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cnn

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Discussion starter · #1 ·
We just bought a 2007 Ody LX.

My previous 2001 Ody OEM thermostat was 75 deg C and it took a long time to warm up, so I changed to 82 deg C thermostat...wife and kids (and other Odyclub people) loved it in the winter:
http://www.odyclub.com/forums/showthread.php?s=&threadid=31696&highlight=thermostat

I know it is now summer, but in the Fall, I will swap the OEM Nippons thermostat out for a hotter 82C thermostat.

Will post the DIY later.

Right now just enjoy the summer heat...:)
 
#2 ·
And just how does a higher thermostat make the engine generate more heat faster? I will have to pose that to the physic peo's. I must have slept through those through those classes:(
 
#3 ·
William Wiles said:
And just how does a higher thermostat make the engine generate more heat faster? I will have to pose that to the physic peo's. I must have slept through those through those classes:(
Click to expand...
I'm pretty sure he meant it took less time to warm up the cabin/passenger area with a higher thermostat rather than heating up the engine faster.
 
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#4 ·
The engine warms up faster because the thermostat doesn't open until a higher temp is reached.

For those still confused, if the thermostat opens earlier the engine will not reach operating temp as fast as one that remains closed longer. Because when the themostat opens coolant begins to circulate through the radiator.
 
#5 ·
That doesn't make sense. The heating sytem in the van (or any car for that matter) is run off the cooling of the engine via antifreeze circulating through it. If the antifreeze doesnt flow, it doesnt flow to the heater core and release heat.

So putting in a higher temp thermostat will only release the heat at a later time when the engine block is a little warmer. The only advantage to putting in a higher temp thermostat would be that the circulating antifreeze is now hotter and the output of the heater core would be hotter.

If you ever had a car that had too low of a thermostat the heat output sucked. Change it up to something a bit higher and all was good. Lowering or removing the thermostat is done on older cars that have cooling system problems. (generally to relieve pressure off the system and not to spring leaks)

Tom
 
#6 · (Edited)
The water pump always runs. Just because coolant isn't going to the radiator doesn't mean that it isn't going to the heater core. Separate lines.

This might help you out...

http://auto.howstuffworks.com/cooling-system10.htm

Changing the thermostat to a different level has no effect on saving a system. Coolant temps of a normally operating engine are much higher than what any thermostat would be. So if it is going to leak it is going to leak no matter if the thermostat opens at 180 or 160 degrees.

So putting in a higher temp thermostat will only release the heat at a later time when the engine block is a little warmer. The only advantage to putting in a higher temp thermostat would be that the circulating antifreeze is now hotter and the output of the heater core would be hotter.
Click to expand...
This is exactly what he was trying to accomplish. The interior of the car warms up sooner because the coolant (including that in the heater core) circulates around the cylinder head for longer thus getting hotter faster.
 
Discussion starter · #8 · (Edited)
DISAGREE

SexyTom,

By the way I am over 40 so I am not sexy anymore....:)

You are both correct and incorrect.

Correct: when the heater valve is opened (Dial set to HOT in cabin) and engine is warmed up, the coolant flowing through the heater core is 75 deg Celsius. Ok, luke warm but not great. The heater core temp is a reflection of the coloant temp coming from the engine.

Incorrect: when a higher temp thermostat is used, let say 82 C, then when engine is warmed up, the coolant temp is 82 C and inside the heater core it is 82 C.

Two more things:

1. I know it works because I am the one that posted this 82 C thermostat....on the Ody 2nd Gen forum. Wife & kids love it.
Also other people did it and loved it and strongly recommend it
Again see the link in my original post above.

We got the Ody 07 and the first thing my wife and kids ask for is a better thermostat than the OEM!!!! They suffer for 5 yeras before I discovered that the OEM factory thermostat was 75 C.
Check any car you like, most run thermostat in the 85-95 C range.
I am not sure why Honda uses 75 C, it makes no sense for the people living in the snow belt!!!!!

I also have a 98 Volvo V70 and it is warm and cozy in the winter because the OEM thermostat is 87 C.

