarket steel, aluminum type coolant bottles, it is sometimes typical for those to leak coolant out of the overflow tube. The OEM Honda/Acura coolant bottle has specific chamber design that the aftermarket ones do not have. Some people have had no problems with the aftermarket bottles because they were lucky or do not drive the car that hard. I have seen quite a few cars that were spilling coolant at the track because of the aftermarket bottles.

The OEM bottles are reliable and cheap. For those that don't like the color, simply paint it silver, black, etc.

Originally posted by DutchBlackNsx:
Spoke to the vendor and he told me there was a problem with some of the caps.

It seems that all the coolant is being thrown out of the overflow tube, and also through the top of the cap itself (easy to see indeed, i.e. white spots).
As Larry pointed out, it would be rather a coincidence (oops, wrong spelling) if a blown headgasket shows up at the same time the coolant tank goes...

I have only 120K kilomters (75K miles).

I might try to find another one locally, so i know what the problem is.

Is the standard one 1.1 bar?

Thankx,


Mich


[This message has been edited by DutchBlackNsx (edited 26 August 2002).]

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www.acrmotorsports.com / 949-929-8973

 

[Andrie Hartanto]

Originally posted by ACR_Motorsports:
If it is one of those aftermarket steel, aluminum type coolant bottles, it is sometimes typical for those to leak coolant out of the overflow tube. The OEM Honda/Acura coolant bottle has specific chamber design that the aftermarket ones do not have. Some people have had no problems with the aftermarket bottles because they were lucky or do not drive the car that hard. I have seen quite a few cars that were spilling coolant at the track because of the aftermarket bottles.

The OEM bottles are reliable and cheap. For those that don't like the color, simply paint it silver, black, etc.

I uses the Dali bottle with no problem. Neither do a friend of mine. And we are always one of the faster guys out there. I've been on a track for 1:20 min non stop, started with full tank of gas and had to stop cause I'm running out of gas with no problem.

 

[ACR_Motorsports]

Andrie, I know you are one of the faster NSX drivers out there. I am not saying that all of the aftermarket bottles leak, however, there is a higher frequency of leaks through the overflow hose that occur with the aftermarket ones. Some of the NSXers I have met personally and some customers have had leaks through the overflow hose and some had to send their bottles back to get it re-welded because some bottles cracked under pressure and rendered their cars undriveable.

Originally posted by Andrie Hartanto:
I uses the Dali bottle with no problem. Neither do a friend of mine. And we are always one of the faster guys out there. I've been on a track for 1:20 min non stop, started with full tank of gas and had to stop cause I'm running out of gas with no problem.

------------------
www.acrmotorsports.com / 949-929-8973

 

[Khuang]

I think I know your problem. I had the stock unit and it work great. Change to the Dali it was overflowing. A friend of my put a drinking bottle and it was catching the overflow. Change back to stock and it work again. Return the unit to Dali and it had some problem with the welding. Got a new unit and worked fine.

It is relatively danger with overflowing at the track as it could hit the tire. My instructor thought I needed rear shocks and the shocks were only 3 months old. Good luck!!

Originally posted by DutchBlackNsx:
On me trip to Monza i had my Honda coolant tank go leaking (the common leak), so i decided it was a good thing, and ordered a aftermarket coolanttank, coz the Honda one looked crap anyway.

Installed the new tank, and eversince i have trouble.

I bled the system a couple of times, refilled the tank a few times, but it seems that everytime again, the coolant gets thrown out again, resulting in hot engines in trafficjams, coz the system sucks air in everytime (i think).
Everytime when i fill the thing i bleed the system at 4 points, so the air should be out.

Possible trouble:

1. I don't know what i'm doing.
2. Cap on the coolant bottle not in spec.
3. Leaky headgasket.


Anyone?

Thankx,

Michel
Holland


[This message has been edited by DutchBlackNsx (edited 26 August 2002).]

 

[Andrie Hartanto]

Originally posted by ACR_Motorsports:
Andrie, I know you are one of the faster NSX drivers out there. I am not saying that all of the aftermarket bottles leak, however, there is a higher frequency of leaks through the overflow hose that occur with the aftermarket ones. Some of the NSXers I have met personally and some customers have had leaks through the overflow hose and some had to send their bottles back to get it re-welded because some bottles cracked under pressure and rendered their cars undriveable.

