Overheating '93 - I Need Your Input

In response to other questions....

The overheating did not occur after doing the tb/wp job, or after changing the coolant

Nothing is blocking the radiator

I'm going to try testing using the "exhaust in the antifreeze" kit this evening

I don't think I've missed any of your questions right??
 
OK here's the update!

I purchased and used the Block Test kit. Although the instructions indicate the color should turn to yellow in a minute or so it did not........but after letting it sit on the coolant bottle (without using the air bulb so as to not draw any coolant up into the tube)) for about 5 minutes it stated to lighten in color. I performed the test three time with the same results. It would not change right away but it did start to change over time. During the final test I got some overflow from the coolant bottle and once the test tube was removed, the flow would spit out intermittedly (with the temp gage reading normal).

So I now conclude that I have a head gasket leak that pressurized the cooling sytem causing the spitting out of the bottle, and this leak is very small because the Block Test results took more than a minute. I'm going to try the test again this evening and moemntarily block off the upper return line to the bottle, and use the air bulb instead of just letting it sit on top.

Urggggh! As much as I hate to admit it, looks like I'll be replacing the gaskets instead of the more simple and less costly radiator repair. Any recommendations on the gasket to use vs a stock one?

Any last thoughts (BrianK?)
 
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Kitaka said:
OK here's the update!

I purchased and used the Block Test kit. Although the instructions indicate the color should turn to yellow in a minute or so it did not........but after letting it sit on the coolant bottle (without using the air bulb so as to not draw any coolant up into the tube)) for about 5 minutes it stated to lighten in color. I performed the test three time with the same results. It would not change right away but it did start to change over time. During the final test I got some overflow from the coolant bottle and once the test tube was removed, the flow would spit out intermittedly (with the temp gage reading normal).

So I now conclude that I have a head gasket leak that pressurized the cooling sytem causing the spitting out of the bottle, and this leak is very small because the Block Test results took more than a minute. I'm going to try the test again this evening and moemntarily block off the upper return line to the bottle, and use the air bulb instead of just letting it sit on top.

Urggggh! As much as I hate to admit it, looks like I'll be replacing the gaskets instead of the more simple and less costly radiator repair. Any recommendations on the gasket to use vs a stock one?

Any last thoughts (BrianK?)
Click to expand...

MLS are generally considered better gaskets... Ask DA, Autowave, SOS or Larry and they can make direct recommendations :biggrin:
 
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ok slow down, these testers are not 100%conclusive, the only test that is, is a exhaust gas infrared analyzer,you will bring car up to operating temp. release pressure in the coolant tank ,put car under a load (pull parking brake and slip clutch in gear, you will be sniffing for CO in the tank,dont worry if it picks up H/C ,you will have to find a shop that will perform this test,the tech has to be very carefull how he does this because if he pulls up any coolant his boss will be pissed.The block leak tester can be confusing,what they fail to tell you is you should place the tester at the exhaust just to see what CO looks like and how fast it reacts,then put in clean air and see how it changes back,also if the leak is bad enough to foul the plug you will have no CO (no combustion no CO,just a ton of H/C &O2 i not familiar with texas emissions but i am sure some shop has to have an infrared gas analyzer.
 
I'm not convinced either. I've fought valiantly on cooling issues on several other cars.

The overheat process should go like this:
1. head gasket/crack injects pressured gas in cooling system
2. system dumps out significant portion of coolant via the pressure relief system
3. causing the engine to overheat (and continue causing #1 to get worse) because it cannot transfer enough heat.

You don't state that you are losing significant amounts coolant: are you?

The block check liquid can ALSO turn yellow when exposed to heat/sun.

Drew
 
I agree with Drew.

Do an openair test with your liquid, an direct exhaust test, en then make your conclusion.
 
The first thing to do is to go back and read the instructions for the kit. Do the test properly following the directions and see the results.

Regards,
LarryB
 
further analysis:

The system operates fine during cooler periods. I noticed that once the temps rise to near the red zone at highway speed, and I disengage the clutch, the temps quickly rise.
Click to expand...

Have you removed the thermostat yet? If not: pull it, drive and let us know what happens.

Get the radiator flow checked (or just replace it at this point).

This really sounds like a coolant flow issue. The spitting coolant is probably because the coolant near the engine is boiling and purging itself.

**

If it were a gas injection issue, you (should) be losing coolant and overheating under any run condition. Which it is not.

Now if you continue to keep this overheating cycle in place, you *will* need to R&R the heads and prove your diagnosis correct!

You could be correct, but my buddy Occam is telling me differently.

Drew
 
The test instructions were followed correctly, and I am not losing excessive amounts of coolant. I'm moving forward with replacing the radiator as the next step. I'll let everyone know the results.
 
Kitaka said:
The test instructions were followed correctly, and I am not losing excessive amounts of coolant. I'm moving forward with replacing the radiator as the next step. I'll let everyone know the results.
Click to expand...

