Okay, I get differing opinions from different sources. My 91 nsx takes at least 10 minutes to get to normal operating temperature. Some say it should be much quicker than that, so the likely cause is a bad thermostat. Still others say 10 minute warmups are normal. So which is it?
Slow warmup revisited..
- Thread starter Lopaka69
- Start date
My first question is at what abient temp are your answers coming from? Although this should be minor, this may be a reason for differing answers.
If in your case 10 minutes means 5-10 miles on the road in 50-60 degrees ambient, it is too long. I go about 1-2 miles and my gauge is rising, by 4 miles or so it is fully warm.
I suspect you need one. This is fairly inexpensive. The "kit" is less then $40 (gasket and thermostat), add a little labor and you are done.
HTH,
LarryB
If in your case 10 minutes means 5-10 miles on the road in 50-60 degrees ambient, it is too long. I go about 1-2 miles and my gauge is rising, by 4 miles or so it is fully warm.
I suspect you need one. This is fairly inexpensive. The "kit" is less then $40 (gasket and thermostat), add a little labor and you are done.
HTH,
LarryB
Automotive engines, even ones with complex mechanical and electronic support systems like the NSX, are basically very similar devices. Do you know of ANY car that takes 10+ minutes to warm up, even in freezing ambient temps? I sure don't - your engine is not warming up correctly. You need a new thermostat or perhaps something else.
I'm not sure what the outside temperature is, but it doesn't seem to matter whether it's cold or hot, still takes at least 10 minutes to warm up. Asked Acura and my independent Acura specialist that I go to, and they both said 10 minute warmups are common for the NSX. So I'm even more confused...
Is 10min's too long ? I have never timed how long my 91NSX takes to warm up but it seems to take a while but I do drive carefully, no heavy throttle or high revs till warmed up. The important question is does your car come up to operating temp? The NSX does have 4 gal.'s of coolant in its cooling system compared to other cars 2 gal.'s and a lot more plumbing warm up. Changing the thermostat would not be a bad idea but you may not see any real change in the warm up times.
Brian
Brian
Is 10min's too long ? I have never timed how long my 91NSX takes to warm up but it seems to take a while but I do drive carefully, no heavy throttle or high revs till warmed up. The important question is does your car come up to operating temp? The NSX does have 4 gal.'s of coolant in its cooling system compared to other cars 2 gal.'s and a lot more plumbing warm up. Changing the thermostat would not be a bad idea but you may not see any real change in the warm up times.
Brian
Brian
Larry Bastanza said:
Larry's point on the ambient temperature is a good one. Living in Chicago, and having driven the X in both warm and cold temperatures, I realize there is a discernable difference in the time it takes the thermostat to reach operating temperature. In cold weather, I find that it takes about 7 - 8 minutes for the car to get fully warmed up. In the warmer weather we are having now, I find it takes closer to 5 - 7 minutes. In both conditions, I don't rev past 4500 RPM until the engine is fully warm. 10 minutes does seem like a little on the long side. I would suggest timing it a couple of times to make sure you are measuring the warm-up time appropriately.
Regards.
Regards.
Lopaka69 said:
My NSX takes about 10 min to warm up. And after I park it, it loses its heat pretty quickly. Within 2 hours, the engine will have cooled down completely, according to the temperature gauge.
On the other hand, my E36 M3 takes only 5 min to warm up. After being parked for 2 hours, the temperature gauge still shows some heat left in the cooling system.
With people saying the NSX has a lot of coolant, I can understand why it would take a lot longer for the coolant to reach operating temperature. However, I would expect all that coolant to be better at retaining its heat after I park the car. I can't explain why it gains heat so slowly yet loses its heat so quickly.
-CiaoBoy
Ciaoboy,
Regardless of how much coolant is in the system it should warm up in 5 minutes or less. That is the point of the thermostat, to keep all that cold coolant out of the engine block so it warms up quickly. Once the engine is up to temp and starting to exceed the defined operating temp. the thermostat opens and allows the cold water to mix with the hot water to regulate the engine overall temp.