I see what you mean. I was just relaying that me and my friend never had a problem. Interesting info. I'll keep an eye on my coolant bottle.

thanks

 

[Honcho]

I just don't trust my car anymore

Bringing this golden oldie back from the dead, because I am having a similar issue. Guys, I am at my wits end with my NSX. $6,000 later and still having the same problem. I don't trust it anymore and it is making me so sad. Here is my problem and background:

July 2012: HPDE 1/2 day session, 98 F ambient. Original radiator, 2008-replaced hoses, 2009-replaced OEM coolant tank and cap. Temp needle normal for sessions 1, 2, and 3. Session 4 on back straight at 7,000 rpm, needle makes RAPID move from normal to RED and we smell coolant. Back off throttle, keep revs under 4,000 and needle quickly returns to normal. Check engine compartment and coolant clearly has blown out of the overflow tube. Coolant tank is nearly empty. No sign of other leaks in engine compartment. No sign of leaks on rad. Start engine in paddock and needle is back in RED, but slowly drops to normal as engine runs. Add some bottled water to tank and drive home 60 miles at 3,000 rpm. Needle normal the whole drive.

September 2012: Honcho freaks out about overheats and buys new Koyo radiator and thermostat, installed by Acura. $1,000.

September 2012: While waxing car night before NSXPO, Honcho notices a puddle of coolant under the front nose. Return to Acura, discover techs forgot to tighten radiator bleed plug. Tighten plug, top off coolant (about 1 liter) and drive home normally.

September 2012: NSXPO rocky mountain drive. Temp needle normal entire drive up to 12,000 ft. Easy cruise, very little VTEC.

September 2012: NSXPO HPDE Day 1, 78 F ambient. Temp needle normal for 6 sessions, though we smelled coolant a few times. Day cut short when rear brakes pads run out.

September 2012: NSXPO HPDE Day 2, 84 F ambient. Very nice NSXCA member sells Honcho his spare Hawk HPS rear pads to get him through the day. Shad generously takes time to install pads at track. After morning delay waiting for pads, 2 final morning sessions, temp needle normal. In 2nd afternoon session, at 7,000 rpm on the back straight, needle makes RAPID move to RED and we smell coolant. Back off throttle and needle goes quickly back to normal. Shad checks out car, notices coolant tank blew out all its coolant through overflow tube. Shad bleeds system trackside adds water to tank, and pressure tests. Shad notices engine bay main pipe bleeder is only finger tight (last ones to bleed car were Acura during Koyo install). Tank holds 19 psi for 20 min. We go back out. Car only makes it 3 laps before another needle move to RED. Backing off returns gauge to normal. Honcho calls it a day and drives home depressed. Shad reluctantly suggests head gasket tests.

September 2012: Honcho chews out Acura for leaving bleed screw loose, who steps up and performs every possible test on car for FREE, twice. Wet compression test: all cylinders at 185 psi. Dry compression test: all cylinders at 180 psi. (these are great numbers for mile high alt) Leakdown test: PASS. Coolant hydrocarbon test: Idle - PASS; 5,500 rpm - PASS. Coolant is clean. Oil is clean. Conclusion: head gaskets are not damaged. Next, Acura inspects cooling system and notices leaking coolant around engine bay main hard lines. Tech suspects pinhole leak in hard lines. Remove and pressure test hard lines yields no leaks. During removal of hard lines, tech notices 3 hose clamps are broken. Clamps replaced and everything buttoned back up. Conclusion: head gaskets ok. Coolant loss likely due to air bubble sucked in through broken clamps overnight after car cooled down from first day of HPDE. NSX drives normally rest of the Fall, but never under track conditions.

December 2012: TB/WP major service done by Chris W at Flatirons Acura. Engine out and everything replaced. Told Chris about cooling issues and he makes sure to inspect while he's in there. $5,000. Chris notices nothing unusual. Fills coolant, bleeds, and like the great tech he is, encourages Honcho to beat the car up and track it. Highly recommend Chris btw. Honcho daily drives car for months with no issues (~4,000 miles), but never under track load conditions.