2. Do NOT argue with the wifey, I never win and risk alot of things, so I will happily do it for her. Wait until October. Too early now...I am enjoying the summer heat.....:)

I will post the DIY later when I get there in October....

(RegisteredUser...you are absolutely correct in your post, even experienced mechanics have poor understanding of how engine thermostat works.....It is Physics 101 anyway)
--------------

Sexytom said:
That doesn't make sense. The heating sytem in the van (or any car for that matter) is run off the cooling of the engine via antifreeze circulating through it. If the antifreeze doesnt flow, it doesnt flow to the heater core and release heat.

So putting in a higher temp thermostat will only release the heat at a later time when the engine block is a little warmer. The only advantage to putting in a higher temp thermostat would be that the circulating antifreeze is now hotter and the output of the heater core would be hotter.

If you ever had a car that had too low of a thermostat the heat output sucked. Change it up to something a bit higher and all was good. Lowering or removing the thermostat is done on older cars that have cooling system problems. (generally to relieve pressure off the system and not to spring leaks)

Tom
Click to expand...
 
#9 ·
no problems with getting heat fast enough here with my factory '05 thermostat...

but changing it out would be a subjective desire I guess. cnn, Nice write up on the other, so will be looking forward to reading your write up on this one.
 
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#10 ·
One more thing

Seems the argument is based on theory of operation, I believe the faster warm up is due to thermostat design. I have not looked at the Ody t-stat so I may be all wet but I have seen stats with bypass holes that allow a small amount of coolant to flow all the time and many (mostly aftremarket) that do not allow any coolant to flow when closed.

If the OEM stat has bypass holes and the replacement does not the water will heat substantially faster. Does the Ody water pump have a bypass hose?

I had a 4 cyl. 1991 Isuzu Trooper that did not like aftermarket parts at all. It was common knowledge among ITOG members that OEM t-stats would solve high idle problems. (The Tropper would idle higher once a certain temp was reached in order to cool itself)
 
#11 ·
75 deg C?

Curious where the 75 Deg C spec came from. The Helms (Honda) Service Manual for the 2005-2006 Odyssey lists the thermostat as, "Begins to open at 169-176 F (76-80 C) and fully open at 194 F (90 C)". Sounds like an 89 deg C t'stat to me, which is what most of the American and European cars are currently using. :confused:


Still coasting.....:zoom:
 
#12 · (Edited)
heat output is constant

Registered User said:
The engine warms up faster because the thermostat doesn't open until a higher temp is reached.

For those still confused, if the thermostat opens earlier the engine will not reach operating temp as fast as one that remains closed longer. Because when the themostat opens coolant begins to circulate through the radiator.
Click to expand...
In truth the engine will warm up at the same rate no matter what the thermostat setting is...

The time it took the engine to reach the point where the 75deg thermostat would open is the same even if you have an 82deg thermostat but in this case it will keep going till it hits 82...

The 82deg thermostat doesn't change the heat output of the engine to the coolant, its just allows the coolant to reach a higher final temp.

But the interior will indeed warm up faster if its getting 82 vs 75 deg air..

Not sure if they use a different thermostat in CDN ody's but I haven't heard any complaints regarding heating even when its
-25C up here in Toronto.. and I have the factory thermostat.

Now when the thermostat on my 1992 voyager stuck open that was a different and very cold story ....
 
Discussion starter · #13 ·
Re: One more thing

Couple issues:

1. HOLE in TSTAT:
Just google "drilling hole in thermostat". It is an old trick that indy mechanics do to drill a small 1-2 mm hole in thermostat at 12 o'clock position to allow trapped air to escape. And that is all. Wahler used to produce thermostat from factory with holes already drilled. For some reasons, newere thermostats have no holes and create air lock issue.

I also own a 98 bmw 528i and did this write-up on bimmer forum:
http://bimmerboard.com/forums/posts/199986
Figure 13 shows you the hole I drilled to prevent "air lock". Other bmw people have had alot of air lock problem, I do not.

The hole is so tiny that it does not affect engine operation at all. Every indy mechanic knows that and taught me the trick.

