Yet another overheating issue

[VBNSX]

Situation:
Overheats at idle

Diagnosis:
New radiator
Water pump replaced with tb about 5 years ago
Dali coolant bottle
Fan switch replaced a few months ago.
All hoses replaced.
At race speeds the car holds rock solid with its highest temp being 220...


I hear the 2 step fan come on at the prospective temps, but it still seems to keep creeping up..

Does anyone have any ideas?

A few ideas I had were:
1. Replace thermostat (maybe stuck closed?? doesn't make sense with at speed temps though)
2. Dali coolant tank? (idk.. i have the oem one.. figured it may be worth a shot)

Thank you for your time,
xavier

 

[NSXclear]

Have you replaced the coolant recently?

Make sure you bleed your coolant system correctly. If not, it will overheat. Look at the service manual for all the bleed nipples locations. Must be bleed in sequence.

 

[ftuhy]

I don't drive in much stop and go traffic, but I've never heard the fan come on in my '96. Going from an hour of sustained 70 MPH driving to sitting at a stop light at the end of an exit ramp, and the temp stays rock solid.

I have to agree with vsy05, check the coolant level and bleed the system.

Another possibility - a hose collapsing, restricting flow. While that usually happens at speed, Murphy always finds new ways to demonstrate his law.

 

[VBNSX]

yeah i've bled the system a few times actually... i did follow the instructions in the book to a 'T' however admittiningly, my garage floor has a very slight slant... I'm wondering if that may cause an issue.

I'm wondering if the dali coolant tank may pose an issue.... have there been issues with aftermarket coolant tanks before?

x

 

[ftuhy]

When I bleed my system, I do it on level ground, and then being a little anal(my wife would say a lot anal), I take it out on my steep driveway and repeat the bleed, once with the nose downhill, then with the nose uphill. Sometimes I actually get one more tiny air bubble out.

A WAG is to change the thermostat. Other than O2 sensors, the only part to ever fail on my NSX was the thermostat. The rubber o-ring around the moving plate mushroomed and stuck the thermostat open. As a result, the car took forever to warm up. Perhaps the o-ring can also mushroom and block the coolant flow. At highway speeds, higher engine speed means higher water pump speed/volume, to force enough coolant past a partially blocked thermostat. But again, that's a WAG. And, for less than $20 (at NAPA, for example) you get get a non-Acura thermostat for the same temp but without the problematic o-ring.

Of course, the above scenario could also say the water pump has lost efficiency and doesn't work well at idle. So, I'd risk the $20 thermostat change first.:biggrin:

I'm running the OEM tank, and so can't comment on the Dali tank.

 

[ncdogdoc]

Hi Xavier,

Long time no talkie. Hope you are well.

The Dali tank has been linked to problems in the past. Do not remember the exact details but would try a swap just to be sure. Then bleed again, and again Could be an air bubble getting stuck before the t'stat opens at higher temps? Just a couple of guesses.

Hope to see you at VIR someday. Broken the 2:10 barrier yet!!

 

[LJSB]

A vacuum coolant re-filler is the only way to do the job, safe, correct and fast.
No heating up the car, it's done with the car cold leaving no air pockets. System is filled in 3 -5 minutes. Done!
Blue Point. Mity Vac, Snap-On, Mac all make them of varying quality according to how much use the tool will see. About $150.00 for a decent one $250 for a really good one.

Example:

 

[docjohn]

Joe ,are you performing grey market colonoscapy at Vinces again??????:tongue:

 

[LJSB]

Atsa "in you endo".:biggrin:

 

[VBNSX]

Hi Xavier,

Long time no talkie. Hope you are well.

The Dali tank has been linked to problems in the past. Do not remember the exact details but would try a swap just to be sure. Then bleed again, and again Could be an air bubble getting stuck before the t'stat opens at higher temps? Just a couple of guesses.

Hope to see you at VIR someday. Broken the 2:10 barrier yet!!

for 2:10 i'm gonna need to step it up to some r-compounds.. :redface: yeah somehow I'm still on streeties... I always told myself I wouldn't upgrade to r's until I was confident I could squeeze out some good times on streets.

I've heard mixed reviews with your race car.... what's goin on with that?

 

[VBNSX]

A vacuum coolant re-filler is the only way to do the job, safe, correct and fast.
No heating up the car, it's done with the car cold leaving no air pockets. System is filled in 3 -5 minutes. Done!
Blue Point. Mity Vac, Snap-On, Mac all make them of varying quality according to how much use the tool will see. About $150.00 for a decent one $250 for a really good one.

I actually have one of those... I used it to load the lines when I re-did all the hoses. I remember seeing all the lines compress and getting a stable system.

From reading the instructions i thought it's only to be used when the system was empty??? I could be wrong here.... if I am can you please explain?? (perhaps too much air pressure from the air compressor?)

 

[LJSB]

If the system has coolant in the system you pull vacuum until the air is out and you begin pulling coolant out. You then stop and refill.