June 2012: While detailing car, Honcho notices coolant level in tank slightly below MIN line. No sign of leaks anywhere. Warms up car, shuts off, and fills to MAX line (about 1 L). Continues to daily drive car. Coolant level does not change.

YESTERDAY: HPDE 1/2 day session, 94 F ambient. Check warm coolant level at MAX line before going to track. Oil full and clean. Sessions 1, 2 and 3 temp needle normal, but I smell coolant each session. Check after session 3 and area under overflow tube is dripping wet. Temp needle still normal. Session 4, lap 5: at 7,000 rpm on back straight needle makes RAPID move from normal to one tick below RED and I smell coolant. Backing off drops needle quickly back to normal. Check tank in paddock and THE COOLANT TANK IS EMPTY No sign of leaks anywhere and it is apparent all coolant blew out of overflow tube. Drive home at 3,000 rpm and needle is normal the whole way. My NSX is sitting in my garage and I haven't touched it since, I am so disgusted with it right now.

So, $6,000 and two dealers later I still cannot drive my car on the track for more than a few laps before it barfs coolant and scares the shit out of me with the damn temp gauge. I am completely beyond frustrated and dissapointed in my NSX. I am talking to Chris tomorrow and hopefully he will have some ideas, but WHAT THE HELL??? Why won't my car hold coolant??? It's not like I have twin turbos or something. The only mod on my car is 1998 OEM headers! I have no idea what to do and don't even want to track anymore after this. Each time I go I end in limping home wondering if I just warped the heads in my $25k engine. It is supposed to be fun, but this totally ruins it. What do I do?

Prime family please help me out!

 

[mr envy]

ok what temperature thermo switch and thermostat are you running? what type of coolant tank also? all oem? mods to the car? sorry im just thinking theres something just causing it to fail under prolonged pressure hopefully its just the coolant system letting some pressure off without damaging your heads...

 

[sca037]

Is there any chance that a coolant hose is collapsing under track conditions, causing an intermittent restriction of coolant flow?

I've seen that on other cars (that needed wire-reinforced hoses) but so far not the NSX.

Brian

 

[silver2002]

What about reservoir cap? I can leak/bleed prematurely - pressure test it off car?

 

[Honcho]

ok what temperature thermo switch and thermostat are you running? what type of coolant tank also? all oem? mods to the car? sorry im just thinking theres something just causing it to fail under prolonged pressure hopefully its just the coolant system letting some pressure off without damaging your heads...

Honda factory thermo switch. Fan confirmed running.

Honda factory thermostat. Replaced in December 2012 at recommendation of Chris due to previous overheat event.

Honda factory coolant tank. Replaced in 2009.

Only mod to the engine is 1998 OEM headers. Everything else is stock.

Is there any chance that a coolant hose is collapsing under track conditions, causing an intermittent restriction of coolant flow?

I've seen that on other cars (that needed wire-reinforced hoses) but so far not the NSX.

Brian

Very interesting, but not sure how you could test this. All 23 hoses were replaced in 2008.

What about reservoir cap? I can leak/bleed prematurely - pressure test it off car?

I was thinking this after reading this thread. I should have swapped caps with whitebois while I was at the track to see if his cap made any difference. But my cap is only 4 years old and is OEM?

 

[docjohn]

I feel for ya..I have had many hpde days ruined by cels, stuff breaking ect.......I can attest to the fact that limping home sucks..and being out on track you must have 100% confidence in your equipment or else you are not having fun.I know you say that your car first started this with the oem radiator .....but could the koyo have anything to do with this? Is the koyo rated to take track work....is anything blocking the front inlets like a stone shield ect.Pm hrant I know he had done some research on hot track days and overheating.

 

[NSXASTY]

Could it possibly be a intermittent water pump failing when driven hard???