Do you loose any coolant? :D
 
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Kitaka said:
The test instructions were followed correctly, and I am not losing excessive amounts of coolant. I'm moving forward with replacing the radiator as the next step. I'll let everyone know the results.
Click to expand...

Sorry I mis-understood your comments prior. If you used the bulb as directed and the fluid did not turn yellow in the first minute then, it is questionable.

You mentioned: "I am not losing excessive amounts of coolant". Are you losing any?? You should not be.

The next thing I would do is a leakdown test and see the results. BTW, Did you pressure test the coolant system?

Regards,
LarryB
 
Larry Bastanza said:
Sorry I mis-understood your comments prior. If you used the bulb as directed and the fluid did not turn yellow in the first minute then, it is questionable.

You mentioned: "I am not losing excessive amounts of coolant". Are you losing any?? You should not be.

The next thing I would do is a leakdown test and see the results. BTW, Did you pressure test the coolant system?

Regards,
LarryB
Click to expand...

Ditto, pressure test the system and that will be a good indicator if you are losing coolant through the headgasket, or leaking anywhere else. I think it's a very bad idea to swap parts and keep overheating the car. If you don't have serious permanent damage, you WILL afterwards.

Leakdown should be next step. If the pressure test looks good, it will tell you what and if any damage is there, and if not, it will tell you more about which cylinder(s) are affected.

Again, this is coming from a guy that blew two engines :rolleyes: - Civic & toyota pickup following the exact same (wrong) methodology you are following... assume/hope for the best, swap out parts and then hope that it will not make things worse (usually does).

No offense, I'm just trying to share my experience in hopes it will save you a 10K+ engine rebuild...
 
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Kitaka said:
The test instructions were followed correctly, and I am not losing excessive amounts of coolant. I'm moving forward with replacing the radiator as the next step. I'll let everyone know the results.
Click to expand...

based on your comments i think your headed in the right direction, overheating at idle or low speed is caused by a restiction like a thermostat or fan inoperative, usually cruising speed problems are more radiator related or air circulation at the rad. good luck
 
Just as nsxotic911 says, its very easy to make a HUGE mistake now (been there, done that), resulting in catastophic failure.
I'd say at this point to take it to a professional, offcourse, if any about.
 
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DutchBlack: A professional means the person does it for a living, it does not mean they know what they are doing.

The real pro's are few and far between, which is why people ship their cars long distances to Larry or Basch. BTW: the pros are here helping!

At $150 for each hour of shop time, you can buy a lot of nice tools, throw a lot of expensive parts at the problem and still be ahead in time and money. And you learn a lot....otherwise you just sit in front of the tube.

I agree with the OP and Ralph: you are on the right track. Keep going.

Drew

/Though, I would have dumped the thermostat long ago. And picked up a IR temperature gun and just start recording differences in temperature along the cooling system.
 
drew said:
A professional means the person does it for a living, it does not mean they know what they are doing.
Click to expand...

I agree, however, i dont clasify the average wrencher as a pro.
To me a pro is Someone like Larry or Mark B.
 
DutchBlackNsx said:
I agree, however, i dont clasify the average wrencher as a pro.
To me a pro is Someone like Larry or Mark B.
Click to expand...

as a professional i have utmost respect for these people ,however i just didnt start turning wrenches, 35 yrs as NIASE /ASE cert. tech,(one of 12 orig. mechanics tested in the north east ) (11 autos instructors & 1/ 19 yr old kid), independant repair shop owner , n.y.s. investigator, journeyman mechanic for G.M. , N.Y.S. AUTO INSTR, Adjunct Col.. Prof. ,yea i been around and learned to not give my opinion because most people can not give accurate data , however when i see a person having a problem i try to help ,oh by the way how many people out there have fixed SABRAS?
 
HOORAY!

Well I installed the OEM replacement radiator and the problem appears to be solved. I'll have the opportunity to take a long drive today (July 4th) in 100 degree weather to see if the problem returns.

Thanks to all for their input on this topic. In solving this problem I purchased a Block Test kit and am willing to circulate to others free if they will pay for the shipping cost (just like is done with the web site ABS bleeder that's rotated around to members). I don't know how many members are dealing with this issue but having the test kit helps in determining the resolve.

PM me if interested

Starting a new list here:

1.
2.
3.
4.
5.
6.
7.
 
you know nobody thought to ask this guy what his driving habits were like? If you don't abuse your car and race it daily, why would a head gasket blow? This was clearly a restrictive airflow issue.

But still everyone had good analysis here... !
 
Yes, but this is the first time I've ever read on prime that an NSX radiator was blocking. Of course, not all blocked radiatior stories get written on prime. :wink:
 
Glad to see you have it fixed.

Nice of you to lend the tool too:).

Regards,
LarryB
 
Well I drove over 105 miles yesterday in the summer heat with no problems. Looks like this thread is now closed for me.

I plan on cutting off the old radiator tanks to see if the core is blocked in some way. I'm just curious about the cause of the overheating.
 

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