1986 Honda Accord - correct thermostat temperature?

gweiss

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Mar 6, 2022
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Make
Honda
Model
Accord
Year
1986
Miles
143,00 miles
Engine
2.0L
Greetings! This is my first post.

My 16 year old son was recently gifted a 1986 Honda Accord from his grand parents. They were the original owners and the car is in very good shape.

One concern I have is the engine coolant temperature gauge barely moves from the coldest position - even after driving for more than 1 hour. I suspect either:

- someone install the wrong thermostat, or
- the coolant temperature gauge isn't working correctly.

To test the engine coolant temperature gauge, I was going to use a thermometer to measure the coolant temperature after the car was running for an extended period of time. Does anyone know the temperature range the coolant should be at? I assume it should be plus or minus X degrees of Honda's thermostat temperature spec.

Unless I am reading their catalogue incorrectly, I believe Rockauto is suggesing 192 degrees is the Honda spec. However, the majority of thermostats they list are 180 degrees or less. So perhaps someone installed a 180 thermostat when the manufacture spec is 192? This would explain the low coolant temperature gauge reading.

I checked the original owner's manual for the spec and nothing. I tried the official Honda.com site and they only have specs going back to 1990 "Detail: ServiceExpress is Honda Canada's online service/repair information for aftermarket shops and vehicle owners. This factory-authorized dealer information covers all Honda vehicles from 1990 to current.

Any suggestions on where I can find Honda's temp spec?


Thanks for any and all help!
 

billr

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T-stats have been commonly in the 190-200F range for a very long time, started in the early 1960's, so I was kind of surprised RA listed so many for 180F, and lower. Then I remembered that Hondas of that era had problems with cylinder heads cracking. Maybe the lower temp t-stats became popular to save heads?
 

grcauto

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Just drop the stat into a pan of water and start heating it. The stat should open just before you get any real boiling. I bet you will find your stat is open at room temperature which is why it will not warm up correctly.
 

gweiss

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I called up the local Honda dealer and they advised me:

- the Honda spec is 180 degrees, and
- they also list a "winter" thermostat (which they never sell) which is 190 degrees.

I will go with 180 degress.
 

dabunk

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Agreed I always used the 180 in the many Hondas I have owned of that vintage. I do drill a small 1/8 hole in them when I install in any vehicle to avoid being air bound upon startup.
 

Mobile Dan

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How does the heater work? If it works great, even when driving at highway speed in cold weather, the thermostat is probably not the problem. More likely, the problem is "bad guage or bad sending unit (sensor)". I think those older Hondas had 2 temp sensors...one for fuel injection computer and another for the guage.
 

dabunk

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How does the heater work? If it works great, even when driving at highway speed in cold weather, the thermostat is probably not the problem. More likely, the problem is "bad guage or bad sending unit (sensor)". I think those older Hondas had 2 temp sensors...one for fuel injection computer and another for the guage.
Correct
 
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