 

[VBNSX]

If the system has coolant in the system you pull vacuum until the air is out and you begin pulling coolant out. You then stop and refill.

thank you... I'll do that today.

 

[docjohn]

Atsa "in you endo".:biggrin:

Classic. Oh and thanks Xavier for letting us have some fun within your thread,and not getting all twisted up like some folks do:biggrin:

 

[LJSB]

How about a product like Water Wetter?
Auto Zone make a version that's quite a bit less expensive and a very good value. I know of a large Porsche race team that uses that.

BTW thermostats don't always stick just open or closed. Sometimes they can just screw around and not open all the way.

 

[VBNSX]

Classic. Oh and thanks Xavier for letting us have some fun within your thread,and not getting all twisted up like some folks do:biggrin:

lol.. but of course... life's way too short to even remotely bother with things like that.. besides, it adds flavor to the post

How about a product like Water Wetter?
Auto Zone make a version that's quite a bit less expensive and a very good value. I know of a large Porsche race team that uses that.

BTW thermostats don't always stick just open or closed. Sometimes they can just screw around and not open all the way.

I can honestly say that I have been considering trying it out... I just get skeptical with things like that... here's an interesting review:
http://www.thetruthaboutcars.com/redline-waterwetter®-review/

 

[LJSB]

Articles sometimes are written by people who are paid to be entertaining and clever more than educational.

The science behind products like water wetter is factual and sound.
The purpose of such a product is to make the bubbles in the coolant much smaller thereby increasing the amount of surface area for increased temperature transfer. Smaller bubbles= more surface contact= more temp transfer, cooler temps.

I'd try the thermostat first and perhaps a check on the coolant for the presence of combustion gases.

 

[VBNSX]

ok so i don't want to sound noob but b/c i want to do it right i'm going to ask the question...

I have the aev700 mac tool air evac.

last time i used this it worked well for testing to see if i had any leaks or issues but when i put put the siphon tube and sucked up all the radiator fluid until the unit hit zero, I had only used a few gallons of radiator fluid... I knew there had to be more used...

somehow I must've used this wrong (no idea how... quite an easy concept)

from there I filled the filler tank and then went on to bleeding (according to sequence) and filling the tank until I used what was required by the book (4 I think)...

any idea what I may have done wrong?

lastly, when i put the stopper and compressor to the unit and shoot this on, is the radiator fluid gonna shoot out the muffler?

now that I think about it... we're probably talking about two different evac's


thanks again,
xavier

 

[LJSB]

AEV700 MAC Tool Air EVAC

That's the one I have as well. Between the various guys in our shop. we have a few of them, all different brands. I think the Snap-On one is the nicest but also the most expensive.
Used properly you should not have to do the bleeding process, that's the point of using this device. After filling and a good warm up you may have to add a small amount to the coolant reservoir but that's about it.
I don't know what you mean about it shooting out the muffler.

 

[VBNSX]

Just in case (doubt it but u never know) anyone was following this, I went ahead and pm'd Joe regarding this.. here is how it ended (so noobs like me will know how to use this)
-------------------------------------------
Maybe it's just the engineer in me that may be over thinking this (nothing new there)but...

Here is what I am referring to:

Main instructions

the first line states to make sure the whole system is empty..

here is the muffler:

If i'm not mistaken this system work on air pressure generated outside from the compressor draws air out from the system within.... then when you switch the adapter to a hose and put the hose in a gallon tank, the negative pressure from the system will draw the fluid into the vehicle....

If I put the adapter assembly on the expansion tank then turn it on, it'll eventually draw up radiator fluid... however, it'll only have one way to go.. out the muffler (1 way)..

maybe I'm over thinking this... idk.. however I am grateful for any light you may be able to shed on this since I have a feeling i am just completely over-thinking this.

thanks again,
xavier



-----------------------------------------------------
reply:


Now I understand your muffler reference.
Yes coolant would come out of the muffler on the Vac unit. You don't let it give you a bath you just make sure you pull vacuum and get the air out and then refill.

I need to clarify something about the Water Wetter product. It will lower operating temps. but if your car is overheating just sitting at an idle it's not going to help that. If your system is working correctly you should not need it but could add it as insurance.

If I were you I would empty your system, hook up the AEV700 and pull vacuum. let it hold and see if it shows any leaks.
If things check out refill the system. if you can't fill the system, save for a few ounces, something is wrong. Either you are not pulling enough vacuum or there is a leak somewhere.

If your fans cycle correctly, the rad is in good condition, coolant in good condition, thermostat working correctly, radiator is not blocked and has proper air flow and there are no visible leaks I would check the coolant for presence of combustion gases.

There are only so many places to look and I am assuming you know how to test and verify for the proper functioning of the various components. The cooling system in this car is very efficient and, as you are well aware, overheating sitting at a idle should not be happening.

Hope the problem is resolved before you need to check for combustion gases.

From what I have seen happen to others, when a NSX overheats it doesn't take much to start having head problems. I hope that hasn't happened.


