coolant thermostat - Honda Pilot

StudentPilot · 01-20-2007, 02:54 PM

How can you tell if the car's coolant thermostat needs replacement?

Where should the coolant temp needle be when it is in normal range?

humanoid · 01-20-2007, 03:56 PM

It should be right in the middle of the gauge or just a little above middle. What's your's reading?

Sportymonk · 01-20-2007, 04:18 PM

The thermostat is a spring loaded looking device that opens and closes, all mechanical, nothing electronic. It fails in one of two ways, (1) It sticks open or (2) it sticks closed.

If it sticks open, option 1 the usually failure I believe, the vehicle will warm up very slowly. Once warmed up it will run fine but until then the heater won't put out much heat and the motor will not operate efficiently. (In the old days with carburetors the choke would be open and the vehicle would consume more gas. Not sure what happens today). Main symptom - slow to warm up in cold weather. Solution - Replace thermostat.

If it sticks in the closed position, not as common, the motor will run hot and can overheat causing engine damage. Sticking completely closed effective seals the radiator off from the engine. Symptoms - Engine rapidly warms up and runs hotter than normal. Solution - Replace thermostat. Used to be simple to do, main problem would be bolts to thermostat being difficult to remove.

Would be surprised to hear of an 03 with a bad thermostat but not impossible. Keep us informed.

rocky · 01-20-2007, 06:05 PM

Its rare very rare for thermostats to fail and its also very rare for the water temperature sensor to fail.

The latter might also cause poor starting especially in cold weather assuming the ecu checks the water temp to decide how much extra fuel/revs are needed during initial start up

StudentPilot · 01-21-2007, 08:02 AM

My coolant temp needle sits right below the temperature symbol on the gauge. Does that mean the thermostat needs to be changed? IF So, where is it in the Pilot and any trick to changing it? (I've changed it on other vehicles before)

Thx in advance!

jay · 01-21-2007, 10:04 AM

Here's what the manual says about where the needle shgould be.

StudentPilot · 01-21-2007, 01:57 PM

Attached is a picture of my coolant temp reading, can someone tell me if this is "normal"? In our Volvo, this would have indicated a failed thermostat.

StudentPilot · 01-21-2007, 01:59 PM

While we are discussing this, I think the picture below shows the thermostat-housing, but what's the removal procedure?

There appears to be 2-3 bolts holding it, only the one on top is visible. Thanks again.

LChisum · 01-21-2007, 02:01 PM

Quote:

Originally posted by StudentPilot
Attached is a picture of my coolant temp reading, can someone tell me if this is "normal"? In our Volvo, this would have indicated a failed thermostat.

Looks the same as my temp gauge always looks. I've got 43,000 miles with that reading!

Larry

whizmo · 01-21-2007, 02:08 PM

A typical recommendation is to replace the thermostat when you change out the water pump. This replacment, in turn, is typically done when you change out the timing belt (at 60K on the Pilot, if I recall correctly).

If you do annual (or even bi-annual) coolant changes, you're very unlikely to have thermostat issues for the life of the part.

I wouldn't put a whole lot of credence into small variances in where the temp gauge happens to rest at normal operating temperatures. Some makes calibrate it to read 1/2 scale or a little more, others 1/3 scale or even a little less. Even on the same make, there is some variance - these aren't precision instruments.

- Mark

jay · 01-21-2007, 02:54 PM

Quote:

Originally posted by StudentPilot
Attached is a picture of my coolant temp reading, can someone tell me if this is "normal"? In our Volvo, this would have indicated a failed thermostat.

Looks normal to me.

StudentPilot · 01-21-2007, 03:15 PM

Thanks everyone!

BLACK03EXLRES · 02-10-2007, 01:00 AM

Quote:

Originally posted by whizmo
A typical recommendation is to replace the thermostat when you change out the water pump. This replacment, in turn, is typically done when you change out the timing belt (at 60K on the Pilot, if I recall correctly).

If you do annual (or even bi-annual) coolant changes, you're very unlikely to have thermostat issues for the life of the part.

I wouldn't put a whole lot of credence into small variances in where the temp gauge happens to rest at normal operating temperatures. Some makes calibrate it to read 1/2 scale or a little more, others 1/3 scale or even a little less. Even on the same make, there is some variance - these aren't precision instruments.

- Mark

I believe the Timing Belt Interval is 100K for Pilot.
You are right about replacing both the water pump and t-stat during this service. Especially the water pump.

goneb4u · 03-21-2012, 06:00 PM

what rating is the stat for a canadian pilot, i am seeing 170 f but would have thought it would be higher, 195 f ?