 

[Honcho]

I feel for ya..I have had many hpde days ruined by cels, stuff breaking ect.......I can attest to the fact that limping home sucks..and being out on track you must have 100% confidence in your equipment or else you are not having fun.I know you say that your car first started this with the oem radiator .....but could the koyo have anything to do with this? Is the koyo rated to take track work....is anything blocking the front inlets like a stone shield ect.Pm hrant I know he had done some research on hot track days and overheating.

Thanks, it really is a bummer. The Koyo is track rated and superior in build quality to the factory rad (solid aluminum vs plastic glued tank). Also I have a Dali stone shield but remove it for hpde days. I may just retire the NSX from track duty rather than keep throwing $$$ at this problem.

Could it possibly be a intermittent water pump failing when driven hard???

Also a good thought, but the pump is virtually brand new. Installed December 2012.

 

[Stephen@NCAutoUSA]

I'm just taking a wild guess but it seems like something is getting "stuck" or is causing the coolant to slow during its way around or cycle. I don't know to much of its path but going to the coolant tank path seems fine since its coming out the over flow tube.

It's the path outward that I'm wondering about. The real issue is the inconsistency of this event. It only happens when you really drive your car hard? Is there something anyone knows of that engages when driven hard?

 

[Honcho]

I'm just taking a wild guess but it seems like something is getting "stuck" or is causing the coolant to slow during its way around or cycle. I don't know to much of its path but going to the coolant tank path seems fine since its coming out the over flow tube.

It's the path outward that I'm wondering about. The real issue is the inconsistency of this event. It only happens when you really drive your car hard? Is there something anyone knows of that engages when driven hard?

Actually it is a very consistent event. This happens every time the car is driven hard in VTEC for sustained periods (10 min +). This NEVER happens in any other driving condition, VTEC or otherwise. Since the only place you can do VTEC for 10 minutes or more is the track, this only happens at the track. Since the car will pass any test Acura can run sitting in the garage, I am considering having Chris do 8,000 rpm pulls for 10 min to see if he can recreate the issue.

 

[tof]

Of course the real question is which came first: Overheat condition or loss of coolant via the overflow tube. If it overheated first, forcing coolant out the overflow tube, the cause could be any number of things from cooling system issues (air still in system?) to timing problems to over-lean afr. Of course some of those things would throw a code and others would have a noticeable effect on performance. So I'd eliminate the coolant loss possibility first. I would install a new coolant cap. Cheap test.

Here's a question for the more technically knowledgeable: What impact, if any, would briefly starving the oil pickup have on coolant temperatures. I have heard/read about nsx owners who had issues with oil starvation from the oem oil pan on tight circuits with lots of high-G corners. Basically I'm trying to think of things that would cause overheating to the point where coolant overflow during hard track use but only after a few sessions.

 

[Honcho]

In my case, the needle does not move and then moves rapidly as the car loses coolant, and then returns to normal after I back off. Spoke to Chris and he is very doubtful it is the HG. He said it was a fairly common issue for NSX's at our track due to thin air, hot temps and track config. His suspicion is the cooling fan high relay and/or fuse is bad and the high fan never comes on, causing coolant to boil over and barf out of the tube. He also suggested going to a 1.3 bar cap and/or adding a switch to keep the fan on high for the track.

I was out there with whitbois and his car was a couple of ticks above normal by the end of the day, but not barfing coolant. Though, he has a NSX-R vented hood, so that could be the difference.

 

[docjohn]

my car had been running lean for over a year throwing lean codes...obd2 ....and i never overheated even at wgi.

 

[JD Cross]

I am not expert in this area.
I've only had my NSX temp needle go close to red once at the HPDE at NSXPO in Phoenix.

Thinking along tof's lines it's possible we have an engine condition that makes more heat than the cooling system can manage and so coolant boils and overflows.
This would make the coolant overflow a symptom but not the problem.

Oil starvation could indeed raise the temperature of the engine and result in the coolant boiling but would the main bearings be adversely affected?

Would a top end condition be the most likely area for excessive heat?
How about detonation? The antiknock sensor would retard timing but the heat generated would be huge for a short time.
A lean condition could also overheat the top end.

There must be engine/track experts out there that have studied this.
Are there any other conditions that would create a burst of heat beyound the cooling's system to carry it off?