------------------------------------------------------
resolution:
Cool... yeah I just went ahead and put the aev on to see what would happen. As expected I did it until the in/Hg setting hit 23. After that I closed the unit and waited 2 minutes (says 30 sec)..... inspected the lines by the radiator to check to make sure they compressed... looked at the gauge and it held rock solid...

then I put the tube in a gallon of honda blue radiator fluid and to my surprise it pulled about a half gallon worth...

After pulling the adapter off, I noticed it filled the expansion tank to the brim... needless to say I siphoned out about around a 1/4 gallon out of the expansion tank to make it set to the right level...

Either way, I must've pulled and found around 1/4 gallon of fluid a new home in that system somewhere... (ie there was definitely an air gap somewhere)

Now that I think I know how to use this tool better I really like it.. =P

On a side note, I saw the heating issue Sunday afternoon (after I got back from track) and Monday night I did a compression check (got paranoid about the overheating)... and I hit 220 even thru all cylinders... (def a good sign)..


-------------------------------------------------------
so.. for anyone who may need this in future... well.. there it is...

cheers and thank you for all the responses (esp Joe :biggrin,
xavier

 

[Daedalus]

I guess I'm not understanding the basis of the question. I don't see how the coolant can go out the muffler, as the muffler isn't even attached when you fill the system with coolant. You create a vacuum in the system with the venturi device, seal off the system at the valve, detach the venturi device from the adapter assembly and attach a fill hose, dunk the fill hose in coolant and then open the valve. The vacuum will draw in coolant until the pressure inside is the same as atmospheric (plus or minus any head from the height of the coolant container). The partial vacuum cannot overfill the system, and the adapter is at the highest point. When you say "draw up radiator fluid", where are you drawing it up from? It sounds like you're doing something a bit different from the instructions.

I'm just slightly concerned with the fact that it's not a perfect vacuum, so I'm not sure how doing this just once will fill the entire system. 23/30 = 77% full. Unless the extra 23% volume is the air volume in the overflow tank, you'll have to do this more than once. Also, any "inverted" air pockets will still have air in them no matter how many times you vacuum-fill. That said, I use a similar tool (Mityvac) and have not had any problems. Small voids will work themselves out.

 

[VBNSX]

I guess I'm not understanding the basis of the question. I don't see how the coolant can go out the muffler, as the muffler isn't even attached when you fill the system with coolant. You create a vacuum in the system with the venturi device, seal off the system at the valve, detach the venturi device from the adapter assembly and attach a fill hose, dunk the fill hose in coolant and then open the valve. The vacuum will draw in coolant until the pressure inside is the same as atmospheric (plus or minus any head from the height of the coolant container). The partial vacuum cannot overfill the system, and the adapter is at the highest point. When you say "draw up radiator fluid", where are you drawing it up from? It sounds like you're doing something a bit different from the instructions.

I'm just slightly concerned with the fact that it's not a perfect vacuum, so I'm not sure how doing this just once will fill the entire system. 23/30 = 77% full. Unless the extra 23% volume is the air volume in the overflow tank, you'll have to do this more than once. Also, any "inverted" air pockets will still have air in them no matter how many times you vacuum-fill. That said, I use a similar tool (Mityvac) and have not had any problems. Small voids will work themselves out.

I see what you're saying. However, as you put the compressor to the attachment, there will be 'splatters' of fluid as all the air in the system is worked out since the fluid level will rise in the expansion tank as the coolant hoses compress. Those splatters will shoot out the muffler (while you have the compressor on the attachment).

in phase 2 (lack of better terms), u remove the attachment and hook the hose up to it while the valve is closed... then the other end of the hose is put into a gallon and the negative vacuum will load the system with fluid (when the valve is opened).

I agree with you on your 77% full statement.. however tbh being new to the system I was just working off of statements 5-7 in the instructions. Had I been more experienced with this system, I would've hit it twice.

I hope I answered (or discussed) this with you in the manner you were looking for..

xavier

 

[Larry Bastanza]

Guys,

I have used this tool more times then I can count. Fill the car as the instructions say. The coolant bottle will be almost full. Test drive the car, get it to full temp, make sure you run the heat at 90 degrees for 1 minute at least. Let it cool down, then add about 1 qt. or so to the coolant bottle, drink beer.

Also remember, when you fill the first time, MAKE SURE the water valve for the heater core is open...

My $.02

Regards,
LarryB

 

[EdinKali]

I've always done coolant changes the hard/cheap way in the past but this tool looks like it makes coolant changes so easy I just had to order one. Found the mighty vac version on amazon for $114.xx + ~$11 shipping.

 

[VBNSX]

I've always done coolant changes the hard/cheap way in the past but this tool looks like it makes coolant changes so easy I just had to order one. Found the mighty vac version on amazon for $114.xx + ~$11 shipping.

now that I know for sure how to use it, it's quite pimp. It's very, very effective and fast.... can't go wrong.

x