01-20-2007, 02:54 PM	#1 (permalink)
StudentPilot Member Join Date: Jan 2007 Location: Motorcity Posts: 34 Feedback Score: 0 reviews	coolant thermostat How can you tell if the car's coolant thermostat needs replacement? Where should the coolant temp needle be when it is in normal range?

01-20-2007, 03:56 PM	#2 (permalink)
humanoid Super Senior Member Join Date: Sep 2004 Location: Sunny SoCal Posts: 2,970 Feedback Score: 0 reviews	It should be right in the middle of the gauge or just a little above middle. What's your's reading? __________________ 2005 EX-L Sage Brush Pearl -->OEM Running Boards, OEM rear mud guards, OEM crossbars, AVS bug deflector, 5000K HIDs, OEM Accord EX emblem, full sized spare, Hella FF 75 driving lamps, Nifty CatchAll Mats <------------ click here first, n0oB!!!

01-20-2007, 04:18 PM	#3 (permalink)
Sportymonk Super Senior Member Join Date: Dec 2004 Location: Rocky Mount NC Posts: 2,413 Feedback Score: 0 reviews	The thermostat is a spring loaded looking device that opens and closes, all mechanical, nothing electronic. It fails in one of two ways, (1) It sticks open or (2) it sticks closed. If it sticks open, option 1 the usually failure I believe, the vehicle will warm up very slowly. Once warmed up it will run fine but until then the heater won't put out much heat and the motor will not operate efficiently. (In the old days with carburetors the choke would be open and the vehicle would consume more gas. Not sure what happens today). Main symptom - slow to warm up in cold weather. Solution - Replace thermostat. If it sticks in the closed position, not as common, the motor will run hot and can overheat causing engine damage. Sticking completely closed effective seals the radiator off from the engine. Symptoms - Engine rapidly warms up and runs hotter than normal. Solution - Replace thermostat. Used to be simple to do, main problem would be bolts to thermostat being difficult to remove. Would be surprised to hear of an 03 with a bad thermostat but not impossible. Keep us informed. __________________ Eagles may soar, but foxes dont get sucked into jet engines. 2005 Steel Blue Metallic EX-L with iPod P.I.E. X3 interface (keeps the cd changer!!), LED lights in doors and overhead, tow package, cargo shield, crossbars (self installed), WWongs stuff, cargo liner, extended warranty. All but the tow pkg at great saving through our sponsor hondacuraworld. 17 - 24 MPG with mileage removed for both the best and the worst atypical mileages. 183,000 miles since June 29, 2005

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01-20-2007, 06:05 PM	#4 (permalink)
rocky Super Senior Member Join Date: Jul 2004 Location: Red Sox Nation Posts: 7,173 Feedback Score: 0 reviews	Its rare very rare for thermostats to fail and its also very rare for the water temperature sensor to fail. The latter might also cause poor starting especially in cold weather assuming the ecu checks the water temp to decide how much extra fuel/revs are needed during initial start up

01-21-2007, 08:02 AM	#5 (permalink)
StudentPilot Member Join Date: Jan 2007 Location: Motorcity Posts: 34 Feedback Score: 0 reviews	My coolant temp needle sits right below the temperature symbol on the gauge. Does that mean the thermostat needs to be changed? IF So, where is it in the Pilot and any trick to changing it? (I've changed it on other vehicles before) Thx in advance!

01-21-2007, 02:08 PM	#10 (permalink)
whizmo Registered User Join Date: Dec 2005 Location: WA State Posts: 1,817 Feedback Score: 0 reviews	A typical recommendation is to replace the thermostat when you change out the water pump. This replacment, in turn, is typically done when you change out the timing belt (at 60K on the Pilot, if I recall correctly). If you do annual (or even bi-annual) coolant changes, you're very unlikely to have thermostat issues for the life of the part. I wouldn't put a whole lot of credence into small variances in where the temp gauge happens to rest at normal operating temperatures. Some makes calibrate it to read 1/2 scale or a little more, others 1/3 scale or even a little less. Even on the same make, there is some variance - these aren't precision instruments. - Mark

01-21-2007, 03:15 PM	#12 (permalink)
StudentPilot Member Join Date: Jan 2007 Location: Motorcity Posts: 34 Feedback Score: 0 reviews	Thanks everyone!

03-21-2012, 06:00 PM	#14 (permalink)
goneb4u Registered User Join Date: Nov 2008 Location: Canada Posts: 10 Feedback Score: 0 reviews	what rating is the stat for a canadian pilot, i am seeing 170 f but would have thought it would be higher, 195 f ?

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