Weird Cooling /temp gauge problem

[Calgary-S2000]

Hi, I am new to this forum, I just got my 2000 s2000 about 2 weeks ago. It had a leak in the radiator and I put this "stop leak" crap in the radiator from the gas station and topped up the coolant.It stopped the leak. A few days later I was driving the S2K and noticed that the temp gauge is still at 1 square showing, but I had been driving for over a half hour and a few minutes before that it had 3 squares(which I belive is normal?). I kept an eye on it and suddenly it goes to 5 then 6 squares, then goes back to normal.It keeps doing that if I keep on driving, but it usally stays at thrird or first square. I suspect the "stop leak" has a hand in this. Im going to order a new radiator ASAP but just wondering what it might be. Any help in solving this problem would be greatly appreciated!

[repiv]

"Stop Leak" forms a gellatinous matrix. This matrix goes into the place where coolant goes through a small leak. That's how it stops the leak. Unfortunately, it also can form a semi-permeable plug in normal passageways in your cooling system. This plug may be migratory in the larger passages and when one gets to a critical part, it can restrict flow enough for the engine to over-heat, which is indicated by your occasional gauge display. It is only meant as an emergency measure and not as a "fix". Eventually, these plugs will find localized places to stay and you will have a heck of a time getting them out. If you get some in your heater core, you may have extreme difficulty getting heat to the interior.
I strongly suggest you do multiple and thorough flushes of the system and bleed the system carefully before you carry on. The S2000 cooling system is particularly difficult to properly bleed. Find and use the instructions to the letter. You might even use some aluminum safe cooling system flush as this will help to disintegrate any gellatinous globs.
In future, stay away from such products. If you have a small leak, monitor and keep putting in coolant/water till you get it fixed. And get it fixed ASAP.

[Calgary-S2000]

Why would the temperature guage show only one square(low)temperature half of the time then ?

[repiv]

It's difficult to say for sure, but I can imagine one of those globs hanging around the end of the temp sensor. It may insulate against the coolant that is going by. It's not a natural resident of your cooling system. Obviously, it's doing strange things to the way your cooling system functions and to the way the temp guage reads what's going on. You can't trust what the gauge is doing, nor can you be confident that the cooling system is performing as it should.

There are two types of product that plugs small coolant leaks. One is the Stop Leak you used and another one is a product called "Keep Cool". Keep Cool is supposed to help your cooling system run cooler in times when it's not working to keep the temps normal. It too, is a leak plugger. Now, one of these forms a gelatinous plug and the other starts off in the form of little pellets that dissolve and forms tiny slivers of material that again, forms a kind of matrix to block a leak. I'm not certain which one your Stop Leak is, but the principle for each is the same. These things are strictly "Band-Aids" and usually result in you having to do far more to make things right than if you hadn't used them in the first place.

[Calgary-S2000]

Thanks for your help, im going to order a new radiator and flush the cooling sytem ASAP.

[repiv]

Since you have a year 2000 car, you may not know if the coolant has ever been flushed. It had ordinary coolant originally. Now might be the time to put in a new thermostat and go to long life fluid like Honda's Type II.

[Goku]

On the note of the temp gauge acting weird. I have seen this a few other times. In those cases it was cause you had a air pocket in the coolent system. When the pocket would move in the system it would affect the temp readings. If the air pocket is over the temp sender the sender will read low as if the car is cold. this is cause the air cant heat the temp sender. And as the pocket moves on threw the system the coolant will come back to the sender. The gague is correct in all cases I saw this in. More than likly you have over heated you engine. You need to follow repivs advice and stop driving the car and get this fixed ASAP. Just cause you added coolant doesnt mean all the air is out. As stated this car is hard to bleed. It can easly trap air pockets which can reek havoc on your coolant system and your engine if you over heat it.

[desmo4]

The car is not hard to bleed as you guys say. I have done it many times in the 84k miles I have driven. You need only follow the shop manual. There ar 2 bleeder locations one at the intake manifold front and one for the heater on the fire wall. Do as was said previously, flush and flush and flush to get that garbage out of the cooling system. Get the leak fixed or buy a new radiator. And fill it up and bleed it after it heats up and the thermostat opens from lowest point to highest and you're done. There is a good chance that glop will never come out of some of the small passages. If you have any engine coolant problems or heater problems then I would recommend a new radiator, thermostat and heater core.

Jonathan

[repiv]

Originally Posted by desmo4

The car is not hard to bleed as you guys say. I have done it many times in the 84k miles I have driven. You need only follow the shop manual. There ar 2 bleeder locations one at the intake manifold front and one for the heater on the fire wall.

Therein lies the problem. Those who don't have the manual and attempt to bleed this system based on how they would bleed some other car, find it tough to get all the air out. This has been witnessed many, many times. Following the instructions, it's "easy".

[Calgary-S2000]

Do you know if the s2000 and the NSX thermostats are the same?

[repiv]

Originally Posted by Calgary-S2000

Do you know if the s2000 and the NSX thermostats are the same?

Nope, I have no idea. Get the part number for each from a dealer to know for sure.

[desmo4]

Why not just get a Mugen low temp thermostat, no confusion and at the same time a fan sw and radiator cap.

As far as bleeding the cooling system:
As long as you heat up the engine and leave the radiator cap off until you see water flow then put on the cap. crack the intake manifold bleed screw until a steady stream of antifreeze comes out. It should take a few seconds and then do the heater bleed.

Jonathan

[repiv]

Originally Posted by desmo4

Why not just get a Mugen low temp thermostat, no confusion and at the same time a fan sw and radiator cap.

For a tracked car, I would agree. However, for a street driven car, especially one that is operated in a temperate climate, low temp cooling mods are not recommended. I've seen too many S2000 owners who have done these cooling mods only to discover that the car simply won't ever warm up to operating temps most of the time. Careful consideration should be taken before deciding to do cooling mods as this car's cooling system works extremely well, even for the occasional track day. I've seen reports from owners who couldn't get past "2 bars". At this temp, the engine will not be operating under optimal conditions.
On the other hand, if you operate the car in places like the hot desert environment or in near tropical climates, then sure, cooling mods will be of some benefit, but only if the owner already experiences elevated coolant temps much of the time.

[Goku]

Just checked on the thermostat. the part numbers are the same for the nsx threw all the yrs just about for the thermostat, but it does not match the S2000. So chances are they will not fit.

[Calgary-S2000]

Yes, the 93-99 NSX are the same part number, I called honda and then acura. So the 93-99 NSX thermostat is the same as the S2000's.