2. RATE OF HEAT RISE:...see post below.

---------
Raw Power said:
Seems the argument is based on theory of operation, I believe the faster warm up is due to thermostat design. I have not looked at the Ody t-stat so I may be all wet but I have seen stats with bypass holes that allow a small amount of coolant to flow all the time and many (mostly aftremarket) that do not allow any coolant to flow when closed.

If the OEM stat has bypass holes and the replacement does not the water will heat substantially faster. Does the Ody water pump have a bypass hose?
Click to expand...
 
Discussion starter · #14 ·
Re: heat output is constant

bbylon5 is absolutely correct,

The analogy is think about your house in winter.

Let say overnight you let the temp go down to 55F.
In the morning if you turn up the tstat to 66F vs 72F.
The rate of heat rise is the same for both situation but:
- for 66F: the furnace stops there and the temp is 66F
- for 72F setting, the furnace continues to run until the temp is 72F.

So back to the car:
- for 75C tstat (this is the opening temp BTW): coolant temp is 75C.
- for 82C tstat: after engine coolant reaches 75C, it continues to climb until 82C when the tstat starts to open.

Engine cooling system in fact is not that hard to understand, yet many experienced mechanics have poor understanding of this subject, it is again basically Physics 101, nothing more than that.



bbylon5 said:
In truth the engine will warm up at the same rate no matter what the thermostat setting is...

The time it took the engine to reach the point where the 75deg thermostat would open is the same even if you have an 82deg thermostat but in this case it will keep going till it hits 82...

The 82deg thermostat doesn't change the heat output of the engine to the coolant, its just allows the coolant to reach a higher final temp.

But the interior will indeed warm up faster if its getting 82 vs 75 deg air..

Not sure if they use a different thermostat in CDN ody's but I haven't heard any complaints regarding heating even when its
-25C up here in Toronto.. and I have the factory thermostat.

Now when the thermostat on my 1992 voyager stuck open that was a different and very cold story ....
Click to expand...
 
#15 · (Edited)
In truth the engine will warm up at the same rate no matter what the thermostat setting is...
Click to expand...
Not correct.

The normal operating temp of a engine is higher than what the thermostat is rated. A thermostat may open at 165 degrees F, but the engine coolant maybe at 210 degrees F during normal operation. The radiator fan helps regulate cooling from the point the thermostat opens.

If the thermostat opens at 165 degrees it is going to take the engine longer to warm to 210 degrees than if it opened at 185 degrees. Because once the thermostat opens the rate at which the engine warms is much slower than before because the coolant is now going out to the radiator. However if the coolant doesn't go out to the radiator the engine warms up sooner. By changing the thermostat to a higher rated one does not cause his Ody to operate at any higher temp than any other Ody. It just warms up to normal operating temp sooner.

After making such a mod just be mindful of any loss in fuel economy and any reduction in performance. I doubt it would cause any problems. In todays ECU controlled engines many of the fueling and timing changes are handled in a certain sequence and if changes from OEM can cause a sequence to be disrupted and may cause the ECU to try to compensate by making fueling or ignition changes. However manufacturers seem to want a quick warm up to get the catalyst burning in order to lower emissions. That is one reason why they don't recommend letting a vehicle idle to warm up, it will warm up much quicker by driving normally.

One of the main reasons for thermostats is to prevent cracking or warping in the cylinder head and block by large differences in temperatures between the engine and head and the coolant.
 
#18 ·
Well, everyone knows that if you push the house thermostat higher, 85, 90, the house warms quicker .... right ? !!!
Duh

Well anyway ...

Registered User said:
Not correct.

The normal operating temp of a engine is higher than what the thermostat is rated. A thermostat may open at 165 degrees F, but the engine coolant maybe at 210 degrees F during normal operation. The radiator fan helps regulate cooling from the point the thermostat opens.
Click to expand...
Not so, the thermostat regulates (and sets) the engine operating temp, unless the cooling system is unable to compensate. Today's stats "modulate" not like the old days when once it's open it's open. Watch your temp guage on a cold day and you'll see the temp rise, maybe above "normal" then take a swing down to rise again. That's the stat opening, cold water flowing, stat closing, etc until the radiator warms up. The cooling system will overcool the engine (worse in cold weather) if the stat doesn't close down.