All Honda products are excellent at this. Gauge comes up quickly, and stays rock steady.
This has also become an issue in regard to emissions. Faster warm ups mean less polution, so this has been paid attenton to a lot over the last few decades.
I think you may need a thermostat too
HTH,
LarryB
Regardless of how much coolant is in the system it should warm up in 5 minutes or less. That is the point of the thermostat, to keep all that cold coolant out of the engine block so it warms up quickly. Once the engine is up to temp and starting to exceed the defined operating temp. the thermostat opens and allows the cold water to mix with the hot water to regulate the engine overall temp.
All Honda products are excellent at this. Gauge comes up quickly, and stays rock steady.
This has also become an issue in regard to emissions. Faster warm ups mean less polution, so this has been paid attenton to a lot over the last few decades.
I think you may need a thermostat too
HTH,
LarryB
Larry Bastanza said:Ciaoboy,
Regardless of how much coolant is in the system it should warm up in 5 minutes or less. That is the point of the thermostat, to keep all that cold coolant out of the engine block so it warms up quickly. Once the engine is up to temp and starting to exceed the defined operating temp. the thermostat opens and allows the cold water to mix with the hot water to regulate the engine overall temp.
All Honda products are excellent at this. Gauge comes up quickly, and stays rock steady.
This has also become an issue in regard to emissions. Faster warm ups mean less polution, so this has been paid attenton to a lot over the last few decades.
I think you may need a thermostat too
HTH,
LarryB
So I may have a thermostat stuck in the open position. I guess that's better than having one stuck in the closed position, eh?
I'll ask Don Lam to look into this when I bring my car to him in two weeks.However, I wonder if the thermostat stays fully closed until the engine reaches full operating temperature? Maybe it's designed to open partially, or even fully, before the engine gets to full operating temperature, so that the temperature difference between the totally cold coolant and the fully warm coolant isn't so great. Perhaps the engineers are trying to avoid the thermal shock of totally cold coolant entering the engine's passages. If that's the case, then having double the amount of coolant would in fact cause the temperature gauge to rise slowly.
Larry, any ideas why my coolant cools down so quickly after being parked? I'm still baffled by this one. Having double the amount of coolant should help retain the temperature.
-CiaoBoy
Ciaoboy,
When I install a thermostat it is fully closed.
I do not think the amount of coolant would change the cool down time, since once the engine stopped there is no circulation. (Not really sure on this though, just speculating)
HTH,
LarryB
When I install a thermostat it is fully closed.
I do not think the amount of coolant would change the cool down time, since once the engine stopped there is no circulation. (Not really sure on this though, just speculating)
HTH,
LarryB
Larry Bastanza said:
My question is, does the thermostat gradually open as temperatures rise?
The difference in cooldown time still doesn't make sense between my M3 and my NSX. Why does my M3 retain its heat so much longer than the NSX?
-CiaoBoy
Yes, it is not a "switch", it opens as temp rises. It will start to open as the water temp is very close to operating temp, about 180F degrees if I recall.
You have got me wondering though if an open thermostat will cause a quicker cooldown, but I really cannot rationalize that.
Maybe if you put a new one in, you will see if the cooldown is slower
HTH,
LarryB
You have got me wondering though if an open thermostat will cause a quicker cooldown, but I really cannot rationalize that.
Maybe if you put a new one in, you will see if the cooldown is slower
HTH,
LarryB
Larry Bastanza said:Yes, it is not a "switch", it opens as temp rises. It will start to open as the water temp is very close to operating temp, about 180F degrees if I recall.
You have got me wondering though if an open thermostat will cause a quicker cooldown, but I really cannot rationalize that.
Maybe if you put a new one in, you will see if the cooldown is slower
HTH,
LarryB
Haha. Don just did the water pump and timing belt service last year, so I'm not too eager to put in a new thermostat.
I really can't think of why the cooldown is quicker.