If the thermostat opens at 165 degrees it is going to take the engine longer to warm to 210 degrees than if it opened at 185 degrees. Because once the thermostat opens the rate at which the engine warms is much slower than before because the coolant is now going out to the radiator. However if the coolant doesn't go out to the radiator the engine warms up sooner. By changing the thermostat to a higher rated one does not cause his Ody to operate at any higher temp than any other Ody. It just warms up to normal operating temp sooner.
Click to expand...
I agree, except about the part that a higher stat will not cause it to operate at a higher temp .... I will operate at the higher temp as set by the stat.

After making such a mod just be mindful of any loss in fuel economy and any reduction in performance. I doubt it would cause any problems. In todays ECU controlled engines many of the fueling and timing changes are handled in a certain sequence and if changes from OEM can cause a sequence to be disrupted and may cause the ECU to try to compensate by making fueling or ignition changes. However manufacturers seem to want a quick warm up to get the catalyst burning in order to lower emissions. That is one reason why they don't recommend letting a vehicle idle to warm up, it will warm up much quicker by driving normally.
[/B]
Click to expand...
If a "lower" stat were being installed, THEN fuel economy, etc can/will be affected. I doubt a higher one will. Take note of the idle speed while the temp guage is below normal, it will idle several hundred RPM's higher then when the operating temp is reached. Higher RPM require more fuel. Now, try this .... on a warm day, in your normal routine, take note of how long it takes for the idle to drop to normal. Then on a cold day, do the same. Note the change. I'll bet your "normal routine" was to turn the heat on right away ? Right ? Now try this ... leave the heat off until the idle drops (and note how long it takes). You'll be surprised at how much shorter (and less fuel) it is.
(However, if your normal routine puts you on the highway in about a mile, this won't matter much)

Remember, when the stat opens it gets cold water, that works against the engine warming up ... SO DOES running the heater (it's a radiator too) ... causing the engine to take longer to warm up (and using more fuel).
 
#19 · (Edited)
just a little abby normal

I guess it come down to what we define as normal..

I do agree that the temp range that the engine will operate in is between the setting of the thermostat and 210deg.

The reason I agree with the 210 degree value is that this is the setting for the radiator fan switch.. (checked in my odyssey shop manual)

Now if normal conditions for you involve nothing but stop and go traffic in texas then your normal conditions may indeed see the engine temp stay as high as 210 and the radiator fan will be operating almost constantly.

But if normal involves driving a route that allows sufficent airflow to the radiator then your operating temp will be determined by the thermostat.

If the engine only operated at 210 then the radiator fan would be on constantly even in the winter or while driving down the highway... We know this is indeed not the case... After driving home from work and pulling into the driveway in the summer the radiator fan isn't on. I have to leave the car idling in the driveway for a couple of minutes before it will kick in. This is so that the coolant temp can rise from the thermostat setting to 210..

Now if we are referring to oil temp instead of cooland temp then the 210 value is probably just about right for the minimum value under normal conditions.
 
#20 ·
I picked the 210 degree value just as a general value not necessarily as what the Ody runs at. Though it would be safe to say it will run at about 200 degrees, and that would be year round, extremes excluded of course. The rad fan doesn't have to run all of the time at these temps because the car is in motion and air is flowing through the radiator.

Not so, the thermostat regulates (and sets) the engine operating temp, unless the cooling system is unable to compensate. Today's stats "modulate" not like the old days when once it's open it's open. Watch your temp guage on a cold day and you'll see the temp rise, maybe above "normal" then take a swing down to rise again. That's the stat opening, cold water flowing, stat closing, etc until the radiator warms up. The cooling system will overcool the engine (worse in cold weather) if the stat doesn't close down.
Click to expand...
No, the engine operates higher than that. The "modulation" you are seeing is when rad fan kicks on. Maybe if it is fairly cold out would it may open and close during operation. But once again, if you think your operating coolant temp is determined by the thermostat rating you are wrong. What it is rated for is strickly what temp it will open at. Most autos operate with coolant temps of 200 to 220 degrees year round.
 
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