I just timed my M3's warmup time today and it was exactly 5 min, pretty much on the dot.
-CiaoBoy
Lud said:
Yes, it has an iron block. You're saying iron can store more heat and also loses it at a slower rate compared to aluminum. That makes sense. I wonder if the difference though is offset by having only half the coolant as the NSX? Hard to say.
-CiaoBoy
Guys,
Just as a point of reference I remembered this thread as I took my car out yesterday morning. 45-50F ambient. Let the car run for about 1 minute idling to get the oil circulating, and drove it 4 minutes (3-4 miles) to get the WATER up to temp, not the oil.
I drive it during this "warmup" phase shifting at about 3500rpm.
HTH,
LarryB
Just as a point of reference I remembered this thread as I took my car out yesterday morning. 45-50F ambient. Let the car run for about 1 minute idling to get the oil circulating, and drove it 4 minutes (3-4 miles) to get the WATER up to temp, not the oil
.I drive it during this "warmup" phase shifting at about 3500rpm.
HTH,
LarryB
I have the same problem. My NSX takes about 10 mins to warm up in cold weather in TX. Now that its the summer, it takes 5-6 mins. I asked the NSX tech last month. He checked it out, and told me the thermostat is fine. His comment was that the NSX coolant takes longer to warm up b/c of the radiator being in the front, and the engine in the back.
I will time it again this wk.
I will time it again this wk.
NSXLuvr said:
This was one of the first questions I had when I got my 02 NSX at the end of January. All of my cars would heat up within the first 5 minutes of drive (approx 1-1.5 miles), the heat would come on, and I'd be comfortable. My office is about 4 miles from my home, and the NSX wouldn't warm up until I was at my office. I asked the chief service technician and he explained to me pretty much what all of you have stated, more coolant, different location of radiator, plus the cooling vents near the engine. Now that the ambient temperature is warmer, the time to warmup is about 1/2 the time, and I'm warmed up in 5 minutes, I don't bring the engine above 3500RPM until fully warmed up. 10 minutes warmup is quite normal for a NSX when it's cold out.
Lopaka69 said:
Sorry to revive an old thread, but hopefully this new piece of information will help. Now that summer has arrived, my NSX takes only 3-4 minutes to get up to full operating temperature. So I don't think 10 minutes is normal anymore, unlessthe outside temperature is cold.
-CiaoBoy
I have an interesting note on this subject. When I purchased my '91 about 6 weeks ago, I elected to drive it home, which was a pretty far distance (~2000 miles). While driving home, I discovered that the water temperature would vary according to the outside ambient temperature. When driving in daytime, in mild summer heat (mid-high 80's), the temp would be around the center of the gauge. At night, in mid 40 degree F weather, the temp needle would drop to the bottom of the gauge! 
It was obviously a stuck thermostat, but I was amazed at how the water temp could fall to practically nothing, all while driving along continuously at 75 mph. *Personal note: Aluminum (as in the engine) is amazing in its ability to dissipate heat.* The oil pressure gauge rose correspondingly higher as the water temp fell, as well. This was a little unnerving while it was happening, but the car ran fine.
Once I got home, I changed the thermostat, which I could see was stuck wide open. It wasn't too hard to change it, for someone who had never worked on a DOHC VTEC before.
Anyway, now car takes about 5 minutes (approx) to get warm now, and it remains at the center of the gauge regardless of the outside temp.
It was obviously a stuck thermostat, but I was amazed at how the water temp could fall to practically nothing, all while driving along continuously at 75 mph. *Personal note: Aluminum (as in the engine) is amazing in its ability to dissipate heat.* The oil pressure gauge rose correspondingly higher as the water temp fell, as well. This was a little unnerving while it was happening, but the car ran fine. Once I got home, I changed the thermostat, which I could see was stuck wide open. It wasn't too hard to change it, for someone who had never worked on a DOHC VTEC before.
Anyway, now car takes about 5 minutes (approx) to get warm now, and it remains at the center of the gauge regardless of the outside temp.
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